With the launch of the ambitious National Infrastructure Pipeline (NIP) and the government’s aim to transform India into a $5 trillion economy by 2024, the construction sector has been witnessing increasing demand. The NIP has projected a capital expenditure of Rs 111 trillion, to be spent over the period 2019-20 to 2024-25. More than 70 per cent of this amount has been allocated for four infrastructure sectors – energy (24 per cent), roads (19 per cent), urban infrastructure (16 per cent) and railways (13 per cent). Alongside, there is a growing use of technology and alternative materials in the sector. There is also an increasing uptake of modular construction and digitalisation in the wake of the Covid-19 outbreak. In the design segment, many new technologies have been adopted such as building information modelling (BIM), which helps in planning resources and early clash detection.
Indian Infrastructure takes a look at some of the best practices in construction in key infrastructure sectors…
The road sector has always been a high-priority area for the government. In the past seven ye-ars, the length of the national highways has gone up by more than 50 per cent, from 91,287 km in April 2014 to around 141,000 km as of December 31, 2021. The road sector has undertaken many green construction initiatives. It is also using a variety of alternative construction materials and technologies to improve the quality and life of the highways and reduce construction time.
Major cities such as Delhi, Mumbai, Chennai and Pune have, for instance, actively started using shredded plastic waste in road construction. On December 18, 2021, the Ministry of Defence announced the signing of an MoU between the National Highways Authority of India (NHAI) and the National Cadet Corps to reuse plastic waste collected by cadets during its latest campaign, for construction of roads across the country.
In August 2021, the Municipal Corporation of Greater Mumbai decided to switch from multiple-pile foundation technology to monopile foundation technology for the construction of pillars for bridges and interchanges of the 10.58 km coastal road project, to be constructed from Princess Street to Worli. The adoption of the new technology is expected to reduce the project cost by Rs 120 million and the project completion time by three months. Further, in order to enhance transparency, ensure uniformity and leverage the latest technology, NHAI has made the use of drones mandatory for monthly video recording of national highway projects at all stages of development, construction, operations and maintenance.
The railway sector is another focus area for the government, with substantial network expansion and decongestion projects being undertaken. There is increasing adoption of digital and technological solutions, innovative tools and devices, and online monitoring systems, as well as the leveraging of BIM for designing and installing railway signalling systems. New materials are being used to improve the durability and strength of railway systems. Further, new construction techniques are being deployed by Indian Railways (IR) for track construction. The Khurja-Dadri section of the eastern dedicated freight corridor (DFC) is among the first track projects in the country to use the new track construction (NTC) machine. Seven NTC machines have been deployed along the DFC. While four have been deployed in the eastern DFC, three have been deployed in the western dedicated freight corridor. The NTC machine has the capability to lay 1.5 km of track per day. The machine brings substantial ease and efficiency in track construction with integrated logistics arrangements for mechanised handling, and movement and laying of heavy track components.
New construction technologies have also been deployed in the Mumbai-Ahmedabad high speed rail project. In September 2021, IR 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 project. This technology helps speed up the process of launching girders, as the precast girders of full-span length are erected as a single piece for double-track viaducts. The Shinso Pile Method, Underwater Static Refraction Tomography for the undersea tunnel, etc. will also be adopted for the project.
Smart machines were also deployed for various activities for the construction of tunnels in the Bhanupali-Bilaspur-Beri new railway line project. The use of these machines accelerated the excavation work, reduced the turnaround time, avoided overcuts and undercuts, and improved blasting efficiency. Clearly, the utilisation of smart machines is the way forward for construction in difficult topography.
Strategies adopted for faster execution of airport projects include the enhancement of resources and deployment of advanced technologies. For resource enhancement, there is a growing focus on the addition of manpower. In terms of advanced technologies, precast systems, plaster machines, horizontal slip forms and elevated platforms are being deployed. The Chennai Annadurai International Airport expansion and modernisation project in Tirusulam, 7 km south of Chennai, is a design-to-fabrication steel project carried out completely within a Tekla BIM software environment. By using Tekla Structures software in the project, material wastage was reduced by about 3.5 per cent and productivity increased by more than 30 per cent.
The country’s urban infrastructure received a major impetus with the launch of metro rail projects, which positively changed the urban transport landscape. The success of metro rail projects in Tier I cities led to a growing demand for similar systems in Tier II and Tier III cities.
In terms of metro rail construction practices, the precast methodology is increasingly being adopted across metro systems in order to expedite work. Several metro corporations such as those in Delhi, Chennai, Kochi and Mumbai have used U-girders, which are full-span girders. Upcoming metro lines are also being developed using these girders. Another trend in elevated station construction is the usage of pi-girders that are precast for platforms, unlike the traditional technique where the platform for metro stations is constructed in-situ. The Mumbai Metropolitan Region Development Authority is using pi-girders for Mumbai Metro Line 2A, which are being cast at the Bandra casting yard.
Various new technologies are being adopted in metro rail construction. Segmental bridges and the launchers for them as well as the shutters for single-span bridges have been modernised. Incremental bridges are being deployed, which were uncommon in the past. The Delhi Metro Rail Corporation (DMRC) was the first to use extradosed bridges for a metro rail project. Longer cantilever bridges are also being constructed. Meanwhile, BIM, advanced analytics, drones and internet of things-based digital monitoring systems are being used to manage projects more efficiently and effectively. Apart from this, intelligent control systems are being installed in new construction equipment to optimise work and increase efficiency. In November 2021, DMRC, in association with Bharat Electronics Limited, demonstrated the functioning of the supervisory control and data acquisition system, which is being developed as a monitoring system for equipment and assets to rationalise maintenance periodicity, manpower requirement and spares management.
Pain points and the road ahead
The construction segment continues to struggle with the issues of inadequate investigation, geological complexities, shifting of utilities, and mismanaged contracts. Projects have also been stalled or surrendered due to contractual issues. The outbreak of Covid-19 only exacerbated the situation. Contractors were faced with shortages of raw materials, equipment and labour, as well as idling plants and machinery.
While project execution has improved over the years, the increased level of activity in the construction sector has highlighted the need for more efficient contracting practices, adoption of new and innovative materials, and the deployment of cost-effective construction techniques and state-of-the-art equipment.
Going forward, both technology and sustainability will play a significant role in the construction sector. The industry is steadily shifting its focus to digitalisation to automate processes across design, construction and operations. The industry is expected to adopt advanced solutions such as cloud-based collaboration, digital twins, artificial intelligence, augmented reality, machine learning and BIM. Most construction companies in India are at an early stage of digital maturity and are prioritising digitalisation to ensure cost-effective and timely completion of projects.