Location

  • San Antonio, Texas

Client

  • TxDOT San Antonio District

Status

CobbFendley was responsible for the design of this pedestrian facilities PS&E project to add 3.2 miles of new accessible facility with sidewalks on both sides of the road in this urban corridor with open drainage and constrained right-of-way (ROW). The design included sidewalks, wheelchair ramps, driveway/intersection replacements, directional islands, cross culvert extensions, retaining walls, pedestrian rail, MBGF, traffic and pedestrian signals, TCP (vehicles and pedestrians), signing, and striping. This project had a compressed design schedule (with only 60%, 95%, and final submittals over four months), and successfully met the letting date. Significant utility challenges in this urban corridor with constrained ROW were magnified due to the compressed schedule and were resolved with clearance prior to letting. Where the sidewalks were separated from the roadway, they traversed challenging terrain, so CobbFendley developed sidewalk profiles in the PS&E to verify the grade was ADA compliant. Due to significant ROW constraints and obstructions, we implemented short cut and fill retaining walls to avoid conflicts and minimize grading. Although the roadway was a curbed urban section, this was an open drainage system where runoff from the roadway drained through slotted curb with flumes into the separation to cross-drainage structures. We designed armor curb with sidewalk bridge inlets (steel plates) throughout the project to maintain existing drainage patterns. Existing and proposed ditch capacities were analyzed to meet hydraulic criteria.

The most significant design challenge we encountered on the project was installing the continuous pedestrian facility across the 150-foot-wide by 15-foot-deep Dietz Creek Channel. The design solution was to reconfigure the section to reduce lane widths (only in vicinity of the bridge) and provide space for a single sidewalk across the existing bridge. Since this was a low-speed condition, we designed an innovative design solution using curb to separate pedestrians/traffic with 6-foot desirable width raised “Bridge Sidewalk” (Item 422) and Type C402 combination bridge rail. This involved retro-fitting the C402 rail to the bridge deck via TxDOT design detail “C-RAIL-R” along the edge of the existing bridge. TxDOT standard “BRSM” was modified to fit our application. We obtained as-built plans, reviewed bridge inspection reports, performed site assessment, and completed a bridge condition survey to confirm that the increased dead loads had no impact to the bridge’s structural integrity. This creative method was cost-effective and met the objective to provide a safe ADA and PROWAG compliant pedestrian route through the corridor.