Advantages And Disadvantages Of Prefabrication

• Prefabrication is a modern construction method in which structural components are prefabricated in a manufacturing or production site and then transported to the site location where their erection is carried out.

• Structural elements such as beams, slabs, walls and floor are prefabricated in a manufacturing site, transported to the location of the structure, lifted by a crane and erected in their positions whereas foundation is constructed in a conventional way.

• This method saves time and cost if the design uses repeated element sizes.

• This method reduces the wastage of materials, time and helps in quicker construction irrespective of suitable climatic conditions.

• The disadvantages lie in the transportation of prefabricated sections, their transportation cost and the

• Prestressed concrete is a modern material in which the stresses resulting from external loads are counteracted to a desired degree by introducing internal stresses of a suitable magnitude.

• In reinforced concrete members, the prestress is commonly introduced by tensioning the steel reinforcement.

• The apparent tensile strength of a material like concrete, which is strong in compression but weak in tension, is increased by application of permanent compressive stresses.

• ¬¬¬¬Once the initial compression has been applied, the resulting material has the features of ductile high-strength steel when subject to tension forces and high-strength concrete when subjected to any compression forces. The tensile strength of the material increases because the subsequent application of tensile stress must nullify the compressive prestress.

• This can result in improved structural capacity and serviceability compared to conventionally reinforced concrete.

• High-strength tendons are used to produce compression. They are made of high- tensile steels, carbon fibers etc. and consist of threaded bars, single or multiple