JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN
CIVIL ENGINEERING
MECHANIZED CONSTRUCTION IN INDIAN
SCENARIO (PRECAST WALL PANEL SYSTEM)
1
MR. SHRIKANT R. BHUSKADE, 2 PROF. ASHOK R. MUNDHADA,
1
P. G. Student, P. R. M. I. T. & R. Badnera, Amravati.
2 P. R. M. I. T. & R. Badnera, Amravati.
shrikantjuly22@gmail.com,ashok_mundhada@yahoo.com
ABSTRACT : The demand and expectations on the Indian construction industry is increasing rapidly. The
Industry has to evolve/adopt/adapt technology to sustain//satisfy these requirements. The need to complete the
project on schedule, with site constraints and lack of availability of skilled workers, there is strong case for
developing expertise in design and construction of precast concrete construction.
Precast wall panel construction system is potentially being a good way to achieve higher efficiency in
construction industry. Advancements in construction equipment’s, pre-stressing techniques coupled with use of
high strength & high performance concrete has enabled precast concrete technology in improving the
construction quality and reducing construction time. More ever, this technology is a blessing in disguise to the
shortage of labour facing the Indian construction industry. Though precast concrete construction is being used
in India for infrastructure projects like bridge construction etc., it is yet to catch up in the building construction
industry.
1. Introduction
1.1 Precast concrete:
Precast concrete is concrete that is prepared, cast and
manufactured at specially equipped plant with a
permanent location. It than transported to the
building site for erection.
The distance travelled from the casting site may only
be a few meters, where on site precasting method are
used to avoid expensive haulage (or VAT in some
countries), or may be thousands of kilometers, in the
case of high value added products where
manufacturing and haulage cost are low.
1.2 Features of Precast Concrete:
Compared with traditional construction
method or other building materials, precast as
construction method, and concrete as material, have a
number of positive features. Precast concrete is
comfortable, versatile, healthy, durable, ecological,
fast and affordable.
The main advantages of precast process are:
 The intrinsic quality of an industrial product,
manufactured in a controlled environment with
accurate methods.
 Advance quality control, which goes far beyond the
checking of the fresh concrete. Dimensional
accuracy, the properties of hardens concrete and the
position of the reinforcement can all be checked
before including an element in the final work.
 Factory manufacture is independent of weather
condition and can be conducted separately from
construction work on site.
 Design Flexibility: For the designer, the first and
most significant advantage of architectural precast
concrete is its tremendous flexibility. The material
offers limitless potential for the development and
manipulation of massing, form, color, texture and
detail. The material can be used to execute design
ideas in a broad range of architectural styles.
 Economy: A second important advantage of precast
concrete is the manufacturing process itself; low
consumption of material (Concrete & Steel). The
prestressing process saves steel up to 50% and even
more. In addition, highly developed factory
production techniques within the precast industry
help to ensure a high-quality finished product,
which meets the project’s requirements for cost and
schedule.
 Environmental Impact: Precast concrete is an
environmentally sound material. It is produced
from natural materials. No toxic substances are
produced in its production or use. Also, the
production energy consumption of the concrete is
quite small.
1.3 Wall panel system:
Precast wall frame construction is
increasingly being used for the entire range of
buildings, from residential to high-rise. Precast
concrete has been used since the early twentieth
century and came into wide use in the 1960s. The
exterior surface of precast concrete can vary from an
exposed aggregate finish that is highly ornamental to
a form face finish that is similar to cast-in-place.
Some precast panels act as column covers while
others extend over several floors in height and
incorporate window openings.
In most cases, the architect selects the
cladding material for appearance, provides details for
weather proofing, and specifies performance criteria.
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The structural engineer designs the structure to hold
the cladding, designates connection points, and
evaluates the effects of structural movement on the
cladding. The precast concrete manufacturer designs
the cladding for the specified loads, erection loads,
connection details, and provides for the Weather
proofing, performance and durability of the cladding
itself. Precast concrete wall systems offer a wide
variety of shapes, colours, textures, and finishes to
the designer. As a result, the assessment of samples is
a key component in the use of precast concrete. The
majority of the review and approval process is
conducted at the precast plant prior to precast panel
production. This assessment is in addition to the
quality control and field testing that takes place
during the production phase.
Typically,
each
precast
panel
is
independently supported to the building structure
using an assemblage of metal components and
anchors. Joints around each of the precast panels are
usually filled with sealant.
2.0 Precast Wall Panel.
Concrete panels can be used either as
cladding to the building, or as part of the loadbearing
structure, supporting roof or wind loads.
There are generally three types of precast wall panels
used as part of building envelopes:
2.1 Precast load-bearing walls.
2.2 Precast Cladding / Curtain / Façade Nonload bearing walls.
2.3 Precast Shear walls.
2.1 Precast load bearing walls.
Load-bearing wall units resist and transfer
loads from other elements and cannot be removed
without affecting the strength or stability of the
building. Typical load-bearing wall units include
solid wall panels, and window wall and spandrel
panels.
Precast load bearing walls provide an
economical solution when compared to the
conventional column/ beam/ infill wall system. The
primary advantages are speed of construction and
elimination of wet trades. In adopting the wall
thickness, structural adequacy is not the sole
consideration. Other factors to be considered include:
 Connection details for supported beams and slabs.
 Sound transmission and fire rating.
 Joint details at panel-to-panel connections.
 Possible future embedded services, which could
reduce the concrete area available.
2.2 Precast Cladding / Curtain / Façade Non-load
bearing walls.
Precast cladding / curtain / façade non-load
bearing walls are the most common use of precast
concrete for building envelopes. These types of
precast concrete panels do not transfer vertical loads
but simply enclose the space. They are only designed
to resist wind, seismic forces generated by their own
weight, and forces required to transfer the weight of
the panel to the support. Common cladding units
include wall panels, window wall units, spandrels,
mullions, and column covers. These units can usually
be removed individually if necessary.
This panel is achieved by any of the following
methods:
 The façade panel is connected to main load
bearing walls and is designed to carry its own
weight between supports.
 The façade panel is connected to the floor slab or
beam, which is then designed to provide support
to the wall.
A typical panel thickness of 120mm is
proposed on the basis of strength considerations and
to accommodate window fixings and profiles around
the window perimeter. Façade panels will often
require three-dimensional architectural features, such
as hoods, sills and ledges. In cases where there is a
reasonable degree of repetition, customised moulds
can be produced, enabling these features to be
economically incorporated into the panels. As an
alternative, when repetition is limited, it will be most
economical to cast the façade panel flat and
subsequently add the features, manufactured
separately using materials such as precast concrete,
GRC, Aluminium or steel.
2.3 Precast Shear Walls.
Precast concrete shear wall panels are used
to provide lateral load resisting system when
combined with diaphragm action of the floor
construction. The effectiveness of precast shear walls
is largely dependent upon the panel-to-panel
connections.
3.0 Preliminary Considerations.
The structural design process is commenced
by dividing the walls into panels of appropriate size.
This involves:
3.1 Site constraints.
The constraints of the site may determine the
maximum size and weight of panel that can be lifted
into position, and whether or not panels can be cast
on-site. For example a narrow allotment, basement or
slope may not allow crane access or space to cast
panels, while overhead power lines may limit the
height of the crane boom.
3.2 Support and Anchorage Systems.
The connections for precast concrete panels
are an important component of the envelope system.
Precast manufacturers utilize numerous different
types of anchors but they are often characterized as
gravity and lateral types of connections. The primary
purposes of the connection are to transfer load to the
supporting structure and provide stability.
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3.3 Joints and Joint Treatments and location.
The numerous joints in a precast concrete
envelope are an important aspect of the façade
design. The joints between precast units or between
precast and other building components must be
maintained to prevent leakage through the precast
wall system. Joint design should consider the
structural, thermal, and all other factors that affect the
performance and movement of a joint. The joint seal
should of course be adequately designed to withstand
the movement of the joint.
Door and window openings should be
considered when determining the location of joints.
The panel width next to an opening, and the panel
depth over a wide opening, must provide sufficient
structural strength to allow for the support of the
panel, plus lifting and erection forces.
The location of joints between external wall panels
should be selected based on careful consideration of
the following factors:
3.3.1 Structural Considerations.
External wall panels may be load bearing (e.g.
side walls of corner terrace, semi-detached or
detached) or non-load bearing (e.g. front and rear
façade panels). In selecting panel joint locations, it is
important to consider the panel stability (i.e. ability to
resist horizontal loads such as wind pressure or loads
specified in the Building Regulations Fourth
Schedule).
3.3.2 Aesthetics.
Whilst in general, panel joints are not highly
visible, locations should be selected which minimise
any potential impact on the external façade
aesthetics. In general, vertical joints should align for
the full height of the building and would preferably
be located symmetrically with respect to adjacent
features.
Figure 3.3.4.1
spandrels, the requirements for each individual panel
need to be considered. Referring to figure 3.3.4.1
 600 mm is usually a comfortable minimum
leg or mullion width.
 900 mm is usually a comfortable minimum
spandrel depth.
Some leg and mullion widths may need to be
more than 600 mm in width, Figure 3.3.4.2. Some leg
and mullion widths could be less than 600 mm in
width, Figure 3.3.4.3. If in doubt, a useful test is to
consider if the panel would still be structurally
satisfactory without the mullion. If the answer is yes,
then it may be possible to reduce the mullion width to
less than 600 mm. However, consideration should be
given to the vulnerability of thin mullions to damage
by accidental loading during erection. For factory
precast panels, minimum leg, mullion and spandrel
dimensions may be controlled by transportation
requirements rather than lifting stresses alone.
3.3.3 Panel Weight.
The weight of panels will dictate the crane
capacity required for installation of the wall panels.
Apart from the disadvantage of higher cost, larger
capacity cranes may not be able to access the site. For
typical conditions, a weight limitation of
approximately 4 tonnes is considered likely to be
applicable. In general, the panel size should be
maximized, leading to increased speed of
construction and reduced number of panel joints to be
treated.
3.3.4 Panel Dimensions.
Having assessed the maximum panel weight
that can be lifted, the panel dimensions can be
determined by considering the all height and lengths
required, and any openings to be included. For sitecast panels with openings, while the following rules
of thumb’ provide a starting point in determining the
minimum dimensions for legs, mullions and
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Figure 3.3.4.2
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3.3.5 Transport Limitations.
For transportation purposes, it is necessary to
limit one of the panel dimensions to 3.6m. In general,
panel heights will be less than 3.6m and panel length
is based on weight or other considerations. When the
required panel height exceeds 3.6m, the length of
panel will be reduced to 3.6m or less. Early planning
for site access must be undertaken, particularly when
houses are built along Category 5 road.
3.3.6 Internal Crack Control.
To minimise the risk of cracks appearing at the
internal face of wall panel joints, the following
considerations are relevant:
 If possible, locate panel joints at internal wall
intersections, inside service ducts or wardrobes
and at other non-visible locations.
Figure 3.3.4.3
 Avoid panel joints towards mid span of floors,
where beam or slab deflections could lead to joint
opening.
 Avoid long continuous runs of panels, where
accumulated shrinkage could result in joint
cracking.
3.4 Economics.
3.4.1 Structural layout.
The structural layout, particularly the rafter
spacing, will often determine the joint locations and
panel dimensions. Panel dimensions should not
dictate the frame spacing as the cost per square metre
for panels of comparable size is about the same,
whereas closer than optimum frame spacing can incur
considerable extra cost. If factory precast panels are
used, transport restrictions on panel size may dictate
the layout.
3.4.2 Construction at or near the boundary.
If walls are located at or near the boundary,
this will affect the footing design. Also, if adjacent
buildings are on the boundary, consideration needs to
be given to matters such as the erection process, base
joint details, sealing of wall joints and flashing
between buildings, as work must be completed from
one side only.
3.4.3 Casting areas.
Can the floor slab be used as a casting bed or
are temporary casting beds required? To ensure the
quality of panels, the surface tolerances, joint details
(sealing of joints) and surface finishing requirements
should be considered. Panels precast off-site will
eliminate the need for areas to be made available for
casting, a significant consideration if the site is
congested.
3.4.4 Stack casting.
The stacking order to enable an efficient erection
sequence should be considered. Panels with openings
should preferably be placed on top of stacks to
eliminate the need for blocking out the openings to
form subsequent panels.
3.4.5 Cranage:
Consideration should be given to matters
such as crane capacity, lifting locations to minimise
the number of setups and access.
Note: While the Engineer needs to consider all these
matters, others involved in the process also have
responsibility for specific areas, eg casting, delivery
sequence, cranage, temporary propping.
3.5 Marketability of the building.
This involves both the utility and aesthetics
of the building. Utility covers items such as the
requirements for access, column free space and
flexibility to meet the needs of subsequent
owners/occupiers. Aesthetics involves an acceptable
level of finish to the panels and façade features to
give an appealing exterior. Provision for later
removal of panels to create openings or allow the
building to be extended may also be a consideration.
3.6 Crane Size.
While the final practicality of lifting panels
must be verified with the crane contractor using
appropriate crane charts (for the available crane), the
information in Table 1 can be used as a starting guide
to the panel weights that can be lifted by various
sized cranes.
‘Heavy’ panels are panels the crane may lift
from a favourable position, i.e. lifted and erected
close to the crane setup position. It is unlikely that all
panels will be ‘heavy’ panels, so a few ‘heavy’
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panels may be able to be accommodated by planning
the casting location or delivery access, and crane
setup with respect to the final panel location. Once
the crane size as been confirmed, the panel area and
size can then be determined. As a guide, for the
common panel thicknesses, the panel eights for a
concrete density of 2400 kg/m3 are given in Table 2.
For heavily reinforced panels, the additional weight
of the reinforcement may need to be considered to
accurately determine the appropriate carnage.
Table 3.6.1 Crane size to panel weight
Crane
Capacity (t)
Panel Weight
50 (hydraulic)
Typical (t)
10-15
Heavy (t)
18
70
120-140
200
12-18
18-25
10-28
23
35
50
Table 3.6.2 Weight of common panel
thicknesses
Panel thickness (mm)
Panel weight
(t/sq.m)
130
0.32
150
0.36
175
0.42
4.0 Precast Floor System.
In Precast floor systems, cast in-situ structural
topping is adopted, based on the following
considerations:
 Precast slabs are less thickness and thus reduced
weight.
 Different composite slab thickness can be
achieved, as required by structural considerations,
by varying the topping thickness but keeping the
precast thickness constant.
 The topping concrete and reinforcement provide a
simple means of tying the floor and wall
components together.
 Services are simply provided at site within the
topping concrete.
Services within the bathroom and toilet
floors are generally of significant diameter and
required to be laid to fall. In these areas, it is likely
that a minimum topping thickness of 85mm would be
necessary to incorporate these services. Assuming
that the slab soffit is flat, to limit the total slab
thickness for the floor adjacent to the bathroom, it is
encouraged to limit to only one drop of 50mm at the
wet areas. For shower areas, it is recommended to
have kerb instead of a second drop to avoid
thickening the slab at non-drop area.
This precast floor system comprises
Prestressed planks spanning between load-bearing
walls. Where voids, stairs and other features prevent
the slabs from spanning between walls, slabs
spanning perpendicularly are provided, supported by
the adjacent planks.
The merits of this system are as follows:
 Floor beams are eliminated, resulting in simpler
components and reduced services coordination
problems.
 Stepping of building line at front and rear are
easily accommodated.
 Full height window and other facade features can
be designed
 Can accommodate irregular layouts, with fewer
requirements for false ceilings.
 In this system, the following factors need to be
considered:
 At roof level, any significant RC gutters will
prevent slabs from spanning between walls.
 For some floor layouts, alignment of stair
openings and voids can prevent slabs from
spanning between walls.
 The volume of concrete for this system is likely to
be 0 ~ 20% higher than conventional RC beam
and slab.
5.1 Case study:
The present study has been concentrated on a
2BHK seven storied (G+7) residential buildings. The
plan of 1 unit (2BHK) of buildings is shown in fig.
Each unit 4 times mirror in horizontal direction and
1time in vertical direction. Total 8 units (Flat) is
present in each story. The height of each story of the
building is 3m. Half slab of thickness 75mm &
structural topping thickness 50mm has been
considered for all stores. Thickness of all walls will
be considered 125mm. As per IS: 875(Part-2)-1987,
Live load intensity of 2 kN/mm2 has been assumed on
each story and the roof has been assumed a uniform
live load intensity in 1.5 kN/mm2. The modeling has
been performed by Staad-Pro V8i Software. Whole
model is a plate model. Including more than 50,000
plates. The seismic zone is III. Grade of concrete is
M40 and for steel Fe500. The values of various
factors have been assumed as per IS: 1893(Part-1) 2002. The design of members will be carried out as
per IS: 456-2000 & ACI 318R-08.
4.1 Floor System - Prestressed Plank and HalfSlab Floor System.
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6.1 Connection:
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7.1 Conclusions:
Pre-fabrication has a great potential to
respond to new market demands. Possible solution lie
not only within the classical advantages related to
working conditions, technology & speed of
construction, but also in new developments of
materials such as high performances & selfcompacting concrete, buildings system such as mixed
structures, manufacturing technology, automation,
service integrated products & others.
Precast wall panel system is a modern
industrialised and environmentally friendly method
of construction, with a bright and promising future.
8.1 References:
 Precast Concrete Structure – Kim Elliott.
 One Day National Workshop on Precast
Concrete Building in India. Organised by:
Indian Concrete Institute (ICE).
 IS : 11447 – 1985 Code of Practice for
construction with large panel
prefabrications.
 ACI 318R-08
 BS EN 1990-2002 - Eurocode- Basis of
Structural Design.
 PCI Industry Handbook, 6th Edition.
 www.elematic.com
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