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Cover Story
Building for Tomorrow
What does it take to build smart? CHARU BAHRI sheds light
on key methods and principles.
While the architectural credo of ‘form follows function’
has now been quoted to death, it is an undeniable fact that
today’s consumers are looking for buildings that not
just look good but are truly comfortable while proving economically
and ecologically sustainable. A tall order? Perhaps, but developers
are delivering. Ultimately, it’s about ‘smart
building’: cutting-edge design, ease of living, resilience
and safety, and a green mindset that conserves resources and
saves costs.
Build green
Indeed, ‘green’ is the buzzword that figures high
on the list of developers now, right from the design stage.
“It is correct to say that efficiency starts at the
design stage,” affirms S Srinivas, Principal Counsellor,
Godrej CII Green Building Council. “If green design
techniques are incorporated in a structure, the building has
the potential to save as much as 40-50 per cent of the energy
it would otherwise consume once operational.” According
to him, the first step to achieve energy efficiency is to
correctly orient the building so that heat ingress is minimal
and it gets maximum daylight – a simple rule is to minimise
exposure on the south and west. “To ensure you get it
right, use simulation tools and techniques,” he explains.
“Insulation in buildings also helps maintain a comfortable
indoor temperature by minimising energy leakages and thus
reduces energy consumption by 5 to 8 per cent.”
Design techniques
Speaking of design techniques that reduce heat gain in high-rise
buildings, Dikshu C Kukreja, Partner, CP Kukreja Architects,
suggests including cavity walls within the framed RCC/steel
structure. Insulating both walls and the roof also figures
in these design techniques. “Lightweight heavy-duty
roof insulation such as PUF reduces heat gain as does the
somewhat more aesthetic method of treating a roof with materials
that have a high reflective value and, hence, absorb less
heat,” he says. “One such material, which is old
fashioned but immensely aesthetic, and has time and again
been successfully used for this purpose is broken ceramic
tiles in different colours and patterns. Creating a terrace
garden is also an aesthetic means to achieve this goal as
the soil acts as a natural insulator.”
Other useful techniques include incorporating architectural
features like pergolas, louvres, trellises, jaalis, sunshades
over window and door openings, and overhangs in the design.
“Alongside insulating the walls and roof, sealing doors
and windows is also important as most buildings lose a high
volume of energy through these routes,” he adds. “Windows
can be sealed by introducing sub-frames and heavy duty sealants
that completely plug any gaps between the window frame and
civil structure. Energy losses from main entrance doors can
be reduced by the use of air curtains or air locks.”
Building blocks
Fortunately, a large palette of building materials and technologies
used in other parts of the world are now available in India.
As Srinivas points out, developers can choose from an array
of ‘green’ insulation mate-rials, like extruded
polystyrene, glass wool and autoc-laved aerated concrete blocks,
for instance. High albedo (reflective) materials or coatings
can also be used to coat building rooftops to reduce heat
ingress. However, the main intent of using reflective coatings
is to minimise heat islands, or the thermal gradient differences
between developed and undeveloped areas. High solar reflective
index (SRI) materials or coatings will have high reflective
properties.
The use of glass in building façades is also increasing,
both for its favourable look as well as its ability to enhance
natural light while offering side insulation. Srinivas lauds
smart developers who choose high-performance vacuum sealed
double or triple glazing with low U-value, low shading coefficient
and high visual light transmittance (VLT). “Another
method to enhance natural light,” in Kukreja’s
view, “is to design the building footprint or floor
plan so that light travels maximum distance from outside.
This necessitates including atriums or courtyards as part
of the design.”
The right tools
Evidently, a choice of architectural attributes and materials
figures at every stage of the process of structural design.
For this reason, modern building information management (BIM)
software has completely transformed old methods of design
and drafting by facilitating the process of adding components
of design. Balaji Sreenivasan, Founder & CEO, Aurigo,
describes how ‘intelligent objects’ like doors
and windows can be selected from in-built libraries, or preset,
and then ‘dragged’ and ‘dropped’ at
the right spot on a digital canvas.
Next-generation BIM software also possesses the intelligence
to point out areas of concern in a given design, by accurately
predicting its performance. The automation of the conversion
of design into figures – accurate area calculations,
schedules and quantity takeoffs based on project specifications
– is another significant advantage. Architectural firms
deploying AutoCAD’s Revit Architecture building design
solution have reported using fewer staff than originally budgeted
to complete a job twice as quickly. Improved quality, performance
and productivity help a project owner, general contractor
or project management firm navigate highly competitive markets
by cutting out waste, eliminating reworks and reducing costs.
Automation also helps developers after the design stage.
As Sreenivasan points out, “Construction management
starts where design ends.” Aurigo’s web-based
construction manage-ment suite BRIX 2009 does not reinvent
the wheel (see box on Construction Management Software). Instead,
it integrates with existing team players in the ecosystem,
further enhancing the use of software products in the design,
scheduling and enterprise resource planning (ERP) phases.
While the software is extensively used in the US, some early
adopters in India are IDEB, Navin Housing, RDS Project Ltd
and Woodcraft.
The pre-engineered way
No mention of the benefits of automation in design would be
complete without speaking of machine-designed and manufactured
structures, or pre-engineered buildings (PEBs). Pre-engineered
building technology, where a building is designed and its
components are manufactured in a factory from A to Z, is rapidly
emerging as a speedy method to erect cost-effective structures
conforming to standards. And especially in the realm of industrial
structures, it is more often than not advisable to choose
a PEB over a structure created by conventional means of construction.
“We believe our system of construction saves immense
time and cost,” avers Manish Kirpekar, Senior Vice-President
- Projects, Sterling Construction Systems (SCS). “As
turnaround time is shorter, it enables faster delivery. This
translates into enormous savings and secures the builder against
inflation in the cost of material inputs.” As an example,
he describes SCS’s Tuscany Terraces project in Neral,
where the construction of 2.5 lakh sq ft was completed in
a record time of 16 months. By conventional means, the project
would easily have taken three years to complete. Cost-savings
accrue on account of the need for less labour; semi-skilled
labour can complete a job without assistance from a skilled
(carpenters, fitters) and unskilled workforce.
PEB technology that makes use of fibre cement boards assures
consistency in quality, durability, finish, and adherence
to ‘green’ technology as it involves minimal waste.
“Besides, conventional construction methods are more
prone to accidents and give rise to tricky situations after
construction, like leakage of rainwater through separation
cracks between RCC and brick walls,” adds Kirpekar.
“Other than doing away with these issues, PEB systems
allow developers to build more spacious units in a certain
area vis-à-vis conventional methods as the thickness
of walls in PEBs significantly reduces. What’s more,
maintenance costs are minimised by the use of PEB technology.”
Safety and strength
The earthquake in Gujarat in 2001 served to reiterate the
role of structural engineering in safe building design. Hiren
Patel, Principal Architect, Hiren Patel Architects, believes
architects and developers cannot afford to ignore design techniques
that enhance the safety of a building in the event of an earthquake.
“As a general guideline, we design buildings in a box
format,” he reveals. “Having a larger base and
structural components tied together like a box makes for a
more homogenous, safer structure. Architects should avoid
unnecessary cantilevers in buildings. We also remain open
to suggestions by structural engineers who are trained to
go by the rules, irrespective of their preference for a certain
design. If even one out of 10 columns of a high-rise building
cracks during an earthquake, the entire structure may collapse.
Architects must rise to the challenge to design safely and
aesthetically.”
Safe design calls for a strong foundation. It holds true
that a building can stand taller, and for a longer time, only
if its groundwork is secure. For his part, Sunil Newatia,
Managing Director, Suretech Infrastructure Pvt Ltd, urges
contractors to give the foundation its due importance, especially
given the rise in the construction of high-rise buildings.
“Conducting scientific soil analysis is a smart move,”
he says. “If you do not have the means to do this, approach
a soil investigation agency or contractor who specialises
in this activity. Once bore log data is available from the
soil investigation reports, a piling equipment vendor can
conduct a pile driving analysis and recommend suitable piling
equipment. After this, the soil analysis reports coupled with
the type of pile selected by the contractor will help to accurately
calculate the load-bearing capacities of the pile considering
the overall structure. Ideally, after the first piles are
cast, the pile should be tested using specialised equipment
to ascertain if everything is going as per plan. Sadly, small
contractors omit this step altogether.”
In other words, why should you decide on the kind of foundation
the structure mandates and your piling equipment needs arbitrarily
when you can reduce your investment in expensive equipment
by proceeding in a scientific manner? After all, driven piles
are faster and cheaper compared to bored piles. But then,
they necessitate the use of a vibratory or impact hammer depending
on soil conditions. If the soil is soft and clayey, the use
of a vibratory hammer is ideal. A little harder soil with
N-values between 50 and 100 is perfect for an impact hammer.
And soils harder than N-values of 100 call for the use of
bored piling rigs.
Independent practising structural engineer Satish C Dhupelia
points out that soil analysis has a bearing on basement construction
methods, which is a critical part of construction. While single
basements may be constructed by open excavation, deeper basements
that go down two to three levels necessitate the construction
of a diaphragm wall, temporary sheet piles or temporary shoring
piles with proper anchorage. The choice of method depends
on the quality of sub-strata soil. “As the subsoil varies
in different parts of one city, such as Mumbai, developers
should not base their decisions on prevailing or popular techniques,”
he says.
Water seepage, the bane of many basements, can be avoided
by waterproofing. “Here too, the developer must take
into consideration the water table in the surrounding area,”
says Dhupelia. “In Mumbai, for instance, the water table
is at the ground level. So the only way to ensure a foolproof,
watertight basement is to adopt external waterproofing, that
is, a box-type construction. Other methods, such as mixing
admixtures in concrete or inner (negative) side waterproofing
do not offer as good a result, especially in coastal regions.
The constant pressure of water on the boundary walls of the
basement often causes the layer of waterproofing material
to detach.”
As it is, Dhupelia notes that land shortage has resulted
in the permissible basement boundaries shifting from 10 ft
of the site boundary to 5 ft and now to the actual plot boundary.
This reinforces the need for developers and contractors to
adopt best practices.
Cool building
Best practices also come into play when fitting a structure
with an air-conditioning (AC) system. A good and effective
air distribution system is a hallmark of sound construction
techniques. According to G Anandkumar, Senior General Manager,
Air-conditioning Projects Division, Blue Star Ltd,
this necessitates air being supplied into the conditioned
space without any draft but at the same time maintaining adequate
room air motion, low noise levels to avoid any discomfort
to the room occupants, minimal losses owing to friction or
leakage, least temperature change because of heat gain, and
maintaining uniform temperature throughout the conditioned
space without any stagnant pockets.
The parameters of noise, vibration and draft are functions
of air velocity whereas duct strength and leakage are a function
of pressure. These two factors must be kept in mind for design
and construction of ducts, which is done either according
to SMACNA standard or IS 655. The overall design of the building
and structural and mechanical system elements govern the ultimate
layout of each duct system, believes Vidur Bharadwaj, Director,
The 3C Company. Generally, ductwork is concealed above drop-down
ceilings, in mechanical rooms, and in vertical chases that
allow ducts and other mechanical systems to pass unseen through
wall divisions and between floors. Factory-fabricated sheet
metal ducts are a cost-effective solution for AC ducting.
Building automation
Finally, a building is never smart until it is infused with
intelligence. Kukreja endorses the use of intelligent building
management systems (BMS) that perform sensory functions such
as identifying doors and windows that have been left open,
whether rooms are occupied or empty, and the extent of daylight
to automatically dim energy-efficient luminaries. These systems
play a large role in conserving energy in large buildings
that cannot be easily manned.That, in essence, is what smart
building is all about – it’s not easy but the
outcome of a methodical approach to construction is a long-lasting,
sustainable structure that gives joy to its occupants.
Construction Management Software
BRIX 2009 seamlessly integrates with suites like Microsoft’s
Dynamics™ AX, Microsoft Project Server and even Primavera.
Once the developer has obtained a Bill of Quantities (BoQ)
either using the quantity takeoff or from a standard library,
the software helps prepare accurate project estimates with
a detailed rate analysis process, manage tenders, administer
the contract, manage formal change orders, conduct field inspections
and finally closely track construction to determine whether
it is on schedule and adheres to budgets. Understanding the
need for office data to correlate with the actual situation
on the field, the software makes use of tablets and PDAs to
facilitate field inspections. Digital dashboards enable every
stakeholder to get real-time project updates and access business
analytics that help project owners and management take mid-course
corrections on failing projects.
Build and Coat
"Using paints and coatings that protect buildings and
enhance their life is an essential part of building smart,"
says Vidur Bharadwaj, Director, The 3C Company. Paints, sealants,
and adhesives with low to zero quantities of toxic chemicals
and low VOC help minimise sources of emissions and thus contribute
towards building performance and enhance the indoor environment.
Elastomeric and nanotechnology-based paints that are low VOC,
anti-fungal, hydrophobic, UV-resistant, heat insulating with
elastomeric (stretchable that cover cracks) properties may
be used for building interiors and exteriors. These are environment-friendly
and enhance the performance and life of the applied surface.
Sustaining Construction Sites
The preservation of essential yet scarce natural resources
is a sign of intelligence. A building may exist but it cannot
serve its occupants without water. Just the same, the process
of construction requires the use of groundwater. Consequently,
smart developers focus on the optimal utilisation and replenishment
of freshwater, a scarce natural resource. S Srinivas, Principal
Counsellor, Godrej CII Green Building Council, suggests that
rainwater, harvested by collecting water from rooftops and
through channels on the ground, should be diverted and stored
in structured or non-structured water bodies. A developer
should ideally plan to treat the collected water to specified
local standards and use it for irrigation, flushing and air-conditioning
water makeup requirements. Rainwater can also be percolated
into the ground through rainwater harvesting pits, percolation
pits or soak pits to recharge and increase the water table.
Best Concrete Practices for Corrosion Protection
In order to protect buildings near the sea from corrosion,
independent practising structural engineer Satish C Dhupelia
cites the need for proper concrete practices. This encompasses
making concrete, transporting it to the site and vertically
upwards, placing, compacting and the curing of fresh concrete.
This is the soundest way to long-lasting construction and
protecting the image of the contractor.
Build on Stilts
Given the shortage of parking space in cities, developers
may prefer to include underground basements as a building
feature. However, in certain cases, a developer may plan a
building with a flexible storey, that is, a ground storey
consisting of open spaces for parking. In the case of such
‘stilt’ buildings, Suryavir Singh, Head - Strategic
Planning, Sahara Real Estate Business, points out that a special
arrangement is needed to increase the lateral strength and
stiffness of the soft/open storey. A dynamic analysis of the
building, including the strength and stiffness effects of
in-fills and inelastic deformations in the members, particularly
those in the soft storey, should be carried out and the members
designed accordingly.
Alternatively, Singh suggests that the following design criteria
be adopted after carrying out an earthquake analysis, neglecting
the effect of infill walls in other storeys: “The columns
and beams of the soft storey should be designed for 2.5 times
the storey shears and moments calculated under seismic loads
specified in the other relevant clauses or, besides the columns
designed and detailed for the calculated storey shears and
moments, shear walls placed symmetrically in both directions
of the building as far away from the centre of the building
as feasible, can be designed exclusively for 1.5 times the
lateral storey shear force calculated as before.”
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