MCRJ Volume 1, No.1, 2007
MCRJ Volume 1, No.1, 2007
MCRJ Volume 1, No.1, 2007
Editorial Committee ii
Editorial iii
The contents of the published articles do not represent the views of the Editorial
Committee and Construction Research Institute of Malaysia
ii
Editorial Committee
Shahuren Ismail
National Productivity Corporation (NPC)
Secretariat
Gerald Sundaraj until February, 2006
Construction Research Institute of Malaysia (CREAM)
Zulkefli Ismail
Construction Research Institute of Malaysia (CREAM)
iii
Malaysian Construction Research Journal; Vol.1|No.1|2007
Editorial
The Editorial welcomes all readers to its first issue of Malaysian Construction Research
Journal (MCRJ), a journal that disseminates on the latest development of Malaysian
Construction technology. Special thanks to all authors who have contributed their papers
and also to all reviewers for editing the papers submitted. The first issue of MCRJ highlights
seven titles from research and development results and a report on productivity performance
on construction.
In this first issue, Noorzaei et al examine the semi-loof element as probably one of the
most efficient element available for the solution of thin shells of arbitrary geometry. Based
on the semi-loof formulations, three dimensional finite element software are developed and
its application to complex structures such as curved beam, scordis shell roof, roofing system
and cooling tower are investigated.
Siti Hawa et al describe experimental and theoretical investigations to determine the
effect of butt joint on the structural behaviour of Profiled Steel Sheet Dry Board (PSSDB)
load bearing wall with door opening. The samples were subjected to axial compressive load
and the results were compared between the two sets of samples and with the theoretical
expressions.
Lee et al present on the recent development of micronised amorphous biomass silica
and the synthesis of nanoparticles. The objective is to develop an economical and
environmental-friendly material and process for sustainable concrete construction. The
synthesis of biomass silica of particle size ranging 20m down to 20nm is expected to
promote renewed interest in concrete research related to packing efficiency of particles
within the concrete matrix for the reduction of water permeability.
Fayda et al examine the development and application of two-dimensional finite element
software to account for the structural modeling of concrete face rockfill dams (cfrd) during
construction phase. The study focuses on the effect of construction sequence on the
structural response of the dam with and without concrete slab.
Othman et al present the application of knowledge management in the construction
industry. This paper reports on the findings of a survey, taking Malaysia contractors as
samples, on the level of knowledge management application in the construction organization
and area of construction management that can be improved by its application.
Harimi et al provide recommendations for the improvement of roofing design under
Malaysian climate and also investigated the thermal performance of metallic roof system
with sealed and ventilated attic. Their study include the impact of different thickness of
fiberglass and foil-aluminium in reducing ceiling temperature on a low cost house that was
mainly built from waste oil palm shell (OPS-Concrete) with galvanized steel-roof.
iv
Malaysian Construction Research Journal; Vol.1|No.1|2007
Editorial Committee
Codification and Application of Semi-Loof Elements for Complex Structures 1
Malaysian Construction Research Journal; Vol.1|No.1|2007
Abstract
Finite element analysis of thin shells received considerable attention during recent years and
a number of finite elements for thin shell analyses have been derived. Among these, the
semi-loof element occupies a special place owing to its generality, type of formulation and
performance. At present the semi-loof element is probably one of the most efficient elements
available for the solution of thin shells of arbitrary geometry. Based on the semi-loof
formulations, the present study deals with development of three dimensional finite element
software and its application to complex structures such as curved beam, scordis shell roof,
roofing system and cooling tower.
Keywords: Cooling tower; Finite element code; Folded plate; Idealisation; Scordis Roof; Semiloof
shell; Semiloof beam.
INTRODUCTION
Shell problems are difficult especially when the shell is very thin and in addition, one of
the principal curvatures is positive and the other negative or zero. To model these types of
structures, several shell elements are available in the literature Zienkiewicz (1993), Bathe
(1996) and Cook (2002). Among the shell elements, the semi-loof shell element is probably
one of the most efficient elements. It is particularly suitable to modal complex civil
engineering structures such as cooling tower including staging columns and ring beams,
flooring or roofing systems. The finite element formulation semi-loof beam, plate and shell
are presented by Iron and Ahmad (1980), Owen and Martin (1981) Martin and Oliveira
(1988a & 1988b) but with limited computer coding and application. A simple hybrid semi-
loof plate bending element where no slave degree of freedom is involved, was presented by
Sze (1994).
side) and YZj (rotation in a plane tangent to the element side); central node combining two
(rotation in a plane perpendicular to the element
types of parameters, displacements ee u 9 , v 9 , w 9 and rotation 9
XZ and YZ
9
along the
local axes.
Codification and Application of Semi-Loof Elements for Complex Structures 2
The initial 45 degrees of freedom (dof) of the element will be arranged in three vectors
as follows:
(3)
After eliminating all the dof at the center node and all the local rotations along the
element sides, the final dof of the element will be 32 (Figure 1b).
N1
1
1 2
2 2 2
1
4
2
1
N2 2
1
2
2 2 2
1
N3 2
1
4
2
1
N4 2
1
2
2 2 2
1
N5 2
1
4
2
1
N6 2
1
2
2 2 2
1
N7 2
1
4
2
1
N8 2
(4)
2
The shape function for defining the variation of displacements at the central node is
given by:
N 9 1 2 1 2 (5)
The shape functions for the interpolation of rotations at the loof nodes are given by:
Codification and Application of Semi-Loof Elements for Complex Structures 3
L1
1
3 3 3 3 3 3
8
3 2 9 2 3 3 3
3
2 2
4 4 2
1
3 3 2 3 2 3 3 2 3 2 3
3 9 3 3 3
8
L2
4 4 2
1
3 3 2 3 2 3 2 3 3 2 3
9 3 3 3 3
8
L3
4 4 2
1
3 3 2 3 2 3 2 3 3 2 3
9 3 3 3 3
8
L4
4 4 2
1
3 3 2 3 2 3 3 2 3 2 3
3 9 3 3 3
8
L5
4 4 2
1
3 3 2 3 2 3 3 2 3 2 3
3 9 3 3 3
8
L6
4 4 2
1
3 3 2 3 2 3 2 3 3 2 3
9 3 3 3 3
8
L7
4 4 2
1
3 3 2 3 2 3 2 3 3 2 3
9 3 3 3 3
8
L8 (6)
4 4 2
The shape function for the interpolation of rotation at the central node is given by:
L9 1 2
3 2
4
(7)
Now, a relationship between the Cartesian coordinates of any of the shell elements and
the curvilinear coordinates is written as:
x N i xi ; y N i yi ; z N i zi
8 8 8
i 1 i 1 i 1
(8)
The displacements along the local axes X , Y and Z will be denoted respectively by
U,V and W and can be obtained as projections of u, v and w , i.e.:
U X T d
Where d N e
(9)
(10)
V Y T d (11)
W Z T d (12)
Codification and Application of Semi-Loof Elements for Complex Structures 4
Considering Equation (10) these displacements are obtained in terms of shape functions
and nodal parameters as:
N e
U X
T
V Y T N e
W ZT N e (13)
At each point of the element the rotations XZ and YZ are interpolated by means of loof
and central node shape functions L j ( j 1,9) and the corresponding nodal values XZ
j
YZj .
and
K B D B dV
The stiffness matrix is formed by the usual finite element procedure, i.e.:
e T
(14)
V
D p 0
where
D
0 Db
(15)
and
1 1
D
0 0
1 0 or D b 1 0
2 3
1 12(1 2 )
Et Et
1 1
P
(16)
0 0 0 0
2
2 2
The element strain matrix [B] is composed of two parts, one corresponding to the plane
(membrane) behaviour and the other to the bending behaviour. Defining the strains by:
= p b
T
Yp XY Xb Yb XY
p p b T
=
U V U V 2U 2V 2U 2V
X
= , , ,
T
X Y Y X XZ YZ YZ XZ
, (17)
Kirchoffs shear constrains are applied by stipulating the transverse shear at loof nodes
to be zero so as to eliminate rotation parallel to the side of the nodes. The variables at the
central nodes are also eliminated and constrained version has only 32 degrees of freedom per
element including 24 translational degrees of freedom at the corner and the midside nodes
and 8 rotations at the loof node (Figure 1b).
Codification and Application of Semi-Loof Elements for Complex Structures 5
The beam element (Figure 2a) possess, before constraining, the following degrees of
freedom:
Of these 21 dof, the local rotations Y and Z along the axes Y and Z at node 4 and 5
are conveniently constrained, the final configuration of the element having therefore 17 dof
e u1 T
(Figure 2b). For later reference the following vectors of parameters are defined:
e1X
v1 w1 u 2 v2 w2 u 3 v3 w3 (18)
Y1 1Z X
4 4 4 5 5 5 3 3 3 T
Y Z X Y Z X Y Z (19)
Note that nodes and variables are defined in order to match the configuration of the shell
element, and that each beam conforms with the neighbouring beams in both slope and
deflection.
x N i xi ; y N i yi ; z N i z i
3 3 3
(20)
i 1 i 1 i 1
1, ,
where the shape function Ni are obtained through the following polynomial basis
2
(21)
The displacement along the global axes of a generic point P(x, y,z)
d u, v, wT (22)
are interpolated using the corresponding displacements of nodes (1,2,3) and shape functions,
Ni defined by Equation (23).
N1
1 2
2
Codification and Application of Semi-Loof Elements for Complex Structures 6
N 2 1 2
1
2
N 3 2 (23)
d N e
Therefore,
(24)
N 0
N 0
1 2 3
0 0 N 0 0 N 0
N1 N2 N3 0
0 N 3
0 0 0 0 (25)
0 N1 0 0 N2 0 0
x , y , z T
The rotations at a generic point, P (x,y,z)
(26)
are obtained using the global rotations at nodes (1,4,5,3) and shape functions Lj (j = 1,4,5,3),
L e
i.e
(27)
1, ,
The shape functions Lj are defined using the following polynomial basis:
2
,3 (28)
These shape functions are presented in Equation (29). The matrix [L] is defined in a same
way as Equation (25).
L1
1
1 3 2 3 3
4
L3 1 3 2 3 3
1
4
L4 1 3 2 3 3
3
4
L5 1 3 2 3 3
3
(29)
4
B DB dv
T
[K] = (30)
Codification and Application of Semi-Loof Elements for Complex Structures 7
U V U Y Z X
[B] = Z , Y ,
T
X X X X X X
, , , (31)
EA 0 0
0 GA 0 0
0 0 0
0 0
0 0
D
0 GA 0 0
0 0
(32)
0 0 EI YY 0
0 0
0 GI XX
0 0 0 EI ZZ
0 0 0 0
The two local rotations, y and z at loof nodes were eliminated by imposing the shear
constrains, i.e x = 0.0 and yz = 0.0 at nodes 4 and 5.
COMPUTER PROGRAMMING
At initial stage of this study, the subroutines SLSTIF and BMSTIF published by earlier
investigator such as Iron et al. (1980) and Martin et al. (1988a &1988b) are implemented
under Fortran environment. These subroutines are concerned with generation of stiffness,
mass and load matrices. Then pre-processor (Noorzaei, 1991), solution routine (modified
frontal technique) developed by Godbole et al. (1991) and post-processor (Noorzaei, 1991)
are added under a master main. The flowchart of the complete program is shown in Figure
3.
The calibration of this upgraded semi-loof computer code has been well established by
analysing some benchmark problems, for which the analytical solutions are available in the
literature. These benchmark problems include curved beam, clamped circular plate and
scordis roof. Furthermore an attempt has been to analyse some structures such as roofing
system and cooling tower using semi-loof elements and the three dimensional finite element
software packages is compatible with Fortran 90 power station computer.
The program further strengthens by adding few standard elements such as brick
elements and infinite elements. The program is multi-element in nature and can deal with
concentrated, pressure and gravity loadings (i.e only static loading). Besides that, there is
compatibility between the shell element and beam element. At present the software
application is limited to linear analysis.
In order to explore the capabilities of the semi-loof elements some benchmark structures
such as beams, plates and shells have been selected for the purpose of verification,
Codification and Application of Semi-Loof Elements for Complex Structures 8
calibration and application of the finite element code developed in the present investigation.
In order to ascertain the generality of the semi-loof beam element the curved beam
shown in Figure 4 is considered. The finite element idealisation of the beam is presented in
this figure. The solution obtained via the present idealisation is very close to the solution
reported by Robinson (1973) (Table 1). As it should be, the value of displacement at node 3
and 7 are the same in magnitude but opposite in direction.
As an illustration for modeling of curved boundary this type of problem has been
chosen. The finite element mesh of the plate including the material and loading are shown in
Figure 5. It is clear from Figure 6 that there is a good agreement between the result
evaluated by present modeling and the other investigators.
This is a cylindrical shell roof under self weight and has been modeled using semi-loof
shell element. The geometry and property of roof problem and the finite element mesh is
shown in Figure 7. This example was also solved by many investigators such as
Zienkiewicz (1979) and Krishnamoorthy (1988).
The comparison of vertical and axial displacement at different sections of the shell roof
is shown in Figures 8 and 9 respectively which shows a good agreement between the results.
The comparison of force Ny and moment Mx along the midspan are shown in Figures 10 to
11 respectively. It is clear from these plots that variation of the moment and force for the
present study and all other investigators are almost identical.
The idea of an umbrella-shaped roof for pavilions is based on the article presented by Li
(1991). The V-section precast panels are assembled into umbrella shape with joints formed
and cast-in-place to fully integrate the structure. Umbrella-shaped folded plate roofs are
supported by beams and columns. Figure 12 shows the roof plan and elevation along with
material and geometrical properties. Figure 13 shows a plan and section of a tapered V-
plate.
Here the roof are represented by means of the semi-loof shell elements while the beam
and column is idealised using the semi-loof beam elements. The structure is subjected to
gravity type of loading. Figure 14 shows the finite element mesh of the structure.
The variation of displacement at section A-A, B-B and C-C (Figure 15) are shown in
Figure 16. Since the section line is symmetrical only half of the section is plotted. As can be
seen from Figure 16, variation of vertical displacement reduces as it goes along the length of
Section A-A because the location of column situated at length 5.25 m from the ring beam.
Codification and Application of Semi-Loof Elements for Complex Structures 9
Similar trend of behaviour is observed for both Sections B-B and C-C which they have
maximum displacement at free end and minimum near the ring beam.
The variation of membrane forces Nx, Ny and Nxy for all the sections are exhibited in
Figure 17 (a,b,c). While the profiles of moments Mx, My and Mxy are illustrated in Figure 18
(a,b,c). The forces Nx and Ny are increasing at the location of near to the column while
moments Mx and My is decrease near the upper ring beam.
The modeling of a cooling tower including ring beam at the staging level and also
without ring beam has been shown using semi-loof beam and shell elements. The geometry
is shown in Figure 19 and finite element idealisation of the cooling tower is presented in
Figure 20. The material properties of the cooling tower and ring beam at level (Z=-
232.1275) are shown in Tables 2 and 3 respectively (Karisiddappa et al., 1995).
MESHING
Due to symmetric of tower only half of it was considered and boundary condition
applied on nodes along symmetric axis. Total number of semi-loof shell element was 72 and
9 beam elements (Noorzaei et al., 2003).
Behaviour of Tower
Vertical Deflection
The variation of vertical displacement along the height of the cooling tower for = 90
is shown in Figure 21. It is clear from this plot that vertical displacements decrease toward
zero at bottom of tower and has a maximum displacement about 0.0175 ft at the top of
tower. Similar behaviour has been noted in the tower when the ring beam is included in the
model. This indicates that the ring beam has no effect on the vertical displacement, as
expected.
Radial Displacement
Radial displacement along height of the cooling tower at = 90 shown in Figure 22. It
is seen from this figure that the ring beam has a significant influence on the radial
displacements and lead to inward displacements of the tower near the mid-height of the
tower.
CONCLUSION
semi-loof shell elements which show the application of this element in predicting
perfect behaviour of these structures.
iv. Semi-loof beam element is suitable for representing the straight curved and its
combination with semi-loof shell element has been clearly worked out.
ACKNOWLEDGEMENT
The authors would like to thank Prof. Oliveira for his help during the development of
computer code for semi-loof elements. The work reported in this paper is part of the
graduate research of civil engineering department, UPM and was supported by project grant
IRPA No. 54039. We wish to thank the Ministry of Science for financial support.
REFERENCES
Bathe, Klaus-Jrgen. (1996). Finite Element Procedures. New Jersey: Prentice Hall.
Cook, R.D., Malkus, D.S., Plesha, M.E. and Witt, R.J. (2002). Concept and Application of
Finite Element Analysis. John Wiley & Sons. Fourth Edition 2002.
Godbole, P.N., Viladkar, M.N., Noorzaei, J. (1991). A Modified Frontal Solver with Multi-
Element and Variable Degrees of Freedom Features. International Journal of
Computer and Structures: 39(5):525-534.
Irons, B.M. and Ahmad, S. (1980). Technique of Finite Element. England: Ellis Horwood
Ltd.
Karisiddappa. (1994). Finite Element Analysis of Cooling Tower Subjected to wind loads.
Department of Civil Engineering I.I.T, Roorkee India.
Karisiddappa, Premkrishna, Godbole, P.N. and Noorzaei, J. (1995). Analysis of column
supported cooling tower under unsymmetrical wind loads. In: 9th International
Conference on Wind Engineering, New Delhi, India. 1995;3:1523-1531.
Krishnamoorthy, S. (1988). Finite Element Analysis. Theory and Programming. New Delhi:
Mc Graw Hill.
Li Zhenqiang. (1999). Design-Construction of Umbrella-Shaped Precast Folded Plate Roof
for Pavilions. PCI Journal 1999;44(1):14-20.
Martin, R.A.F. and Oliveira, C.A.M. (1988a). Semi-loof shell, plate and beam elements-
new computer versions: Part 1. Element Formulation. Engineering Computation;
5:15-25.
Martin, R.A.F. and Oliveira, C.A.M. (1988b). Semi-loof shell, plate and beam elements-
new computer versions: Part 2. Elements programming. Engineering Computation;
5:26-38.
Noorzaei, J. (1991). Non-linear soil structure interaction in framed structure. Ph.D thesis
Department of Civil Engineering I.I.T, Roorkee India.
Noorzaei, J., Thanoon, W.A., Jaafar, M.S. and Emamzadeh (2003). Analysis of cooling
tower using semi-loof elements. In: Proceedings of the 5th Asia-Pacific Structural
Engineering and Construction Conference, Malaysia :347-355.
Owen, D.R.J. and Martins, R.A.F. (1981). Elasto plastic and geometrically nonlinear thin
shell analysis by semiloof element. International Journal of Computers and
Structures;13:505-513.
Robinson, J. (1973). Integrated Theory of Finite Element Methods. John Willy and Sons.
Sze, K.Y. (1994). Simple Semi-Loof Element for Analyzing Folded-Plate Structures.
Journal of Engineering Mechanics;120(1):120-134.
Codification and Application of Semi-Loof Elements for Complex Structures 11
Wong, J.N., Noorzaei, J., Thanoon, W.A. and Jaafar, M.S. (2004). Modeling of Precast
Flooring/Roofing System Using Semi-Loof Elements. In: Proceedings of the 8th
International Conference On Concrete Engineering and Technology (CONCET 2004),
Malaysia.
Zienkiewicz, O.C. (1979).The Finite Element Method. New Dehli: Tata McGraw-Hill
Publishing Ltd.
Effect of Butt Joint on PSSDB Wall Panel with Door Opening under Axial Load 12
Malaysian Construction Research Journal; Vol.1|No.1|2007
Abstract
Profiled Steel Sheet Dry Board (PSSDB) system as a load bearing wall is structurally efficient
and economical in transferring loads to the foundation. This paper describes experimental
and theoretical investigations to determine the effect of butt joint on the structural behaviour
of PSSDB load bearing wall with door opening. PSSDB wall panels formed from proprietary
profiled steel sheet, Bondek II (0.75 mm thick), sandwiched by two skins of Cemboards (12
mm thick), via self-drilling, self-tapping screws, were used for the tests. The samples tested
were three (3) PSSDB walls with door opening and butt joint between the Cemboards, and
three (3) PSSDB walls with door opening but without butt joint on the Cemboard. The
samples were subjected to axial compressive load and the results were compared between
the two sets of samples and with the theoretical expressions. The average value of the
ultimate load capacity for PSSDB load bearing door panels with butt joint was found to be 328
kN, while that for the samples without butt joint was 322 kN. The average maximum lateral
deflections at first cracks for both types of PSSDB panels were 4.1 mm and 5.0 mm
respectively. The final failure mode was a combined crushing and lateral buckling.
INTRODUCTION
Profiled Steel Sheet Dry Board or PSSDB system is a new and innovative composite
construction system with a potential to be extended in application as an alternative to
flooring, wall unit and roofing system. The idea was originally conceived by Wright and
Evans (1986) in the United Kingdom. At present, further research works are being
conducted extensively at Universiti Kebangsaan Malaysia. The panel system consists of
profiled steel sheeting compositely connected to dry boards (plywood, Cement boards or
particle boards) by mechanical or selftapping screws to form panel that has far better
features and attributes in comparison to the materials in their original forms separately (Wan
Hamidon, et. al, 1996). The research done previously was concerned with PSSDB system as
flooring, roofing units and wall without opening. The present study focused on the effect of
butt joint in the dry boards on the behaviour of PSSDB system as walling. Therefore, the
PSSDB system can be said to have an unlimited potential. It is also very light and therefore
easily transportable, and can be erected quickly. PSSDB serves as an alternative and a more
practical solution to existing traditional forms of construction.
PSSDB system gives superior bending stiffness, higher load bearing and higher
resistance to buckling failure compared to using profiled steel sheet (PSS) alone (Ehsan et al
2000). Furthermore, the depth of floor or wall can be designed much lesser than the
traditional design to carry the same loading, thus a saving in cost and space. Various tests
were carried out on the system including fire resistance, sound proofing, water resistance
and others. In exploiting its usage further so as not to concentrate purely as a flooring
structure, various studies were carried out as to its ability and behaviour as wall and roof
structures (Mengesha 1992, Benayoune 1998, Ehsan et al. 2000, Suzaimy 2000, Mohd.
Zahri 2000, Benayoune & Wan Hamidon 2000, Ehsan et al. 2002, Yong C.B. et al. 2002,
Siti Hawa et al. 2003a, Siti Hawa et al. 2003b, Wan Hamidon et al. 2003a, Wan Hamidon et
Effect of Butt Joint on PSSDB Wall Panel with Door Opening under Axial Load 13
al. 2003b, Siti Hawa et al. 2004a, Siti Hawa et al. 2004b).
THEORETICAL ANALYSIS
The theoretical investigation of the load bearing capacity of the PSSDB wall panels
using a different PSS called PEVA 45 was proposed by Benayoune and Wan Hamidon
(2000). The ultimate load capacity of the panel is the ultimate load in which the composite
panel would fail under applied axial load. It is based on the concept that the capacity is
derived from individual components, namely the PSS and the Cemboard, and the interaction
between them. They have proposed a semi-empirical equation to evaluate the crushing load
for short wall panel. This equation takes into account of the effective width and the local
buckling (BS5950 Part 6) by introducing a reduction factor k:
As the height of the wall increases the failure may be due to overall buckling. Euler
formula is used to evaluate the PSSDB panel elastic buckling load.
In this section, the experimental study on the PSSDB is described. The aims of the
experimental work are to gain an understanding of the behaviour of PSSDB as load bearing
wall panels with door opening, and to study the effect of the butt joint in dry board on the
structural capacity of the PSSDB panel due to compressive axial load.
Effect of Butt Joint on PSSDB Wall Panel with Door Opening under Axial Load 14
The PSSDB load bearing wall system consists of two skins of dry boards (Cemboards)
attached to PSS (Bondek II) as the main core of the panel, using mechanical connectors
(selfdrilling and self-tapping screws). Bondek II of 0.75 mm thick (the dimensions of
Bondek II may be obtained from the web site listed in the reference) and Cemboard of 12
mm thick were adopted in this study. The size of each sample is 1000 mm high x 1320 mm
wide x 78 mm thick with door opening of size 700 mm x 300 mm x 78 mm. These
dimensions represent 1/3 the actual size of a wall. The thickness of the panel however is not
reduced. The connectors were fixed at a 100 mm and 200 mm centre to centre in the
longitudinal and transverse directions respectively. There were 46 screws on the front panel
and 63 screws on the back panel. Butt joint is formed by putting two pieces of Cemboard
side by side without adhesive being applied. Butt joint is necessary for a full size wall
because a standard size Cemboard has 1220 mm width. A typical cut-out for the opening in
PSSDB and the screw positions are as shown in Figure 1.
Experimental Set-up
The test rig consisted of a support beam at the lower end, and a movable loading frame
on the upper end. In addition, to allow for equal distribution of the load, the upper C-
channel was put on rollers. PSSDB wall sample was placed vertically on C-channel, which
was clamped to the bottom beam. The samples were tested under in plane axial load
delivered by means of hydraulic jack connected to a load cell having a capacity of 1000 kN
placed at the upper end of the sample. Displacement transducers to measure deflections
perpendicular (lateral) to the height of the wall panels were placed at various locations as
shown in Figure 2. Transducers T1 T4 were located in a vertical line so that the deflection
profile can be obtained. Transducer T5 was placed above the door opening. The load cell
and transducers were connected to a portable digital electronic data logger. The initial
values for deflection and load were zeroed on the measuring device once the sample, the
loading system and the transducers had been assembled in position on the supporting and
specimen frames. This condition was considered to represent the initial unloaded state of the
panel.
Loads were then applied incrementally. The loads at initiation and propagation of cracks
in different locations were observed and noted. The loading and the corresponding
deflection were also recorded. Readings were recorded at interval of 0.2 kN. After the
loading had peak and then decreased significantly the test was stopped. The load and the
corresponding deflection measurements taken from the experiment were then used to
investigate the crack patterns and the behaviour of the PSSDB wall panels. The
experimental set-up is shown in Figure 3.
All the six samples showed quite similar characteristics in load-deflection. The
loadlateral deflection responses of the samples exhibited approximately linear relationships.
The linear relationship persisted until the maximum load of each sample. After the
maximum load was exceeded, the deflection increased significantly as the load decreased
rapidly. This is an indication of the beginning of lateral buckling before failure. A typical
load-deflection is as shown in Figure 4.
The deformation profiles of samples with butt joint (ODB 1, ODB 2 and ODB 3)
obtained from transducers T1-T4 showed that maximum lateral deflection occurred at about
the same position, located at a height of about 700 mm. Stress concentration occurred at this
location due to the fact that the crosssectional area is reduced. The deformation profiles for
the samples are as shown in Figure 5. ODB 1 had the lowest lateral deflection and showed
slightly double curvature. On the other hand, ODB 2 and ODB 3 exhibited single curvature.
The maximum lateral displacements at ultimate load were 16.1 mm, 7.2 mm and 11.6 mm
respectively (see Table 1). Similarly, maximum lateral displacement of samples without butt
joint (OD 1, OD 2 and OD 3) also occurred at about the same height as shown in Figure 6.
Effect of Butt Joint on PSSDB Wall Panel with Door Opening under Axial Load 17
The corresponding maximum lateral displacements were 20.1 mm, 6.7 mm and 11.1 mm
respectively.
The ultimate load is the maximum load achieved before the load decreased when the
wall panel started to undergo an overall buckling. The ultimate loads recorded for ODB
samples ranged from 279 kN to 393 kN and for OD samples, they ranged from 286 kN to
370 kN. The scattering results may due to the difficulty in obtaining a perfectly level surface
at the ends of the panel. This was expected when the cutting was done by hand. The results
showed that the PSSDB wall with butt joint has similar average strength compared to
PSSDB wall without butt joint. The theoretical ultimate load calculated using equation (1)
gave Pu = 375 kN, based on a coefficient of reduction = 0.6 and the cross-sectional area of
the two legs of the panel. The reduction takes account on the reduction of strength due to
effective width. From Table 1, the average experimental ultimate load is about 13% less
than that based on equation (1). This might be due to the present of eccentricity of axial load
and in-plane bending. The elastic buckling load using equation (2) against the wall height is
as shown in Figure 7. It can be seen that up to about 1.7 m, the buckling load is higher than
the theoretical crushing load. It can be said that the buckling load is not likely to happen for
domestic loading (Benayoune and Wan Hamidon 2000)
It was observed that the loads at which first crack appeared on the samples were only
about 40% to 55% of the ultimate loads as shown in Table 2. Therefore, it is significant to
determine the lateral deflections at that loads. The maximum lateral deflections at 40%
ultimate load are also given in Table 2. The transducer where the deflection was obtained is
given in the parenthesis. The average deflection value for ODB samples was 4.1 mm whilst
that for OD samples was 5.0 mm. This showed that the two samples have no significant
difference in stiffness. As it can be seen, the two sets of samples had only 30 % of the height
differed in its configuration, which is the butt joint in the ODB samples. However it is worth
to note that the butt joint exhibits hinge reaction at the upper section of the opening. This
contributes to flexural stress release at this joint for samples with butt joint.
Table 2. First crack load and lateral displacement at 40% ultimate load
Similar crack patterns were observed for all ODB samples. A typical crack pattern of
PSSDB ODB samples is as shown in Figure 8. The crack started on the sides of the door
opening at the upper corners that were considered as high stress areas because of the sudden
Effect of Butt Joint on PSSDB Wall Panel with Door Opening under Axial Load 19
decreased in the cross-sectional area. Similar crack patterns are also exhibited on OD
samples. A typical crack pattern of OD samples is shown in Figure 9. The difference
between the two crack patterns was that there was a crack under flexural at upper middle
portion of opening in the OD samples. The butt joints in the Cemboard act as predetermined
cracks in ODB. Some cracks were observed to pass through screw positions. The final
failure mode for both type of PSSDB was a combined crushing and lateral buckling on the
sides of the samples at a height of about 700 mm (Figure 10).
CONCLUSION
The experimental study dealt with the behaviour of PSSDB wall under compressive
axial load. It can be concluded that the ultimate load capacity for PSSDB walls with butt
joint (ODB) was about the same as that without butt joint (OD). The average loads were 328
kN and 322 kN respectively. The proposed theoretical crushing load was compared to the
experimental results. It was found that the average load was 13% less than that obtained
from the proposed expression. The average deflection value obtained at 40% ultimate load
for ODB was 4.1 mm whilst that for OD was 5.0 mm. The lateral displacements for the
samples were small and the ultimate load capacity were high indicating that the PSSDB wall
panels could be recommended for load bearing wall in domestic building construction.
Nevertheless, a full-size investigation is recommended.
ACKNOWLEDGEMENT
The authors wish to express their sincere thanks to Universiti Teknologi MARA,
Universiti Kebangsaan Malaysia, Bluescope Steel Sdn Bhd, Hume Cemboard Sdn Bhd,
Mohd Rashid Yaacob and Muhammad Zihan Kisson for making this study possible.
REFERENCES
Benayoune, A.G., 1998, Behaviour of profiled steel sheeting dry board panel as wall units.
MSc Thesis. Universiti Kebangsaan Malaysia.
Benayoune, A.G. & Wan Hamidon W.B., 2000, Limit state behaviour of profiled steel
sheeting/dry board wall panel. Proceeding of the 4th Asia-Pacific Structural Engineering
& Construction Conference, APSEC 2000, Malaysia.
BS 5950 Part 6, Structural Use of Steel Work in Building: Code of practice for design of
light gauge profiled steel sheeting, British Standard Institution, 1995
Ehsan A., Wan Hamidon W.B. & Wright H.D, 2000, Experimental and finite element study
Effect of Butt Joint on PSSDB Wall Panel with Door Opening under Axial Load 21
of profiled steel sheet dry board folded plate structures. Journal of Thin-Walled
Structures, Vol. 38, pp 125-143
Ehsan A., Wan Hamidon W.B. & Wright H.D, 2002, Two-way bending behaviour of
profiled steel sheet dry board composite panel system. Journal of Thin-Walled
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http://www1.bluescopesteelasia.com/BlueScopeSteel/country/singapore/lysaght/en/inde
x.cfm
Mengesha, W.J., 1992, Composite profiled steel sheeting / dry board panels. MSc Thesis.
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(Hons) Final Year Project Report, Universiti Kebangsaan Malaysia.
Siti Hawa H., Yong C.B., & Wan Hamidon W. B., 2003a, Structural behaviour of profiled
steel sheet dry board system wall panel with door opening. Proceedings of the Fifth Asia
Pacific Structural Engineering and Construction Conference (APSEC 2003), J. Bharu,
26-28 Aug, pp 421-431
Siti Hawa H., Yong C.B., & Wan Hamidon W. B., 2003b, Crack patterns in profiled steel
sheet dry board, Proceedings of the 2nd International Conference on Construction
Technology (CONTEC 2003), Sabah, 13-15 Oct, pp 135-142
Siti Hawa H., Yong C.B, Nadiah S. & Mat Som M., 2004a, The effect of butt joint on the
structural behaviour of PSSDB wall panel, Proceedings of Conference on Scientific and
Social Research (CSSR 2004), Sarawak, 19-21 May
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Arrester, Proceedings of 22nd Conference of Asean Federation of Engineering
Organisation (CAFEO 22), 18 19 Dec, Myanmar
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(Hons) Final Year Project Report, Universiti Kebangsaan Malaysia.
Wan Hamidon W.B., Zain, M.F.M, Akhand, A.M., & Ehsan A., 2003a, Dryboards as load
bearing element in the profiled steel sheet dry board floor panel system Structural
performance and applications, Journal of Construction and Building Materials, Vol. 17,
pp 289 297
Wan Hamidon W.B., Zain, M.F.M, Sodiq, H.M., Akhand, A.M., & Sahari, J., 2003b, Fire
resistance performance of profiled steel sheet dry board (PSSDB) flooring panel system,
Journal of Building and Environment, Vol. 38, pp 907-912
Wan Hamidon W.B., et. al, 1996, Lightweight composite wood / profiled steel sheeting
system. Ministry of Science, Technology and Environment Malaysia Research Grant:
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Wright H.D. & Evans H.R., 1986, Profiled steel sheeting for the replacement of timber
flooring in building renovation. SERC Grant GR/D/76875.
Yong C.B., Siti Hawa H., & Wan Hamidon W. B., 2002, Structural behaviour of profiled
steel sheet dry board system wall panel with window opening. 20th Conference of
Asean Federation of Engineering Organisation (CAFEO 20), Cambodia, 2-4 Sept, pp
76-80
Micronized Biomass Silica and Nanoparticles Synthesis Recent Development 22
Malaysian Construction Research Journal; Vol.1|No.1|2007
Abstract
This paper reports some recent development on micronised amorphous biomass silica and
the synthesis of nanoparticles. The objective is to develop an economical and environmental-
friendly material and process for sustainable concrete construction. The experimentation
focused on the synthesis of off-white biomass silica. Rice husk experimented in a controlled
o
incineration temperature regime of 500 C within an hour has produced encouraging findings.
The biomass silica thus produced was amorphous when examined with XRD. Particle size
reduction was conducted with jar mill, Los Angeles abrasion equipment and the opposed jet
mill. The smallest average particle size produced was 5.25m in the form of dry powder.
Research into nanoparticles synthesis with ultrasonic technique revealed the potential of
producing particle size of around 90nm in the form of colloidal silica. The synthesis of
biomass silica of particle size ranging from 20m down to 20 nm is expected to promote
renewed interest in concrete research related to packing efficiency of particles within the
concrete matrix for the reduction of water permeability.
Keywords: Micronised silica, nanoparticles, colloidal silica, opposed jet mill, water permeability
INTRODUCTION
The natural process of materials synthesis has inspired the human race to learn and
explore beyond the frontiers of knowledge. Huang et al (1997) reviewed the assessment of
chloride diffusion in high strength concrete using the accelerated ionic migration test. To
improve the quality of clinker, Singh et al. (1997) studied the addition of 3% boiler-fired
rice husk ash to the black meal of a vertical shaft kiln. Amer et al. (1997) studied blended
cements made from rice husk ash fired at 450 C and portland cement. Water demand was
increased with the increase of rice husk ash content. Lin and Hwang (1997) described the
hydration mechanism of rice husk ash with calcium hydroxide which starts by the release of
the water absorbed in the porous silica structure of the ash. This enables the quick reaction
of silica with calcium hydroxide to form growing calcium silicate hydrate (CSH gel). Sugita
et al. (1997) designed a semi-industrial prototype furnace to produce a highly reactive and
homogeneous rice husk ash. By controlling the burning temperature and grinding, the
concrete strength, resistance to acid attack, chloride penetration and carbonation have been
improved.
The pozzolanic properties of palm oil fuel ash (POFA), a waste material obtained on
burning of palm oil husk and shell, was studied by Hussin et al. (1997). Compressive
strength test with Portland cement substitution levels between 10-60% indicate the
possibility of replacing 40% ash without affecting concrete strength. A maximum strength
gain at the 30% level was achieved. Awal et al. (1997) utilized POFA to reduce the
expansion of mortar bars containing tuff as a reactive aggregate. According to the results,
Micronized Biomass Silica and Nanoparticles Synthesis Recent Development 23
However the present applications are limited to produce antigen, antiseptic, purified air
composite paint or other ecological building materials using nano-TiO2, nano-SiO2 or nano-
FeO3 (Hui, et al. 2004). It is important to have strong fundamental understanding of cement
chemistry and the resulting hydration products is necessary before any attempt to improve
cement and concrete in nano-scale (Corr & Shah, 2005). Nanosilica particles with an
average size of 10nm helps to improve the porosity of the hydrated cement paste by filling
the voids left in the spaces between larger particles. Nanosilica could also reduce the cement
requirement for concrete, thus reducing the heat generation and shrinkage problems
associated with high cement contents (Corr & Shah, 2005). Attempt is made to develop
suitable methods to produce micronised and nanoparticles of biomass silica to promote
advanced materials research.
RICE HUSK
Rice husk constitutes one-fifth by weight of paddy harvested. Its average density is
3
around 100 kg/m . The rice milling process in Malaysia generates about 3.41 million cubic
meter of rice husk annually (Lee et al. 2002). Although rice husk has its traditional uses, it
is mostly causing disposal problem in most countries. Due to growing environmental
concerns and the need to conserve energy and resources, alternatives have been developed
to dispose this biomass. Innovative application is crucial to avoid environmental pollution
and the waste of energy.
Micronized Biomass Silica and Nanoparticles Synthesis Recent Development 24
It is known that amorphous silica (SiO2) will react with calcium hydroxide to form
calcium silicate hydrate (CSH). CSH crystal contributes to compressive strength and will
grow with time resulting in pore refinement in the microstructure. The water permeability in
cementitious composition is thus reduced. Therefore biomass silica ash with high content of
SiO2 is suitable for use in cementitius composition. Reactivity of SiO2 depends on the
morphology and particle size. Amorphous (non-crystalline) silica is found to be highly
reactive if micronised to the region of 5m. Thus, the off-white biomass silica ash have to
be produced in such a way that it is amorphous, low impurity with less that 15% by weight
of carbon content.
Colloidal Silica
Colloidal silica is a watery dispersoid of silicon dioxide. Its molecular formula can be
mSiO2 - nH2O. It has many industrial productions, such as investment casting, vacuum-
formed fibrous shapes, refractory materials, inorganic coatings, stool and mould coatings,
textile industry, paper and film making, hot-top insulating boards, catalyst binders and
supports, treatment of carbon products, and the production of enhanced foamed rubber. It
has also been used as water-purifying agent, clarification agent, polishes, reinforcing agent
and molecular sieves. The potential of developing high purity colloidal silica in
concentration from 15% to 40%, with or without alkali, and particle size varying from 5nm
to 120nm is being explored.
PROCESS DEVELOPMENT
TEST RESULTS
Table 1 shows the colour of ash at different incineration temperature for an hour in the
rotary reactor furnace. It shows that organic constituents of the biomass are not decomposed
to an adequate extent if the temperature is below 450 C. Above 550C, heating-up is
spontaneous and the ash is grey. If the temperature is increased beyond 600C, there is no
improvement in the purity of the end product, compared with incineration temperature of
450C to 550C. The greatest loss of weight occurs during spontaneous heating at
approximately 500C. Therefore, the test results indicated that the quality of the ash
progressively decreases above and below 500C. The off-white biomass silica is found to be
amorphous as shown in the XRD test result in Figure 3.
Table 2 shows the particle size distributions of biomass silica with different methods of
processing. Figure 4 shows the SEM micrograph of micronized biomass silica. The mean
diameter of the unprocessed biomass silica was around 142.08m. The methods used to
reduce the particles sizes were the Los Angeles Abrasion Machine using steel rod and steel
ball, jar mill, opposed jet mill and ultrasonic. The jar mil process was experimented for
every 3, 6, 12, 24, 48, 60 minutes. The particle sizes reduction experiment showed that the
mean particle size for Los Angeles Abrasion with steel ball was two times smaller than
using steel rod with 1000 rotation. The smallest particle size achieved was using the
ultrasonic method with mean diameter of 92 nm. The test report is included as Appendix A.
Micronized Biomass Silica and Nanoparticles Synthesis Recent Development 27
m
Time Mean Diameter,
Methods Rotation
Minute
Control - - 142.08
Los Angeles Abrasion Machine (Steel Rod) 1000 18 64.77
Los Angeles Abrasion Machine (Steel Ball) 1000 18 35.12
- 3 55.50
- 6 36.78
- 12 30.18
Jar Mill
- 24 24.35
- 48 19.12
- 60 17.61
Opposed Jet Mill - 15 5.25
Ultrasonic Method - - 0.93
CONCLUSION
The optimum temperature to produce off-white amorphous biomass silica with the
rotary reactor furnace is 500C. Particle size reduction with the opposed jet mill produced
micronised silica of particle size around 5m in the shortest time compared with the other
methods. The synthesis of nanoparticles from biomass silica is possible in the form of
colloidal silica with the ultrasonic method.
concrete products has been prepared for the ready-mix concrete industry in Malaysia.
Cementitious composites derived from the innovative exploitation of micronised biomass
silica have been identified for use in the experimental construction of wall for low-cost
housing. The synthesis of off-white amorphous silica from controlled incineration of
biomass particularly rice ask has attracted much research interest in undergraduate and
postgraduate studies.
A method of soft soil stabilisation with micronised silica is therefore proposed for a
postgraduate programme. The material is proposed to be experimented with innovative
formulation for rural and plantation road system. Precast lightweight concrete pile
containing micronised silica is also proposed to provide cost-effective geotechnical
solutions for construction on soft soil.
ACKOWLEDGEMENT
The authors wish to acknowledge the fundamental research grants (Vot No. 84211,
84220 and 0178) awarded by the Ministry of Education Malaysia, and further funding by
Construction Industry Development Board Malaysia (CIDB) (Vot. No. 8006) managed by
the Research Management and Innovation Centre (http://ppb.kuittho.edu.my). Special
appreciation to Supracoat (S) Sdn Bhd for the financial support for pre-commercialisation
activities, Evergreen Fibreboard Berhad, Petro-Pipe Concrete Piles Sdn. Bhd., Gobel
Industry Sdn. Bhd., Kimberly Clark and Ban Heng Bee Rice Mill (1952) Sdn. Bhd.
(www.malaysiarice.com) for the contribution of raw materials, TCK eSolutions Sdn. Bhd.
and (www.ewarns.com.my) for technical support related to remote monitoring of the rotary
reactor furnace and Your Website Solution Sdn. Bhd. (www.1.com.my ) for the
maintenance of the research portals (www.1.edu.my) and (www.ashmann.com).
REFERENCES
production of highly reactive rice husk ash and its effect on cement and concrete
properties. 10th International Congress on the Chemistry of Cement. Volume 3.
Warid Hussin, M. and Abdul Awal, A.S.M. (1997) Palm oil fuel ash - a potential pozzolanic
material in concrete construction. Journal of Ferrocement. Vol. 27. 4 Oct 1997 Int.
Ferrocement Information Center Bangkok, Thailand. 321-327 pp.
Abdul Awal, A.S.M. and Warid Hussin, M. (1997) Effectiveness of palm oil fuel ash in
preventing expansion due to alkali-silica reaction. Cement & Concrete Composites Vol.
19. 4 Aug 1997. 367-372 pp.
El-Hosiny, F.I., Abo-El-Enein, S.A., Helmy, I.M. and Khalil, K.A.(1997) Effect of thermal
treatment of rice husk ash on surface properties of hydrated Portland cement-rice husk
ash pastes. Journal of Thermal Analysis. Vol. 48. 4 Apr 1997. J.Wiley & Sons Ltd
Chichester Engl. 809-817 pp.
Kearsley, E.P. and Wainwright, P.J. (2000) The effect of high fly ash content on the
compressive strength of foamed concrete. Journal of Cement & Concrete Research.
Vol. 31. 105-112 pp.
Kearsley, E.P. and Wainwright, P.J. (2000) Porosity and permeability of foamed concrete.
Journal of Cement & Concrete Research. Vol. 31. 805-812 pp.
Kearsley, E.P. and Wainwright, P.J. (2002) The effect of porosity on the strength of foamed
concrete. Journal of Cement & Concrete Research. Vol. 32. 233 - 239 pp.
Kearsley, E.P. and Wainwright, P.J. (2002) Ash content for optimum strength of foamed
concrete. Journal of Cement & Concrete Research. Vol. 32. 241 246 pp
Lee, Y.L. et. al. (2002) Acoustic thermal insulation composite panel. Proc. 4th International
Conference on Quality, Reliability and Maintenance. 299 302 pp
Qing, Y., Zhang Z., Kong D. and Chen R. (2005) Influence of nano-SiO2 addition on
properties of hardened cement paste as compared with silica fume. Construction and
building materials.1-7 pp.
Tao, J. (2005) Preliminary study on the water permeability and microstruture of concrete
incorporating nano-SiO2. Journal Cement and Concrete Research. Vol. 35. 1943-1947
pp.
Hui L., Hui-gang X., Jie Y. and Jinping O. (2004) Microstructure of cement mortar with
nano-particles. Cement & Concrete Composites. Vol. 35. 185-189 pp.
Balaguru, P.N. (2005) Nano technology and concrete: Background Opportunities and
Challenges. Applications of Nanotechnology in Concrete Design. 113-122 pp.
Jo B.W., Kim C.H. and Park J.B. (2006) Characteristics of cement mortar with nano-SiO2
particles. Construction and building materials. 1-5 pp.
Corr D. and Shah S.P (2005) Concrete materials science at the nanoscale. Applications of
Nanotechnology in Concrete Design. 1-12 pp.
Micronized Biomass Silica and Nanoparticles Synthesis Recent Development 30
Appendix A
Structural Behaviour of Bakun Concrete Faced Rockfill Dam during Construction 31
Malaysian Construction Research Journal; Vol.1|No.1|2007
Abstract
This study covers the development and application of two dimensional finite element
software, to account for the structural modeling of concrete face rockfill dams (CFRD), during
construction phase. Dead, Birth and Ghost element technique has been adjusted in the
physical modeling. Bakun concrete slab rockfill dam which is currently under construction at
Malaysia has been modeled using different types of finite elements to simulate different dam
zones along with concrete faces. The study focuses on the effect of construction sequence on
the structural response of the dam with and without concrete slab. The structural responses in
terms of deformations characteristic, stress distributions have been highlighted. The results
indicate that concrete slab has an effect that reduces the displacements and stresses on the
body of dam.
INTRODUCTION
Concrete-faced compacted rockfill dams become popular for the last three decades as a
result of their good performance and low cost compared to other types of dams. They show
high level of safety, and the stability compared to other type of dams, due to the large mass
of the rockfill embankment. How-ever, the concrete face is the critical part in this type of
dam due to the possibility of cracking and leakage of water. Cracking are occurred due to
differential settlement of the underlying rock stratums.
Recently the analyses for rockfill dams are carried out using finite element method to
identify the various factors affecting the distribution of stresses and strains in the face slab
and the body of the dam. Furthermore, most embankments are constructed by incremental
process and the loading is accumulated gradually during the construction stages. For
realistic assessment of the dam, the analysis should provide the effect of the load being
applied in incremental rather than being applied in one stage. The application of finite
element method was demonstrated by Clough et al. (1967) for the analysis of earth dam.
Boughton (1970) noted that the design of concrete face is largely empirical; modification to
design practice was made in the light of the performance of new dams. Finite element
method was adopted in the analysis of 36m high Wilmot rockfill dam using triangular
elements.
Modeling of slippage between the concrete slab and body of the dam was ignored in the
analysis; Khalid et.al (1990) used finite element method to simulate the prototype behavior
of various component of a rock fill dam. The analysis includes the effects of sequential
construction and the nonlinearity behavior of the materials.
This study is a continuation of author previous work Noorzaei et..al. (1999) and Fayda
et al. (2003) where Birth, Dead, and Ghost element technique was used to study the effect
of construction sequence in the concrete faced rockfill dams. Moreover, this study focuses
on the effect of the concrete slab on the displacements and the distribution of the stresses
developed due to gravity load.
Structural Behaviour of Bakun Concrete Faced Rockfill Dam during Construction 32
In this study the paper focuses on the effect of construction sequences on the
structural response of the dam with and without concrete slab for Bakun dam, using 2-D
finite element program in the analysis.
In order to simulate the sequences of dam construction in this study, the Death-Birth-
Ghost element technique was implemented. The finite element discrimination of the dam
body is same as to that used under single shot loading. In this algorithm the physical
discretization of the dam body is defined completely, while the mechanical properties of the
dam body will depends on whether the layer is previously loaded or currently loaded or yet
to be loaded.. Sequence of construction schedule and accordingly three cases of loading is
defined namely:
Figure-1 showing the layers of the dam in each step of analysis the Birth elements are
assigned with the material properties of the dam while, the Dead elements are assigned with
the material properties of the dame with zero density. The Ghost layers are assigned very
small young modulus and passion ratio.
The following elements are used to idealize the cross section of the Bakun dam.
The finite element formulations of elements in (i) and (ii) are well established and are
available in finite element text book, Cook et al. (2002), Zeinkiewics, O.C. (1979).
However, a brief description is presented here for the formulation of interface element.
x N i xi y N i yi
u N i ui v N i i
, (1)
, (2)
N a ( 1) , N b (1 2 ) , N c ( 1)
1 1
(3)
2 2
u1T , u1B , v1T , v1B , u 2T etc , are the nodal displacements in x and y directions, and the indices
T and B indicates top & bottom continuum respectively. The above relationship can be
expressed as.
u1T
B T a
u a 1 0 1 0 v1T
a
va 0 1 0 1 u1
(5)
v1B
Structural Behaviour of Bakun Concrete Faced Rockfill Dam during Construction 34
a b c T 6 * 12 12 *1
T
(6)
u a
As in the case of isoparametric elements, the relative displacement
v
a
u N a 0 u b
N c vb
0 Nb 0 Nc
v 0
(7)
u c
Na 0 Nb 0
vc
N 2*6 6*1
u
v
(8)
By substituting equation (6) into Equation (8) to get the following equation:
N T N
u
v
(9)
The strain at any point in the joint defined by local coordinate system
t 1 u ' 1
' RN Bi
n t v t
(10)
t and n are the tangential and normal strains respectively at the point, [R] is a rotation
respectively.
matrix and transfers global strains to local strains, (t) is the thickness of the element and
[B] is the strain displacement matrix of the joint
K Bi T Di Bi ds (11)
Where [Bj ] is the strain displacement matrix [D i ] is the elasticity matrix for the joint, and
ds is a small length of the joint and
Structural Behaviour of Bakun Concrete Faced Rockfill Dam during Construction 35
Di
n
(12)
D
0
Kss
0 Knn
(13)
Where Kss, and Knn are the shear and normal stiffness respectively.
The project is mainly composed of three parts: concrete rockfill dam, power generating
system and water release system. The project has a maximum dam height of 205m with total
installed capacity of 2400MW (the first stage installed capacity of 900MW) and concrete
consumption for the main project of 1,100,000 m. The dam consists of different zones as
shown in Figure 3.
205 m
3A
2B
1B Concrete
slab
1A 3B 3C
2A
3B
3
Grout blanket
Concrete slab with variable thickness reduced with the height.
Zones (1A, 1B) at the upstream zone, over the lower deck of perimeter joint.
Zone 2A, a well compacted of processed fine filter having low.
Zone 2B, well graded processed filter, this zone be immediately behind the face slab.
Zone 3A, transition zone placed adjacent to zone 2B with maximum size of 0.3
Zone 3B, the upstream zone forming approximately 50-60% of the embankment
meters.
Zone 3C, a zone within the downstream placed and compacted in layers about 1
including the integrated cofferdam.
meter thick.
Structural Behaviour of Bakun Concrete Faced Rockfill Dam during Construction 36
Zone 3D, placed and compacted in layers up to 2 meters thick and dozed to
downstream face of the dam to serve as slope protection, also used within the valley
bottom to serve a high-capacity under drain.
The finite element idealization of the whole dam section is illustrated in figure 4 along
with total No. of elements, total number of nodes, total numbers No. of layers and different
types elements. This finite element mesh illustrates two models namely:
8 nodded and 6
isoparametric
- No of layers= 28
elements for concrete
- No. of nodes=2870
and dam body
- No of elements 935
The proposed finite element model, take into consideration different material properties
at different zones of the dam, and the sequence of construction described above.
In this paper only the loading due to the sequence of construction has been taken into the
consideration.
The structural behavior of the dam has been studied with respect to displacement and
stress developed in the body of the dam.
Figures 5, 6, 7, and 8 indicate the vertical displacements across the width of dam at
elevation 9.4, 52.5, 110.16, and 170 respectively. Each figure shows the displacements for
both finite element models; with and without slab. It is clear from these plots that the
concrete slabs reduces the deformations in the body of the dam and increase the
displacements nearby the region of the concrete slab.
Vertical displacements at level 9.4m due different vertical displacements at level 9.4 due to different
sequance of construction [Without slab] sequance of construction [w ith slab]
0 0
Vertical displacements (m)
-0.04 -0.04
-0.06 -0.06
-0.08 -0.08
(m)
-0.1 -0.1
-0.12 -0.12
-0.14 El.9.4 -0.14
9.4
-0.16 -0.16
-0.18 -0.18
Distance along w idth of dam (m)
Distance along w idth of dam(m)
ST-1 st-4 st-6 st-13 st-16 St-1 St-4 St-6 St-13 St-16
Vertical displacementat El. 52.7 due to different sequance vertical displacements at 52.5 due to different sequance
of construction[w ithout slab] of construction [w ithslab]
0 0
-0.1 0 100 200 300 400 500 600 0 100 200 300 400 500 600
Vertical displacements
displacements (m)
-0.2 -0.2
-0.3
Vertical
-0.4
(m)
-0.4
-0.5
-0.6 -0.6
El.52.
-0.7 El.52.7
-0.8 -0.8
Distance along w idth of dam (m)
Distance along w idth of dam (m)
St-6 st-11 st-13 st-16
St-6 St-13 St-16
st-18 st-21 st-25 st-28 St-18 St-21 st-25 St-28
Vertical displacements at El.110 due to sequance of Vertical displacements at level 110.16 due to sequance
construction[w ithout slab] of construction [w ith slab]
50 150 250 350 450 550
50 150 250 350 450 550
0
0
Vertical displacements
displacements(m)
-0.2
-0.2
Vertical
-0.4
-0.4 El.110
(m)
-0.6
-0.6 El.110
-0.8
-0.8
-1
-1 Distance along w idth of dam (m)
distance along width of dam(m) st-13 St-16 St-18
st-13 st-16 st-18 St-21 St-25 St-28
st-21 st-25 st-28
cL 1.2
0.9 cL
Vertical displacements(m)
0.8 1
0.7
0.6 0.8
0.5
0.6
0.4
0.3 0.4
0.2
0.2
0.1
0 0
-1.2 -1 -0.8 -0.6 -0.4 -0.2 0 -1.2 -1 -0.8 -0.6 -0.4 -0.2 0
h/H
h/H
st-4 st-13 st-21 st-28 st-4 st-13 st-21 st-28
When analysing the dam in single shot (ignoring the effect of construction sequence),
the maximum displacement calculated found to be larger at the top and lower in the middle
part of the dam. The contours of the vertical displacements are shown in figure 10 and 11
for the two models with and without slab respectively.
Results obtained considering the gradual lifting of the dam reflects that the construction
sequences are important and have to be considered in the analysis.
Structural Behaviour of Bakun Concrete Faced Rockfill Dam during Construction 39
Figure 10. Vertical displacements due to single shot loading [with slab]
Figure 11. Vertical displacements due to single shot loading [without slab]
Fig.12, 13 shows normal stresses x, y, plotted across the width of the dam, at elevation
of 52.5. It can be seen that the maximum vertical stresses occurred at the mid width of the
dam. Moreover, the presence of concrete slab reduces the stresses on the body of the dam,
and increases the stresses nearby the concrete slab.
Normal stresses at level 52.5 due to sequance of Normal stresses at level 52.5due to sequance of
construction [w ith slab] construction [w ithout slab]
-50 50 150 250 350 450 550
0 100 200 300 400 500
300
-250
0
KN/m
KN/m
-850
-300
-1450
-600
-2050 52.5
52.5
-900
-2650
-1200
-3250
Distance along w idth of dam (m) Distance along w idth of dam (m)
Normal stresses at level 52.5 due to sequance of Normal stresses at level 52.5 due to sequance of
construction [With slab]
construction [Without slab]
0 100 200 300 400 500
0
0
0 100 200 300 400 500
-500
-1000
KN/m
-1000
KN/m
-1500
-2000
-2000
52.5
-3000 52.5 -2500
-3000
-4000
Distance along w idth of dam (m)
Distance along w idth of dam (m)
St-6 St-13 St-16 St-18 St-21 St-28 St-6 St-13 St-16 St-18 St-21 St-28
Figure 13. Normal stresses y at level 52.5 for different stage of construction
CONCLUSION
The paper describes the finite element analysis of Bakun concrete rock fill dam under
gravity load. The effects of construction stages and the presence of concrete face slab on the
deformations and stresses distribution in the dam have been covered. It is concluded that,
the Dead-Birth, and Ghost element technique is very useful as far as the data preparation for
the finite element analysis is concerned since only one mesh is required to simulate all the
stages of construction. The concrete slab has a significant effect on the deformation and
stresses distribution. The high stiffness of the concrete faced slab will alter the distribution
of the stresses leading to lower values of stresses in the body of the dam and higher values
in the concrete faced slab. Maximum value of settlement occurs in the mid height of the
dam for both models, with and without slab
ACKNOWLEDGMENT
The Authors wish to thank SARAWAK HIDRO SDN. BHD.,Bhg. Perkhidmatan For their
assistance in providing the data and drawings concerning Bakun dam.
REFERENCES
Bougton, N. O. (1970),Elastic analysis for behavior of rock fill J. Soil Mech. And found.
Div., ASCE, 96(5) 1715-1733.
Clough, R., W (1967) Anaysis of embankment Stresses and Deformations JSMFD, ASCE,
Vol. 93, No. SM4
Cook, R.D., Malkus, D.S, Plesha, M.E. and Witt. R.J. (2002), Concept and Application of
Finite Element Analysis, Fourth Edition, John Wiley & Sons, Inc.
Fayda F. ,Noorzaei,J.(2003),Structural Response of Concrete Faced Rockfill Dam,
prceeding of 5th Asia-Pacific APSEC
Khalid, Bharat Singh, Nayak G.C.,and Jain O.P 1990.Nonlinear Analysis of concrete Face
rockfill Dam ,Jl.of Geotechnical Engineering, ASCEVol.116,No.5
Noorzaei J., Golinavaz Herls and. Pakbas,M.C. (1999), Non-linear analysis of Earth and
Rockfill Dams Considering The sequence of construction Computational Mechanics
for the Next Millennium Solid Mechanics and Fluid Mechanics Vol. 1.
Zeinkiewics, O.C. (1979), The Finite Element Method, Third Edition, Tata McGraw-Hill
Publishing Ltd., New Delhi
Evaluation of the Thermal Performance of Metal Roofing under Tropical Climate Conditions 41
Malaysian Construction Research Journal; Vol.1|No.1|2007
Abstract
The assessment of the thermal performance was carried out on a low cost house mainly built
from waste oil palm shell (OPS-Concrete) with galvanized steel-roof. It was noticed that
reasonable thermal comfort took place during the night for the roof without ceiling and without
insulation, and during the day at a peak temperature of a highly ventilated attic area. For such
situation, it was recommended to install insulating horizontal plated surface under the roof,
which should be turned into a vertical position during the night. Other alternatives may be
creating small adjustable openings around building envelope just under the ceiling or making
an open roof-ceiling system. This technique will reduce the heat flux from insulated ceiling by
the flow of the cooling air at night, but the impact of surrounding microclimate on human
thermal comfort should be considered. The mathematical model used to predict the attic
temperature for a lightweight roof system was obtained by correlation, which can be used for
a quick inspection. Insulation materials of 50 mm fibreglass and foil-aluminium were used with
o o
sealed attic, and found the ceiling temperature reduced by about 3 C and 2 C respectively.
For the case of fibreglass of thickness beyond 50 mm, the reduction of ceiling temperature
o
was recorded less than C, really not attractive.
Keywords: thermal performance, metal roofing, attic temperature, sealed attic, ventilated attic,
insulation
INTRODUCTION
Kota Kinabalu city (the capital of the Sabah state of Malaysia) experiences a typical
equatorial humid climate with heavy rainfall usually in the afternoon time, where the
temperatures are uniformly high and extremely invariable throughout the year. A good
thermal performance of any house in Kota Kinabalu has to have an indoor temperature
between 25 oC and 28 oC (comfort range). The analysis of bio-climatic chart indicated that
the ventilation should be considered for this type of climatic conditions. The utilization of
active cooling system seems to be the only solution during the peak air temperature when no
passive strategies could minimize the effect of radiation and air temperature to the
acceptable indoor comfort range.
Metal roofing in Kota Kinabalu practically became the norm for low-cost houses,
considerably contributing to heat gain and increasing the indoor temperature. A such roof
system requires particular attention, since it is the most envelope building part exposed to
solar radiation. Berdahl et. al. (1997) and Miller et. al. (2004) have studied the effect of roof
colour in minimizing surface temperature, and found that high solar reflectance and infrared
emittance of roofs surface reduce heat gain and also the UV radiation received by roofs. The
utilisation of lighter colour is very highly recommended under Malaysia climate due to their
high solar reflectivity, but it is less diffused and not well accepted by the population. Several
solutions are possible to minimize the ceiling temperature such as the insulation of roof,
Evaluation of the Thermal Performance of Metal Roofing under Tropical Climate Conditions 42
attic ventilation, selection of roofing materials more suitable under warm humid conditions,
the realisation of high-pitched roof, and may be other suitable and practical techniques.
The objective of the present study is to provide recommendations for the improvement
of roofing design under Malaysia climate. Therefore, the assessment of the thermal
performance of metallic roof system with sealed and ventilated attic will be considered. In
addition to that, the impact of different thickness of fibreglass and foil- aluminium in
reducing ceiling temperature will be studied. The model house used in this research is the
low cost house built inside the campus of the Universiti Malaysia Sabah (5.93oN, 116.05o-
about 2.3 m above sea level) using waste oil palm shells OPS as aggregate for the
realization of walls, whereas the roof is made from galvanized steel.
EXPERIMENTAL PROCEDURES
The low-cost house used as a case study is a single story detached one family house
which is considered as model house utilizing agricultural solid waste namely oil palm shell
OPS in an innovative light weight concrete mix, based on financial and environmental
design factors. This has double advantage of reduction in the cost of construction materials
and solves the disposal of waste products generated at the palm oil mills. Mannan et. al.
(2001, 2004) reported that the trend of behaviours of OPS concrete and control concrete is
very similar construction and building materials. It was established that OPS performs as
aggregate in concrete and possesses the potential of being used in building construction. The
OPS concrete is also considered environmentally sustainable building materials, friendly
product and does not have any health hazard since it is covered with cement paste and no
deterioration is taking place. The model-house realised with the OPS concrete is considered
socially acceptable for the low-income families. The roof system was built with red pre-
painted galvanised steel sheet, and with ordinary plywood 6 mm in thickness used as ceiling
without insulation, for all rooms. Table 1 describes the OPS building materials used and
figure 1 shows the plan view of the house.
The building consists as shown in figure 1, of one living dinning room, kitchen, shower,
study room and two bedrooms, with floor to ceiling heights of 3.1 m, occupying an area of
58.68 m2. The walls are constructed with small windows opening in most exterior walls
except on the west-south side, which represents around 7.59% of the surface building
envelope. These openings were covered with single plane glazing 6 mm, but no kind of sun
shading was used for the openings. Solar radiation reaches the interior of the living and
bedroom 2 during the sunrise and the kitchen during the sunset, which produces direct and
immediate heating effect. The roof was built with narrow overhang of 0.9 m giving a little
protection to the walls. The attic space is well ventilated as it appears clearly in figure 2.
The external walls colours are beige and the house is located in an open area without
landscaping. The vertical distance between the inlet and the outlet of the vent area facilitate
the increase of the ventilation rate in attic space. However, the outlet vent area in this attic is
less than the inlet vent area, which in turn minimizes airflow through the attic. The net free
ventilating area in the attic space was about 1/13, which is higher than the minimum
recommended of most codes at least a 1/150.
Data Monitoring
The field test includes mainly measurements of air temperature with the utilisation of
data-loggers HOBO thermometer during two series of measurements, ventilated and sealed
attic. The data-loggers were positioned in the centre of the house, outside the house, and at
the centre of the attic space. The daily average monthly radiation was estimated on possible
sunshine hours, nearly the same during these two periods about 20.22 MJ/m2 from 8 July
until 8 august 2004, and 20.77 MJ/ m2 from 21 October 2004 until 22 December 2004. The
assessment of different ceiling configurations was evaluated with sealed attic and
summarized in table 2.
Data reported in figure 3 shows a sequence of the indoor, mid attic and outdoor
temperature from 8 July 2004 until 4 August 2004 with ventilated attic. The indoor
temperature was recorded 1.5m above the floor.
39
Temperature *C
37
35
33
31
29
27
25
23
07/08/04
07/10/04
07/11/04
07/13/04
07/14/04
07/15/04
07/17/04
07/18/04
07/20/04
07/21/04
07/23/04
07/24/04
07/26/04
07/27/04
07/29/04
07/30/04
08/01/04
08/02/04
08/04/04
08/05/04
The thermal mass of the OPS house brought the maximum indoor temperature which is
below the maximum daily outdoor temperature. The thermal capacity of walls has the effect
of delaying the impact of external conditions on the interior of the building. The low thermal
mass roof system, which is simply red galvanized steel and plywood for the ceiling, shows
the tendency of similarity between the outdoor and attic temperature with slight variation
during the daytime. This could be due to the roof surface temperature raised by absorption
of solar radiation. The system of ventilation was judiciously chosen for this house in
Evaluation of the Thermal Performance of Metal Roofing under Tropical Climate Conditions 45
reducing the heat transfer through roofing materials. The hourly evolution of attic
temperature for one hot sunny days variation recorded on 25th July 2004 was slightly
similar to the outdoor temperature, while the maximum indoor temperature was lower by
about 4.58 oC below the maximum outdoor temperature. Note that the variation of attic air
temperature during the night was lower than the indoor air temperature by about 3.16 oC.
The outdoor temperature range (difference between maximum and minimum) recorded was
about 10.14 oC. This means the utilisation of thermal mass under Malaysia climate to reduce
the indoor temperature by about 7 oC or at least 4 oC during the peak indoor temperature
could be quite acceptable. The correlation between hourly attic and outdoor temperature is
shown in figure 4.
C
o
38 y = 1.542x0.8741
36
Attic temperature
34 R2 = 0.9636
32
30
28
26
24
22
20
22 24 26 28 30 32 34 36 38
Outdoor tem perature oC
Figure 4. Correlation between hourly attic and outdoor temperatures with ventilated attic
An analysis of the hourly attic temperature was plotted versus outdoor air temperature.
The daily maximum attic temperature was best predicted on the basis of the mean daily
outdoor temperature as shown in figure 5, yielding good correlation between measured and
calculated maxima.
Maximum daily attic
y = 38.416Ln(x) - 96.21
temperature oC
37 R2 = 0.8505
35
33
31
29
27
25
26 28 30 32
Mean daily outdoor
tem perature oC
.
Figure 5. Correlation between max. attic and mean daily outdoor temperatures with ventilated attic
Evaluation of the Thermal Performance of Metal Roofing under Tropical Climate Conditions 46
The best curve fitting correlations for hourly and maximum daily attic temperature
prediction, are as follows:
Where;
Th-attic : Predicted hourly attic temperature. Th-out: Recorded hourly outdoor
temperature.
Tdmax-attic: Predicted daily maximum attic temperature. TdMean-out: Recorded daily mean
outdoor temperature.
Figure 6 shows the measured and the computed maximum ventilated attic temperature
based on Eq. (2), which are quite similar in terms of temperature. The difference between
them was found statistically not significant using t-test (t-test = 0.04206) with total degree
of freedom equals to 52, for the 2 samples (measured and computed), and each one contains
27-recorded data of temperature.
C
36
o
35
Temperature
34
33
32
31
30
29
28
07/13/04
07/17/04
07/21/04
07/25/04
07/29/04
7/9/04
8/2/04
After the attic was sealed, the correlation between daily maximum attic temperature and
maximum outdoor temperature was less predictable, conversely to the hourly prediction of
attic temperatures plotted in figure 7.
Evaluation of the Thermal Performance of Metal Roofing under Tropical Climate Conditions 47
42 y = 0.9073x1.0468
o
C 40 R2 = 0.96
Attic temperature
38
36
34
32
30
28
26
24
23 25 27 29 31 33 35 37 39
Outdoor tem perature oC
Figure 7. Correlation between hourly attic and outdoor temperatures with sealed attic
The predicted hourly attic temperature with sealed attic is expressed by the following
formula;
(3)
The predicted hourly attic temperature with ventilated and sealed attic for a possible
outdoor temperature variation from 24 oC to 35 oC were computed using Eq. (1) and Eq. (3)
respectively, and plotted in figure 8.
39
o
C
36
Attic temperature
33
30
27
24
21
18
15
23 25 27 29 31 33 35 37
Outdoor tem perature oC
Predicted tem perature before sealing the attic
Predicted tem perature after sealing the attic
It is clear that the effect of ventilation in reducing attic temperature was more noticed
with the increased outdoor temperature, and the difference between ventilated and sealed
attic reached about 3 oC when the outdoor temperature attained 35 oC. The temperature with
ventilated attic was always lower than the sealed one, and the difference between them
becomes more significant when the outdoor temperature increases.
The interior surface temperature of the OPS concrete wall as well as the temperature
under metal roofing and the ceiling surface temperature were recorded and plotted against
outdoor temperature as illustrated in figure 9. Inspection of figure 9 shown that the OPS
concrete walls was always lower than the outdoor temperature, generally from 10 am to 15
pm. The OPS concrete wall rose after that and reached its maximum usually before 20 pm.
The main issue of any building components particularly realised with concrete or bricks
under tropical humid conditions, are the heat storage released during the early evening or
before the outdoor temperature reaches its minimum. As for the case of the traditional
building materials made with lightweight materials such as wooden, bamboo or thatched
walls, used since the past in Malay architecture, are considered suitable under Malaysia
climate, but could be warmer than concrete walls during the daytime since they follow
greatly the outdoor temperatures. These traditional building materials are more suitable
when the microclimate surrounding the building is modified with the plantation of trees or
simply when the house is located in the jungle. Moreover, walls in traditional houses permit
air to pass through gaps, which decreases the thermal sensation of the effect of temperature
on human body. The problem of overheating was rather solved in the traditional houses in
terms of human thermal comfort and not limited on building thermal performance. The
designer under warm humid conditions should take into consideration not only the
characteristic and the thermal performance of building materials but also the impact of
surrounding microclimate on human thermal comfort.
C
52
o
48
Temperature
44
40
36
32
28
24
20
01 2 /0 2 H
01 /05 6 H
01 2 /0 0 H
01 /05 H
02 2 /0 8 H
02 2 /0 2 H
02 /05 6 H
02 2 /0 0 H
02 /05 4 H
03 2 /0 8 H
03 /05 2 H
03 2 /0 2 H
05 H
H
31 /05 0H
31 1 /0 4H
01 1 /0 18H
01 /05 2H
02 /05 2H
4
2/ 6
0
/0 5:1
/0 :1
2 2
2 2
/0 :0
/0 5:0
/0 :1
/0 5:1
/0 :1
/0 :0
/0 5:0
/0 :1
/0 5:1
/0 :1
/0 5:2
/0 :0
/0 5:0
:1
/0 5:
/0 4:
/0 5:
31 1 /0
1
2
/0
31
The hourly solar radiation and relative humidity are plotted with respect to roof surface
temperature, and shown in figure 10.
Evaluation of the Thermal Performance of Metal Roofing under Tropical Climate Conditions 49
60 100%
Temperature oC
Radiation Mj/m 2
50 80%
40 60%
30
20 40%
10 20%
0 0%
/ 5 H
/0 05 H
/0 5 H
/0 5 H
/ 5 H
/0 05 H
/0 5 H
/0 5 H
/ 5 H
/0 05 H
:2 H
H
02 2 /0 :00
02 02 / :02
02 2 /0 :04
02 2 /0 :06
02 2 /0 :08
02 02 / :10
02 2 /0 :12
02 2 /0 :14
02 2 /0 :16
02 02 / :18
05 0
2
2 / :2
/0 5
02 2 /0
/0
02
Radiation
Surface tem perature under roof
Relative Hum idity
Figure 10. Hourly solar radiation and relative humidity versus roof temperature
It is evident from figure 10 when the roof surface temperature reaches its maximum
limit the radiation attains its maximum level. This is not the case with the relative humidity,
since the relative humidity increases when the outdoor temperature decreases which occurs
during the nighttime. These results could be also encouraging for possible utilisation of
evaporative cooling even under warm humid climate during the peak outdoor temperature
when the relative humidity attains its minimum (Harimi et. al., 2005).
Thermal insulation is an important factor in minimizing the effect of heat absorbed and
transmitted by metal roofing materials. When solar radiations as well as the roof surface
temperature reach their maximum level, the radiant temperature from warm ceiling causes
the greatest discomfort and increases the physiological heat stress as reported by Vecchia
(2001). This could be reduced with the installation of insulation above the ceiling or just
under the roof, and it may well reduce the energy consumption, which lowers utility bills in
residential buildings under active cooling system. The role of fibreglass is to minimize
conduction and convection, thereby decreasing the ceiling temperature, whereas, the
principal function of reflective insulator (radiant barrier) is to reflect radiant heat rays and
acts also as vapour barriers. Its capacity to insulate could be lost after a few years. The
reflective insulation material is installed in general on a ceiling for more effectiveness.
Figure 11 shows the variation of ceiling temperatures without insulation, and with different
characteristics of insulation materials.
Evaluation of the Thermal Performance of Metal Roofing under Tropical Climate Conditions 50
C
35
o 33
Temperature
31
29
27
25
01 /04 H
01 /04 H
01 /04 H
02 /04 H
02 /04 H
02 /04 H
02 /04 H
02 /04 H
03 /04 H
03 /04 H
04 H
H
31 /04 H
01 /04 H
01 /04 H
0
5
0
1
6
1
6
1
2
7
2
7
2 / 03
8
/0 :1
/0 :1
2
/0 :0
/0 :0
/0 :1
/0 :1
/0 :2
/0 :0
/0 :0
/0 :1
/0 :1
/0 :2
:0
:
:
31 04
1/
1
1
2
2
2
2
2
2
2
2
2
2
2
/0
/0
/0
31
As it was expected, the fibreglass has more effect in reducing ceiling temperature in
comparison to foil- aluminium. This is due to the low emissivity of metal roofing, which has
the ability to minimize considerably the emitted radiation into attic before reaching the foil-
aluminium. The efficiency of foil-aluminium could be more significant for a roof system
made of concrete or clay tile with a ventilated attic space. The temperature difference
between insulated ceiling with fibreglass and plywood ceiling could attain 3 oC; while the
maximum difference recorded using foil-aluminium was about 2 oC. The increase of
insulation thickness beyond 50 mm was not appreciated, because the maximum temperature
reduction was found less than 0.5 oC. Table 3 summarize the ceiling surface temperature
with different thickness insulation materials that was recorded on the second February 2005.
It comes into view from table 3, that the minimum surface ceiling temperature recorded
during the night was always higher than the ceiling temperature without insulation. The
ceiling insulated with fibreglass recorded the highest temperature. Givoni (1994), has
recommended in such situation the installation of hinged interior insulating horizontal plated
surface under the roof, and should be turned into a vertical position during the night. This
special roofing design recommended by Givoni (1994) is more detailed in page 120 of his
book and could be very useful under Malaysia climate particularly for low-cost houses.
However, the application of such technique needs some improvements in the area of
aesthetic and psychological side. Other possibilities could be simply making small
adjustable openings all around building envelope and just under the ceiling to reduce the
heat flux from insulated ceiling with the cooling air during the night, or by the realisation of
an open roof-ceiling system as shown in figure 12.
Evaluation of the Thermal Performance of Metal Roofing under Tropical Climate Conditions 51
The overhang design should be large enough to protect the penetration of rain into
ceiling floor and at the same time should allow the winds to penetrate easily in this area,
which in turn can be slightly inclined to avoid the stagnation of rainwater in case.
CONCLUSIONS
From the thermal assessment of the OPS house, many observations have been recorded.
It was noticed that during the night, roof without ceiling and without insulation performs
thermally better than any roof system under tropical climate conditions. When the outdoor
temperature reaches its maximum, the low-mass corrugated metal roof cools down rather
quickly than the ceiling temperature, whereas, the highly ventilated attic area performs
thermally better than the sealed attic area. This system is highly recommended under
Malaysia climate with no additional cost, but the designer should take into consideration not
only the characteristic and the thermal performance of building materials but also the impact
of surrounding microclimate on human thermal comfort.
The prediction of attic temperature with lightweight roof system is possible and has
been well established using a mathematical model correlation, which can be applied in the
future for a quick inspection. The use of 50 mm fibreglass with sealed attic significantly
lowers the ceiling temperature by about 3 oC, while for the case of foil-aluminium, ceiling
temperature decreases by about 2 oC. It should be highlighted, that the advantage gained by
increasing insulation thickness of fibreglass beyond 50 mm does not decrease ceiling
temperature significantly, and the maximum temperature reduction was recorded less than
o
C.
ACKNOWLEDGMENTS
The authors would like to acknowledge the financial support of CIDB Malaysia for
funding this project under grant No 02-002. Also a special thank to Prof. Dr. Eduardo l.
Kruger-CEET-PR, Brazil, for his advice and useful suggestions.
Evaluation of the Thermal Performance of Metal Roofing under Tropical Climate Conditions 52
REFERENCES
Berdahl, P. and Bretz, S. 1997, Preliminary survey of the solar reflectance of cool roofing
materials, Energy and Building, Vol. 25, pp. 149-158.
Givoni, B. 1994, Passive and low energy cooling of building, New York, F. (ed.), Van
Nostrand Reinhold, pp. 120.
Harimi, D., Harimi, M., Kurian, V. J., Nurmin, B., Ideris, Z., and Lilian, G. 2005.
Evaluation of the thermal performance of concrete tile under tropical climatic
conditions, Conference on Sustainable Building South East Asia, 11-13 April 2005,
Malaysia.
Mannan, M.A. and Ganapathy, C. 2002, Engineering properties of concrete with OPS as
aggregate, International Journal of Construction and Building Materials, Vol16.
Mannan, M.A. and Ganapathy, C. 2004, Concrete from an agricultural waste oil palm shell
(OPS), Building and Environment, 39, pp.441-448.
Miller, A. W., Desiarlais, A., Parker, D. S. and Kringer, S. 2004, Cool metal roofing for
energy efficiency and sustainability. CIB World Building Congress, Toronto Canada.
Vecchia, F., Givonu B., Silva, A.C. 2001, Analysing thermal performance of occupied
houses in Descalvado, Brazil, In Proceedings of the Eighteenth Conference on Passive
and Low Energy Architecture, PLEA Florianopolis Brazil, Paper Code PLO1-185, pp.1-
7.
53
Malaysian Construction Research Journal; Vol.1|No.1|2007
INTRODUCTION
The construction sector had been affected by rapidly changing economic environment,
the privatisation of public utilities and the internationalisation of production. The
construction sector is sensitive to changes in the economic environment, and needs to adapt
its business strategies accordingly. The construction of industrial and commercial buildings
and infrastructure will contribute to the growth of construction related activities. The
Construction Sector is a catalyst for economic growth as it stimulates development in other
sectors.
In 2005, the construction sector contributed 2.7% share to Gross Domestic Product
(GDP), with a value of RM7,168 million as compared to RM7,248 million in 2004. The
decline of 1.1% in growth was due to the completion of mega projects that were planned
during the 8th Malaysia Plan. The sector recorded a 0.6% growth in employment. The
positive growth in construction employment was partly attributable to the improved
business condition in the residential sub-sector and the implementation of new and on-going
major infrastructure projects in 2005, such as the Stormwater Management and Road
Tunnelling (SMART). The employment of the sector is expecting to be sustained with the
completion of current and new projects including the second phase of the East Coast
Expressway and the upgrading and replacing of the existing water pipe system.
Productivity of the sector registered a decline of 0.7%. The decline was due to lower
civil engineering activities with the completion of major projects and the reduction in value
and number of infrastructure contracts awarded. However, it was partially mitigated by
higher demand in the residential and non-residential sub-sector. The demand for houses,
especially affordable houses in prime locations with good accessibility as well as office and
retail space supported the performance of the construction sector.
In 2004, the construction sector contributed to 2.9% share of GDP, accounting for a
value of RM7,248 million. The sector recorded a declining growth of 1.5% due to the lower
Government spending on new large infrastructure projects. The slow performance of the
construction sector was cushioned by the higher construction activity in residential and non-
residential sub-sector. Strong economic and business activities with higher demand for
office and retail space supported the performance of the non-residential sub-sector.
Furthermore, residential sub sector continued to be sustained by stable demand for
residential property especially affordable houses in prime locations with good accessibility.
3.00
2.50
2.00
1.50
1.00
Percent
0.50
0.00
-0.50
-1.00
-1.50
-2.00
Added Added
Added Total Labour Fixed
Value per Unit Labour Value per
Value per Output per Cost per Assets per
Labour Cost Fixed
Employee Employee Employee Employee
Cost Assets
2003 0.68 1.36 0.72 -0.04 -1.38 0.48 0.20
2004 1.04 1.49 -1.36 2.44 0.94 -0.77 1.82
The competitiveness of the construction sector was sustained in 2004 with a marginal
increase of 0.9% in Unit Labour Cost. Added Value per Labour Cost declined by 1.4%
while Labour Cost per Employee grew by 2.4%.
Productivity Performance of the Construction Sector 55
Added Value per Fixed Asset measures the degree of utilization of fixed assets and it is
defined as added value generated per RM of fixed assets. In 2004, Added Value per Fixed
Assets grew by 1.8% from 2.50 to 2.55. The performance was attributed to the improvement
in demand for residential and non-residential properties. The construction sector can
improve their Capital Productivity performance by embarking on the efficient utilization of
assets in construction activity and enhancing the capability of their management system.
Capital Intensity indicates the amount of fixed assets allocated to each employee. This
ratio is used to measure whether an industry is relatively capital-intensive or labour-
intensive. Less investment in fixed assets were made in 2004 due to the slow performance
in the sector and the completion of several projects especially in civil engineering sub-sector
during the year. Fixed Assets per Employee declined by 0.8%.
Residential Sub-sector
Residential sub-sector includes the construction of entire dwellings such as houses, flats
and apartments. In 2004 the residential sub-sector accounted for RM10.4 million or 29.0%
of the share to total output of the construction sector. This sub-sector also contributed 29.1%
and 31.1% in terms of added value and employment respectively (Table 7.1).
Table 7.1. Total Output, Added Value and Employment of the Residential Sub-sector
In 2004, Added Value per Employee of the residential sub-sector increased by 2.0%
while Total Output per Employee increased by 3.4% (Figure 7.2). The stimulus package
introduced by the Government to encourage the purchase of residential properties led to
increase demand and thus enhance sales.
Productivity Performance of the Construction Sector 56
4.00
3.00
2.00
1.00
Percent
0.00
-1.00
-2.00
-3.00
Added Added
Added Total Labour Fixed
Value per Unit Labour Value per
Value per Output per Cost per Assets per
Labour Cost Fixed
Employee Employee Employee Employee
Cost Assets
2003 1.04 2.10 1.12 -0.08 -2.14 0.71 0.33
2004 1.99 3.38 -0.39 2.39 -0.95 0.33 1.66
In 2004, labour cost competitiveness of the sub-sector sector was sustained as shown by
a marginal increase in Unit Labour Cost by 1.0%. Added Value per Labour Cost decline by
0.4% while Labour Cost per Employee grew by 2.4%.
Fixed Assets per Employee for the residential sub-sector recorded a growth of 0.3% in
2004 to RM9,807 from RM9,774 in 2003 while Added Value per Fixed Assets grew by
1.7%. The performances were attributed by the continuous investment in fixed assets in the
sub-sector. The increased of housing approvals, advertising permit and new sales also
supported the good performance of the respective indicators.
Non-residential Sub-sector
Table 7.2. Total Output, Added Value and Employment of the Non-residential Sub-sector
6.00
4.00
2.00
Percent
0.00
-2.00
-4.00
-6.00
Added Added
Added Total Labour Fixed
Value per Unit Labour Value per
Value per Output per Cost per Assets per
Labour Cost Fixed
Employee Employee Employee Employee
Cost Assets
2003 0.74 1.48 0.80 -0.06 -1.52 0.51 0.23
2004 0.23 1.34 -1.85 2.12 0.76 5.11 -4.65
Labour cost competitiveness of the sub-sector sector was sustained in 2004 as shown by
a marginal increase of 0.8% in Unit Labour Cost. Added Value per Labour Cost grew by
1.8% while Labour Cost per Employee grew by 2.1%.
Fixed Assets per Employee for the non-residential sub-sector recorded a growth of 5.1%
in 2004 as investments were made and new machines and equipment were set up for new
projects. However, Added Value per Fixed Assets decline at 4.7% due to the gestation
period that occurred and the equipment that not fully utilized.
Productivity Performance of the Construction Sector 58
In 2004, the civil engineering remained the largest contributor to total output, added
value and employment of the construction sector. This sub-sector constituted 45.2% to total
output share, 44.4% in terms of added value share and 37.5% in employment share (Table
7.3).
Table 7.3. Total Output, Added Value and Employment of the Civil Engineering Sub-sector
The sub-sector registered a moderate growth in Added Value per Employee of 0.9%
valued at RM38,392 and also recorded a growth in Total Output per Employee of 3.9%
(Figure 7.4). The increased was due to the implementation of new and on-going
infrastructure projects.
Capital intensity or Fixed Assets per Employee recorded a decline of 4.6% in 2004. This
shows that the sub-sector still depends on the labour-intensive methods. However, Added
Value per Fixed Assets grew by 5.7% that was due to the completion of construction
projects that highly utilized the existing fixed assets.
Productivity Performance of the Construction Sector 59
Figure 7.4. Productivity Indicators for the Civil Engineering Sub-sector (Growth %)
8.00
6.00
4.00
2.00
Percent
0.00
-2.00
-4.00
-6.00
Added Added
Added Total Labour Fixed
Value per Unit Labour Value per
Value per Output per Cost per Assets per
Labour Cost Fixed
Employee Employee Employee Employee
Cost Assets
2003 0.45 0.87 0.43 0.02 -0.84 0.41 0.03
2004 0.87 3.88 -1.70 2.62 -1.21 -4.57 5.70
CONCLUSION
The performance of the construction sector is expected to improve in 2006. The sector is
expected to benefit from the development of housing sector as outlined in 9 th Malaysia Plan,
under Thrust Four (Chapter 21): Providing Quality Houses and Urban Services. The
housing sector will continue to focus on the provision of adequate, affordable and quality
houses for all Malaysians. Emphasis will continue be given to the development of low- and
low-medium cost houses at suitable locations provided with adequate public amenities to
meet the needs of low income group. The strategic thrusts of housing development during
the Plan period will be as follows:
Providing adequate, affordable and quality houses, particularly to meet the needs of
the low-income group, with greater emphasis on appropriate locations and conducive
Reviewing laws and regulations to ensure proper development of the housing sector;
living environment;
In the 2006 Budget as announced by the Hon. Prime Minister, under the Fourth
Strategy: Enhancing The Well-Being and Quality of Life of the Rakyat Providing
Comfortable Homes, the Government proposed that capital expenditure on moulds to
manufacture IBS components be given accelerated capital allowance to be claimed for 3
years. This measure will reduce the cost of building components such as pillars, beams,
walls and floors. The Government will ensure that the IBS components meet the Malaysia
Standard MS 1064. The adoption of the standard will ensure quality and control of
construction costs.
Productivity Performance of the Construction Sector 60
To improve the productivity and competitiveness, the sector needs to embark on the
following initiatives:
The competitive cost of doing business that can be achieved by improving the
Less dependency on foreign labour and develop high skilled local manpower for the
capacity and capability of the company;
Nurturing an innovative mindset in carrying out R&D and adopting benchmark and
practical fiscal policy and increase exports;
best practices.
Tendering On-line or On-the-line Does It Matter? 61
Malaysian Construction Research Journal; Vol.1|No.1|2007
Abstract
This paper examines the validity of the claim through an analysis of an IT-led construction
tendering initiative soon to be implemented in Malaysia. The National ETendering Imperative
(NETi) is a national initiative that integrates and bridges every process and component of the
entire construction tendering supply chain onto an electronic or digital medium in the hope
that it can then transcend geographical, time, economical and people-based error and
inefficiency barriers, making it faster, more efficient and more profitable for all the players in
the industry. Online or e-tendering is a good test subject for validating the IT/Business
connection, because it has met with a mix of responses in real-life implementation recently
like in the USA, UK, Japan, Singapore, Hong Kong and other countries. In some, like in Hong
Kong, the program itself had changed fundamentally after strong industry consensus, in
others like with the CALSEC program (Japan), it has been touted as a new patch for inter-
country collaboration with the introduction of new standards and protocols. Some had been
industry/contractor driven (Singapore), others client driven (e.g. Tesco UK). Professional
associations has not been quiet either, like their outright rejection of new reverse auctions
systems in Canada and the UK or applauding budding new collaborative units like in Japan,
Hong Kong and Malaysia (NeTI) or for others, close-knit communities of contractor-suppliers
(USA). By highlighting the need for good governance, one of the focus areas of the paper is
the examination of how the legal, business and process protocols combine and integrate in e-
tendering. It examines whether there area any universal trends in a unified tendering protocol
and formal control if projects are tendered electronically across borders.
INTRODUCTION
the introduction of new standards and protocols. Some had been industry/contractor driven
(Singapore), others client driven (e.g. Tesco UK). Professional associations has not been
quiet either, like their outright rejection of new reverse auctions systems in Canada and the
UK or applauding budding new collaborative units like in Japan, Hong Kong and Malaysia
(NeTI) or for others, close knit communities of contractor-suppliers (USA). Quite an array
of responses, not even mentioning new calls for a review of the tendering process itself - its
laws, policies and standards, in light of a new-found awareness of the possibilities of
increased transparency, efficiency and value-selections in the construction procurement
process made possible with IT. Perhaps after all, we have found a new elixir or have we
really?
INDUSTRY BACKGROUND
Now is a good time as any for a revival of enhanced levels of transparency, efficiency
and collaboration in construction. There is beginning to be a gradual liberation of global
trade in this industry brought out by the new developments in the General Agreement on
Tariffs and Trade (GATT) and the General Agreement of Trade in Services (GATS) from
1993 onwards. There have also been new developments in easing trade restrictions like a
reform in construction procurement by over 20 countries agreeing towards a Government
Procurement Agreement initiative which came into force in 1996. Nevertheless, the
objectives of the tender system in construction even in the global context remains
unchanged, that is to devise a most efficient framework to select capable contractors who
can complete the construction project within set parameters of time, money and quality.
Preparing tendering documentation and conducting tenders for employers and obtaining,
processing and submitting tenders for contractors are costly. For contractors, the costs
associated with preparing and submitting a tender will go to waste if their tenders are
rejected. Studies conducted by Holt, etc. (1996) and Pasquire and Collins (1996) further
showed that contractors would have invested their own resources in preparing and
submitting items like brochures, presentation materials, estimating resources, administration
and clerical assistance. These can be significant. They would put an extra strain against
contractors finances, especially on those whom already would have to cut down their profit
margins when tendering competitively for a project (Williamson (1981), Alsagoff (1996),
Walker and Chau (1999), Bridge (1999)). Sometimes, in order to ensure selection in the face
of the risks of abortive tender costs, some contractors may even go as far as conducting
Tendering On-line or On-the-line Does It Matter? 63
themselves in underhanded and sometimes illegal practices (CBM Construction Sdn. Bhd. v.
Buildcon And Development Sdn. Bhd.).
For employers, factors other than tendering costs may be important. Apart from the
employers belief that the lowest prices can be only obtained through a competitive process,
there are other aspects that must be considered in selecting a contractor for his project. For
some employers, especially those linked with government authorities or large corporations,
accountability may be paramount. If tenders are assessed through negotiations only, it is
difficult for the employers agents or his employees to show that the negotiations have been
conducted purely objectively and that the best package has been secured through this
process. Transparency becomes more important in situations where the contract has been
substituted or novated, or where there are further requirements to show that the employer
has discharged an unprejudiced selection of replacement contractors (see circumstances in
Government Of The State Of Selangor v. Central Lorry Service & Construction Ltd.)
In addition to these legacies, there have great difficulties to restrict uncompetitive tactics
practised by contractors themselves. For contractors, the submission of a cover price and bid
peddling is as much a norm as it is a strategic manoeuvre. An industry study in Australia
conducted by Ray et. al (1999) concluded that a majority of employers considers bid
peddling as important to obtain a competitive price from a preferred contractor. In another
study in the UK, Pasquire and Collins (1997) found a similar majority showing support for
cover pricing practices and concluded that this majority felt that it was necessary to avoid
offending the employer or prejudice the contractors future opportunities.
The Malaysian Statistics reported (MER, 200) that there are over 100,000 dependent
businesses in the Malaysian construction industry. Even so, construction-based competitive
based improvements are not relegated to these businesses it affects directly the
competitiveness of the nation. It has often been said that pushing demand from the
construction sector directly benefits other sectors. Some statistics come to support this
contention, For example, there is a correlation between the value added generated by the
construction industry and the competitiveness index of a nation. Data from the World
Economic Report 1999, the International Institute for Management Development,
Switzerland (IMD) and the World Economic Forum (WEF) shows (Table 1):
Table 1. WEF Economics Report (1999)
Malaysia Singapore Australia Hong Kong
Basing itself on this premise, for Malaysia, in OPP3 (Rancangan Malaysia ke-8
RM8), a strategic economic plan tabled for the formation of a Dasar Wawasan Negara
(National Strategy), the Malaysian government highlighted the need to increase the
competitiveness of national industries. According to OPP3, such improvements can be
implemented by the use of high technology that generates higher value added and
productivity, promoting the awareness for a knowledge-driven society and to stimulate more
demand for industries, both locally and internationally.
Tendering, although appearing elementary at first, has had its share of implementation
problems. In Malaysia, over 90% of the total number of projects awarded during the past 10
years are for those valued under RM20 million. These projects often become the target of
unethical bid practices in the construction industry. It is a truism as evidenced in numerous
industry researches that for contractors, the submission of a cover price and bid peddling is
as much a norm as it is a strategic manoeuvre. An industry study in Australia conducted by
Ray et. al (1999) concluded that a majority of employers considers bid peddling as
important to obtain a competitive price from a preferred contractor. In another study in the
UK, Pasquire and Collins (1997) found a similar majority showing support for cover pricing
practices and concluded that this majority felt that it was necessary to maintain an amicable
relationship with the employer otherwise prejudice the contractors future opportunities.
Malaysia, as is many other countries, is not immune to these problems. The effect of these
practices, just taking an approximate calculation could cost taxpayers close to RM200
million per year even if there is a 1% artificial wastage in the tender process.
In response to these problems, in a sitting of the 29th August 2001, the Malaysian
Cabinet highlighted an immediate need to enhance efficiency in managing construction
projects that had systematically resulted in procedural delays and late implementation of
capital injection into the economy. Further to this, the Cabinet called for a study of
contractors in a Cabinet letter ref. PM(R)11880/A/94 Jld. 2 dated 9 th September 2001.
Subsequently, in this study,, the Ministry of Finance has highlighted the underlying cause of
the problems lies in the lack of specific integration policies in the tendering value chain in
the Malaysian construction industry. It then called for a need for a different approach to
overcome fundamental problems in the production, posting, retrieval, submission and
analysis of tender documents that must be addressed by the Malaysian construction industry
as one step towards promoting better integration into what is considered a fragmented
sector of the general economy.
During 1980-85 the construction industry contributed 4.9% to the nations GDP, in
1986-90 this reduced to 3.5% before recovering to 4.4% in 1996-98. The average annual
growth was 2.9% in 1980-85, 4.7% during 1986-90 and increased to 13.0% during 1991-95
before declining at 8.3% during 1996-98. At the peak of the economic crisis, the
construction industry contracted by more than 20% (MER, 2000).
Tendering On-line or On-the-line Does It Matter? 65
Although the sector's share of the GDP contribution was small in terms of value-added
over, it supported extensive upstream and downstream linkages. Demand for construction
was driven by increasing demand for capacity and efficiency as is evident in the share of
employment the construction sector. In 1991-95, the sector's employment enjoyed a growth
of 11.2% before declining by 2.9% in 1991-95. The sector therefore accounted for 7.6%
share of total employment in 1991-95 and 9.5% share in 1996-98. In term of productivity,
the GDP per employee grew at 1.6% in 1991-95 before declining by 5.6% in 1996-98 (MER,
2000).
Even so, the added value per employee for the construction sector was calculated to be
at 10.6% in 1988-93 which is considered to be relatively low. An increase of 12.2% fixed
asset per employee during the same period indicated a shift from being labour-intensive to
capital-intensive construction operations. This means that there is a capacity for inducing
capital to be spent in investments like IT to increase productivity per worker from these low
levels to those comparable with other sectors.
With a clear potential for economic improvement in the sector, coupled with a general
drive for IT related knowledge intensive government policy, it is easy therefore to mount a
nationwide call for the Malaysian government to inject a vision of IT for the construction
industry. The advances that are forecast by this vision is for Information Technology (IT) to
provide for significant improvements through dramatic reductions in cost and speed,
increases in performance and functionality of such magnitude as to provide opportunities
that cannot be fully conceived at this time. This is similar to the ways how the telephone
made possible new ways to run organisations that were not foreseen at the time it was first
introduced; it is claimed.
Technology adoption and utilization in construction for Malaysia is evolving from the
infancy stage and poised to enter the growth stage in the coming years. According to an
IT Masterplan for Malaysia (ISIS, 2002), as the Malaysia government progress to the new
phase of ICT deployment, it is focusing more and more on the systematic alignment of
people, policies, processes and technology. The technology investment constitute only the
small portion of the total investment in the initiative, as more resources and time are needed
for the soft elements e.g. policies, skills, culture, governance. Due to the magnitude and
interest in ICT as a key driver and differentiator in the Malaysian ICT Agenda Context over
the last 5 years, as evidenced in the examples of successes like the MSC Project, Broadband
and ADSL penetration, ICT has emerged as a popular and reliable business enabler and
transformer. However, many have yet to feel the impact of various eGovernment initiatives.
A survey conducted by the government, (SIRIM, 2003) found that the majority of the
respondents are not aware of ongoing eGovernment initiatives such as eSPKB, PMS2
(SPP2) and ePerolehan. This comes with a realization that it is important for educating and
sensitizing organizational members on the initiatives to better prepare them to leverage the
eGovernment initiatives.
represents the intellectual capital of the organization and its value is significantly increased
if it is easily accessible organization-wide (information at the fingertips of the right people
at the right time). Paperwork can be reduced further if staff can access share information
digitally. Staff can enter the data/information once and can be accessible many times across
the organizations. Also, research and information gathering can be done with ease as the
repository of information can be accessed and retrieved with greater efficiency and
effectiveness.
Therefore we are left with policy, process, people and technology variables in the hunt
for the three main objectives of construction tendering (Diagram 2). IT solutions typically
focus on the process (Workflow re-engineering) and Technology (security, architecture,
etc.) but not the qualitative measures of Policy (laws, regulations, standards, etc) and the
People (users, knowledge implementation, trust factor, etc.)
Government electronic
Country Functions
procurement system
FACNET
USA FACNET applies to open Announcing governmental procurement
procurement processes if simplified opportunities
procurement process requirement is Providing related governmental procurement
met
information
Accepting bidding electronically
Processing online payment towards contractors
Collecting related governmental procurement
information
MERX
Canada MERX applies to open procurement With built-in procurement matching system,
processes and contractors can be informed immediately with
some limited procurement appropriate procurement cases and receiving
processes related information
Accepting bidding electronically
Providing documents to contractors, confirming
orders online and inquiring buyers ordering history
Transigo
Australia Transigo applies to open and limited
procurement processes
GITIS
Singapore GITIS applies to all new Providing online procurement information, bidding
procurement information accessing processing, government procurement handbook and
and bidding submitting services, application from government procurement contractor
including open, selected and limited registration
procurement processes
JETRO
Japan JETRO applies to open and limited Supplying information such as government procurement
procurement processes announcement, item category, construction category,
procurement institution and location announcement
CALSEC publication date, application deadline, bidding winner
A scalable and replicable private- announcement dates and procurement dates
public architecture for online
tendering in construction
Government electronic
Country Functions
procurement system
Moreover, despite a doubling of computer ownership in the last five years, studies have
showed (SIRIM, 2003) that local contractors had simply used IT to automate existing
processes. Perhaps in the fragmented nature of the construction industry at present, no
single organisation can dictate and therefore be responsible for establishing and maintaining
the necessary communication networks for a construction project. Consequently, this
industry sector is faced with ineffective communication and information processes, which
have inadvertently contributed to project cost and time overruns.
Why? One answer, which came to light during a national survey commissioned by the
Malaysian Economic Planning Unit (SIRIM, 2003) was that although over 80% of the
construction industry had said that they cannot manage without IT and that IT
contributed significantly to their operations, over 90% of respondents wanted the
Malaysian Government to take the lead in strategic directions and applications. A Top-
Down implementation policy was also favoured by the respondents in the Malaysian
construction sector.
These findings show that the Malaysian construction sector differs somewhat in its
readiness for e-commerce and full scale IT implementation. While research in Australia by
Love, et. al (2001) suggested behavioural barriers must be overcome as a first priority for
their Australian counterparts, other research focussed on strategic awareness for example
Cheng et. al. (2000) (re-examiniation of business relationships), Love and Gunasekaran
(1997) supply chain collaboration evaluations, Alsagoff (2001) suggesting project
coalition buy-in and Gulati (1999) who suggested trust, interdependence and bargaining
power.
Instead, the Malaysian study has given the government an affirmative action to lead the
construction industry in IT adoption. It enables the government to feel the pulse of the
industry and hence becoming more responsive to industry shifts. There seems to be an
underlying awareness that todays IT enables the industry to become more networked by
providing the possibilities to communicate, coordinate and collaborate with external
stakeholders with greater efficiency.
Following the needs of the industry, a clear direction, for instance the issue of A
GOVERNMENT DIRECTIVE from the government is necessary. For its successful
implementation, initiatives shall then take the micro-projects approach as a strategy, to
Tendering On-line or On-the-line Does It Matter? 69
leverage on an implement-via-use and produce a quick benefit return model. This not only
ensures support, ownership and relevance, but also produces maximized and immediate
returns for the effort.
With these objectives, a taskforce under patronage by the Ministry of Works (MoW or
KKR) Malaysia conceived an initiative for e-tendering or NeTI (National ETendering
Initiative). Taking stock of the industrys needs and national aspirations and armed with
case studies from similar government backed initiatives, the National eTender initiative
(NeTI) promises to integrate and greatly improve on the tedious and multi-faceted tendering
process into a streamlined, progressive and 'intelligent' one by use of procedural
streamlining and technology empowerment. A key business driver, the eTender initiative
will not only serve to consolidate and strengthen the industry and defrayments its value, but
also to provide a sound and manageable basis for standardization, accreditation and
knowledge-based recognition.
With the Construction Industry Development Board (CIDB) and the Public Works
Department (JKR) as its key players, NeTI is a product of the principals of prioritised
projects under the MoW as its mission for
Diagram 2. NeTI
Diagram
as a Collaborative
2. NeTI as anUndertaking
Inter-Agency
Between
Collaborative
Government
Government
Construction
Effort Agencies
Tendering On-line or On-the-line Does It Matter? 70
What distinguishes NeTi from her other international counterparts is that it is designed
to integrate with the Malaysian eGovernment Flagship as a 2nd tier infrastructure to like up
and interface with all other agencies for construction procurement and tenders as well as
project management. By doing this, as illustrated in Diagram 3, NeTi will synthesize all
aspects of pre, during and post tender processing for government projects as well as private-
based projects; providing not only integration but also streamlined processing of all data and
payment directly by the Auditor General Department.
Tendering On-line or On-the-line Does It Matter? 71
Is IT the sole and definitive solution for tendering efficiency in Malaysia? Many have
claimed that efficiency generated vis--vis IT/electronic tendering, for some, coining a
paradigm shift in tendering automation will automatically be an elixir to the ills of the
construction tendering process. Perhaps. Or perhaps not; it is argued that the notion of IT
as a cure-all for tendering is a funnelled utopian vision. Considering that automation will
bring about some improvements, the legacy system of tendering must be re-examined in a
new way if indeed the vision for efficiency can be realised. Transparency and the legal
process cannot be overlooked. Instead, it is suggested here that efficiency in tendering is
first and foremost linked to transparency of the process itself. Transparency or Ethics
has many interpretations. It has been described as rules of conduct, moral principles or
values or principles of right conduct. In tendering, what is viewed as efficiency in a
process must also embody sub-elements of trust, acceptance and adaptability as suggested
by Love, et. al (2001) to infuse some form accepted ethical codes of conduct governing both
the employers and the contractors. These codes should not only be recognised in law but
more practically goes beyond that. They are conditions upon which individuals and
organisation and trusted and respected by those they deal with. Only with trust established
can efficiency be tackled successfully.
No doubt, by and large, tendering ethics are based on the principles of good faith and
good professional practice (C.U.P., 1997, De George, 1995, Donaldson and Werhane, 1996).
At times, they may border into those acts that are otherwise enforceable by law for example
against tendering fraud or corrupt practices. It is clear therefore that the principle means of
incorporating duties of fairness, and hence efficiency, in Malaysia has to be by express
provisions in the contract or under certain government legislation eg. in Chew Chee Sun v.
Public Prosecutor, 1975. Nevertheless, construction tendering is not all in disarray though.
It can just be fundamentally uncontrollable. Take the extreme point tender corruption
and fraud for instance. While it is true to say that corrupt practices and proven frauds are
actionable by law; the treatment for opportunistic tendering tactics is not that
straightforward. There will always be debates on what is considered transparent, ethical
and what is considered as lawful. In law, some guidelines in Richardson v. Silvester
(1873) have been offered as a cornerstone where it has been shown that if an employer has
no intention of letting the contract to the person invited to tender, or to one of a number so
invited, the invitation is clearly fraudulent and an action will lie to recover any tendering
expenses by incurred by the contractor. In short, the tender can be both unethical and
unlawful. Making the process on-line (with IT) does not change it one bit.
Tendering On-line or On-the-line Does It Matter? 72
Does IT make tendering transparent enough that any fraudulent act can be nipped at
the bud? For any tender to be unlawful per se, fraud must be proven. This is constantly a
moot point as evidence of clear fraud in law is always circumspect in most legal
jurisdictions. Otherwise, clear of fraud, unethical conducts although to some may
arguably be transparent may be better described as an abuse of the competitive tendering
process, opportunistic manoeuvres or sometimes as anti-competitive tactics. There are
many examples of these in the day-to-day practice in the construction industry, both by the
employers and also by the contractors like Dutch auctioning, repeated tendering and
negotiated reductions to name a few. IT, with its penchant for instantaneous inter-
location communication may have made matters worst at least a revival of reverse or
Dutch auctions. A variant of the system has been used in a few major projects in Malaysia
like in the Westport project (New Straits Times, 2002). While the response from Malaysia
is lukewarm, elsewhere, Dutch auctions in e-tendering has been met with strong opposition
and views across some construction industries (for example in the UK reported by Wood,
2002 and Pearman, 2002). For others, it may just be another cost-cutting avenue albeit
rightly or wrongly.
There is some reprieve if (some say opportunistic) manoeuvres like Dutch auctions in
construction tendering are carried out too far, though. The law do intervene to aid
contractors by limiting post-tender, forced pricing negotiations. In Ben Bruinsma & Son
Ltd. v. The Corporation of the City of Chatam et. al, the Canadian courts refused to permit
an employer to manipulate a conforming tender by deleting items from the work. By an
action brought on by one of the tenderers, the employers have had to discard all of the
tenders and start again with the new requirements. This point has also been discussed by
Dorter (1996) and Bailey (1999) and further demonstrated in other jurisdictions as well like
in Australia in Hunter Bros v. Brisbane City Council concerning post-tender readjustments
for project manning levels for a refuse collection contract.
Despite a trend for a move towards a stricter legal control of unethical tendering
practices, the Commonwealth and accordingly the Malaysian courts have been reluctant to
imply an straightforward obligation for good faith or good practice outside those in
fiduciary relationships (principal/agent, employer/employee) or where there is an
implication of full disclosure (ubberimae fidae) for instance in insurance contracts. Even so,
case law has some examples where the courts have decided on other means to imply good
practice. In Ooi Kiah Inn Charles & Anor v. Kukuh Maju Industries Sdn. Bhd., the courts
have considered the implications to public policy when deciding on the conducts of the
contracting parties. The courts have also have been referred to issues on non diligence in
conduct where performance was delayed in Kuala Lumpur Landmark Sdn. Bhd. v. Standard
Chartered Bank and have had to decided on common law guidelines for frustration (if not
breach for the evasion of the spirit of the deal). Similarly, in Polygram Records Sdn. Bhd. v.
Search & Anor, the Malaysian courts have considered but rejected arguments that there are
grounds for a covenant of restraint to trade in recording contracts.
All support the line of argument that as the need for transparency is fulfilled, the law,
technology and efficiency will automatically follow.
Tendering On-line or On-the-line Does It Matter? 73
CONCLUSION
Have we found the elusive elixir for construction business ills in e-tendering? Is it in IT?
Well perhaps it is more of a dichotomy of solutions. On the one hand, IT will truly improve
communication and make work more efficient and most importantly make people
collaborate more, judging from the implementation across and within countries recently,
whether it has been a success or not. One outlook is apparent though, the industry is more
and more aware of the need for group effort within itself over and above the fragmented
label it used to carry as participants scour for more business across blurring country borders.
Along these lines, as tendering protocols seems to be merging, what is also clear is that there
is a governing universal trend in a unification of tendering contract standards in its laws and
formal control across countries. Transparency, efficiency and good governance will follow,
in due time of course. On the other hand, there are and always be opportunists. They come
in many guises. For some, they are the rogue clients, as when e-tender means a bigger
catchments net of willing contractors who will undercut each others margins for their
benefit. Reverse auctions or not. For others, they are the insatiable IT vendors, with their
superfluously complex tendering solutions, profiteering from the ever willing customers.
For Malaysia though, having recognized and learnt from others, it is more of implementing
a pathway to better collaboration and more knowledge intensive communities with the
government as catalyst. IT is one but not exclusive source of transparency, efficiency and
value. Perhaps we were looking at the wrong tier solution. IT is a 2nd tier solution as it is a
mere catalyst to 1st tier solutions of better standards, improved communication and more
acceptable laws those are the true elixirs to business problems, it is submitted.
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Guide to Authors 76
Guide to Authors
Aims and Scope
The Malaysian Construction Research Journal (MCRJ) is the journal dedicated to the
documentation of R&D achievements and technological development relevant to the
construction industry within Malaysia and elsewhere in the world. It is a collation of
research papers and other academic publications produced by researchers, practitioners,
industrialists, academicians, and all those involved in the construction industry. The papers
cover a wide spectrum encompassing building technology, materials science, information
technology, environment, quality, economics and many relevant disciplines that can
contribute to the enhancement of knowledge in the construction field. The MCRJ aspire to
become the premier communication media amongst knowledge professionals in the
construction industry and shall hopefully, breach the knowledge gap currently prevalent
between and amongst the knowledge producers and the construction practitioners.
Articles submitted will be reviewed and accepted on the understanding that they have
not been published elsewhere. The authors have to fill the Declaration of the Authors form
and return the form via fax to the secretariat. The length of articles should be between 3,500
and 8,000 words or approximately 8 15 printed pages (final version). The manuscripts
should be written in English or Bahasa Melayu an abstract in English must be included. The
original manuscript should be typed one sided, single-spacing, single column with font of 10
point (Times New Roman). Paper size should be of Executive (18.42 cm x 26.67 cm) with 2
cm margins on the left, right and bottom and 3 cm for the top. Authors can submit the
manuscript:
By website to http://www.mcrjcidb.com.my/
Authors name (full name): Arial Bold, 9pt. should follow below the title.
1
Jamalodin Noorzaei , Mohd. Saleh Jaafar, Abdul Waleed Thanoon, Wong Jern Nee
Affiliation (including post codes): Arial, 9pt. Use numbers to indicate affiliations.
1
Department of Civil Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM,
Serdang, Selangor, Malaysia
Abstract: Arial Bold, 9pt. Left and right indent 0.25 inch.
Keywords: Arial Bold, 9pt. Left and right indent 0.25 inch.
Keywords: Cooling tower; Finite element code; Folded plate; Semiloof shell; Semiloof beam
Body Text: Times New Roman, 11 pt. All paragraph must be differenciate by .25inch tab.
Figures: Figures should be in box with line width .5pt. All illustrations and photographs must
be numbered consecutively as it appears in the text and accompanied with appropriate
captions below them.
Figures caption: Arial Bold + Arial, 9pt. should be written below the figures.
39
C
o
36
Attic temperature
33
30
27
24
21
18
15
23 25 27 29 31 33 35 37
Outdoor tem perature oC
Predicted tem perature before sealing the attic
Predicted tem perature after sealing the attic
Table caption: Arial Bold + Arial, 9pt. Caption should be written above the table.
pH 5.5-9.0 6.5-9.0
(Source: Twort et al. 1985; MWA,1994)
Reference: Times New Roman, 11pt. Left indent .25inch, first line left indent .25inch. Reference
should be cited in the text as follows: Berdahl and Bretz (1997) found or (Bower et al. 1998).
References should be listed in alphabetical order, on separate sheets from the text. In the list of
References, the titles of periodicals should be given in full, while for books should state the title, place
of publication, name of publisher, and indication of edition.
Journal
Sze, K. Y. (1994) Simple Semi-Loof Element for Analyzing Folded-Plate Structures. Journal
of Engineering Mechanics, 120(1):120-134.
Books
Skumatz, L. A. (1993) Variable rate for municipal solid waste: implementation, experience,
economics and legislation. Los Angeles: Reason Foundation,157 pp.
Thesis
Wong, A. H. H. (1993) Susceptibility to soft rot decay in copper-chrome-arsenic treated and
untreated Malaysian hardwoods. Ph.D. Thesis, University of Oxford. 341 pp.
Chapter in book
Johan, R. (1999) Fire management plan for the peat swamp forest reserve of north
Selangor and Pahang. In Chin T.Y. and Havmoller, P. (eds) Sustainable Management
of Peat Swamp Forests in Peninsular Malaysia Vol II: Impacts. Kuala Lumpur: Forestry
Department Malaysia, 81-147.
Proceedings
Siti Hawa, H., Yong, C. B. and Wan Hamidon W. B. (2004) Butt joint in dry board as crack
nd
arrester. Proceeding of 22 Conference of ASEAN Federation of Engineering
Organisation (CAFEO 22). Myanmar, 55-64.
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22
31
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