Speeding Up Construction: Increasing adoption of prefabricated technology

The construction and infrastructure sectors play a huge role in propelling the ov­er­all development of a country. The In­di­an government focuses on infrastructure development and construction through enab­l­ing policies and increased budgetary allocations. India aims at becoming the third-largest construction market globally by 2025. To that end, the government and private developers are focusing on deploying techniques that make construction faster, easier and more efficient. One of the key techniques that can help accelerate construction activities is the use of precast or prefabricated components. The construction sector is deploying prefabricated te­ch­nology primarily in the metro, real estate, road and railway sectors.

Over the past few decades, prefabrication has brought substantial change in the development of the construction industry worldwide. Pre-assembly, prefabrication, modularisation and precasting are various terms used to des­cribe the processes of manufacturing modular units on-site or off-site. Prefabrication is a feasible solution in place of existing conventional techniques, and helps in expediting the constr­uc­tion process. Many advanced nations have accepted the prefabricated construction technique to reap benefits from the same.

Need and benefits of prefabrication

At present, the Indian construction industry is swamped with issues of time overruns, labour dependence and clearance issues. The sector also continues to be dependent primarily on con­ventional construction practices. Even though the cost of transitioning to prefabricated construction is higher, in the long term, prefabrication can provide developers and contractors with the advantage of time, security and quality construction. This will allow them to complete projects quickly and meet the demand. Pre­ca­sting or prefabrication is a technique of construction wherein various components are built off-site or at manufacturing sites. They are then transported to construction sites where workers assemble them on-site.

Apart from being a dependable means of construction, prefabrication has various other advantages including increasing pace of work, security, sustainability, quality maintenance, en­ergy efficiency, and minimal wastage and in­s­pection woes. The requirement for formwork, shuttering and scaffolding is significantly re­du­ced as self-supporting ready-made componen­ts are used in prefabricated construction. With the reduction in construction time, labour costs are also reduced. Further, the reduction in construction time also allows an earlier retu­rn of the principal invested in projects.

In the case of real estate, prefabricated buil­­dings ensure accurate conformity to building standards and the use of good quality material. The prefabrication site can be positioned where skilled labour is readily accessible and expenses on labour, power, materials, space and overheads are, therefore, minimised. Fur­ther, in off-site constructions, the safety and com­fort level of workers are higher, which correspondingly increases their work efficiency. According to the Ministry of Road Transport and Highways (MoRTH), industrialised precast concrete has benefits of all-weather and faster construction, reliable quality and enhanced perfor­mance durability, aesthetics, minimum user time delay, reduced carbon emission, and lesser noise and air pollution due to reduced construction activities at site.

Applications of prefabrication in India

In India, road is one of the key sectors that is working towards the adoption of prefabrication/precast technology. To that end, in April 2022, MoRTH launched the National Highway Precast Concrete Policy. In order to harness the benefits of prefabrication in the construction of national highways, expressways and other centrally sponsored road projects, MoRTH has man­dated the use of factory-manufactured precast concrete elements in projects within 100 km radius of a precast factory. The minimum mandatory usage should be 25 per cent of the total concrete volume, other than foundations and substructures of bridges, viaducts and road over-bridges.

In January 2023, MoRTH announced the use of prefabricated material for making roads, which is expected to increase the pace of highway construction from 33 km a day at present to 100 km-150 km a day. Meanwhile, in Nov­em­ber 2022, the Bruhat Bengaluru Mahana­gara Palike (BBMP) launched a “rapid road te­ch­nology,” whi­ch used precast concrete slabs to white-top a 500 metre stretch at the Binna­mangala junction. This was a pilot project under which BBMP embedded prefabricated concrete slabs (20 feet in length and 5 feet in width) on the road. The concretised slabs were then connected by steel cables on either side of the joints using cranes. According to BBMP officials, the rapid road technology helps in white-topping 0.5 km of road in a day and the entire project can be completed in five days (as opposed to 26-28 days using conventional me­thods) including one or two days for preparatory work such as milling and levelling, before placing concrete slabs. In a similar way, the state public works department in Nagpur constructed a cement concrete road of 100 me­tres within six hours in 2020. This was done using prestressed precast concrete pavement technology. The completion of work on the same stretch would take one month or more using conventional ways.

Another sector where prefabrication technology is being deployed for faster construction is railways and metro. In September 2021, In­dian Railways successfully launched the in­di­genously designed and manufactured full-span launching equipment-straddle carrier and girder transporter to expedite the construction of the viaduct for the Mumbai-Ahmedabad high speed rail project. This technology helps speed up the process of launching girders, as precast girders of full-span length are erected as a single piece for double-track viaducts.

Redevelopment works for the Gurugram and Chandigarh railway stations will also use precast segments to ensure speedier completion. The projects are dubbed “lighthouse projects”, wherein the contractor develops a sc­heme and method based on modularisation. The station will be developed under the modular concept, in which pre-engineered and prefabricated components will be used. The established technique will then be replicated in all station development works to be carried out on the network.

The Lucknow metro (Phase I) involved construction of an 8.5 km stretch that was completed in 36 months, with the help of precast construction. The pier caps were precast; cast in a yard in moulds and transported to site on low bed trailers and erected on in situ piers. Si­milarly, precast construction was used to en­sure speedier completion of the Kanpur me­tro. The National Capital Region Transport Cor­po­ration has also decided to construct a uni­que precast slab track system for the Delhi-Meerut rapid rail transit corridor. The technology produces high capacity ballastless track slabs that have a longer life cycle and require less maintenance, which also lowers the overall life cycle cost of the track.

Issues and challenges

The requirement of skilled labour at site and shortage of on-site automation are amongst the major issues faced in the acceptance of prefabrication technologies in construction. As the technology requires accuracy and precision, it is imperative that the workforce handling prefabricated components is well trained. Thus, skill development is mandatory for the installation of the prefabricated systems. For prefabricated construction, machine-oriented skills are re­qui­red both on-site and in the manufacturing pro­cess. Another challenge faced in prefabrication is the high initial cost of set-up and higher transportation costs for huge prefabricated sections. Further, an increased production volume is necessary to make sure aff­ordability can be ac­hieved through prefabrication. Huge prefabricated sections need heavy duty cranes and accuracy measurement from handling to working on site.

Apart from this, lack of standardisation, certification and testing facilities; contractual iss­ues and taxation; non-availability of tools; technology and equipment; and lack of government incentives and promotion are some of the major challenges that are faced by Indian contractors for the implementation of prefabrication.

Potential of prefabrication in India

Keeping in line with the ambitious National Infrastructure Pipeline and the government’s aim to transform India into a $5 trillion economy by 2024, infrastructure development and construction are witnessing burgeoning de­mand. It is imperative that the timelines of all these projects are met in order to ensure holistic development of the country. Use of prefabrication or precast components is a tested way that ensures timely project completion, along with maintaining the quality of work. With a robust line-up of projects across various infrastructure sectors, it is expected that prefabrication will play a significant role in construction activities.

Disha Khanna