The Texas Department of Transportation (TxDOT), in coordination with project developer Flatiron/Dragados LLC (FDLLC), successfully completed the removal of the centre span of the historic 1959 US 181 Harbor Bridge. The milestone marks a significant step forward for the Harbor Bridge Replacement Project in Corpus Christi, Texas.
After more than 60 years of service, the truss-style steel bridge was replaced by a modern cable-stayed structure designed with safety improvements to better serve maritime traffic, roadway users, pedestrians and the surrounding community. The removal of the centre span was carefully planned and executed with safety, environmental stewardship and stakeholder coordination as top priorities.
Flatiron/Dragados selected Mammoet to advise on the best and safest method to remove the old Harbor Bridge central span. TxDOT provided oversight and leadership to ensure the work met stringent safety, environmental and operational standards. FDLLC was responsible for coordinating aspects of the removal effort, including marine operations, construction sequencing, safety planning, and engagement with impacted stakeholders. Mammoet provided specialised heavy-lift expertise and equipment to identify and execute the safest and most effective removal method.
Choosing a safer, lower-impact solution
Multiple removal options were evaluated, including piece-by-piece dismantling and controlled explosive demolition. After thorough analysis, the project team selected a lift-and-lower method that allowed the entire 2300 ton centre span to be removed in one piece and placed onto a barge.
This approach offered several benefits. It enhanced safety by reducing the number of workers required to operate at height. It reduced the project’s environmental impact by protecting a nearby aquarium and the surrounding marine environment. The method improved navigation efficiency, allowing shipping lanes to reopen more quickly, and offered greater schedule certainty through a highly controlled and predictable operation.
Lowering the span as a whole unit represented a collaborative engineering solution driven by TxDOT’s priorities and FDLLC’s integrated project planning.
Precision planning to final execution
Four 900-ton strand jacks, two positioned at either end of the bridge, were used to take the full weight of the span so that the connection points could be cut. For safety, lowering was scheduled during daylight hours.
“Before the initial lift, an ‘eyebrow cut’ was made above the pin to allow a small opening that enabled us to lift the span until we saw daylight,” said Bobby Martija, Mammoet project manager. “This gave us an opportunity to check the deflection of the bridge and ensure everything was stable. Once everyone was satisfied that all the clearances were correct, the cutting began.”
The night before the lowering operation, a barge was fully equipped with winches, support grillages and Mammoet self-propelled modular transporters (SPMTs). A tightly managed 36-hour operational window then began to lower the span and clear the navigation channel.
The span weighed 2300 tons, estimated from historical records, and the engineers added a contingency to ensure the strand jacks had sufficient capacity. The shaft was lowered nearly 50 metres using 54 strand wires.
“We had two ways of setting up the strand jacks. Initially, it was a simple umbrella configuration with the strand wires resting on the deck of the bridge,” adds Martija. “We realised that this would be too time consuming, with people required to manage and arrange them, so we decided it would be better to pre-coil the wires instead. We used two coilers, one for each strand jack, which we sub-assembled at our yard in Rosharon and brought directly to the site.”
Once the span was safely loaded onto the barge, it was shipped 10 nautical miles to a nearby dock, where it was offloaded and placed onto supports. Two sets of 54 lines of SPMT were used to lift the structure and transport it from the deck. The underside of the span was reinforced with steel work carried out on the deck of the barge where it was far easier and safer than working at height.
Dependable support for complex projects
The successful removal of the Harbor Bridge centre span reflects the strength of collaboration among the Harbor Bridge Project team and Mammoet. This milestone shows how coordinated expertise, innovative engineering and disciplined execution can overcome the challenges associated with major civil infrastructure projects, while protecting workers, the public and the environment.
Mammoet focuses on finding the safest, most efficient method to overcome any heavy-lift or transport challenge and on being flexible if plans change. Its systems and teams work hand in hand with those of its customers, overcoming engineering challenges together so that projects are completed in the best possible way. Whether it is minimising environmental impact or downtime, or making work environments safer, Mammoet is a dependable partner for complex civil and infrastructure projects.
For more information contact Mammoet Global,
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