Prefabricated structures are structures that are built-in pieces at the factory and assembled on the construction site, prefabricated structures can be portable or non-portable (permanently fixed to the foundation).
Sometimes, the components are cast on the site itself and assembled.
The method in which various components of a construction structure such as linear members, rigid frames, roof, and floor members are cast into the factory then moved to the location where they are assembled is called a prefabricated structure.
Here we will learn about prefabricated structures, components of prefabricated structures & much more.
Introduction to prefabricated structure:
Structures constructed by the method of pre-fabrication and precast are called prefabricated structures.
Prefabricated structure can be easily transported, assembled and dismantled.
After dismantling, it is again moved to the required location, where it can be reassembled easily.
Methods of prefabricated structure:
The process in which various precast concrete components are manufactured in the factory itself called plant pre-fabrication.
In-plant pre-fabrication, precast concrete components are manufactured under precise quality control and each precast member is inspected and tested then transported to the site.
These members are operated by hoist and crane equipment, the site requires heavy transport fees to carry a precast member.
When the process in which various precast concrete components are manufactured on site called site pre-fabrication.
It does not require any transportation fees to carry the precast member, but does require lifting equipment to assemble the precast components.
Laboratory testing for various materials required for components and precast components cannot be performed in site pre-fabrication.
Components of prefabricated structure:
This includes members such as beams, lintels, columns, walls that are forecast for pre-construction work.
This includes R.C.C. Portal frames, these rigid frames are manufactured at the factory and then transported to the required site.
This is very difficult to transport a rigid frame to the site because the overall size of the frame is high therefore desirable to construct a rigid frame on site.
Roofing and flooring members:
The various roofing and floor members are prefabricated in the factory then transported to the place where they are assembled.
R.C. doors and windows:
Reinforced concrete doors and windows are prefabricated at the factory then transported to site for installation.
Various wall panels of desired size and shape are prefabricated then transported to the site where they are assembled.
Advantages of prefabricated structure:
1.Mass manufacturing of units:
Automation of the manufacturing process can save labor and reduce the price, designers can use units of requirements and prepare entries for details.
2.The discount on prices and construction time on site:
Much less work to be accomplished on-site, saving the use of formwork on the site.
Precast units could be erected in a dangerous climate.
3.Effective use of formwork:
Metal formwork is often used and increases the diversity of users up to 200 times.
Precast units can be formed so that they are self-stripping and impose labor exemption on molds.
4.Improved high quality of units:
Factory manufacturing under strict high-quality control.
Prefabricated structure units could be carefully checked after manufacture.
5.The particular shape and surface finishes:
Items can be cast in any place, similar to an upside-down on their sides and so on.
Coloured concrete could be produced by using white cement and colour pigment.
6.Casting under cover:
Safety from scorching or drying winds.
Bolted connections could be easily dismantled and re-erected in other places.
8.Construction over and underwater:
No or little formwork is required, falsework will not be required.
Minimal disruption to visitors, the precast bridge could be constructed without falsework.
Disadvantages of prefabricated structure:
- Cautious handling of prefabricated parts similar to concrete panels or metal and glutes panels is required.
- The insert strength and corrosion resistance of the prefabricated sections should be considered to keep them away from joint failure.
- Equally, prefabricated parts might leak at the joints.
- Transportation prices could also be higher for voluminous prefabricated sections than for the materials that are made or might often be packed more compactly.
- Massive prefabricated sections require heavy-duty cranes to place in position, exact measurement, and handling.
- A small variety of units required might prove to be uneconomical.
- Particular connections, similar to special bearings to transmit vertical and horizontal loads can add value to the system.
Also read: RCC framed structure, Shell structure & Space frame structure
These prefabricated structure are inbuilt a managed factory environment.