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 provided launch shaft, excavator digger shield and thrust block design services for a 108-inch-diameter water line project along city easements from Milner Road to Aldine Westfield Road in Houston, Texas, near the Intercontinental Park area. Two shoring pits, each more than 30 feet deep, were designed with soldier piles, steel plates and timber lagging. Waler beams were used to support the soldier piles. At the launch pit, a jacking frame was designed at the bottom of the pit to resist the thrust from the excavator boring shield system. The jacking frame consisted of three extra waler sets and diagonal bracings connected to a portal support frame using king beams, a header beam and a footer beam.

Stiver Engineering provided liner plate tunnel and bore pit design (launch and receiving) for 10 tunnel crossings as part of this integrated pipeline project. We also provided a trench safety design for pipeline installation, calculations for required jacking loads for carrier pipe in tunnels, and a grouting plan that accounted for pipe buoyancy calculations. This $21 million project for the Tarrant Regional Water District included 2,000 linear feet of 9-foot, 5-inch excavated diameter tunnel in 10 different tunnels crossing Texas Department of Transportation roads, each with launch and receiving shafts (20 shafts).