3S Structural Engineering Design Manual - Revision 5 - Pgs 1 To 52
3S Structural Engineering Design Manual - Revision 5 - Pgs 1 To 52
3S Structural Engineering Design Manual - Revision 5 - Pgs 1 To 52
System
3S Structural Engineering
Design Manual
Revision 5
COPYRIGHT
All rights reserved. No part of the information contained in this document may be reproduced or copied
in any form or by any means without written permission from Dincel Construction System Pty Ltd
DISCLAIMER
The information contained in this document is intended for the use of suitably qualified and experienced
structural engineers. This information is not intended to replace design calculations or analysis normally
associated with the design and specification of buildings and their components. The information
contained in this document is not project specific. Structural engineers are required to assess
construction site conditions and provide design/details and appropriate safe work method statements
accordingly. Dincel Construction System Pty Ltd accepts no liability for any circumstances arising from
the failure of a specifier or user of any part of Dincel Construction System to obtain appropriate project
specific professional advice about its use and installation or from failure to adhere to the requirements of
appropriate Standards, Codes of Practice, Worker Health & Safety Act and relevant Building Codes.
Revision 3 The 2005 version was certified by the University of New South
February 2007 Wales following company name change.
Retaining Walls Basement walls below permanent water table, earth retaining,
mining, erosion control, river embankment protection, sea walls.
Storage Tanks Water (detention, retention, stormwater pits), fish farming tanks,
waste water, sewerage, sludge, petrol, manure, grain and
contaminated soil.
Dincel forms are precise factory manufactured forms. The formwork’s defective
work tolerances built in the concrete codes for design purposes are not relevant
for Dincel forms.
The DINCEL DESIGN TOOL Zone Method for Dincel Wall/Blade Columns
based on the EuroCode which is a more reliable design methodology in
comparison to AS3600-2009.
The DINCEL DESIGN TOOL calculates the ultimate strength and various fire
ratings for fire on one side or all sides which offer better accuracy and
significantly minimises design time for engineers.
Refer to the Dincel website for “Information for Design Engineers” for further
information.
Dincel Wall complies with the requirements of the Building Code of Australia,
Australian AS3600-2009, EuroCode 2 and American ACI318.
Dincel Walls are preferred by the industry because they are lightweight, flexible-
versatile, easy and fast to install. Eliminates the majority of occupational, health
and safety issues. Refer Dincel’s website “Dincel Solution for Construction
Safety”.
3.2 Design of Axial Loaded Walls Subject to Vertical Loads for Sway
Prevented Structures
3.3 200mm Dincel Wall Design for Flexural Bending Strength and Deep
Beams
List of References
Appendices
This manual has been developed as a technical reference for design Engineers and
other similar building professionals. It is not intended to replace the services and
expert advice of suitably qualified structural design Engineers. Whilst care has been
taken in the preparation of this design manual, errors and / or omissions may occur.
Dincel Construction System Pty Ltd will not accept any responsibility for any
consequence arising from the use of this design manual.
This design manual covers the following applications for structural elements within
building structures.
Structural engineers may also refer to the Dincel Construction Manual for Designers
and Builders for typical examples of detailing including steel reinforcement.
One of the most important building materials in the construction industry is concrete.
Concrete based on Portland cement has the following attributes:
Inadequate attention or allowance for any these factors will result in the concrete
cracking. This cracking is unavoidable in the majority of cases when using concrete
based on Portland cement.
The inevitable fact is that concrete cracks. Cracks allow the ingress of water, oxygen,
carbon dioxide, chloride and sulphate compounds. The ingress of these items can
induce corrosion of the steel reinforcement that in turn leads to spalling of the concrete
and the loss of concrete strength.
Therefore the key concerns are the degradation of the concrete matrix and presence of
steel reinforcement and the cracking of the concrete elements. Concrete has low
tensile strength and low ductility, reinforcement is therefore used to enhance
concrete’s inherent low tensile strength and ductility. This is especially the case due to
external lateral forces such as wind, earthquake, liquid or earth pressure, flexural
stresses by out-of-plane vertical loads or resultant tensile stress cracks due to
shrinkage and temperature effects during its service life.
The majority of reinforcement is placed at the external faces of concrete slabs and
walls to resist the applied loads. This requirement places the reinforcement closer to
the concrete face in which most of the cracking occurs, hence the corrosion of the
reinforcement. Therefore the quality and permeability of the concrete along with
concrete cover affects the durability and hence service life of the concrete structure.
With the need to reinforce concrete structures, the issue is to control concrete
cracking. This will in turn provide protection to the reinforcement, reduce or eliminate
the risk of water / air leakage to the human living environment and to avoid unsightly
concrete cracking.
Formwork Movement
The conventional formwork movement ’s formwork is factory
depends on the quality of formwork made, precise dimensions which are
and installation methodology. not reliant on the workmanship
skills.
FIGURE 1
FIGURE 1
(a) Walls associated with in-situ reinforced or post-tensioned concrete floors poured
on removable formwork.
(b) Walls associated with precast concrete floor systems. This way,
must be poured prior to placement of precast planks.
The time of loading in this case may be limited to a minimum of two days after
the concreting of . The concrete compressive strength to be
specified by the design engineer to suit precast flooring installation.
(c) Walls subjected to lateral loads, i.e., earthquake, soil/liquid pressure, high
wind loading (cases where allowable tensile strength is exceeded). Refer
design engineer to specify the design strength for these cases.
(a) Walls used for cladding (e.g. similar to steel portals with pre-cast walling)
purposes f’c 28 days = 20 Mpa is considered adequate. Design engineer to
check final design stresses on wall panels depending on the panel length/depth
ratios and wind loading.
(b) Walls replacing tilt-up methodology if roof rafters are propped in such a way that
loadings are not exerted onto wet concrete wall panels, the design criteria of (a)
above will be applicable. Otherwise the concrete strength at the time of load
application as early as 2 days after concrete pouring is to be specified by the
design engineer.
200mm 110mm
2 2
Per cubic metre of concrete 5.5m of wall area 9.5m of wall area
3
Per square metre of wall area 0.182m of concrete 0.105m3 of concrete
Concrete Pump Nozzle with internal diameter of 75mm maximum. (100mm nozzle size
Nozzle Size: can be considered provided the concrete flow pressure is controlled).
Dincel adopts the Eurocode2 – Zone Method which is a higher tier and more accurate method in
accordance with Eurocode2 than Table 5.7.2 of AS3600 which is also a table adopted from the
Eurocode.
AS3600/Eurocode’s fire design is based on the spalling values of conventional concrete under a
cellulosic fire curve, with 3% moisture by weight (as recommended by BS EN 1992 – 1 – 2 : 2004
Clause 4.5.1).
At the time of a fire, if the moisture content is greater than this recommended value by the
Eurocode, the spalling will be excessive under cellulosic fire conditions hence premature buckling
and structural failure can happen even under small loads. This is why AS3600 – 2009, Clause
B2.3 states that if any “alternative solution” is to be verified by fire testing, the test load shall be
100% equivalent of the design load (i.e. no product as an alternative solution can be used above
the fire test load).
Can a structural design engineer rely on a fire test report of an alternative solution for the
determination of the fire resistance period for structural adequacy? The answer is NO. This is
because firstly, AS3600, Appendix B, Clause B2.3 and secondly, under real life conditions all
conventional building walls are porous and absorb moisture from the ambient unless they are
protected by impervious membrane type paints having ongoing maintenance. Relative Humidity
(RH) of 90% represents 3% moisture content by weight in any concrete wall, including in-situ,
precast, proprietary concrete walls with porous cladding systems (i.e. magnesium oxide, fibre-
cement or gypsum). Refer Moisture in Concrete by the Cement, Concrete & Aggregates Australia
(http://www.concrete.net.au/publications/pdf/Moisture.pdf - Moisture in Concrete). This means that
the moisture exceeding RH of 90% plus the moisture that already exists in the concrete wall itself
exceeds the limitation given by the Eurocode (BS EN 1992 – 1 – 2 : 2004 Clause 4.5.1) hence
AS3600, Table 5.7.2 is adopted from the Eurocode.
The Dincel concrete mix design (as shown in the above table) aims to have 3% water or slightly
more content where the excess water not required by hydration will be further reduced by capillary
actions of the floor slabs where Dincel walls are placed on. During the life of the structure,
impervious/waterproof Dincel walls (refer CSIRO waterproof Dincel Wall certification) installed in
accordance with the Dincel Construction Manual will avoid any quantity of relative humidity related
moisture entering through the Dincel polymer formwork protection; hence Dincel walls will always
satisfy the Eurocode’s fire spalling design control criteria during the life span required by AS3600.
However, this will be impossible for any other non-Dincel wall unless they are protected by true
membranes with ongoing maintenance so that they are not affected by conditions of RH > 90%.
Engineers need to be aware that all commercial paints, except for true membranes, are porous, i.e.
breathable which are not membranes.
The Building Code of Australia defines the “Deemed to Satisfy” condition – if the concrete structure
can be designed in accordance with AS3600 – Concrete Structures Code. Dincel Wall can be
designed in accordance with AS3600, EuroCode and American Code as verified by the report from
the University of New South Wales. It is an obvious fact that if the Dincel polymer is removed from
its concrete infill, the remaining concrete wall is identical to the prototype defined by the
Eurocode/AS3600.
Structural design engineers should refer to the Dincel website – The Use of AS3600 – 2009
Eurocode for Dincel Walls for further information on this very important topic. (Refer Common
Engineering Questions, Item No: 27)
http://www.dincelconstructionsystem.com/documents/Common%20Engineering%20Questions.pdf
For earthquake design a building structure can accommodate shear walls at stair and
lift shaft locations. These elements are designed by the Structural Engineer to resist
the lateral loads induced by an earthquake event. The remaining major walls within
the building structure including perimeter façade walls and party walls between sole
occupancy units may be designed to support the vertical gravity loads only i.e.; not for
lateral loads. The concrete floors act as diaphragm plate elements to transfer the
lateral forces to the shear walls.
The design engineer can then adopt the appropriate slenderness ‘k’ value depending
upon the adopted design model in relation to AS3600-2009 (Ref. 1). As further
reference, the designer may consider the slenderness values in accordance to
AS3700-2011 (Ref 2) for the determination of effective wall heights also.
The following design methodologies are available for engineers to follow for the design
of concrete wall elements using :
General
In accordance with AS3600 – 2009 a column can be designed as a wall if the longer
dimension of a member of a member is minimum 4 times than the shorter dimension.
It is therefore:
Wall = Blade Column = a vertical element where the minimum cross sectional
wall length is not less than 4 x tw (wall thickness) AS3600-2009 Clause 5.6.2.
The structural design of concrete walls must be carried out in conformance with local
building codes and the applicable concrete design standard. However, Australian
design engineers are not limited to the use of Australian Concrete Structures Code
AS3600 provided their design is based on other recognized building standards.
Notation
Plain Concrete Walls are allowed via AS3600-2009 – Section 11.5 AS3600-2009 – Section 10
Clause 5.3 of AS3600-2009 by For Hwe/tw ≤ 30 with Clause 11.2.1 (a) (ii)
EUROCODE Refer Item 3.2.1.1 and Appendix A of provision
this manual Refer Item 3.2.1.2 of this
manual
Note
Building Code of Australia requires –
(i) Structural walls functioning as fire walls are to be designed with appropriate fire
rating.
(ii) Structural walls not functioning as fire walls but are however carrying a fire
rated building element such as a floor above, the walls must be designed for
minimum appropriate fire rating for the element it is supporting.
For the purposes of fire wall design, wall load limitations are governed by the wall
slenderness in accordance to AS3600, Clause 5.7.2 as a “lower tier” approach which
is adopted from the EuroCode.
AS3600-2009, Clause 5.3 recommends the use of EuroCode (Zone Method) as a
“higher tier” approach.
AS3600, Clause 5.6.2 (b) and its following footnote about double face reinforcement
and vertical bars being restrained can be ignored when EUROCODE ZONE METHOD
is adopted.
The fire wall design is governed by slenderness, load, concrete grade and design
eccentricities.
(a) AS3600-2009, Table 5.7.2 is a lower tier approach which ignores design
eccentricities, concrete grade and only allows two load cases with very high
slenderness ratio of 40. This approach is conservative however in cases of low
grade concrete, low load, high eccentricity and slenderness ratio it can be very
dangerous.
(b) AS3600-2009, Clause 5.3 allows the use of EuroCode which is a higher tier
approach and takes into account all design parameters, i.e. slenderness, applied
load, concrete grade and design eccentricities.
This is a more reliable approach adopted by the Dincel Design Tool.
Page 19 of 74 3S Structural Engineering Design Manual - Revision 5.doc
Design of Concrete Walls
American ACI Standard 318
`
klc klc kl c kl c kl c
≤ 75 ≤ 75 ≤ 100 ≤ 150 ≤ 200
r r
r r r
lc lc lc lc lc
≤ 24 ≤ 25 ≤ 30 ≤ 50 ≤ 65
h h
h h h
h h h Rebar at Rebar at
e ≤ e > e≤ each centre
6 6 6 face
Pu
≤ 0.06 f”c
Ac
For the design of utilising the polymer shell as a formwork with infill
concrete, the design axial strength per metre length of a braced concrete wall in
accordance with section 11.5 of AS3600 is:
Nu = ( t w - 1.2e - 2e a ) 0.6 f ’c
Pnw = lbs. per foot - design axial strength h = 7.36 in - thickness of wall cross-section
Eurocode Model
Nrd = b × hw × fcd,pl × Ø…………….…..BS EN 1992-1-1:2004 Clause 12.6.5.2
AS3600-2009 – Section 11
The design axial strength for per unit length of a braced wall in compression;
ØNu = 0.6 ( tw - 1.2e - 2ea ) 0.6 f'c
This eccentricity is to account for defects related to workmanship issues which require
codes to allow additional eccentricity for the safety factory. Dincel being factory
manufactured with precise dimensions eliminates the defects related to workmanship
issues resulting imperfections in formwork.
EuroCode BS EN 1992-1-1:2004
Nrd = b × hw × fcd,pl × Ø – for ultimate strength axial load capacity.
Ø = the equation for eccentricity including second order effects and normal effects of
creep which is based on the:
The following graph is developed having first order eccentricity equal to tw/6 for all
comparisons. Engineering codes for the EuroCode provides the highest load carrying
capacity because the first order eccentricity is calculated from frame analysis and is
most likely much smaller than the e = tw/6 adopted for comparison purposes in the
following graph.
AS3600, Section 11, Clause 11.7.1 states “Walls shall have a reinforcement ratio ... in
the vertical direction, of not less than the larger of either 0.0015 and the value required
for strength”. It should be noted that the wall design equation of AS3600 Clause
11.5.1 does not include steel reinforcement for strength calculations i.e. the wall
strength is evaluated by the concrete only. This design is conditional to the applied
loads acting within the middle third of the wall thickness / bearing area. This loading
condition is typical to load-bearing type buildings designed in Australia and is
applicable to the design of .
In the internationally recognised American ACI Building Code (Ref 3), Chapter 22.6
states that walls can be designed as plain concrete elements with no reinforcement
provided the wall load(s) are located within the middle third ( emax ≤ tw / 6 ) of the
overall wall thickness ‘ tw ‘ in the same manner as stated above for AS3600. In the
same manner, both the Canadian (Ref 4) and German Code (Ref 5 and 7) and
EuroCode2 (Ref 8) adopt a similar methodology for the design of concrete walls also.
It will be advisable for the designer to read the commentary about unreinforced
wall design by the University of New South Wales located in Appendix B of this
Manual.
The wall construction details as shown on Figure 3, with the exception of Detail A/5 of
Figure 3, ensure the same maximum eccentricity requirement are not exceeded i.e.
emax ≤ tw / 6. As the ACI Building Code, German Building Code and EuroCode allow
for the design of concrete walls without vertical reinforcement with the same
eccentricity conditions for AS3600, it would be deemed acceptable to adopt the same
wall design principal and have no vertical reinforcement.
Further to the above, Section 3.2.4 of this manual also show designs of
unreinforced walls/blade columns by EUROCODE.
References (7) and (8) state that concrete walls subject to compressive stresses can
be designed as unreinforced concrete walls where crack limitation is guaranteed by
improved curing. The general practice of concrete wall construction in the building
industry is by removable forms that provides very little concrete curing. on
the other hand has a permanent, impervious polymer membrane that provides the
ideal curing conditions. Following the pre-requisite of AS3600-2009, the crack widths
that develop within the can be controlled and kept within reasonable
limits as a result of the improved curing along with crack controllers. It is therefore
important to understand the following explanation on extended concrete curing.
The object of curing is to keep the concrete as nearly as saturated as possible until
the original water-filled space in the fresh cement paste has been filled to the desired
extent by the products of cement hydration.
The necessity of curing arises from the fact that cement hydration takes place only in
water-filled capillaries within the concrete. This is why loss of water by evaporation
from these water-filled capillaries must be prevented. In the case of conventionally
formed wall construction, due to early formwork removal, active curing stops nearly
always long before the maximum possible hydration has taken place because of the
above described water evaporation.
If however the water-filled space in fresh concrete is greater than the volume that can
be filled by the products of hydration, greater hydration will occur that will lead to both
a higher compressive and tensile concrete strength along with lower permeability.
It is a known fact that maximum rate hydration can only proceed under conditions of
relatively high saturation - this is why the surrounding air relative humidity of 85% is
vital for the late hardening of concrete. This can only be achieved if the concrete is
protected against evaporation by an impervious membrane that is provided
permanently by .
Therefore, :
Retains the water within the ‘wet concrete wall that promotes hydration of
cement and increase of concrete strength.
Therefore the combined worst case effects for combined shrinkage and thermal
expansion is as follows:
It can be seen from the above shrinkage and thermal expansion calculations
that for the worst possible case of combined shrinkage / thermal effects, there
is no resultant expansion and therefore no need for any special expansion joint
provisions.
Based on the above, one could interpret the Australian Concrete Code requirement for
minimum reinforcement for crack control because of the less than “ideal curing
conditions” that are typically associated with conventional formwork concrete wall
construction.
FIGURE 4
The webs of the components are cored at 150mm centres to horizontally align with
each other during on-site assembly. Approximately 50% of the concrete is monolithic
at the corings of each component. The concrete occurring through the cores of the
component webs interlocks the concrete fill and the polymer component thus creating
composite action between the two materials.
Dincel Construction System Pty Ltd however does not recommend the use of polymer
reinforced design in the case of walls subject to fire unless the polymer is covered by
a non-combustible material. Even though has excellent fire characteristics,
the polymer shell will burn if it is subjected to externally applied fire sources (the
material does not support its own combustion, it requires an externally on going fire
source for itself to burn) resulting in a significant loss of strength provided by the
polymer / concrete composite actions, unless the polymer is protected from fire
sources.
recommends Engineers to design fire walls (such as sole occupancy
corridors, stair walls) and shear walls ignoring the additional capacity provided by the
polymer unless it is covered by a non-combustible material. However where reserve
capacity is required for earthquakes or extreme winds, the contribution of the polymer
design may be included as an additional factor of safety given the extreme
remoteness of a structure experiencing an earthquake or extreme winds at the same
time as a fire. Engineers are to check load combinations provided by codes such as
AS1170 which do not show fire plus earthquake, or wind plus fire, or wind plus
earthquake plus fire load combinations together.
The tensile forces on the composite structural member for uplift loads (i.e.: wind,
earthquake) or horizontal loads (i.e.: shrinkage and thermal effects on concrete) or
impact loads or static loads (i.e.: earth pressure or water pressure) creating flexural
action within a cross-sectional plane of the member are expected to be significantly
resisted by the high tensile capacity of the polymer skin, webs and the additional
stiffness contributed by the services spacers at each face of each module.
Structural adequacy fire rating is no longer based on the wall thickness alone as
referred earlier in the Australian concrete code versions such as AS1480 and
AS3600-2001. The designer is now required to consider slenderness, applied
load, load eccentricities and concrete grade under the AS3600-2009 version.
(a) Lower Tier Method – AS3600, Table 5.7.2 which is an adaptation from the
EuroCode for conservative approximation. This table only provides values for
minimum 120mm walls which do not cover 110mm Dincel Walls (refer detailed
explanation in Dincel’s website, Item No: 27 of “Common Engineering
Questions”).
(b) Higher Tier Method – AS3600, Clause 5.3.3.1(b) by EuroCode BS EN 1992-1-
1:2004. This methodology calculates the ultimate and fire design capacities for
walls less than 120mm and thicker walls/blade columns as well.
The higher tier EuroCode Zone Method adopted by the Dincel Design Tool is a
calculation method to determine the appropriate fire resistance period for a given wall
thickness, wall height, concrete grade, concrete spalling values and first order
eccentricity which is much more reliable than Table 5.7.2 of AS3600-2009.
Slenderness check.
Ultimate strength and fire limit state strengths for:
Mu = A st f sy d ( 1 - 0.6 A st f sy / b d f ’c )
beff : effective width of wall section, with allowance for wall recesses – 1000 mm
Deep beams are advantageous where there is a need to transfer high loads from floor
levels above or to utilise the depth of the wall to span large distances.
The principles of deep beam design are in accordance with AS3600 – 2009, Section
12 – Design of Non-Flexural Members, End Zones and Bearing Surfaces.
When designing deep beams utilising strut tie action it is important to consider the
following:
Check bearing stresses at the supports (refer AS3600 – 2009, Clause 12.6).
Calculate tension tie force in bottom of beam and provide necessary tension zone
reinforcement (refer AS3600 – 2009, Clause 2.2.4).
Calculate compression strut forces – note that typically for an applied UDL at the
top of the wall the maximum compression strut stress will occur above the
support element bearing surface. The compression strut shall be checked in
accordance with AS3600 – 2009, Clause 7.2.3.
Check vertical shear capacity giving consideration to shear plane at Dincel web
element (i.e. Ø 115 holes @ 150 cts vertical). Refer to “Section 3S – 3.5 Vertical
Shear Capacity for 200mm Wall” of this manual.
The design for in-plane horizontal shear stress will be reduced if the Dincel Guide
Track (PG) is used at the base of Dincel Wall. Dincel does not recommend the use of
‘PG’ for this reason. Therefore, we design accounting for the full cross section.
The below formulas can be used in a similar way for future Dincel walls thicker than
200mm.
The design in-plane horizontal shear stress strength of the concrete wall per metre
length of wall is calculated as follows:
τu where -
τu = μ (Asf f sy / sbf + gp / bf) + kco f ’ct
≤ lesser of (0.2 f ’c , 10MPa)
: capacity reduction factor for shear = 0.7
gp = permanent distributed load normal to the shear interface per unit length,
newtons per millimetre (N/mm). For a conservative result gp = 0 is adopted
bf = average width of the shear plane (mm) for 200mm Dincel Wall = 192mm.
Asf = area of fully anchored shear reinforcement crossing the interface (mm2).
f sy = minimum yield strength of reinforcement - 500 MPa
s = spacing of anchored shear reinforcement crossing interface (mm)
f ’ct = characteristic principal tensile strength of the concrete
Refer to Figure 5 for typical shear wall configuration and construction arrangement.
τu = μ (Asf fsy / sbf + gp / bf) + kco f ’ct ≤ lesser of (0.2 f ’c , 10MPa) ………………………………………………… Clause 8.4.3
- design horizontal / longitudinal shear strength per metre length of wall
- model adopted to calculate in-plane shear at the interface of base wall-to-floor.
- it is not possible to produce the tabulated value below if gp = 0 is not adopted.
Designer may adopt gp = 0 for a conservative result or calculate the values below manually for a given gp value. Ast - mm 2 / m
bf = 192 mm f'ct f'c = 0.36 f'c 1/2 at 28 days …. …..Clause 3.1.1.3 N12 - 384 286.00
- characteristic tensile strength of concrete at 28 days N12 - 288 382.00
N12 - 192 573.00
f'ct 25 MPa = 1.80 Mpa f'ct 32 MPa = 2.04 Mpa f'ct 40 MPa = 2.28 Mpa N16 - 384 520.00
N16 - 288 694.00
fsy = 500 Mpa d= length of section adopted under horizontal shear - 1000mm N16 - 192 1042.00
2 2; 2
Asf = area of single reinforcement bar - N12 = 110mm ; N16 = 200mm N20 = 310mm
f'c = characteristic design strength of concrete in MPa as listed below 0.7 - for shear
μ= 0.90 ….. Table 8.4.4 kco = 0.50 ….. Table 8.4.3 Calculation checks
(a) (b) (a) (b)
25.0 25.0 32.0 32.0
Equivalent concrete shear interface area per metre length of wall at wall base-to-floor interface 0.00 0.00 0.00 0.00
2
based on 192mm width × 1000mm length / metre = 192000 mm / metre 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00
s = …. reinforcement spacing, see reinforced
wall tables below
f'c Unreinforced
25.0 120.96
32.0 136.85
40.0 153.00
The below formulas can be used in a similar way for future Dincel Walls thicker than
200mm and with different size of web holes.
The shear stress capacity per metre height of wall is calculated as follows:
τu where -
τu = μ (Asf f sy / sbf + gp / bf) + kco f ’ct
≤ lesser of (0.2 f ’c , 10MPa)
: capacity reduction factor for shear = 0.7
gp = permanent distributed load normal to the shear interface per unit length,
newtons per millimetre (N/mm). In case of vertical shear gp = 0 (e.g. no
prestressing force).
bf = For 200mm Dincel Wall, equivalent width of the shear plane (mm)
accommodating Dincel web holes = 115Ø at 150mm centres = area ÷ length
(i.e. 1m) = 6.67 x (π x1152 ÷ 4) ÷ 1000 = 69.2mm
Asf = area of fully anchored shear reinforcement crossing the interface (mm2).
f sy = minimum yield strength of reinforcement - 500 MPa
s = spacing of anchored shear reinforcement crossing interface (mm)
f ’ct = characteristic principal tensile strength of the concrete
Refer to Figure 5 for typical shear wall configuration and construction arrangement.
This model relies on shear wall elements being sufficiently located throughout the
building structure to resist earthquake induced loads.
The earthquake actions to be considered are clearly defined in AS1170, Part 4, 2007 –
Earthquake Actions in Australia.
The Dincel shear wall elements are designed in accordance with AS3600 – 2009,
Section 11 – Design of Walls and in accordance with Section 3S – 3.4 and 3.5 of this
manual.
All other vertical loads carrying elements that do not resist lateral earthquake loads
must be designed to satisfy the requirements of AS1170.4, Section 5, Earthquake
Design and in particular Clause 5.2.4 – Walls, which requires walls to be restrained at
all floors and anchored at the roof.
In the case of a single length of wall, each end is considered a boundary element.
In the case of a 4 sided wall element such as lift shaft or stair well there are no
boundary elements with the exception of the opening.
Boundary elements shall be provided where the reinforcement within the storey
height is not restrained in accordance with Clause 10.7.4 and the calculated
extreme fibre compressive stress in the wall exceeds 0.15 f’c.
For buildings not more than 4 storeys in height, the above condition is deemed to
be satisfied if additional edge reinforcement consisting of 2N16 bars are provided
at the ends of single length walls (i.e. boundary elements). This would also be
provided around all free sides of an opening.
For buildings greater than 4 storeys we recommend that 4 sided lift shafts/stair
wells be adopted as the primary earthquake lateral load resisting system
eliminating discontinuous edges and minimising extreme fibre compressive
stresses to maximum 0.15 f’c.
The reinforcement ratio pw in the vertical direction shall be not less than 0.0025.
As the theoretical wall thickness for Dincel Wall is 192mm (<200mm), only central
reinforcement is required.
τu = μ (Asf fsy / sbf + gp / bf) + kco f ’ct ≤ lesser of (0.2 f ’c , 10MPa)……………………………… Clause 8.4.3
- design longitudinal shear strength per metre height of wall
- gp = 0 for vertical shear
f'ct 25 MPa = 1.80 Mpa f'ct 32 MPa = 2.04 Mpa f'ct 40 MPa = 2.28 Mpa
fsy = 500 Mpa d= height of section adopted under longitudinal shear - 1000mm
Asf = area of single reinforcement bar - N12 = 110mm 2 ; N16 = 200mm 2; N20 = 310mm 2
f'c = characteristic design strength of concrete in Mpa as listed below 0.7 - for shear
Equivalent concrete shear interface area per metre height of wall based
2
on 6.67 x 115mm diameter holes at 150mm centres - ( b f d ) eqv. / metre = 69245 mm / metre
f'c Unreinforced
25.0 43.62
32.0 49.36
40.0 55.18
Reference 6 Concrete Structures (1998)., Warner R.F., Rangan B.V., Hall A.S.,
Faulkes K.A.
Reference 8 EuroCode2
APPENDIX A
APPENDIX B
tw = 187 mm - wall thickness 0.6 6.000 metres - maximum wall height
k= 0.75 Effective design heights: 0.75 Hw for rotational restraint at end of walls;
Nu ( kN / m) Nu ( kN / m)
e min = 0.05 tw e = tw / 6
f'c 25.0 32.0 40.0 25.0 32.0 40.0
Hw 1.000 1560.36 1997.26 2496.58 1324.74 1695.67 2119.59
(m) 1.125 1554.61 1989.90 2487.38 1318.99 1688.31 2110.38
1.250 1548.18 1981.67 2477.09 1312.56 1680.08 2100.10
1.375 1541.07 1972.57 2465.72 1305.45 1670.98 2088.73
1.500 1533.29 1962.61 2453.26 1297.67 1661.02 2076.27
1.625 1524.83 1951.78 2439.73 1289.21 1650.19 2062.74
1.750 1515.69 1940.09 2425.11 1280.07 1638.49 2048.12
1.875 1505.88 1927.53 2409.41 1270.26 1625.93 2032.42
2.000 1495.39 1914.10 2392.62 1259.77 1612.50 2015.63
2.125 1484.22 1899.80 2374.75 1248.60 1598.21 1997.76
2.250 1472.38 1884.64 2355.80 1236.76 1583.05 1978.81
2.375 1459.86 1868.62 2335.77 1224.24 1567.02 1958.78
2.500 1446.66 1851.72 2314.65 1211.04 1550.13 1937.66
2.625 1432.78 1833.96 2292.46 1197.16 1532.37 1915.46
2.750 1418.23 1815.34 2269.17 1182.61 1513.74 1892.18
2.875 1403.01 1795.85 2244.81 1167.39 1494.25 1867.82
3.000 1387.10 1775.49 2219.36 1151.48 1473.89 1842.37
3.125 1370.52 1754.26 2192.83 1134.90 1452.67 1815.84
3.250 1353.26 1732.17 2165.22 1117.64 1430.58 1788.22
3.375 1335.32 1709.22 2136.52 1099.70 1407.62 1759.53
3.500 1316.71 1685.39 2106.74 1081.09 1383.80 1729.75
3.625 1297.42 1660.70 2075.88 1061.80 1359.11 1698.89
3.750 1277.46 1635.15 2043.93 1041.84 1333.55 1666.94
3.875 1256.82 1608.72 2010.90 1021.20 1307.13 1633.91
4.000 1235.50 1581.43 1976.79 999.88 1279.84 1599.80
4.125 1213.50 1553.28 1941.60 977.88 1251.69 1564.61
4.250 1190.83 1524.26 1905.32 955.21 1222.66 1528.33
4.375 1167.48 1494.37 1867.96 931.86 1192.78 1490.97
4.500 1143.45 1463.62 1829.52 907.83 1162.02 1452.53
4.625 1118.75 1432.00 1790.00 883.13 1130.40 1413.00
4.750 1093.37 1399.51 1749.39 857.75 1097.92 1372.40
4.875 1067.31 1366.16 1707.70 831.69 1064.56 1330.70
5.000 1040.58 1331.94 1664.92 804.96 1030.34 1287.93
5.125 1013.17 1296.85 1621.06 777.55 995.26 1244.07
5.250 985.08 1260.90 1576.13 749.46 959.31 1199.13
5.375 956.31 1224.08 1530.10 720.69 922.49 1153.11
5.500 926.87 1186.40 1483.00 691.25 884.80 1106.00
5.625 896.76 1147.85 1434.81 661.14 846.25 1057.82
5.750 865.96 1108.43 1385.54 630.34 806.84 1008.54
5.875 834.49 1068.15 1335.18 598.87 766.55 958.19
6.000 802.34 1027.00 1283.75 566.72 725.40 906.75
2
ea= ( Hwe ) / 2500 tw - Hwe being effective design wall height in mm
tw = 105 mm - wall thickness 0.6 4.200 metres - maximum wall height
k= 0.75 Effective design heights: 0.75 Hw for rotational restraint at end of walls; 2.800
Nu ( kN / m) Nu ( kN / m)
e min = 0.05 tw e = tw / 6
Hw f'c 25.0 32.0 40.0 25.0 32.0 40.0
1.000 849.73 1087.65 1359.57 717.43 918.31 1147.89
1.100 841.63 1077.28 1346.61 709.33 907.94 1134.93
1.200 832.76 1065.93 1332.41 700.46 896.59 1120.73
1.300 823.11 1053.59 1316.98 690.81 884.24 1105.30
1.400 812.70 1040.26 1300.32 680.40 870.91 1088.64
1.500 801.51 1025.94 1282.42 669.21 856.59 1070.74
1.600 789.56 1010.63 1263.29 657.26 841.29 1051.61
1.700 776.83 994.34 1242.93 644.53 825.00 1031.25
1.800 763.33 977.06 1221.33 631.03 807.72 1009.65
1.900 749.06 958.79 1198.49 616.76 789.45 986.81
2.000 734.01 939.54 1174.42 601.71 770.19 962.74
2.100 718.20 919.30 1149.12 585.90 749.95 937.44
2.200 701.61 898.07 1122.58 569.31 728.72 910.90
2.300 684.26 875.85 1094.81 551.96 706.51 883.13
2.400 666.13 852.64 1065.81 533.83 683.30 854.13
2.500 647.23 828.45 1035.57 514.93 659.11 823.89
2.600 627.56 803.27 1004.09 495.26 633.93 792.41
2.700 607.11 777.11 971.38 474.81 607.76 759.70
2.800 585.90 749.95 937.44 453.60 580.61 725.76
2.900 563.91 721.81 902.26 431.61 552.47 690.58
3.000 541.16 692.68 865.85 408.86 523.34 654.17
3.100 517.63 662.56 828.21 385.33 493.22 616.53
3.200 493.33 631.46 789.33 361.03 462.12 577.65
3.300 468.26 599.37 749.21 335.96 430.03 537.53
3.400 442.41 566.29 707.86 310.11 396.95 496.18
3.500 415.80 532.22 665.28 283.50 362.88 453.60
3.600 388.41 497.17 621.46 256.11 327.83 409.78
3.700 360.26 461.13 576.41 227.96 291.79 364.73
3.800 331.33 424.10 530.13 199.03 254.76 318.45
3.900 301.63 386.08 482.61 169.33 216.74 270.93
4.000 271.16 347.08 433.85 138.86 177.74 222.17
4.100 239.91 307.09 383.86 107.61 137.75 172.18
4.200 207.90 266.11 332.64 75.60 96.77 120.96
2
ea= ( Hwe ) / 2500 tw - Hwe being effective design wall height in mm
Effective Heights: Both ends of wall restrained against roatation; 0.75 Hw or 0.75 L l