The Baltimore City Department of Public Works (DPW) is converting open-air drinking water lakes to buried tanks to help preserve the city’s drinking water system and comply with federal Safe Drinking Water Act regulations. Stiver Engineering provided a custom shoring pit with support frame, plans for pipe supports and pipe hangers for large diameter steel pipe. We also provided the review of pipe plugs and the design of thrust restraint steel frames for large diameter pipe plug testing. Stiver Engineering performed bi-monthly slope stability reviews for the tank executions which were 430 ft. diameter and 50 ft. deep. We also provided excavation plans in rock material at critical locations for the installation of the influent pipes and the tank foundations. We reviewed rock borings and provided a trench safety plan. DPW is investing in safer and more secure drinking water with underground tanks.

The sewer system in the city of Las Vegas was disjointed and inefficient. Connections to the main sewer line were sporadic, and relief sewers could not adequately intercept flow. To support the City’s waste management, Stiver Engineering provided key design services for the Paradise Whitney Interceptor in Las Vegas.

The project consisted of a 32,000-foot gravity sewer that conveys flow from the Enterprise Water Resource Center and existing interceptors. Over 26,000 lf of trenchless construction were installed, making it one of the most significant trenchless new installation programs in terms of footage undertaken in the United States. The project received an honorable mention for trenches project of the year by Trench Technology.

Stiver Engineering provided a trench excavation safety plan for the open cut sections including fall restraint systems in addition to the trench shoring, bore pits for the tunnel operations, tunnel design, steel casing design, tunnel grouting design and tunnel settlement analysis.

Stiver Engineering provided key design services for the Northeast Transmission Line (NETL) project in Houston. The NETL will transmit 365 million gallons of water a day from the Northeast Water Purification Plant through a 108-inch steel waterline to approximately 900,000 homes in Harris County. Stiver provided a shoring design using soldier piles, wale sets, and steel plate and timber lagging. We also developed a design for a temporary bulkhead to grout fill the annulus of the waterline pipe inside the casing pipe and a cradle design to support the existing 84-inch diameter waterline.

Photo Credit: LAN

Stiver Engineering provided a shoring design for the launch and receiving tunnel shafts, including portal design implementing soldier piles and the shaft design implementing sheet piling and wale sets. Calculations and a finite element analysis (FEA) were performed for a 108-inch diameter tunnel steel casing pipe. Calculations for grout pressure used to fill voids outside the casing pipe were also provided.

Stiver Engineering designed a 204 ft. x 66 ft. x 24 ft deep multi-phase shoring system using piles, wales, and knee bracing. Implemented access ramps and phases, this shoring design allowed the contractor to complete the project despite the excavation being adjacent to large storage tanks.