Using pre-stressed precast hollow core walls and slabs can save a minimum of 30% construction time in greenfield projects. This technology allows work to begin on casting floors before the entire site is acquired or foundations are fully complete. It provides advantages like faster construction, higher quality, and more flexibility in scheduling compared to cast-in-place concrete. Adopting this proven precast technology can help fast-track major infrastructure projects in sectors like power, steel, and warehousing.

1. Usage of Pre-Stressed Precast Hollow Core Wall
& Slab in Green Field Project
PRE-CAST TECHNOLOGY
W
ith the current Govt’s focus on Fast tracking of
the Mega projects in Power, Steel, Fertilizer, Coal,
Warehousing etc., it becomes very essential that
a proper solution to construction is found out which can give
advantage on the 3Ms of the project i.e reduce manpower,
Reduce waste of material, Reduce cost. This is where Precast
comes in to picture.
Today, in any green field project, the greatest challenge to
the engineers & project managers is to manage time. Delay and
hurdle often arises due to non availability of site and sequencing
of cast-in-situ concrete limits the construction time flexibility of
the construction manager.
For example in early times, a power plant used to take 48
months to build & mostly all activity from fabrication to Civil
works was done on site. To cut on time, trend of prefabricated
structures started in which steel was prefabricated in shop and
brought to site when foundations are ready & erected.
Then all the steel beams & columns were erected and given
to GCW contractor to put concrete on various levels of floor &
hand over the floors to different teams for further works. Often
this needs a great coordination and yet all Project Managers
were under pressure to deliver and due to movement of unskilled
labours, the area also becomes unsafe.
Hollow core Pre-stressed Precast presents a unique model of
working and is perfectly feasible in the most economic way to avoid
or minimise the cast-in-situ works on the project site. This will also
help the project managers to pre plan & do works in parallel, even
if site has not been fully acquired & work on casting of floors can
commence in parallel with area grading and foundation in a project.
This can save a minimum of 30% construction time.
There is a need to change the mindset of the designers
to adopt the proven technology which is available and use it
innovatively. Another typical
example is of large warehouse
sheds in that the perimeter
wall (which is currently
made up of bricks and RCC
bands) could be replaced with
precast walls. This is very
cost effective and fast to
implement. Quality of work
improves as the product is
produced from factory setup.
How to Do This in Green Field Projects
- Plan from the design stage
- Make the design Precast friendly
- Prepare tenders keeping in provision Prestressed Precast
hollow core. For walls & slabs
- Set aside a space in plant for the precast yard & factory of
about 15 Acres
- Issue the slabs to the contractor on area basis free of cost just
like issue of steel
Operation of the plant can be done by manufacturer of the
machine.
Spancrete® Hollowcore Advantages
- Fast, safe erection with minimal crews.
98 CE&CR July 2015
Out Door Plant
Long Span Slabs Ideal for Podium Parks, Covering Over Nallahas, etc
Perimeter walls in Factory Shed,
Ware Houses

2. - Install in excess of 1000m2
/10,000 ft2
per day on steel
beam, precast, masonry or poured structures.
- All year construction.
- Once in place, Spancrete® hollowcore slabs provide a secure
deck that allows other trades to begin working.
- Each slab’s smooth surface can be carpeted or tiled directly
with minimal preparation.
- Slabs can be lifted and installed directly from delivery
vehicles.
- Horizontal or vertical hollowcore wall panel capabilities.
- Hollowcore spans can be up to 20m/65ft, the world’s longest.
- Fire ratings of up to 4 hours.
- Offers reductions in sound transmission, for a quiet
environment.
- Significant energy savings are achieved with Spancrete
Insulated Hollowcore wall panels.
- Fast Turnaround
- Compared to site-cast concrete, precast concrete erection is
faster and less affected by adverse weather conditions.
- Plant casting allows increased efficiency, high quality control
and greater control on finishes.
In addition to the above other advantages are:
Highest Production
Rates: The Spancrete
machine produces at a
rate of 2.5+m/8+ ft.per
minute, resulting in
1200+m2
/12,000+ft2
per
8 hour shift.
Most Accurate
Tolerances: The Spancrete
Machines’ hydraulic
tamping and troweling mechanisms result in smooth, flat surfaces
which can be carpeted or tiled directly with minimal preparation.
Unmatched dimensional specifications within +1.5mm / .063in,
the highest standards in the industry.
Advantages of Building with Precast, Prestressed
Concrete
Architects, engineers, general contractors, developers and
owners have been specifying Spancrete® precast products for
more than 69 years. These time-honoured architectural and
structural precast components combine to form strong, long-
lasting fixtures in our everyday lives. Every member involved in
the construction project benefits from the many advantages of
using precast building products.
Precast Offers Design Versatility
“Versatility” is synonymous with precast. The selection of
structural and architectural precast concrete products offers
aesthetically pleasing yet economical solutions for many types
of construction projects. Precast concrete offers a variety of
surface finishes and textures. Choose ribbed, raked, broomed,
sandblasted or exposed aggregate finishes. Colour and reveals are
available, enhancing the architectural treatment choices. Precast
wall panels are not only ideal for new construction projects, but
can be matched to existing structures for additions. Precast
concrete components can easily be designed to accommodate
future growth. Interiors can be reconfigured simply and quickly
for the changing needs of the building. Precast products can
span over long areas, resulting in large, open interiors without
obstructions or expensive support structures.
100 CE&CR July 2015
Spancrete 4’ wide (1.2 m) Hollow Core Slabs
Spancrete Floor Slabs Used on Various
Structural Elements / Frames
Spancrete Vertical and Horizontal Wall Panels
(Insulated and Non-insulated)
PRE-CAST TECHNOLOGY

3. Beauty
Nothing combines beauty with versatility, economy, and
efficiency like precast concrete. With all the choices of decorative
finishes, wall panels combine a custom architectural exterior with
a durable interior surface to create an attractive, long-lasting
building. The pattern, texture, and color variations are practically
unlimited, from exposed aggregate finishes to thin brick patterns.
Durability
Durability is the one quality that allows precast, prestressed
concrete to outlast competing materials. With its durable
design, Precast is exceptionally resistant to impact, corrosion,
weathering, and abrasion, rendering it virtually maintenance free.
Project Efficiency/Speed of Construction
Precast concrete offers rapid, all-weather construction. It
can be constructed year-round, in all types of weather, making
fast-track construction a routine job meaning projects are done
faster and occupied sooner, for a quicker return on investment.
In addition, insulated wall panels maximize thermal efficiency
to save energy costs and conserve natural resources. Durable,
fire-resistant precast concrete also lowers maintenance costs
and insurance rates, for even greater savings, while plant
manufacturing of precast concrete under an established quality
assurance program ensures consistent reliability, and saves
production costs through repetitive operations. As soon as
Spancrete® Hollowcore Plank is secured in place, it becomes
a working surface for trades such as mechanical contractors,
electricians, and plumbers. This advantage accelerates the entire
construction process, facilitating earlier occupancy. Because
construction crews work year-round, in all types of weather,
Spancrete® projects stay on or ahead of schedule.
Green Building Construction
Precast concrete components reduce energy consumption in
several ways: precast construction allows minimal air infiltration,
thermal mass delays internal temperature changes and reduces
peak heating and cooling loads, and sculpted shapes facilitate the
design of shading devices for window areas. Precast components
can be cast with insulation attached during manufacturing
process, to increase the structure’s R-factor.
Long Term Cost Savings
Low maintenance costs and insurance premiums, coupled
with greater occupant satisfaction and higher resale values, are
demonstrated benefits of building with precast. The durability of
precast, prestressed concrete components means that buildings
last longer and look better over the years.
Occupant Satisfaction
Precast building systems reduce vibration, assist in noise
control, and create a safer environment. Occupants can enjoy
the inherent quiet and comfort that precast concrete provides.
In fact, precast concrete buildings typically have higher
occupancy rates, greater tenant satisfaction, better lease rates,
and outstanding resale values. One of the most remarkable
competitive advantages of precast concrete is its performance
on life safety issues. Precast components and precast structural
systems have demonstrated added value in fire safety, wind,
flood, earthquake protection and noise control for overall
occupant comfort.
Fire Safety
Precast is unsurpassed in providing fire protection and
containment when incorporated into a comprehensive, balanced
design. Precast concrete does not burn or give off lethal fumes in
even the hottest of fires, and it maintains its structural integrity,
giving occupants more time to evacuate safely and extinguish
the fire. The fire rating of precast hollowcore plank saves on
insurance costs and enhances tenant satisfaction.
Weather Resistance
Precast concrete provides protection against the winds of
hurricanes and thunderstorms, and has recently been cited as
an effective barrier to damage from tornadoes as well. Precast
concrete also is impervious to termites and dry rot, creating a
structure that does not weaken over time.
Low Sound Transmission
Precast is a high-density material that provides excellent, if
not unsurpassed, sound reduction, allowing tenants to benefit
from a quieter and less disruptive environment. Precast floors,
roofs, and walls have high STC ratings and offer superior sound
absorption and impact sound reduction.
For more information contact Suresh Tripathi - sctripathi1963@gmail.com
Spancrete Highway Noise Barriers and Perimeter Walls
PRE-CAST TECHNOLOGY
102 CE&CR July 2015