By Allan Jamail
East Harris County – June 26, 2018 — Harris County’s largest-costing single project in history is underway along the Sam Houston Tollway, between Highway 225 in Pasadena and I-10 in the North Channel area. The Harris County Toll Road Authority (HCTRA) is overseeing the project, with a cost of $1 billon.
The massive project, which began in April, will be paid for from toll revenues and without an increase in the $1.50 toll bridge fee county officials said. The new bridge, projected to open in 2024, will have 8 lanes (4 in each direction), full shoulders, no bridge supports in the water, and no reduction of lanes during construction.
The Port of Houston has been working to widen and deepen the navigation channel for several years. The new cable-stayed bridge will look similar to the Fred Hartman Bridge. HCTRA says the addition of inside and outside shoulder lanes and a gentler slope will make the new bridge safer.
The 4-mile-long program corridor will be constructed in three design-bid-build construction projects with a combined estimated construction cost of just under $1 billion and construction duration of 6-1/2 years. The first contract, which includes the cable-stayed main span bridge, is the largest single contract ever advertised by Harris County, and was awarded to Ship Channel Contractors. Mike Perez and Wade Bonzon, Planning Engineers, wrote in Road & Bridges that the existing opening has a span for ships to travel through of 750 feet and has supports inside the ship channel waterway. The new bridge design will not have any supports in the waterway and will increase the opening for ships to enter to 1,320 feet.
The Sam Houston Tollway (SHT) is one of only five available means of crossing the Houston Ship Channel. It has experienced significant increases in traffic over the last several years, and traffic demands are expected to grow from 54,000 vehicles per day in 2013 to almost 158,000 vehicles per day by 2035. Where it crosses the channel, the existing SHT is offset to the east side of a 200-ft-wide right-of-way and is surrounded by industrial facilities. When the existing bridge was constructed, it was envisioned that a twin span might someday be needed to upgrade traffic capacity on the tollway. However, the existing bridge, with only two lanes of traffic in each direction with no shoulders, was too narrow to satisfy future traffic needs.
To accomplish the SHT widening within the existing right-of-way while maintaining all four existing lanes of traffic throughout construction, the project team developed a phased construction sequence. First, a new four-lane southbound bridge would be constructed directly adjacent to the existing bridge. Traffic would then be switched to the first new bridge in a temporary bi-directional configuration while the existing bridge is demolished. The new northbound bridge would then be constructed along the alignment of the existing bridge. One final traffic switch would then allow each new structure to carry four lanes of traffic with full shoulders.