Built at a cost of Rs.34.47 billion by IRB Infra, the 189.6-km Goa-Karnataka border highway project is an important north-south highway link on India’s western coast with a concession life of 28 years.The 189.6-km Goa-Karnataka border-Kundapur four-lane highway project has been recently commissioned by IRB Westcoast Tollway, the SPV of IRB Infrastructure Developers. Part of NH-17, the stretch is an important north-south highway link on the western coast of India. Built at Rs.34.47 billion (including viability gap funding of Rs.5.36 billion), the project has a concession life of 28 years. The company had bagged this project under the National Highways Development Project (NHDP) Phase-4 on design, build, finance, operate and transfer basis.Construction milestonesBefore the four-laning of the project, the time taken by buses to reach from Karwar to Kundapura was eight hours – now, it takes just four hours. Thus, by widening the existing highway, travel time is reduced drastically, besides benefits such as lesser wear and tear of vehicles and reduction in fuel consumption to a great extent, thus achieving pollution control. This project is a peculiar one that passes through plain, rolling and hilly terrain. It has tunnels and major challenging structures over perennial rivers. “Identification of the bottlenecks and converting these into the achievement of the target through proper planning from the site level to the management level was crucial to complete the project in time,” shares ML Gupta, Joint Managing Director, IRB Infrastructure Developers.Civil specs and scope of workThe project has a service road of 61.26 km, 17 major junctions, six minor junctions, 83 cross-road junctions, 14 major bridges, 39 minor bridges, 573 culverts, four flyovers, three vehicular underpasses, 13 pedestrian underpasses, six cattle underpasses, two road-over-bridges, one road-under-bridge, two twin tunnels, three toll plazas, four truck lay byes, and 53 bus bays and bus shelters. “The safety measures for the project were carried out as per the provisions under the Concession Agreement; for example, proper diversion boards, provision of blinkers and barricading construction zones, among others,” says Gupta. Safety measures are in place and monitored 24 x 7 to avoid any mishap to users of the project. Construction methods At the heart of the project are the technologies, equipment and machineries deployed for construction. The better and more appropriate the machineries, the speedier the progress of the work, enabling completion in the stipulated timeframe. “We had deployed jack-up rigs for the geotechnical investigation, which facilitated speedy work, along with cantilever construction gantries for construction of the large-span bridge on Kali River, launching girder on barges at Sharavathi River and the use of precast girders for other bridges,” elaborates Gupta. “Also, hydraulic piling rigs were used along with conventional rigs.” Further, high-quality materials have been used in construction, which will increase the life of the structures and highway, and result in maintenance cost reduction during the O&M period. Major challenges Major challenges involved the construction of the major bridges across the major perennial river and the construction of the twin tunnels. “This could be completed owing to the deployment of advanced machineries and special construction techniques,” says Gupta. He adds that construction of the road by hill cutting to the extent of about 50 m depth and keeping the existing road traffic-worthy was another major challenge, which was overcome with a combination of advanced technology and rich domain knowledge.  Considering the geographical and topographical conditions, construction was the toughest job, says Gupta. The project had witnessed major challenges involved in highway engineering, such as the construction of major bridges spanning up to 120 m each close to the Arabian Sea; 1.2-km-long bridges over the perennial river; tunnel construction in both hard and soft rock; and rock cutting for 60 m height and cutting in lateritic hill for about 50 m height. Indeed, it took IRB Infra’s experience and expertise, spanning over two decades, to overcome all these challenges, delivering world-class highway infrastructure for the coastal regions of India.  - SERAPHINA D’SOUZAKnow of a landmark project ? Write in at feedback@ConstructionWorld.in