Project Overview
In western India, a new bridge constructed over the Nira Canal offers an important connection for travelers in the region. Located at Palkhi Marg near Pune, the bridge is on a dedicated route that’s heavily traversed during the annual Pandharpur Wari pilgrimage. During this pilgrimage, hundreds of thousands of devotees, known as “varkaris,” walk for three weeks through nearby villages and cities, many traveling more than 150 miles to reach the Vitthal Temple in Pandharpur. This is a significant event in the region that serves as a three-day celebration and time of reverence. The new 335-ft-long bridge supports varkaris in their journey—along with the region’s many other travelers—thanks to the installation of 156 precast concrete segments.
A Major Advancement in Indian Bridge Engineering
To design the bridge, Longspan Structures Pty Ltd leveraged an innovative ultra-high-performance fiber-reinforced concrete (UHPC) U-girder system with a conventional deck slab. According to Sudeep Joshi, head of design at Longspan Structures, the original design called for steel, but the team opted for a precast concrete approach to take advantage of the material’s wide array of benefits.
“UHPC was chosen to achieve high strength, durability, and precision in construction while ensuring safety during erection,” Joshi says. “The 335-ft-long span demanded materials that could handle extreme loads, slender sections, and minimal maintenance. Precasting also allowed controlled production conditions, ensuring consistent quality that is difficult to guarantee on-site.”
In total, the project used six UHPC U girders, each spanning 335 ft and weighing approximately 456 tons. Each girder consists of 26 precast concrete segments. Once the segments arrived on-site, they were positioned and aligned on a temporary support structure built adjacent to the main bridge. Workers used a trolley-rail system to temporarily assemble the segments, which were then permanently joined via post-tensioning. After the project team stressed and grouted the tendons, the girders were then shifted into their final positions. This innovative method streamlined construction and eliminated the need for heavy, complex beam-launching equipment.
The project team’s decision to select precast concrete also delivered significant sustainability advantages. Using data generated in material quantity take-off reports, the team determined that, while installing precast concrete U girders increased the weight of the bridge superstructure by 15%, the precast concrete design resulted in a 69% reduction in embodied energy, 63% reduction in embodied carbon, and a 63% reduction in global warming potential over 100 years compared with the structural steel I-beam composite solution. These reductions represent substantial decreases in greenhouse gas emissions, resulting in energy savings and a lower environmental impact.
Beyond the environmental advantages, the decision to use precast concrete resulted in numerous benefits to the project team and the greater Maharashtra region. The precast concrete approach reduced costs by 52% compared with the steel solution. The innovative construction method required no road closures, allowing travelers to move through the area without delay. And, thanks to the inherent characteristics of the building material—such as low permeability and high durability—the new bridge is expected to continue serving Pandharpur Wari pilgrimage participants and all those in the community for decades to come.
According to Joshi, “Being the first of its kind in India, this bridge establishes the region as a pioneer in advanced infrastructure technology, encouraging further development in the future.”
Mason Nichols is a Grand Rapids, Mich.-based writer and editor who has covered the precast concrete industry since 2013. |