India has an extensive network of bridges, including river and sea bridges, rail bridges and road bridges. They are critical infrastructural components that contribute to the advancement of transportation systems and enhance connectivity, particularly in regions that are geographically challenging to access. Moreover, these structures are designed with the purpose of mitigating traffic congestion and providing an alternative and expedited means of transportation. In India, bridges improve the overall infrastructure, establish linkages between cities and promote socio-economic progress.
Mapping evolution
Throughout the years, there have been significant advancements in bridge design and construction techniques. The shift from simple log bridges to complex suspension bridges and cable-stayed bridges showcases constant innovation and engineering prowess.
The upcoming bridge projects aim not only to connect remote areas but also to become tourist destinations. Furthermore, the contractors’ perspective has shifted towards creating bridges that are not just visually appealing with basic functionality, but also safe to use, environment friendly, technologically advanced and material efficient.
Enhancing workflow with technology
BIM for bridges: The bridge design and construction process has evolved significantly with the introduction of smart digital technologies. Building information modelling (BIM) is one such technology, which covers the architecture, engineering and construction segments. A version of this, bridge information modelling, customised to suit bridge projects, is a highly collaborative process that helps streamline the design process by integrating various types of data, from computer-aided design files and geographic information system, into a single platform.
This technology is gaining traction in bridge construction. As of April 2024, the Ahmedabad Municipal Corporation is planning to deploy this software on the Panjrapol flyover. The software will help alert the authority about any deviations. The deployment of such advanced digital tools at the municipal level is a step forward in the sector.
Precast advantage: Precast segmental construction technology has gained popularity as it is used to achieve accelerated bridge construction, better quality control and reduced life cycle cost. In addition, congested reinforcement can be handled at the ground level. The use of precast elements also provides significant economical and schedule savings. Off-site fabrication is much cheaper compared to delivering and placing cast-in-place concrete at remote project locations. In March 2024, 40 girders required for 10 spans on the foot over bridge connecting Sarai Kale Khan RRTS station with Hazrat Nizamuddin railway station were prefabricated off-site.
High performance concrete: The use of high-performance concrete with reduced permeability is the foremost strategy for managing corrosion. Stainless steel is another emerging option for reinforcement in extremely harsh environments. It is exceptionally adherent, inert and self-repairing. Epoxy-coated reinforced steel has been the most popular choice among transportation agencies to address premature bridge corrosion. In addition, ultra-high-performance fibre reinforced concrete technology has been deployed for the construction of a 111-metre-long bridge in Masalga, Latur, and the Taloja Creek bridge in Maharashtra.
The recently inaugurated Atal Setu bridge features cutting-edge traffic management technology. This system can identify foggy conditions, poor visibility and speeding vehicles. The balanced cantilever approach was adopted for the construction of the bridge. The use of precast concrete segments underscore the project’s commitment to efficiency.
Sustainable strides
Several attempts have been made to reduce the environmental effect of concrete. These include the use of industrial by-products called supplementary cementing materials such as fly ash and slag cement. 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 for bridge construction.
The first geogrid reinforced fly ash approach embankment was constructed for the Okhla flyover bridge in Delhi. During the construction of the Bandra-Worli sea link bridge, environment friendliness was a top priority. Thherefore, fly ash was mixed with concrete to make the construction durable and eco-friendly. Furthermore, as of June 2024, the Dhola Sadiya bridge in Dibrugarh will feature around 484 solar lights.
As of June 2024, the Indian Stainless Steel Development Association released India’s first Stainless Steel Bridge Design manual. This manual aims to advocate for the use of stainless steel in bridge construction, highlighting its sustainable qualities and its contribution to the goal of carbon neutrality.
Safety check
Safety considerations are paramount in bridge construction. Several Indian bridges have been found to be precarious. For instance, in June 2023, the four-lane Sultanganj-Aguani Ghat bridge collapsed, followed by another under-construction bridge in Panalpur, Gujarat, in October 2023. Shortly after, in November 2023, sections of the under-construction Silkyara tunnel in Uttarakhand collapsed, trapping 41 workers. There is an urgent need to address such construction mishaps. With advancements in technology and safety measures, there is room for improvement in construction practices and conceptual specifications governing bridge construction methods.
Innovative assessment tools now predict the remaining life expectancy of bridges, streamlining the monitoring process. The Ministry of Road Transport and Highways (MoRTH) has set up a bridge monitoring system to identify the bridge assets across the country. Condition assessment of bridges is crucial for preventive maintenance, repair, rehabilitation, retrofitting and reconstruction.
For instance, recently, trial runs have been conducted on the Chenab Bridge in Jammu and Kashmir. It is being monitored by advanced equipment, including over 100 sensors, a 780-metre-long blast protection platform and a control room equipped with 150 servers. This state-of-the-art infrastructure ensures the safety and security of the world’s tallest rail bridge during rail traffic operations.
As of March 2024, MoRTH plans to implement real-time sensors for monitoring bridge conditions on national highways. This initiative aims to enhance maintenance procedures and prevent potential bridge failures. In addition, the inclusion of health monitoring sensors for bridges will be integrated into detailed project reports for highway projects. The specific type, number and location of sensors for current bridges will be determined by a committee of experienced senior engineers.
Measures for future growth
In recent years, many construction firms have taken proactive measures to participate in India’s development story by capitalising on the surge in infrastructure investment and developing bridge infrastructure. Programmes like the Smart Cities Mission, Make in India and Vision 2047 have further accelerated the construction of bridges towards a more promising future.
Collaboration, innovation and dedication to overcome industry challenges are essential for advancing bridge construction. The implementation of digital innovations in these structures will enhance quality and safety. Another area that necessitates attention is the utilisation of geospatial technology to remotely monitor the condition of these structures.
India is also exploring the widespread adoption of self-healing roads. The implementation of this technology has the potential to considerably improve bridge infrastructure. As India continues to prioritise connectivity and urban development, bridge construction will play a pivotal role in shaping the country’s infrastructure landscape.
Harman Mangat
