Prefabricated Buildings

PREPARED BY:

RAVI KUMAR

M.TECH,2ND SEMESTERBEDM

INTRODUCTION

Prefabrication is the practice of assembling components of a structure in a factory or other manufacturing site, and transporting complete assemblies or sub-assemblies to the construction site where the structure is to be located.

Prefabrication, in architectural construction, is a technique whereby large units of a building are produced in factories to be assembled, ready-made, on the building site.

THE HISTORY OF THE PREFABRICATED BUILDINGS

Possibly the first advertised prefab house was the Manning Portable Cottage. A London carpenter, H. Manning, constructed a house that was built in components, then shipped and assembled by British emigrants.

The peak year for the importation of portable buildings to Australia was 1853, when several hundred arrived. These have been identified as coming from Liverpool, Boston and Singapore (with Chinese instructions for re-assembly).

Aims of Prefabrication

Speed up the construction time.

Lower the labour cost.

Allow the year round construction.

Ensure precise conformity to building codes , standards and greater quality assurance.

Allow less wastage of materials than n in site- built construction.

Ensure higher worker safety and comfort level than in site- built construction

Prefabricated Housing

Prefabricated building is a type of building that consists of several factory-built components or units that are assembled on-site to complete the unit. “Prefabricated” are built in:

Manufactured homes (Transportable sections )Modular homes (Modules)Components (panels)

Manufactured Homes

"Manufactured homes are built as dwelling units of at least 320 square feet (30 m2) in size with a permanent chassis to assure the initial and continued transportability of the home.“

Assembled in factories and then transported to sites of use.

Modular Homes

They are sectional prefabricated buildings, or houses, that consist of multiple sections called modules.

They are transported and to the home site for construction and installation.

Modular and Manufactured homes are NOT the same.

Prefabricated Building Systems

Large-panel systems Jump form system Frame system

Large panel system

It is composed of large wall and floor concrete panels connected in the vertical and horizontal directions so that the wall panels enclose appropriate spaces for the rooms within a building.

Frame System

Precast frames can be constructed using either linear elements or beam-column.

Advantages

Mass production of units Reduction of costs and construction time on site: Aesthetic Appeal Maintenance Free Large Clear Spans Controlled Quality

Disadvantages

1. Careful handling of prefabricated components such as concrete panels or steel and glass panels is required.

2. Prone to corrosion attack at the joints.

3. Similarly, leaks can form at

4. Transportation costs may be higher.

5. Large prefabricated sections require heavy-duty cranes and precision measurement and handling to place in position.

6. Local jobs are lost.

Works at CBRI-Roorkee

Design and development of prefabricated componentsHollow panel unit

Prefabricated Housing Unit for Disaster Management

Invented by Dante Bini A super-low-cost self-erecting

prefab housing unit used for disaster relief that can be easily moved from location to location, and takes less than a half-hour to build.

Conclusion

Their shorter build time will save you money on the overall construction.

They are much more energy efficient, and environmental friendly.

Due to the flexibility of the structure in expandability and appearance this prefab houses are the best choice.

From the several advantages like reusability, high scrap value, less construction time makes this user friendly. Also, they can be installed in passive weather conditions also.

References

1. Leblanc J T, Patent-Apparatus and process for placement of prefabricated structures, US 4517781 A, 21-05-1985

2. Firoz Syed et al. “Design concept of pre-engineered Building” IJERA, Vol. 2, Iseue-2, March-April-2012, pp-267-272

3. http://freshome.com/2013/03/27/10-basic-facts-about-modular-homes/

4. Annual Report 2009-10, CBRI Roorkee