Project Overview
Cities across Malaysia are in desperate need of durable, low maintenance bridge structures to improve the country’s transport infrastructure and link isolated communities to the broader regional network. However, many of the cities in greatest need are in remote areas where sourcing materials, site access, and access to talent are all major constraints to successful construction. To combat these obstacles, the Ministry of Rural Development of Malaysia has been exploring the benefits of ultra-high-performance concrete (UHPC) to accelerate these projects.
In a recent success story, local precaster Dura Technology designed and constructed a single-span, 328-ft-long, concrete box-girder bridge over the Perak River, giving the city of Gerik road access across the river for the first time ever.
Precast Solution
The government was eager to give the citizens of Gerik a safer, more convenient mode of transportation, however the project team faced considerable challenges building a bridge in such a remote area where logistic and access to construction equipment was limited. The budget on the project was also very tight, says Voo Yen Lei, executive director & CEO of Dura Technology. “Using a precast-prestressed-segmental solution certainly helped to overcome the obstacles on this project,” he says.
The use of UHPC was especially beneficial given the limited access to the site. “Using UHPC technology, we were able to achieve a long, light and shallow-depth box girder,” he says. The lightweight durable elements of the UHPC box segments meant the team was able to assemble the structure without the need for major floating structures, such as pontoons or barges. It also didn’t require temporary posttensioning, and the temporary falsework and supports were much less substantial than on a traditional project, which helped to accelerate the project, he says.
Once the precast concrete elements were onsite, the project team was limited in how they would manage assembly. “Crane access was only possible on one bank, which meant assembly of the bridge falsework and positioning of the segments required a 600-ton crawler crane with a 354-ft boom length,” Lei says. “Even then, the last end segments at Abutment B could not be lifted into position and an innovative strategy was needed.”
To address this challenge, the team built a rail system on the falsework to locate the precast concrete segments with the accuracy needed for threading of the tendons.
All of these benefits means the project teams were able to assemble all 40 segments in just 18 days—including 2 rest days. “This translated into huge cost and time saving,” Lei says. “It also ensured the finished product was of a much better quality than a cast-in-place design.”
Going forward, the UHPC design will provide superior durability, which is critical for the longevity of this vital new piece of infrastructure, Lei adds. “It is a better quality bridge, than conventional concrete designs, that requires negligible maintenance, and delivers better functionality and a better look at the lowest cost.” |