An Innovative Solution for Bridge Construction


Crowder Construction, as a Subcontractor to Blythe Zachry JV, played a pivotal role in South Carolina Department of Transportation’s I-85 widening project particularly in the replacement of a CSX railroad bridge in Spartanburg, SC. One of the most critical challenges involved transporting massive steel girders for two larger spans of the new railroad bridge, each spanning 145 feet, standing 13 feet tall, and weighing over 300,000 pounds. These enormous structures posed a logistical challenge as traditional roadway transport was impractical, prompting Crowder to employ rail shipment from Coalfax, NC to Spartanburg, SC. However, it was the utilization of Self-Propelled Modular Transporters (SPMTs), provided by subcontractor, Mammoet, that transformed the project.

The project demanded "accelerated bridge construction," prompting the strategic decision to employ SPMTs to ensure success and minimize disruptions to public traffic. SPMT trailers, commonly used in ports and just recently in bridge construction projects, facilitated the transportation of each prefabricated span, weighing a staggering 1.4 million pounds, over a quarter-mile distance to the bridge site. This intricate process required meticulous precision, as the spans were transported across all lanes of I-85 during night-time traffic slow rolls, then elevated 20 feet to bearing height and precisely lowered onto their bearings within 1/16 of an inch.

The deployment of SPMTs enabled the construction of larger spans off-site, reducing the duration and magnitude of traffic detours on I-85. Notably, the middle bridge span was positioned within a mere 6-hour shutdown window, necessitating a complete detour of traffic in both directions—a testament to the efficiency and effectiveness of this cutting-edge technology.

Moreover, the adoption of SPMTs minimized the impact on the traveling public. Unlike traditional approaches requiring nightly lane closures and detours spanning several months, using SPMTs significantly expedited the construction process while ensuring the safety of work

ers and minimizing inconvenience to the traveling public. Heavy picks were minimized using a crane next to the existing railroad tracks for off-loading the girders, and temporary falsework needed for constructing spans over traffic was limited. Once the railroad ballast and track were installed on the newly constructed bridge, the old CSX bridge was demolished utilizing a 600 TN truck crane within two 6-hour full interstate detours.

While the use of SPMTs incurred additional costs associated with specialized equipment and engineering, the benefits far outweighed the expenses. Not only did it save valuable time by allowing concurrent construction of spans and sub-structures, but it also provided a safer working environment for crews, reducing the need for night-time operations under traffic control.

In conclusion, the decision to embrace SPMT technology was not merely pragmatic; it was transformative. The successful integration of SPMTs in the I-85 widening project stands as a testament to the transformative power of innovative technology in modern construction. By prioritizing efficiency, safety, and minimal disruption, Crowder Construction and their partners set a new standard for bridge construction methodologies, ultimately delivering exceptional results for the SCDOT and the community at large.

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