Pedestrian and Highway Bridges, Horseshoe Design-Build, TxDOT
Dallas, TX

IEA designed 3 highway bridges and 4 pedestrian bridges and performed independent design reviews for 7 bridges.

This $798M design-build freeway reconstruction project located in Downtown Dallas involved reconstruction of the IH35E-IH30 mix master, IH35E and IH30 bridges over the Trinity River, additional ramps and structures for managed lanes, and new pedestrian crossings over the Trinity River. The project incorporated provisions for future roadway improvements for the “ultimate” configuration in this area.

Pedestrian Bridges

IEA designed 4 shared-use path bridges for the Horseshoe project. Two of these bridges serve as the western approaches to the Margaret McDermott Signature bridges along IH 30 over the Trinity River. A third serves as the south eastern approach.

All are prestressed concrete girder designs with spans ranging from 35-ft to 115-ft and are 20-ft in width. Substructures consist of either single column inverted Tee or flared bents. Both inverted Tees and flared columns have a unique aesthetic look where most of the surfaces of the substructure are rounded. Column heights vary from 10-ft to 50-ft.

IEA developed special aesthetic treatments and details for the substructures. The aesthetic treatment developed is consistent with the unique all rounded corners and flared columns specific to the project.

IEA assisted in realignment of the bridges due to post award changes requested by the City of Dallas. IEA reconfigured the bridge layout to enable contractor to reuse formwork between bent locations at multiple pedestrian bridges, saving construction costs. One challenge encountered was the small radius in the horizontal alignment used to allow the bridge to change direction by 270 degrees while minimizing overall structure length. 

The last bridge is a single span bridge for a shared use path spanning over the existing United States Army Corps of Engineers (USACE) sump behind the western levee. 

The alignment of these bridges was designed in conformance to the AASHTO Guide for the Development of Bicycle Facilities and ADA and Texas Accessibility Standards. Structural design for the bridges conformed to the AASHTO LRFD Guide Specifications for the Design of Pedestrian Bridges and the AASHTO LRFD Bridge Design Manual and incorporated TxDOT guidelines and standards.

Trails

During the design phase and as part of the coordination efforts with the City of Dallas, IEA developed alternate routes for the trails connecting to the Margaret McDermott bridges to accommodate the City’s vision of the final configuration. The final configuration resolved right-of-way encroachments and horizontal and vertical conflicts with the proposed bridges.