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 numerous services for capital improvements to a 108- inch-diameter water line running from Aldine Westfield Road to Willis Street in Houston, Texas. We created shoring and portal designs for launch and receiving shafts — some as deep as 31 feet — using sheet pile and soldier piles, wale sets, steel plates, timber lagging, and other methods. Stiver also created trench safety designs for installation, special shoring requirements with trench boxes, steel plates and soldier piles, and steel casing designs.

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).

The Eastern New Mexico Rural Water System project will provide potable water to eight city and county member agencies and Cannon Air Force Base in east-central New Mexico. It will replace current groundwater supplies from the Ogallala (or High Plains) Aquifer with a renewable surface water supply, the Ute Reservoir. Stiver Engineering performed excavation plans, dewatering design, CLSM backfill calculations and pipe buoyancy calculations for this project.

Stiver Engineering provided key services as part of the largest and most complex sanitary sewer improvement project that the San Antonio, Texas Water System (SAWS) has ever undertaken. The project involves replacing a deteriorating, 5-mile-long pipeline, known as the “W-6 Upper Segment” main, that serves approximately 500,000 residents in the San Antonio area. The replacement pipe will be designed to last 100 years.

Stiver’s work included designs for steel casing, bore pit/access shaft, and grouting plans along with a concrete thrust block analysis. Buckling and jacking calculations were provided for the 36-inch casing pipe. Stiver also helped the contractor with a plan to grout fill around the 8-inch and 12-inch PVC carrier pipes inside the 36-inch casing. A custom concrete thrust block was provided to the contractor to help with the installation of the 36-inch casing pipe. Stiver Engineering provided the support/restraint design for the 60-inch and 104-inch diameter Hobas carrier pipes along with the buoyancy calculations and grout pour designs.