Mabey’s most recent bridge jacking project recently wrapped-up in Marquette, Michigan and the results were overwhelmingly positive. Late last year, Iron River, Michigan-based Hebert Construction Company was awarded a contract to replace piers and repair concrete beams that supported the M-553 Bridge that runs through the Upper Peninsula city. Due to years of deterioration caused by harsh weather, road salts and heavy traffic, the bridge pier had become worn and in need of replacement. Hebert needed to provide structural support to the bridge and lift the deck off of its concrete piers in order to replace the structures and perform needed repairs. Complicating matters was the fact that, rather than being supported by concrete girders like those running the length of the underside of many bridges, the underbelly of the M-553 Bridge was flat which makes point propping – strategically placing props along each girder – much more difficult. Doing so would place uneven stress on the bridge deck at each of the propping points and damage the structure. Instead, Hebert needed a solution that would evenly distribute the propping pressure along the underside of the bridge as it was raised off of its bearings.
Hebert conducted an extensive search for a company that had the equipment and skill set that would allow them to prop the bridge and perform their work. Structural shoring specialist Jim Porreca located Hebert and initiated contact with the firm. After sharing plans and requirements, Hebert decided that Mabey, and our Heavy Prop system, was right for the job. The Heavy Prop is a modular, heavy-duty system capable of supporting up to 490 kips per leg. The system can also be fitted with header beams, below which, jacks are used to raise the load that is supported by the legs. The gear provides a unique combination of height adjustment, strength and ease of assembly, and it was the ideal solution for Hebert’s particular project. Mabey engineers provided the design that made it all work together. “This was one of the most unique bridge jacking job of its kind here at Mabey,” said Jim Porreca. “We were confident that the equipment could do the job and that we would make the contractor happy.” Porreca was right. The Heavy Prop gear was quickly delivered and pinned together on-site by Hebert’s team, which was overseen by project manager Steve Hebert. Once in place, it took 32, 55-ton jacks and a very complex manifold system to gently lift the bridge from its pier. Thanks to Mabey structural shoring, Hebert Construction was able to conclude their work over the summer, without the need for time-consuming custom-fabrication.