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.
· 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.
· General consideration for crane selection.
1.Total lifting weight.
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.
8.Installation of vertical components.
9.Verification of delivered panels.
10Check. the panels delivered for correct marking liftinglook and position etc.
11Surface. finishing conditions.
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
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
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