When the construction of a bridge faces delays, the cost overrun is much higher compared to any other road or rail projects.Hardik Agrawal, Director, Dineshchandra R Agrawal Infracon, says “Bridge construction is heavily dependent on construction materials such as cement and steel, which are price-sensitive. If the material cost is quantified compared to the overall project cost, it is much higher than any other segment.”The most complex bridge projects are the ones across deep valleys, wide rivers and sea crossings. “Geological surprises at the foundation are among the complexities involved,” says NN Sinha, Chairman, National Highways Authority of India (NHAI), and Managing Director, National Highways & Infrastructure Development Corporation (NHIDCL). “Technical expertise, in terms of design and supervision, is shallow, leading many clients to look to foreign shores. Also, lack of local manufacturing and testing of advanced materials such as cables, weathered steel and fibre-reinforcement are other weaknesses.”RVR Kishore, Project Director, Hindustan Construction Company, agrees that the challenges in bridge construction basically revolve around the geology of the river. “Detailed investigation and preliminary planning are crucial and should be done by the client or contractor,” he suggests. “It is important to first determine the construction methodology, followed by the design of the structure.” For his part, Vivek Gautam, COO - Strategic Business Group – Core Infra, Tata Projects, points to complexities such as terrain type, RoW, vehicular traffic congestion, dense urban localities and green and regulatory clearances. He mentions the company’s recent project involving DMRC’s 9.63-km Dilshad Garden-Ghaziabad New Bus Adda elevated metro extension. “It included a 170-m bridge across Hindon River. The bridge section was challenging as it was on the upstream side of the river barrage and almost full of water. To reduce time and overcome challenges, we opted for the precast method and the bridge was executed in two parts, thereby safely completing it within 180 days.”Nitesh Kumar Asati, Joint General Manager, IRCON, says, “Various challenges in bridge construction include selection of girders and bearings, methodology of stressing, finalisation of borrow pits, launching schemes, CRS inspection, etc, with all quality and safety standards as per the statutory requirement. However, use of specialised equipment and technology will definitely help in ensuring timely project completion. During construction, we need to ensure the achievement of various milestones as per the programme submitted by the agency by conducting regular progress review meetings with our agencies and the client. It is imperative for a dedicated team to focus on the various sequential and parallel activities of a bridge, which is a great managerial challenge.”Referring to Bogibeel Bridge as a feather in the cap of Indian Railway engineers, HCC and Gammon, Shashikant Limaye, Member Expert Committee, Pune Metro Project, says, “Several new technologies were used in this bridge comprising 124-m span steel through girders with a composite RCC deck carrying a two-lane road.” He further mentions the Chenab Bridge along the Udhampur-Srinagar Rail Link, which comprises a 467-m steel truss arch span rising 350 m above the riverbed, as a unique example of a bridge in an earthquake-prone region. Afcons is steadfastly making progress on this unique project. A 145-m-tall viaduct on the Jiribaum-Tupul Railway Line between Silchar and Manipur is another unique project in progress.That said, if we were to compare India’s approach to bridge construction to other parts of the world, we are still at a nascent stage. However, with the 20-km MTHL and several other bridges coming up across the Ganga and Brahmaputra, the future is bright – and connected!SHRIYAL SETHUMADHAVAN