SL 20 from Chacon Creek to Spur 400

Cost Effective. LJA widened an existing bridge spanning a railroad with the ancillary correction of the cross slope to meet interstate standards. Funding was limited however, necessitating creative value engineering to accomplish the additional work. To realize cost savings, we proposed retaining the existing substructure including foundations, columns, and bent caps, and placed new beams and the bridge deck on modified bent caps to meet minimum roadway cross slope requirements.

Widening the SL 20 main lanes in Laredo over the KCS Railway Company right-of-way, while adding new frontage roads and a pedestrian crossing will reduce congestion and promote safety in this busy area. LJA’s design provided continuous frontage road access over the railroad as well as a secure crossing for bikes and pedestrians. There were numerous challenges and constraints surrounding the project that required specific engineering solutions such as replacing only the bridge beams and bridge deck to obtain the required cross slope, creation of crash walls due to column placement, and the connection of the pedestrian bridge to the frontage road bridge to expedite coordination with the railroad. A 3D “drive-thru” animation was prepared to illustrate construction phasing to the public and to gain buy-in on the engineering design solutions. It is anticipated that SL 20 will be upgraded to an interstate highway in the future.

For more information regarding this project, please contact Chris Mundie, PE at cmundie@lja.com.

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Transportation

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Schematic Design

Plans, Specifications, and Estimates

Construction Phase Services