b)

The slenderness ratio is the effective length of a column in relation to the least radius of
gyration of its cross-section. If this ratio is not sufficient then buckling can occur.

Column slenderness can be classified as:

 Long or slender column

The length of the column is greater than the critical buckling length. Mechanical failure would
typically occur due to buckling. The behaviour of long columns is dominated by the modulus
of elasticity, which measures a column's resistance to being deformed elastically (non-
permanently) when a force is applied.

 Short column

The length of the column is less than the critical buckling length. Mechanical failure would
typically occur due to shearing.

 Intermediate column

In between the long and short columns, and its behaviour is dominated by the strength limit
of the material. Classification will depend on the column's geometry (its slenderness ratio)
and its material properties (Young's modulus and yield strength). 
Axial Loading

Axial loads and bending moments both cause normal stresses on the column cross-section.
We analyze the normal stresses from these combined loads in the same way that we
analyze the normal stresses due to bending only in a beam, with two exceptions.

 The sum of the normal stresses is now equal to the axial load (Pu), instead of equal to
zero, and
 We sum moments about the centroid of the column cross-section, instead of the centroid
of the compressive stress on the concrete

We calculate the internal forces in a column at ultimate strength just as we do for a beam:

 Assume a strain profile for the column cross-section. Ultimate strength of a column
occurs when the compressive strain in the concrete reaches 0.003, just as for a beam
 Calculate the stresses in the concrete and steel.
 Calculate the stress resultants.
 The sum of the stress resultants is equal to the axial capacity of the column (Pn)
 The sum of the moments caused by each stress resultant about the centroid of the
column is equal to the moment capacity of the column (Mn).

Whereas a beam has only one moment capacity, a column has different axial and moment
capacities for each ratio of Mn / Pn. This ratio is called the eccentricity for the reason
demonstrated in the figure below

Steel Columns

Columns are those structural elements which predominantly carries axial compression in a
structural system. In steel construction, the column is the vertical member which is subjected
to axial load and strut is the inclined member subjected to the same. Steel is a very strong
material but it does lead to slender members. Each and every joint should be checked
against the force which it will experience.

The capacity of a column or a strut to carry axial compression depends on the following
factors generally:

 End conditions – how it is attached to other parts of the structure or foundation.

 Material strength.
 Cross-sectional shape.
 Overall length.
 Manufacturing process.
 The structural concept of the global structure of which it is only a part (i.e. braced,
unbraced, sway frames cantilever etc.).
 The presence of local transverse loading or eccentric axial loading.
 The presence of simultaneously acting bending moment and shear, as in multistory rigid
frames.

Squashing capacity

As in a very small stocky column where the yield stress Py may be applied uniformly over
the whole cross-sectional area. Here the failure occurs when direct axial stress is higher
than the yield stress. This can be averted if the cross-section of column is increased
accordingly

Squashed column

Flexural buckling capacity

As in a slender column where the column deflects laterally about the weaker principal axis
and the failure occurs before the entire cross-section can be loaded to the yield stress Py.

Buckling of column

Torsional buckling capacity

As in an unsymmetrical shape made of thin plate thickness where the member twists about
its longitudinal axis and failure occurs before the section can attain the yield stress Py. This
type of failure is very uncommon and is normally encountered in cold-formed thin sections.

Reinforced Concrete Column

Interaction Diagram

The plot of axial capacity (Pn) vs. moment capacity (Mn) is called an interaction diagram.
Each point on the interaction diagram is associated with a unique strain profile for the
column cross-section. An interaction diagram has three key points, as shown in the figure
below. Each point and each region between the points is discussed below.

Point 1 to Point 2 (compression-controlled failure): The concrete crushes before the tension
steel (layer furthest from the compression face) yields. Moment capacity decreases because
the steel does not reach its full strength.

Point 2 (Balanced failure): A so-called “balanced” failure occurs when the concrete
crushes (εc = -0.003) at the same the tension steel yields (εs = 0.002).

Point 2 to Point 3 (tension-controlled failure): As compression force is applied to the

section, the compression area can increase beyond the area balanced by the tension steel.

Larger compression force leads to larger moment.

Point 3: The column behaves as a beam. The compression area is limited by the area
balanced by the tension steel.

Strength Reduction Factor. The reduced nominal axial capacity (φ Pn) and the reduced
nominal moment capacity (φ Mn) are obtained by calculating the strength reduction factor
(φ) based on the strain in the tension steel (the layer furthest from the compression face).

Max. Axial Capacity. ACI limits the axial force in a column

φPn,max = φ fc Ag − As + f y As (flat portion at top of φMn, φPn curve) Various methods

exist for checking the combined normal stresses due to axial and bending in a column. Two
methods are discussed here:

 Single Point—useful when checking column for only one set of loads
 Multi-point (full interaction diagram) —useful when checking column for multiple sets of
load

Corrosion Resistance

Corrosion of Steel Reinforcement in Concrete -Causes and Protection

The corrosion of steel reinforcement in concrete is complex, but basically it is an

electrochemical reaction similar to that of a simple battery. The composition of mild steel
varies along its length and potential anodic (more negatively charged) and cathodic
(positively charged) sites can be set up at various points.

From the days of yore when the great pyramids of Egypt or the Hanging Garden of Babylon,
were constructed, mankind were in search of a construction material that can withstand the
vagaries of nature, without any maintenance.

In quest of such material, mankind ultimately found a wonder material ‘Portland Cement’.

For the last one and a half century, cement concrete has been extensively used for various
structures which man could dream or conceive of with the misconception that they will last
forever. Most of the failures or non-functioning of the structure to its desired service condition
is mainly attributed to the lack of understanding of the environmental condition nd lack of
proper, systematic and scientific maintenance. Calculate the axial load carrying capacity of
steel and reinforced concrete columns

Valuable assets of a country are created through construction. Construction plays a vital role
in economic development. It is a forerunner activity and hallmark of development process of
any nation.

Steel reinforcement which is used in RCC, though on one side complements the concrete for
its weakness in tension (tensile stress), it also impairs the durability and longevity of
concrete, due to its proneness to corrosion.

Repairs and rehabilitation of concrete structures, which of late has become an activity
comparable to construction itself worldwide, is mostly because deterioration of concrete due
to corrosion of embedded steel.

In the earlier part of this century when the Reinforced Concrete Construction began to be
widely used, replacing almost completely the hitherto used construction materials viz.
Timber, (stone) Masonry and steel sections etc., the life expectation of the R. C. structures
was of the order of 100 years. However, at the turn of century we find these expectations
belied and ironically newer constructions say 20 to 25 years old, show serious deterioration
and distress.

The durability of concrete has become a highly discussed topic in global development. Even
though several factors are responsible for early distress in reinforced concrete structures it is
observed that in majority of cases, it is because of the corrosion of steel.

The corrosion seems to be an all-pervasive phenomenon causing widespread destruction of

all types of structures in all countries across the world and has come to be termed as
‘Cancer’ for concrete.

Ideally speaking, a good concrete is supposed to provide adequate protection to the

embedded steel. This is due to the protective alkaline environment (pH value as high as
12.5) provided by fresh concrete resulting in formation of protective coating on the surface of
the steel, which passivates it from further corrosion.

However, over the passage of time, due to carbonation or ingress of chloride ions, pH value
starts declining slowly and alkaline surrounding of the reinforcement bar is lost, heralding the
corrosion process, which in turn causes cracks and spalling of concrete. It would thus be
realized that the crucial factor giving quality and durability of concrete appears to be its
impermeability, which can be ensured by providing sufficient cement content, low w/c ratio,
complete compaction and curing. The same can be further improved by using proper
admixtures and providing increased concrete cover.

However, these measures are firstly difficult to realize in practice fully and secondly the
same are not found good enough in aggressive environment. Thus, it becomes necessary to
provide additional protection to reinforcement steel, especially because of chloride induced
corrosion (worse than carbonation corrosion) which can develop even in good quality
concrete.

Most of the deterioration of RCC structures is mainly due to corrosion of reinforcement.

Therefore, basic understanding of corrosion technology for both durability of structure and
rehabilitation work is a must.

Steel embedded in hydrating cement paste rapidly forms a thin passivity layer of oxide which
strongly adheres to the underlying steel and gives it complete protection from reaction with
oxygen and water, that is from formation of rust or corrosion. This state of the steel is known
as passivation.

Maintenance of passivation is conditional on an adequately high pH of the pore water in

contact with the passivating layer. Thus, when the low pH front reaches the vicinity of the
surface of the reinforcing steel, the protective oxide film is removed and corrosion can take
place, provided oxygen and moisture necessary for the reactions of corrosion are present.

Causes of Corrosion of Steel Reinforcement in Concrete

Corrosion of steel in concrete is an electrochemical process. The electrochemical potentials

to form the corrosion cells may be generated in two ways:

 Composition cells may be formed when two dissimilar metals are embedded in concrete,
such as steel rebars and aluminum conduit pipes, or when significant variations exist in
surface characteristics of the steel.
 Concentration cells may be formed due to differences in concentration of dissolved ions
near steel, such as alkalies, chlorides, and oxygen.

The differences in electrochemical potential can arise from differences in the environment of
the concrete. Electrochemical cells form also due to a variation in salt concentration in the
pore water or due to a non-uniform access to oxygen.

Thus, one of the two metals (or some parts of the metal when only one metal is present)
becomes anodic and the other cathodic. The fundamental chemical changes occurring at the
anodic and cathodic areas are as follows. Calculate the axial load carrying capacity of steel
and reinforced concrete columns

When there exists a difference in electrical potential along the steel in concrete, an
electrochemical cell is set up: there form anodic and cathodic regions, connected by the
electrolyte in the form of the pore water in the hardened cement paste.

The positively charged ferrous ions Fe++ at the anode pass into solution while the negatively
charged free electrons e– pass through the steel into the cathode where they are absorbed
by the constituents of the electrolyte and combine with water and oxygen to form hydroxyl
ions (OH)–. These travels through the electrolyte and combine with the ferrous ions to form
ferric hydroxide which is converted by further oxidation to rust. The reactions involved are as
follows:

 Anodic reactions
 Cathodic reaction

Carbonation of Embedded Steel

It is recognized that steel embedded in a heavily alkaline medium with pH values from 9
upwards will not rust. During the setting of concrete, cement begins to hydrate, this chemical
reaction between cement and water in the concrete causes calcium hydroxide to be formed
from the cement clinker. This ensures the concrete’s alkalinity, producing a pH value of more
than 12.6 which renders the steel surface passive.

Protection of the reinforcement from corrosion is thus provided by the alkalinity of the
concrete, which leads to passivation of the steel. The reserve of calcium hydroxide is very
high, so there is no need to expect steel corrosion even when water penetrates to the
reinforcement of the concrete. because of this, even the occurrence of small cracks (up to
0.1 mm in width) or blemishes in the concrete need not necessarily lead to damage.

Fig: Carbonation leads to the general corrosion along the full length of the bar.

The above figure shows the first outward signs of general corrosion taking place is surface
cracking of the concrete along the line of the steel.

The above fig. shows that as the corrosion proceeds, the concrete will spall away completely
to expose the steel.
Environmental influences and carbon dioxide in particular, will reduce the concrete’s pH
value (carbonation) and thus removed the passivating effect, in conjunction with existing
humidity, the result is corrosion of the reinforcement.

Carbonation is the effect of CO2 from the atmosphere reacting with alkaline component in
concrete Ca(OH)2 in the presence of moisture thereby converting the calcium hydroxide to
CaCO3. The calcium carbonate is slightly soluble in water.

The pH value of the pore water is generally between 12.5 to 13.5 but due to carbonation the
pH is reduced to less than 9. The reinforcement therefore is no longer in the passivating
range and corrosion occurs. The corrosion is accelerated in the presence of further moisture
and oxygen.

Ca(OH)2 + CO2 + H2O = CaCO3 + 2 H2O

The process of carbonation reaches the depth of cover.

The factors influencing the depth of carbonation are:

 Depth of cover
 Permeability of concrete
 Grade of concrete
 Time

Whether the concrete is protected or unprotected

The environmental influences.

The ultimate result cracking, spalling and corrosion.

Chlorides
Chlorides are generally acidic in nature and can come from a number of different sources,
the most common being, de-icing salts, use of unwashed marine aggregates, sea water
spray, and certain accelerating admixtures (their use is now prohibited).

In the presence of chlorides localized pitting corrosion occurs which does not always have
associated with it the early warning signs of surface cracking.

Chlorides induced corrosion is potentially more dangerous than that resulting from
carbonation. Like most of the aspects of concrete durability, deterioration due to corrosion of
the reinforcement can take place years (5 to 20) to manifest itself.

Factors Influencing Corrosion of Steel Reinforcement

The factors which generally influence corrosion of reinforcement in RC structures are:

 pH value,
 Moisture,
 Oxygen,
 Carbonation,
 Chlorides,
 Ambient temperature and relative humidity,
 Severity of exposure,
 Quality of construction materials,
 Quality of concrete,
 Cover to the reinforcement,
 Initial curing conditions, and Formation of cracks.

Damages to Concrete Due to Corrosion of Steel Reinforcement

The process of corrosion, once set off, results in deterioration and distress of the RC
member. The various stages of destruction are as follows:

Stage 1: Formation of white patches

If the reinforcement is embedded in a concrete which is pervious enough to allow the

passage of water and carbon dioxide, then carbonation advances from surface to interior
concrete. Carbon dioxide reacts with calcium hydroxide in the cement paste to form calcium
carbonate. The free movement of water carries the unstable calcium carbonates towards the
surface and forms white patches. The white patches at the concrete surface indicates the
occurrence of carbonation.

Stage 2: Brown patches along reinforcement

When reinforcement starts corroding, a layer of ferric oxide is formed on the reinforcement
surface. This brown product resulting from corrosion may permeate along with moisture to
the concrete surface without cracking of the concrete. Usually it accompanies cracking or
cracking of the concrete occurs shortly thereafter.

Stage 3: Occurrence of cracks

The products of corrosion normally occupy a much greater volume about 6 to 10 times than
the parent metal. The increase in volume exerts considerable bursting pressure on the
surrounding concrete resulting in cracking.
The hair line crack in the concrete surface lying directly above the reinforcement and running
parallel to it is the positive visible indication that reinforcement is corroding. These cracks
indicate that the expanding rust has grown enough to split the concrete. Even at this stage
the reinforcement looks as though it is rust free if the concrete is chipped off.

Stage 4: Formation of multiple cracks

As corrosion progresses, there will be formation of multiple layers of ferric oxide on the
reinforcement which in turn exert considerable pressure on the surrounding concrete
resulting in widening of hair cracks. In addition, several new hair cracks are also formed. The
bond between concrete and the reinforcement is considerably reduced. There will be a
hollow sound when the concrete is tapped at the surface with a light hammer.

Stage 5: Spalling of cover concrete

Due to loss in bond between steel and concrete and formation of multiple layers of scales,
the cover concrete starts peeling off. At this stage, there is considerable reduction of the size
of the bar.

Stage 6: Snapping of bars

The continued reduction in the size of bars, results in snapping of the bars. Usually snapping
occurs in ties / stirrups first. At this stage, there will also be a considerable reduction in the
size of the main bars.

Stage 7: Buckling of bars and bulging of concrete

The spalling of the cover concrete and snapping of ties (in compression member) causes the
main bars to buckle, thus resulting in the bulging of concrete in that region. This follows a
collapse of the structure.

Minimizing the Risk of Steel Reinforcement Corrosion

The quality and depth of concrete in the cover zone are all important in minimizing the risk of
corrosion as shown in fig. below.

Quality of Concrete

Quality is controlled largely by minimizing permeability.

Depth of Reinforcement Steel Cover

Recommendations for minimum depths of cover are given in the codes of practice and are
based on exposure conditions and minimum cement contents. Higher cement contents infer
lower water cement rations leading to permitted reductions in cover.

At no time should the normal cover be less than the maximum size of aggregates+5mm.

Materials of Concrete Construction

Blended cements made from combinations of PC/PFA and PC/GGBS can lead to significant
reduction in chloride penetration. However, in situations where these materials are not cured
properly there is a risk of increased carbonation. Care must be taken that all aggregates and
admixtures contain limited amount of chlorides

Environmental Methods and Footprint Schemes towards Sustainable

Building Design

The aim of this report is to contribute towards sustainability and building design optimization
with the introduction of a new approach to design buildings both for safety and sustainability.
EU policy initiatives aim at addressing sustainability in the building sector, while reduced
energy consumption and carbon emissions are defined as crucial targets for this sector.

In the first part of the report, a comprehensive description of state-of-the-art for building
assessment methods is provided. In addition, a description of the general framework
towards sustainable buildings is given. Those methods have been developed by the
industry, research community and organizations as well as by the European Commission.

The analysis involves:

 the European framework towards environmental sustainable buildings;

 the Standardised framework developed by the International Organisation of
Standardisation (ISO)
 the Sustainable construction framework developed by CEN
 description of methods such as BREEAM, LEED, SbTool

The central focus of these methods lies on the environmental aspect. More specifically, the
sustainability assessment of a building is involved at a later design stage on the basis of the
environmental impacts that are produced throughout its lifecycle. In addition, footprint
methods provide the assessment on a product-level approach. This approach is questioned
when is applied to buildings; taking into account the interactions involved in building life cycle
it seems insufficient to consider building components in isolation.

A building is better described as a process rather than a product. This process involves
correlating and complementary technical, environmental and economic parameters. To this
regard, the environmental information could be better addressed and more effectively used
in the general design process. In this early design stage the principles of structural response,
durability and reliability of a structural system are also involved, while all these various
parameters are closely related and significant in resolving cost, resource and environmental
constraints.

Sustainable Structural Design (SSD) Methodology in the second part of the report, a new
approach to design buildings is presented. The Sustainable Structural Design (SSD)
methodology, based on a life cycle approach, incorporates the environmental results in the
structural design.

Sustainable Structural Design (SSD) methodology

Environmental Assessment +¿ Structural Performance Assessment = Combination of results

expressed in economic terms

The first step of this method follows the life cycle assessment (LCA) approach as it has been
introduced by the ISO 14044 Standard. This method provides a framework to define and
quantify the environmental impacts resulting throughout the building’s life cycle: the
production, construction, use-phase and demolition of a building, including considerations of
recycling and reuse. The output is the environmental impacts in terms of air, water pollution
and energy consumption, produced through constructing, using and disassembling.

The Performance-Based Assessment (PBA) of structural systems involves the

implementation of probabilistic scenarios for the evaluation of the response of the structures
under uncertain and/or extreme events. Structures are designed in a way to Sustainable
Structural Design (SSD) methodology

performance objectives as well as needs tailored to user/customer requirements. More

specifically, in a structural aspect, such methods provide more reliable and predictable
results in terms of safety and operability. In an economic perspective, those methods involve
the estimation of the costs needed to repair damaged buildings as well as the calculation of
the downtime losses. These costs are considered along with the initial construction cost.
The environmental impacts are converted into costs in the third step of the SSD method.
Prices that are defined by the EU market, they are used both for the energy consumption
and for the carbon emissions data. All the environmental impacts associated with the global
warming potential (GWP) are converted into CO2 equivalent and are multiplied by the
carbon price defined under the European Union emissions trading system (EU ETS). A
global assessment parameter, as the result of environmental (emissions, energy
consumption) and structural costs (repair costs, downtime losses, initial construction cost) is
obtained. Using this approach, stakeholders are able to evaluate, compare and make
decisions between alternative building design solutions

Alternative materials

Alternative materials include waste materials and industrial by-products and offer an
alternative to traditional engineered building materials such as asphalt, concrete, natural
aggregates and others. In addition, they offer both economic and environmental incentives.

Benefits of alternative materials

Companies that incorporate sustainable alternative materials into their process often see an
increase in revenue because they end up using fewer resources, which in turn reduces
production costs.

 Innovation

When engineers are challenged to find innovative solutions, the result is often the
emergence of new ideas and alternative materials that improve performance, practices and
products.

 Sustainable materials management

Reusing materials in the most productive and sustainable way throughout their life cycle
reduces waste and mitigates harmful effects on people and the planet. When industries
focus on reducing greenhouse gas emissions and adopt sustainable materials management
measures, they improve their performance.

 Improving product properties

When it comes to finding new solutions, alternative materials are often at the forefront,
solving problems or issues that would otherwise not be possible with traditional materials.
This happens in all kinds of industries, from food to construction.
The alternative material influences and improves properties such as weight, load capacity
and robustness, suitability for certain environments or uses, food compatibility, resistance to
corrosion, resistance to extreme temperatures, etc.

Besides being eco-friendly, the other advantages of using these materials for
construction are:

 Better functional efficiency.

 Cost effectiveness.
 Better durability.
 Ease of construction.
 Better finish.
 Minimum waste.
 Less maintenance cost.
 Minimum defects.
 Less energy intensive.
One of the major component of Eco-housing practices using ‘Alternate Building Materials’ is
Sustainable Construction Practices.

Eco-Friendly Materials

“Products or services that have a lesser or reduced effect on human health and the
environment when compared with competing products or services that serve the same
purpose.”

The use of Eco-friendly Materials became a necessity because of the following reasons;

 Phenomenal growth in the construction industry that depends upon depletable sources.
 Production of building materials leads to irreversible environmental impacts

Features of Eco-friendly materials

 Renewable Source.
 Reuse of Waste product.
 Low Embodied Energy.
 Local Availability.
 Reduction in air, land and water pollution.
 Durability & Life span.
 Aids Energy Efficiency in buildings.
 Durability & Life span.
 Biodegradable.
Stabilized Mud Blocks
These are dense solid blocks compacted using a machine with a mixture of soil, sand,
stabilizer (cement/lime) and water. After 28 days curing, the stabilized mud blocks (SMB) are
used for wall construction. Two block sizes (305 × 143 × 100 mm and 230 × 190 × 100 mm)
have been standardized. These blocks are 2.5 to 2.8 times bigger in volume when compared
with locally available conventional burnt clay bricks. Compressive strength of the block
greatly depends upon the soil composition, density of the block and percentage of stabilizer
(cement/lime). Sandy soil with 7% cement can yield blocks having wet compressive strength
of 3–4 MPa. High strength for the block can be obtained by increasing the quantity of
stabilizer. Major advantages of SMB are: (a) energy efficient, do not require burning, 70%
energy saving when compared to burnt bricks, (b) economical, 20–40% savings in cost when
compared to brick masonry, (c) plastering can be eliminated, and (d) better block finish and
aesthetically pleasing appearance.

BAGASSE – Cement Building Boards

Numerous composites (Medium Density Reconstituted Boards) have already been

developed using different natural and synthetic and man-made fibres in polymer matrix. Most
of the boards are being used for replacing wood and other conventional reconstituted wood
products. Some of these fibres have also been used for making high density fibre-board
using cement (inorganic) as binder. The development is aimed to develop building boards
and door shutter using Bagasse fibre. Building board is suitable for partitioning, panelling
etc.

ARHAR STALK – Cement Board

Composites have great potential in replacing wood in building industry, but their
development is associated with problems related to their processing, production and
performance. The work carried out is intended to explore the possibilities of using fibrous
biomass such as Arhar Stalks, Groundnut Shells etc. for the production of composite
materials. Composite panels developed using Arhar Stalks meet the requirements of ISO,
BS, and BIS specifications. The output of this article will help utilize fibrous biomass and
preserve environment due to conservation of wood in building and construction industry.

COIR – Cnsl Board

The Coir-CNSL Board is a wood alternative which can be used for surfacing, door and
window shutters, partitioning, false ceiling, panelling, furniture, cabinets, packaging etc. It is
a single layer flat pressed class Medium Density Fiber (MDF) Board. It has low water
absorption, negligible change in dimensions due to water absorption, workable with normal
wood working tools, paintable, pre-laminable, nail able and screw able, passes IS-3087. The
board is eco-friendly and can replace wood or re-constituted wood by 100%.

Salient features of Coir-CNSL Board are as under;

 Both the starting materials i.e. coconut fibre and cashew nut shell liquid are available
substantially in coastal areas and are renewable agro-wastes.
 Technology is developed at pilot level and ready for transfer.
 The technology and product both are patented.
 The Technology is techno-economically viable as per pre-estimates.
Lightweight Sandwich Panels

The cellulosic refuse of paper industries are rich in small fibres and can be used to make
value added product, which can be used for acoustics, thermal insulation and false ceiling
purposes in buildings. The laboratory scale developed technology yielded a light-weight
sandwich panel which is very much suitable for above mentioned purposes. These
developed panels have their end applications in partitioning, panelling, thermal insulation
and false ceiling with its unique aesthetics. The technology as well as product has been
patented. The estimated economic viable capacity is 2 tonnes per day and most suitable for
paper industries as a downstream process.

Fine Concrete Blocks

The concept and process is similar to the one employed for SMB production except that
instead of soil, some fines are added to the mix. Fines like fly ash, polished stone waste, etc.
are mixed with either sand or stone quarry dust, along with cement and water. The mixture is
then compacted into blocks using a machine (manual or mechanized) and then cured for 28
days. Fines (like fly ash, polished stone waste, etc.) in the range of 20–25% by weight of
sand can result in a good grading for the mixture and with 6–7% cement good quality block
with wet strength > 3 MPa can be achieved. In addition to fines, about 10% red loamy soil
addition can result in good natural mud colour for the block. The major advantage of fine
concrete block is the utilization of waste products like fly ash, polished stone waste, mine
wastes, etc. which otherwise cause pollution and environmental degradation.

Steam Cured Blocks

A mixture of lime, industrial waste products like fly ash or expansive soils like black cotton
soil and sand can be compacted into a high-density block. Lime reacts with fly ash/clay
minerals forming water insoluble bonds imparting strength to the block. These reactions are
slow at ambient temperatures (~ 30°C) and hence steam curing for about 10 h at 80°C can
accelerate these reactions leading to high strength for the block.

The process involves:

 Mixing of raw materials like lime, cement, fly ash or black cotton soil, sand and water in a
mixer,
 Converting the mixture into a dense block using soil block press,
 Stacking the blocks in a steam chamber and steam curing for 10–12 h.
Blocks of any convenient size can be manufactured. Compressive strength of the block
depends upon the composition of the mix, density of the block and percentage of stabilizer
(cement/lime). A combination like 25% fly ash, 6% lime and 2% cement can yield blocks
having wet compressive strength of > 6 MPa. This kind of strength will be sufficient to
construct 3–4 storey load-bearing buildings with spans in the range of 3–4 m. Blocks of
higher strength can be easily achieved by adjusting the mix proportions. It should be noted
here that the block quality is much superior when compared to local burnt bricks and SMB.
Advantages of using these blocks are: (I) Ideal process for a small-scale or cottage industry,
(ii) utilization of industrial waste products like fly ash and problematic soils like black cotton
soil and high clay soils, (iii) energy efficient and environment friendly, and (iv) higher strength
for the blocks.

Causes of Poor Acceptability of Alternative Building Materials

 Lack of knowledge about new materials.

 Non-inclusion in various National codes and specifications.
 In-appropriate environment for research and development.
 Non-availability of proper forum for promoting new materials.
 Ineffective and improper publicity.
 Unawareness among users.
 Poor competition among new material manufacturers.
 Higher price structure of new materials.
 Lower emphasis on research on eco-friendly materials.
 Negative attitude of engineers/architects towards non-scheduled items.
 Lower confidence on quality.
 Negligible technological thrust for wider acceptance and adoption.
(Anon., n.d.)

Assess the use of Building Information Modelling in the production of accurate

structural design information and the collaborative environment of structural design.

Building Information Modeling (BIM) is increasingly getting the attention of organizations

involved in architecture, engineering, and construction (AEC), as well as the owners and
operators of buildings (facility managers and real estate managers). In this context, BIM is a
digital model representing physical, technical, and functional characteristics of a building.
BIM is a shared data and knowledge platform for all stakeholders involved and provides a
basis for decision making during the entire lifecycle of a building:

 Design
 Build
 Maintain
 Operate
 Demolish
Different stakeholders at different phases of the lifecycle of a building add, query, or edit
information in the Building Information Model to support their own function and share this
information with other stakeholders.

Building Information Modeling is much more than a 3D CAD drawing representing a floor
plan or construction detail. BIM includes data of interest to many stakeholders during the full
lifecycle of the building, such as buyers, owners, occupants, facility and real estate
managers, safety inspectors, lawyers, and emergency planners. BIM can also support in
creating surrounding processes, including geographical analyses, urban planning, and
landscaping.

As building maintenance and operations reflect over 90% of total lifecycle costs, real estate
and facility managers have an increasing interest in using Building Information Modeling
(BIM) because the model keeps essential information on multiple aspects of a building or
asset. These include spatial information, technical documentation, cost information, vendor
data, or operating guidelines. BIM reduces the traditional information loss associated with
handling a project from the AEC team to the building owner and operator. By closing this gap
between construction and building operation, all available data helps in saving time, effort,
and money in running and maintaining the building during its entire life cycle, including its
demolishment.

Many dimensions in Building Information Modeling

BIM can include many dimensions of data to support processes for different stakeholders. A
Building Information Model includes 3D coordinates and vector information that represent
the geometry of the building and its components, including eventual geospatial data.
4D BIM adds time as a new dimension to the model. This enables planners and constructors
to visualize activities subsequently on a time line, for example in the sequence the
construction needs to be created.

5D BIM includes the linking of cost related data to any component of the Building Information
Model, allowing designers, contractors or investors to visualize the progress of construction
activities and its related costs over time.

6D BIM is the “As-Built” model including information such as product data, maintenance
manuals, photos, warranty data, manufacturer information, and contacts. 6D BIM plays a key
role in using BIM successfully during the operations phase of buildings and therefore needs
special attention from Facility Managers and Real Estate professionals.

BIM in architecture, engineering, and construction (AEC)

Using Building Information Modeling as a central information and collaboration platform

during design, engineering, and construction of any building brings many benefits. It reduces
the number of data sources drastically, resulting in

 Less failure
 Increased speed of delivery
 Improved productivity and collaboration
 Higher quality and reduced costs
As multiple technical disciplines like construction detailing and electro technical and
mechanical engineering are unified in one BIM platform, the impact of any change in any
discipline is immediately visually available for all other disciplines. This increases
interdisciplinary collaboration and drastically reduces failures or clashes during the design,
engineering and construction phase.

BIM in operations

Building owners, facility and real estate managers, and service providers can benefit from
BIM as it keeps vital information for many processes during the operations phase of a
building’s lifecycle. Information such as spatial data, asset details, documentations, and
graphical information can support processes during the operation of buildings like space
management, asset management, maintenance planning, energy management, and
reconstruction projects during the lifecycle. To ensure that the BIM gets enriched with
relevant and useable information for building maintenance and operations, it’s key to analyze
this information during the initiation of the AEC phase.
For processes supported by IWMS or CAFM solutions, a bidirectional BIM connector allows
data exchange between BIM and IWMS. Because the geometrical data remains maintained
and changed in the BIM, data exchange with IWMS occurs on a frequent basis.

Software for BIM

Software can be used to build, maintain, and visualize all aspects of BIM. This includes
interactive capabilities, such as clicking on a floor level of a building to see who the tenants
are, rendering a view of the urban landscape from a particular window of a building, or
determining which vendor has installed the heating installation. Elements such as time (4D)
and cost (5D) enhance the capability for lifecycle management.

Some leading products for BIM are Revit (Autodesk), ArchiCAD (Graphisoft), Bentley and
Tekla. To re-use BIM successfully in operations, the previously mentioned integration with
IWMS and CAFM solutions is a key requirement. BIM software vendors and the AEC
industry are taking several initiatives for standardization exchange formats like the
Constructions Operations Building Information Exchange (COBie) in the United States.

Legislation

In several countries, it has become mandatory to use BIM during the design and
construction phase, including an efficient information transfer to the building operations
phase. Frequently, this is combined with new financing and operating contracts like Design
Build Finance Maintain Operate (DBFMO) or Public Private Partnerships (PPP). Many facility
managers and real estate managers will be faced with these Building Information Models in
future years and need to consider how to benefit and how to exploit them succesfully.

In the United Kingdom, the government started the Government Soft Landing (GSL) program
that aims to reduce operating costs and improve carbon performance by involving users and
operators during the design process. “Soft Landing” also refers to a smooth transition from
the construction phase to maintenance and operations. For any governmental project in the
UK, the use of BIM becomes mandatory from 2016.

How can you benefit from BIM as a Facility Manager?

Facility and property managers are becoming more and more interested in BIM. This is not
surprising given that BIM contain a great deal of relevant information for this target group ‒
for example, information about the composition of the building and the properties of building
components. At the same time, the use of a BIM is raising many questions. For example,
“How can a BIM help me as a facility.
Planon Connect for BIM

Planon Connect for BIM is a unique solution that provides a bidirectional data exchange
between a BIM and the Planon Universe platform to ensure consistent and relevant re-use of
information for building operations, including processes like maintenance management,
space management, portfolio management, and contract management.

What you need to know about BIM

Today, BIM is primarily used during the design and construction phase, specifically when it
improves the collaboration between the various building partners. Learn more about the
possibilities of linking a BIM with your Facility Management Software.