B&N led the preliminary study and final design of the Arena District Connector for the Olentangy Trail. With planned improvements to Nationwide Boulevard and the development of Confluence Village, home to the new Columbus Crew Stadium, the new bicycle and pedestrian bridge over the Olentangy River connects the existing Olentangy Trail to the downtown area and amenities.
Preliminary engineering studied the location of the abutments of the structure to place them outside of the floodway. A hydraulic analysis of the structure pier in the Olentangy River was performed to determine zero rise in the 100-year flood event. In finalizing the preliminary study of the alignment, a preferred crossing location was identified to coordinate the eastern plaza with the proposed Nationwide Boulevard and Confluence Village improvements and the anticipated private redevelopment of an existing water intake building. This created a venue for residents and patrons to relax and enjoy the area’s amenities and attractions.
The work was coordinated with the reconstruction of an existing boat ramp and livery that provides canoe and kayak rental for the downtown Columbus waterfront. The project scope included assessment of the geotechnical borings in the area to determine suitable foundation types for the substructure and to address potential scour issues that are common to riverfront areas. Cultural Resources Environmental Screening was performed. The preliminary engineering effort included stakeholder coordination with the City of Columbus Departments and developers in the area.
Additional public and stakeholder engagement was required to coordinate with the adjacent Confluence Village construction. Final construction documents were prepared to meet the accelerated schedule and coordinate the structure opening with the completion of the Confluence Village area and the new Crew stadium. Additional environmental effort and floodplain permitting was also completed. The opening of the crossing coincided with the first Columbus Crew home game in the new stadium.
Design Cost Containment
While the original scope prescribed a single-span pedestrian bridge across the Olentangy River, B&N advised that a two-span bridge would reduce design and construction costs. Typically, adding a pier in the floodway can cause an increase in the 100-year flood elevation and necessitate preparing a Conditional Letter of Map Revision (CLOMR) for FEMA’s review and approval. This can add many months to the design schedule and added cost for the analysis and regulatory coordination. B&N considered the current hydraulic effects of an old abandoned interurban railway bridge pier that had collapsed on the riverbed, along with small existing remnants of an old dam. Through hydraulic modeling, B&N demonstrated that removing the remnants fully offset the new pier in the river and opened the door to using the more cost-effective two-span bridge.
The Columbus Recreation and Parks Department (CRPD) had long desired to completely remove a few small remaining remnants of an old dam. B&N determined that the contractor’s temporary river causeway for constructing the new bridge could also be used to efficiently remove the small dam remnants at a much-reduced cost while the bridge contractor performed the work. Folding this ancillary work into the bridge project saved the City from paying for stand-alone project plans.
The structural system that used to support the new bridge is an inclined Vierendeel truss. Members of a Vierendeel truss structure are arranged to form trapezoidal openings rather than traditional triangular openings. The design of this system is more complex than a traditional truss because the joints between the members are required to resist moments in addition to axial forces. This structure type was selected for the Arena District Connector because it eliminates the need for bracing members in the truss openings, giving the bridge a more open and modern appearance.
The individual truss lines were fully shop-welded and transported to the site as a single unit. The truss lines were bolted to the transverse floor beams on-site, and each span was lifted into place fully assembled. The bridge railing consists of a steel handrail and stainless-steel cables, making it largely transparent when the bridge is viewed from a distance. The aesthetic lighting system consists of linear up lighting to highlight the trusses and LED pod lights in the handrails to illuminate the bridge deck.