Prefabricated Materials :
Prefabricated
building materials are used for buildings that are manufactured off-site and
shipped later to assemble at the final location same of the commonly used
prefabricated building materials are aluminum steel, wood, fiberglass and
concrete.
Prefabricated
metal buildings use galvanized Steel and galvalume as s the chief materials for
building. Galvalume is a form of Steel coated
with aluminum Zinc.
This is
to protect the building against corrosion rust
and fire. It also provides a sturdy and protective covering to the
prefabricated building. Almost all the components of a metal building such as
beams, frames, columns, walls & roofs are made of steel. Most prefabricated military buildings use
steel or aluminum frames.
(Synthetic materials are used for the
walls & roofs. To provide enhanced security a combination of both metal and
cloth materials are used. Plastic flooring materials can be quickly assembled and are very durable)
Prefabricated,
building materials used for small prefabricated buildings are steel, wood,
fiberglass. Plastic or aluminum
materials. These materials are cheaper than regular brick and concrete
buildings. Materials like steel, fiberglass, wood and aluminum are used as
prefabricated building materials for sports buildings. These materials provide
flexibility and are preferred rfor making structures and accessories like
stands and seats for stadium and gyms.
For making low cost housed, prefabricated
materials like straw bale, Ferro cement calcium silicate. Products, campsites
and other cheap wood based materials are currently being used calcium silicate
bricks are strong and durable. Ferro cement consists of a cement matrix
reinforced with a mesh of closely-spaced iron rods or wires. In this type of
construction, the techniques used are simple & quick.
Using Prefabricated materials one can make durable
water and fire resistant and cheap prefabricated buildings. Most of the
prefabricated building materials are eco-friendly & affordable.
Ø Precast structure
Installation (Erection)
The
following steps to be followed to erect the precast structure :
5. Planning
for precast installation
6. Installation
process.
7. Installation
using Big canopy
8. Installation
construction Management.
9. Mishandling
of precast panels.
10.Common
defects in precast panels.
11.Precast failures.
·
Planning for precast installation.:
1.1 Planning co-ordination. It is important to have the
precaster erector / installer and builder working together to achieve best
performances.
1.2 Site Access and
storage :
¨ Check for
site accessibility and precast panels delivery to site especially low bed
trailers.
¨ Check
whether adequate space for temporary storage before installation and ground
conditions firm ground & leveled)
¨ Uneven
ground will cause overstress & crack
panels.
1.3 Planning
crane Arrangement :
1. Plan the
crane capacity and lifting gears based on
1. Heavies
weight of precast panels.
2. Lifting
heights.
3. Working
radius.
4. Position
of crane in relation to final location.
·
Plan other equipments
1.Boom lift
and scissor lift for unhooking installed panels. 2.Lifting gears.
·
Skilled personnel's :
1.Competent
crane operators.
2.Rigger
3.Signaled
etc.
·
General consideration for crane selection.
1.Total lifting weight.
2.Crane Model
3. .Crane safe working load (SWL)
i.e. Based on 75% capacity build in F.O.S,1.33 - Lifting
capacity must be 1.5 times the total weight i.e) F.O.S. 1.5
4.Lifting
and swing radius.
5.Crane
counter weight.
6.Crane boom length is relation to the vertical and horizontal clearance
from the building.
7.Installation
process.
8.Installation
of vertical components.
9.Verification
of delivered panels.
10Check. the panels delivered for correct marking liftinglook and position
etc.
11Surface. finishing
conditions.
12Pc.Dimension
compliance.
13Reinforcement. provision
14Architectural. detail
compliance.
·
Setting out.
1. Check the
panels delivered for marking lifting hook and condition.
2. Set the
reference lines & grids.
3.Check starter bars for vertical components
before hoisting for installation.
v Setting
out quality control points.:
1. Ensure
correct offset line.
2. Check
'Shim Pad'/plate level and firm.
3. Rubber
gasket property secured.
4. For
external wall / column place backer rod.
v Hoisting,
Rigging and installation :
1. While
tilting provide rubber pad to avoid chip off.
2. Lift and
rig the panel to designated location.
3. Adjust
the panel in position and secure.
4. Lifting of
space adding items with balanced center of gravity.
5. Ensure
horizontal alignment correct.
6. Ensure
panel vertically to correct plumb.
7. Check
panel to panel gap consistency.
8. Check
stability of prop before releasing hoisting cable.
v Grouting
works :
1. Prepare
and apply non shrink mortars to seal gap
2. For
corrugated pipe sleeve or splice sleeve pour NSGT or proprietary grouts into
pipe sleep.
3. Keep
installed panels undisturbed for 24 yrs.
4. Check
joint widths are consistent before grouting.
5. Grout
used should be same grade of components and self compacting to prevent
cracking.
6. Collect
test cube sample for testing for critical elements or load bearing elements.
v Connecting
joints :
1. Cast
in situ joints, install rebar's as required
2. Set up
forms for casting joints.
3. Do
connecting.
4. Remove
forms after sufficient strength.
5. For
external connections welding as required.
Installation of Horizontal
Elements :
·
Setting out :
1.Set reference line / offset line to required alignment and
level of slab / beam
during
installation.
2.Put temporary prop to support the precast slab / bear
elements. 3.Before hoisting check dimensions.
4.Check
level and stability of shim.
5.Check protruding / starter bars are within the specified
tolerance any obstruction
Specified
colerance to prevent any obstruction during the erection process
Hoisting
installation
1.Put temporary props to support slab or beam. 2.Lift and rig
the elements to designated location 3.Align and check the level before
placement 4.The beams shall prop atleast two locations
5. check
level of precast elements
Connection
and jointing
1.precast with cast-in0situ joints place the lap rebars as
required. 2.Set formwork for casting joints
3.Remove formwork after concrete strength is achvieved
4.Supporting beams shall be designed to form part of formwork
joints
5.The connecting or lapping rebars tied and secured
6.same
grade of concrete to be used that of panel
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