Project Location: Houston, Texas
Category: Water + Stormwater + Wastewater
Started: June 30, 2020
Completed: June 1, 2022
Project Summary: As the fourth most populous city in the nation, Houston bustles with nonstop activity day and night. Like many large metropolitan cities, Houston’s public transit system offers light rail service: METRORail. Over 40,000 residents depend on METRORail’s 23-mile system daily. It also connects downtown to the City’s vital medical center district, which is extremely important to patients, doctors, medical students and visitors who rely on it as their primary method of transportation.
Houston is under a consent decree, which means the 6,000+ miles of sanitary sewers, 381 wastewater lift stations and 39 wastewater treatment plants are subjected to regulatory commitments.
The City’s ongoing extensive inspection of its vast sewer system identified 2.8 miles of 60-inch sanitary sewer suffering from severe I&I and high likelihood of failure due to years of corrosion. This segment is below Fulton Street, a major artery running through downtown Houston that also hosts a METRORail line, which increased the consequence of failure. However, any excavation or access requirements would not only shut down the rail line but also negatively impact businesses, schools, commuters and residents. In addition to safely restoring structural integrity to the impacted pipe, the City also needed to expedite renewal to meet regulatory commitments.
The City evaluated multiple options for rehabilitation and selected spin-cast geopolymer lining because of site restrictions. Work was issued on an existing contract with Vortex’s Quadex Lining System® (QLS), a spin-cast geopolymer application process that utilizes GeoKrete® geopolymer. Vortex designed an innovative internal bypass system that avoided road and light rail closures. Following cleaning and extensive patching and repair of the sewer line cracks, voids and offset joints, the contractor spray-applied GeoKrete to non-round areas and obstructions and spin-cast the geopolymer to a 1.5″ design thickness throughout the pipe. Following the successful completion of the initial and subsequent work orders, another work order for approximately 4,700 linear feet is in progress.
In addition to the minimally disruptive rehabilitation, the high level of cooperation between multiple government and private entities was noted by the City of Houston. From the City’s point-of-view, never before has there been this level of cross-entity cooperation and collaboration, which was so critical to this project’s success.