George P. Coleman Bridge Replacement
Georgetown, Virginia

Tidewater Construction Corporation (TCC) was retained by the Virginia Department of Transportation (VDOT) to replace the two-lane George P. Coleman Bridge and its approaches with new structures accommodating four lanes. With an overall length of 2,540 feet, the bridge had six main steel struss spans; the longest 560 feet long and weighing 4,000 tons. Two of the spans were designed as swing sections, allowing the bridge to open for the passage of tall ships.

TCC elected to construct the new spans on temporary piers over water in a fabrication yard 30 miles from the old bridge. Each completed span was lifted from its fabrication piers using towers mounted on two barges placed under the span. The barges could then transport the bridge to the permanent site, where each span was dropped onto the piers by adding ballast to the barges.

This approach enabled TCC to complete the installation in a mere nine days, earning the VDOT’s gratitude (and a substantial bonus). But the solution created complex engineering issues of its own. DMJM+HARRIS solved those issues by conducting myriad calculations of load stresses, shear forces, chord deformations, and structural requirements. Since most hydrodynamic analysis tools were not designed to consider the interaction among two barges and an interconnecting span, DMJM+HARRIS developed its own analysis approach, using pre-and post-processors to generate, organize, and dissect the load requirements. After meticulously modeling each bridge span, the barges, and the towers, we designed load equalizer systems that would make the system work, reducing the support steel required by 110 tons in the process. Our work was so successful that TCC expanded Harris's scope to include final design of the entire support system and necessary bridge strengthening.