Project Location: Austin, Texas
Client: Dept. of Public Works and Transportation, City of Austin, Texas
Dates: June-1998 to August-1999

The City of Austin is extending the existing South first Street for a total length of about 10,000 ft south of its current termination. The roadway covers a total width of 120 ft, carrying four lanes of traffic, two bike lanes, two pedestrian sidewalks, and a median of 20-ft width. Two bridges of about 500 ft and 400 ft lengths are necessary for the crossings of the new roadway over Slaughter Creek and Nichols Branch Creek. The roadway crossings are designed with twin-bridge structures over the creek, each bridge with a width of 39 ft, each carrying two lanes of traffic, a bike lane, and a pedestrian sidewalk.

The clients retained the services of LCR&A to coordinate and perform the conceptual design for the bridge components in cooperation with the structural designers. LCR&A investigated structural alternatives of precast, prestressed U-beams and standard AASHTO I-beams. Alternatives were presented for different columns and bent caps. Options to enhance the structure by detachment of the pedestrian bridges were also investigated.