In a scenario of largely scarce and expensive labour force, need of fast track projects and high quality, construction industry is slowly moving towards precast construction. The study speaks about the scope for precast technology in urban and allied infrastructure domains in the form of culverts, bridges and pipe lines infrastructure that leads to faster, neater construction with much less site labour, better site control, greater accuracy and quality of finish.

Precast technology in bridges and flyovers is common all over the world and consequently India has also leaped into it in the form of segmental construction for bridges, culverts, deck slab and segments for viaducts for metros.

Bridges and Flyovers

Precast technology ventured into pre-stressed bridge planks, pre-stressed Double T Slabs and I girders, post tensioned girders, piles, modular deck units, railway box girders, bridge piers, headstocks, abutments, etc. and other heavy constructions.

Most common prefabricated elements for bridge connections are pre-stressed elements such as I beam, box beam, channel/U shaped elements and other segments.

Urban infrastructure: As the concept of smart cities is being materialised in India, infrastructure is expected in short time period with minimal maintenance in the form of water drains, pathways, walkovers, service ducts, underground chambers, precast electrical poles and their foundation, road dividers, traffic barrier, etc.

This category also comprises of pre-stressed kerbs, tactile tiles, bollards, tree guards, precast paving slab, grease interceptors, headwalls, road medians, precast bicycle tracks, precast bicycle tracks with storm water drainage underneath, precast slabs with finishes, storm water channels, signage, precast benches, precast steps, precast reinforced ramp system, precast traffic islands, precast planter boxes. Precast elements like trenches, road elements can be re-used in case of change in service alignment with minimal damage to the elements.

Precast in allied infrastructure

Pipe line infrastructure: Pipe lines are laid across states for conveyance of different resources. Where the alignment passes through the adverse locations, the use of precast elements simplifies the execution. Precast pipes, precast pipe holders, pipe chambers are some of such elements.

Culverts: Precast elements can be put to use in Canal lining, culverts, channels, river intake cabins, spillways, walkover bridges, sewage drains, water storage tanks, ground irrigation, it can minimise wastage and ensure quality and delivery of infrastructure projects in stipulated time-frame.

Precast in infrastructure can also find its use in culverts. They may be three sided or four sided. Three sided units allow for stream crossings maintaining the natural stream-bed. A four-sided box culvert unit is generally used as a permanent service tunnel or a carrier tunnel for underground piping. Precast box culverts are superior quality, require low maintenance and have large number of applications including storm sewers, service tunnels, or small bridges for stream crossings.

Precast box culverts

As a part of external development works of the multilevel car park, Precast India produced culverts to cater for future provision of underground services of the state Industrial Development Corporation, without the need to excavate the newly laid concrete road at the main gate of the car park.

The culverts were installed overnight so as not to disrupt the traffic during the peak traffic hours of the day. The hollow core slabs were placed over the culverts and cast in place screed was done.

Conclusion

Precast construction has a wide scope to establish itself in infrastructure. However, the challenge lies in the fact that cities are highly populated, and traffic is increasing day by day. Precast is the best suitable option, as it does not hinder the traffic flow with construction taking place at a faster pace. The governing authorities must thereby encourage precast in infrastructure tenders.

As the efforts to transform cities to smart cities are gaining momentum in the country, precast satisfies the requirements like underground services, subways, tunnels, roads, pavements, flyovers etc.

The conventional construction methodologies are highly un-standardised even today. In case of complex projects, probability of human error and accidents is high. Precast Construction standardizes various construction methodologies and work procedures both on site and off site. Cost and time, the two driving factors of every project can be controlled efficiently in Precast Construction. Need for huge construction labour, cost and time overruns, accidents at site, time consumption, resource wastage are alleviated to a greater extent in Precast Construction.

The  un-paralleled   advantages of precast in infrastructure projects viz. superior quality due to controlled environment, reduction in project duration, minimised material wastage,standardisation of methodologies, effective pre-engineering by use of BIM software for modelling the structure at element level, reduction in on-site activities definitely supersedes the additional cost incurred in Precast in terms of machinery and transportation of elements.

Authored by:
Kapilesh Ajit Bhate
Deputy Manager – Tendering, Planning and Control,
Precast India Infrastructures Pvt Ltd
Mob: +91-9822013316
Email: ajitbhate@precastindia.co.in