Unlocking Potential: Market trends, advancements and strategies

Indian bridges are crucial components of the transport infrastructure, serving as vi­tal links between cities and enabling sm­ooth mobility. India is home to a network of di­stinctive bridges, which include river and sea brid­ges, rail bridges and road bridges. The co­untry also has a robust pipeline of up­co­ming projects, as a result of growing urbanisation and the ambitious infrastructure initiatives of the government.



Tracking growth

Historically, Indian Railways (IR) has been a front runner in bridge construction. Besides, IR has its own codes and manuals for bridges, which prescribe stringent inspection and maintenance schedules. Some of the notable ac­c­om­plishme­nts are the construction of India’s longest brid­ge, the Bogibeel bridge, and its ta­llest bri­d­ge, the Chenab rail bridge. India’s engineering ex­per­tise is reflected in these significant proje­c­ts. Additionally, dedicated freight co­rridors include a variety of bridges with innovative designs and methods of construction.

The Udhampur-Srinagar-Baramulla Railway Link Project (USBRL), a national project aimed at providing all-weather rail connectivity to the Ka­sh­mir Valley, is an ongoing mammoth project. The USBRL involves construction of numerous tu­nnels (38) and bridges (927) in highly rugged and mountainous terrain. The combined length of these bridges is over 13 km. This includes the construction of the Anji bridge (725 metres), the first cable stayed bridge by IR. Furthermore, the ministry aims to build 1,000 rail overbridges (ROBs)/rail under passes in 2023-24.

Several landmark road bridges have also been constructed in the road sector. For ins­tance, the Ministry of Road Transport and Hi­gh­­­ways (MoRTH) constructed the 5.56 km-long Mahatma Gandhi Setu in Bihar. The technological research done for this engineering marvel serves as a case study for other up­coming complex bridge projects. Similarly, the construction of ROBs on the Firozabad-Eta­wah section of the Agra-Lucknow Express­way was challenging. One of the ROBs built along the busy Delhi-Howrah rail line had an abnormal skew of 460 degrees.

Strong backing

Increasingly, new technologies, designs and construction methods are being deployed during the construction and maintenance phases in an effort to mitigate challenges in bridge co­ns­truction.

The bridge design and construction pro­cess has evolved significantly with the introd­uction of smart digital technologies. Building information modelling is one such technology, which serves the architecture, engine­ering and construction segments. MoRTH has set up the Indian Bridge Mana­gement Sys­tem (IBMS) to identify distres­sed bridge as­sets and inform the concerned implementation agency to take corrective measures. South Central Railway (SCR) has introduced drones for improving the inspection and maintenance of bridges. How­ever, geospatial technology to remotely monitor the condition of bridges is an area that needs focus.

A few of the principal factors considered for the selection of a bridge construction me­thod are regularity of the span lengths, horizontal and vertical profiles of bridge decks, and soil strata. Some of the commonly used construction methods in India are cast in-situ, balanced cantilever, span-by-span, full span and the incremental launching method. Pre­cast seg­mental construction has also gained popularity and is used to achieve accelerated bridge construction, better quality control and re­duced life cycle cost.

After design and engineering, the material plays a critical role in construction. Common construction materials include structural steel, reinforced concrete and pre-stressed and post-tensioned concrete. Additionally, the use of su­s­tainable construction materials, along with ot­h­er environment-friendly interventions, is an emerging trend within the sector.

Green moves

Several attempts have been made to reduce the environmental effect of concrete, which is used in volumes second only to water. These include the use of industrial by-products call­ed supplementary cementing materials such as fly ash and slag cement. The first geogrid reinforced fly ash approach embankment was constructed for the Okhla flyover bridge in New Delhi.

Further, in order to alleviate the problems of scarcity of natural materials and reduce greenhouse gas emissions, alternative materials such as manufactured sand and iron, steel, and copper slag aggregates are being used. Dif­fer­ent types of concrete are being developed, whi­ch includes self-compacting concrete, high performance concrete, fibre-reinforced concrete and ultra-high-performance concrete. Fibre-reinforced bridges could practically last for the longest time as they are completely non-corroding in nature, while wooden and steel bridges ty­pically need refurbishment. The use of high-performance concrete with reduced permeability is the topmost mitigation strategy with respect to corrosion management.

Furthermore, the utilisation of tunnel muck, a waste product of tunnel excavation, in the USBRL project has resulted in the reduction of carbon emissions by 80 per cent, while simultaneously decreasing the project cost by 30 per cent.

Improving safety

Over the years, several Indian bridges have been found to be precarious to some degree. More needs to be done to remedy this. There is a sco­pe for improvement in the conceptual specifications governing bridge construction methods. For instance, high levels of engineering diligence could go into detailed project reports. Additio­na­lly, it is imperative that the government counterparty’s capacity be enhanced in terms of strict contract enforcement.

The railway sector has been making concerted efforts to uphold safety standards. Seve­ral Indian railway bridges date from prior to 1947 and are constantly monitored. As a result of centralised regulatory supervision, feedback is efficiently incorporated at the earliest, as are lessons learned for future safety measures.

However, with a number of government en­titi­es and regulators at the national, state and rural levels, the road sector is yet to raise its standards at all safety levels. Nonetheless, the la­unch of the IBMS by the Indian Academy of Hi­gh­way Engineers is a positive step forward. Over the past few years, with the help of the IBMS, a multitude of bridges have been identified for renovation and replacement.

Currently, bridges in India necessitate performance-based standards, with the objective of averting failure, irrespective of the size of the structure.

Major upcoming projects

The Mumbai Trans-Harbour Link, the upcoming longest sea bridge in the country, is 21.8 km long and will constitute six lanes with a holding capacity of 70,000-80,000 vehicles. The brid­ge is scheduled to be completed by December 2023.

The Pamban bridge, a vertical leaf-type bridge, being implemented by Rail Vikas Nig­am Limited, involves the construction of a new 2.05 km-long bridge near Pamban in Ta­mil Nadu in lieu of the existing scherzer rolling lifting bridge on the Manda­pam-Pam­ban rail line at an in-vestment of Rs 2.5 billion. The construction wo­rk is expected to be completed by mid-2023.

The Chenab bridge is a 1,315 metre-long railway bridge being constructed in Jammu & Kashmir. It is part of the USBRL project. As of February 2023, IR has commenced the track-laying work. The project is scheduled to be completed by early 2024.

Going forward

Construction of modern structures for bridges is complicated. Thus, there is a need for skilled and trained engineers and experts to plan the construction of these structures using the best methods and equipment. The evolution of bri­dge engineering is strongly linked to the advan­cements in materials, construction processes and technology. To this end, around Rs 50 billion will be invested in Uttar Pradesh to introduce new technologies to construct bridges on railway crossings.

Bridges need to focus on the conceptual and computational aspects to construction, al­o­ng with service life performance. Innova­tions in design and construction techniques, and ad­aptation of global best practices to Indian conditions hold great potential. As safety is paramount, more effort to remedy safety-related challenges is needed, keeping in mind that preventive maintenance is always better than post-damage work.

Going forward, bridge construction will provide huge opportunities to contractors, developers, consultants and investors. A few of the an­nounced projects are the Versova-Virar sea link and Kopari-Patni bri­dge on Th­a­ne Creek in Mumbai, the Kushiyara bri­dge in Assam, Belani bri­dge in Uttarakhand, Dehra bri­dge in Hima­chal Pradesh and Kotlien bri­dge in Manipur. Additio­na­lly, the Uttar Prade­sh government recently ap­proved funds worth Rs 1.83 billion to cons­truct three ROBs at the Harauni, Bharwara and Kesar­ikheda railway crossings in Lucknow.

Ishita Gupta and Harman Mangat