In an effort to accelerate the construction process and minimize impact to commuters, self-propelled modular transporters were recently used to replace two New Jersey Transit bridges in Plainfield, N.J.
“The use of Self-Propelled Modular Transporters (SPMTs) as an accelerated bridge construction technique is an emerging technology in the engineering field,” said Phil Christian, project manager at HNTB, the project’s lead design firm. “When utilizing this technology, a majority of the major construction activities for a project, such as structural steel erection and existing structure demolition, take place at a remote offsite construction staging location out of the way of the public. When ready, the bridge structure is loaded onto falsework erected on the SPMT units and transported to its final location.”
Work began in March 2015 on the two Raritan Valley line bridges, which transport upwards of 25,000 New Jersey Transit passengers daily. The project’s team, comprised of HNTB, Cornell & Company, Inc., Lynn Drobbin & Associates and Americon Corporation, did the majority of the work remotely; construction included the restoration of the existing girders and lattice columns, reproduction of the riveted construction with round-headed high-strength bolts, and rehabilitation of the original stone masonry abutments. The bridges required two SPMT units to carry out the replacement; each was done over a single weekend, allowing for minimal disruption of train service.
Following additional exterior work, the project is expected to be complete in February 2016.