The new TxDOT bridge will replace the existing truss bridge over the Colorado River in Columbus, Texas. Stiver Engineering provided construction consulting to the bridge contractor with cofferdam designs for crane access on both banks of the Colorado River. The cofferdams allowed the crane to get closer to the center of the proposed bridge so that the bridge beams could be lifted and installed. The cofferdam was constructed using driven sheet piles, wales and cross ties.
The City of Houston’s Northeast Water Purification Plant (NEWPP) Expansion Project is a design-build project that will add 320 million gallons per day (mgd) by 2024 to the existing water plant’s capacity. The expansion project will allow the City and the regional water authorities to meet projected demands, while fulfilling requirements set by the Harris-Galveston and Fort Bend Subsidence Districts resulting in a shift from historical groundwater usage to a predominant reliance on surface water.
Construction on the $1.7 billion project started in early 2018 and has been called the largest expansion project in the world. The NEWPP expansion is required to comply with subsidence district rules for conversion from groundwater to surface water supply, resulting in a reduction of the subsidence rate. Features of the project include the design, construction and commissioning of:
- Intake pump station
- Twin 108-inch transmission mains
- Pre- and post-treatment chemical addition
- Flocculation/sedimentation basins
- Ozone treatment
- Finished water storage tanks
- High service pumping station
Stiver Engineering provided construction consulting through the following designs for contractors working on the NEWPP Project:
- Shoring design for 10,200 LF of twin 108-in.-dia. raw water transmission mains in common trench at a depth of 18 ft. to 40 ft.
- Pipe buoyancy calculations for the 38,000 CY of controlled low strength material (CLSM) backfill.
- Entry shaft, exit shaft and tunnel design for the 360-LF, 132-in.-dia. tunnel using liner plate.
- Shoring design for the filter/transfer pump station.