Pre-engineered buildings allow a large part of the construction activity to be carried out off-site, thus offering an economic solution by cutting down the project duration.
A Pre-engineered building is basically a kit of parts with specified assembly details, fabricated to suit a range of design conditions.
They are fully fabricated in a factory under controlled conditions, transported as an inventory of components and assembled and erected on site.
Design considerations deal with spanning and loading criteria while also considering practical issues like convenience of transport and on-site assembly. The metal building is composed of primary structural framing members, secondary members (which support and fix the cladding) and the S panels. Typically the steel frame is in– I sections, castellated beams, or trusses.
Sheet materials may be fibreglass, galvanized iron or pre-coated sheets.
Since fabrication is an off-site activity, it can be simultaneous with other activities and cut down project time by 30 to 40 per cent.
Savings in design costs and economies of mass production also make it an economic option. It is an ideal solution in partially occupied sites, since it limits the disturbance to existing activities by speeding up construction. The customer enjoys the benefit of procuring the entire building from a single source.
The building can be dismantled and relocated.
Most materials can be reused and the modular basis allows easy expansion. Variety in panels, colours and finishes allows variations in aesthetic appearance. Prefabricated insulated panels are also available and help in energy savings by offering thermal insulation.
Concerns and safety measures
The building requires careful integration with the physical system of the site and services like power, ventilation, water supply and fire fighting.
It is imperative to adhere to manufacturer’s data regarding design loading and standard assembly details while also checking for compliance with local building rules.
All finishes may not be included and requiring further work on finishes and fit-outs. Requisite fire protection, an area of weakness in steel buildings and particularly relevant to optimized sections, can entail higher costs. Despite available variety, they can have a monotonous and industrial look.
What are they ideal for?
They are ideal for spaces which require clear spans and have a modular, repetitive plan.
Transport structures like railway stations and aircraft hangars, industrial buildings, warehouses, service stations and agricultural buildings are common examples. This technology has extended to showrooms, retail outlets and office buildings. Portable office cabins are regularly used on construction sites.
In the residential sector, pre-engineered systems are common in garden structures, greenhouses, garages and carports. Final word
Smaller components of buildings such as canopies, mezzanine floors and stairs may also be pre-engineered.