The Joes Creek Interceptor project in Dallas involves 8,370 linear feet of 60-inch excavated diameter tunnel that will house 36-inch HOBAS carrier pipe. There are 20 shafts (ranging from 21 to 48 vertical feet in depth), and ground conditions include sand, sand with gravel, sandstone, sandy clay, shaley clay, and shale (Eagle Ford). Stiver Engineering provided steel casing pipe calculations for 8 runs. We also created designs for various sizes of shoring pits using sheet piling and wale sets, as well as designs for a 32-foot-diameter liner plate and ring beam shaft at various locations and TBM face pressure calculations.

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.

Stiver Engineering performed analysis and design work for rock anchors and HSS steel frames for a 44.5-inch diameter pipe support inside a 96-inch diameter tunnel. The supports were designed for critical load combinations generated from buoyant forces and self-weight of the pipe.

As part of a micro-tunnel project in Charlotte, North Carolina, Stiver Engineering created plans for seven tunnel boring machine runs along with launch and receiving shaft design. The plans included designs for a trench box bore pit, pile and lagging shafts at various depths and soil conditions, and a liner plate circular shaft with multiple ring beam portals. We also provided casing calculations, monitoring plans, settlement calculations, thrust load calculations and thrust blocks, as well as plan and profile drawings for a set of parallel sanitary sewer and storm sewer tunnels.

The Integrated Pipeline is a $48.5 million joint water supply project between Dallas Water Utilities and Tarrant Regional Water District. It involves building 150 miles of pipeline to transport up to 350 million gallons water daily from three East Texas Reservoirs into the Metroplex to increase reliable water access. Crews are installing 4,400 linear feet of pipe using an open face tunnel boring machine with hydraulic jacks and concrete segmental lining. The project recently reached a new milestone when the new tunnel under Trinity River was completed. Workers are now beginning to add 50‐foot sections of 108‐inch diameter steel pipe.

Stiver Engineering performed full design work for the IPL tunnel. Our work included several trench safety plan designs, pipe buoyancy and support calculations, shoring design, a design for a CMU bulkhead, and an alternative design using steel plates and members for grouting abandoned tunnel. We also created a plan and profile drawing set for a new tunnel profile including new geotechnical data, as well as analysis and design for increasing the depth of an existing liner plate and ring beam shaft, among other services.

The design/build project scope included construction of approximately 3,802 linear feet of 108‐inch water line including 2,614 linear feet of tunnel under the Trinity River and the remainder in deep open cut segments along the proposed alignment of Section 17. Other aspects include tunnel launch and retrieval portals/shafts, deep open cut approach ramps with temporary shoring at approximately 12:1 slope, pipe laying within approach ramps and tunnel initial support, pipe encasement with flowable fill and reinforced concrete, tunnel grouting, a 15.6‐foot diameter custom designed tunnel boring machine, and precast segmental tunnel lining.