It is an engineering design and construction marvel
Tata Projects, one of the fastest-growing and most admired infrastructure companies in India with expertise in executing large and complex urban and industrial infrastructure projects, secured the contract to design and build a part of India's longest sea-bridge – the Mumbai Trans Harbour Link (MTHL). To learn what cutting edge technologies and techniques were used in this project, R SRINIVASAN spoke to Vinayak Pai, Managing Director, Tata Projects. Excerpts: Please share your Mumbai Trans Harbour Link (MTHL) journey. MTHL is an iconic project for us. Construction began in March 2018 and the whole sea-bridge was completed in five-and-a-half years. This project was completed at the same speed as some of the big global sea-bridges. Despite going through some remarkable challenges, including monsoon cyclones and two waves of COVID, the project was still completed on time with zero fatalities. MTHL Package 2, which Tata Projects executed along with our partner Daewoo E&C (South Korea), had 0.36 million cu m of concrete, almost 65,000 MT of reinforcement steel and 208 spans of 60 m each, which is formed from 3,100 precast segments and needed almost 6 km of post-tension strands to hold it all together. It is an engineering design and construction marvel and we are proud to have been part of this iconic project, which is the longest sea-bridge in India. Please elaborate upon maximum threshold of the bridge in terms of an earthquake’s magnitude. Conventional bridges are designed for the operating base earthquake (OBE), featuring a ground motion with a 10 per cent probability of exceeding within a five-year span, which is equivalent to a 475-year return period. But the Atal Setu is a unique structure specifically designed for the maximum considered earthquake (MCE), where the ground motion has a 2 per cent probability of being exceeded in 50 years, which is equivalent to a 2,500-year return period, showcasing its exceptional resilience and preparedness for seismic events. What went into the concrete blend to ensure long-lasting durability? The concrete mix was very carefully calibrated. It's engineered for a robust 100-year durability, incorporating ordinary Portland cement (OPC) fly ash ground granulated blast furnace slag (GGBS) Alccofines and advanced polycarbonate ethers, admixtures that are used to combat corrosion and harsh weather. Crafted in a temperature-controlled environment using chilled water and ice flakes, the mix achieved a lowered placing temperature. It underwent rigorous quality measures to ensure rapid chloride penetration tests were done and chlorine was monitored to safeguard its designed life. Tell us about the benefit of pile foundations in a project of this magnitude. Building a marvel like this in a very eco-sensitive zone took a lot of care and design. The ground strata was studied and the bridge foundation designed for the intertidal and marine section. Pile foundations were used for the marine section and the land and interchanged; these are open foundations. The pile foundations incorporated state-of-the-art, reverse circulating drilling technology, chosen for its capacity to minimise vibrations, eliminate noise pollution and efficiently dispose of excavated material. This approach safeguards the surrounding environment from potential damage during foundation construction. Please tell us about underwater foundations, challenges involved and how were they overcome? The underwater pile foundations used cutting-edge reverse circulation drilling (RCD) technology with RCD machines mounted on 2-m diameter steel liners. A dedicated team of skilled sea divers were used to navigate construction, especially around the seabed oil pipelines, which were along the route. This highlights our commitment to safety and we could not have done this project safely without using all these methodologies. The barge positioning and anchoring plan were meticulously monitored using GPS to ensure complete safety. The company won the Engineering News-Record (ENR) Global Best Projects Awards for the new Parliament project. Your views. ENR goes through a rigorous monitoring process of all global projects. Submissions must be made in a lot of detail. Some factors are very simple; adherence to safety has to be flawless; the project should be accident-free; the quality has to be exceptional; and all the quality metrics have to be submitted. Apart from architectural elegance, importance is also placed on the national or industry significance – being the Parliament House of India, this was a high scoring element for the project. ENR also evaluates projects for innovation and provides an opportunity to showcase teamwork and overcoming challenges, which this project went through during the multiple COVID timelines where we worked very well with the ministry and PWD to deliver this project. All these factors combined to make this project unique. We used a lot of technology and real-time tracking; the whole project employed building information modelling (BIM) and Primavera was used for advanced resource-based planning. BIM was used for clash detection so that we constructed fast and didn't recycle things. We used laser scanning for deviation detection, so that all architectural features could be adequately covered. We also used our indigenously developed project management app called DQ Digital X, where monitoring of the project was done seamlessly. Please update us on your plan to turn profitable in FY2023-2024. This industry has a lot of opportunities but also a lot of risks. We’ve had pretty good results on our projects and the fourth quarter, from January to March, is always the big quarter. We are very hopeful of turning profitable this year as we had indicated at the beginning of the year. And we will move on to the next stage and generate cash seamlessly across quarters and years. Operational excellence is very important for us so we are making a lot of investments in technology, including one of the most advanced ERP systems and working with SAP, which has done a lot of these projects globally for ERP systems. But they tell us that such an integrated, full suite of products has not been used by this industry, either in India or globally. So, we look forward to bringing those technologies to achieve operational excellence and top quartile performance in future.