Stiver is proudly supporting the Ashbridge’s Bay Treatment Plant Outfall. This $300 million project for the City of Toronto will replace the current outfall tunnel, which is at the end of its service life. It is set to be the largest wastewater outfall in Canada. The project includes a 16-meter diameter shaft by 85-meter deep, a 3.5-kilometer TBM excavated tunnel that has a 7-meter ID and precast concrete segmental lining. We are providing riprap placement plans for the riser sections on the lakebed. These cages will be placed at the bottom of Lake Ontario and will be guided in place by divers. The riprap baskets will be installed around each of the fifty – 1-meter diameter risers that extend from the tunnel to the lakebed. Learn more about this project in Tunnel Business Magazine: http://bit.ly/tbm-stiver-1-2022

The City of Houston has spearheaded the Northgate Regional Lift Station project as part of its plan to reduce operational and maintenance costs by consolidating 39 wastewater treatment plants and more than 380 lift station facilities. As a result, the project will decommission the Imperial Valley Wastewater Treatment Plan, which handles 4 million gallons of water per day.

As part of the Northgate project, Stiver Engineering successfully delivered to the contractor an expedited alternate design for a 70-foot-deep caisson. Stiver performed a detailed finite element analysis, and the structure was checked against various load cases. We designed the outer shell along with the interior partition wall, bottom slab and the top slab.

The design was performed and checked for each phase of construction, including casting, sinking, and installing the bottom slab, the partition wall and the top slab. Each condition was analyzed and optimized to provide the field crews with a more normalized rebar pattern and installation procedure.

Stiver Engineering provided critical design services and analyses for a process water treatment facility at HEB’s warehouse complex on Space Center Drive in San Antonio, Texas. Our work encompassed pipe support designs and analysis, CMU block wall designs, and foundation designs for the operations building and the canopy structure. The pipe support designs included thermal, gravity, seismic and thrust analysis for the process piping, overhead pipe support structures, and a 43.5-foot-tall pipe support tower between process tanks. Multiple CMU block walls were designed for the operations building. Foundation designs were for the operations building, canopy structure, slabs for rolling dumpsters and a foundation design for the pipe supports.

As part of a major infrastructure project at the Schoharie Reservoir in Gilboa, New York, Stiver Engineering provided a variety of services for a low-level outlet designed to release water downstream into Schoharie Creek to facilitate dam maintenance and emergency response, mitigate flood risk, and enhance downstream habitat for fish and wildlife. The work includes construction of a 9.5-foot diameter micro-tunnel at a depth of 160 feet. Stiver provided designs for the gate shaft as well as analysis of the steel jacking frame for the tunnel machine and steel pipe. We also provided trench safety designs, thrust block designs, steel pipe casing designs, anchor bolt attachment designs, and a structural review of the Herrenknecht tunnel launch seal and pipe break frames, among other services.

The Chelford City Diversion project will consolidate and upgrade public works facilities in part of Houston through the installation of sanitary sewer lines, manholes, reinforced concrete pavement, and curbs. As part of the project, Stiver Engineering redesigned a concrete vault at the junction of a 60-inch sanitary sewer pipe and a 108-inch sanitary sewer pipe. The bottom of the 22-foot-tall concrete vault was 70 feet below the existing ground.