Grout Bonded Anchor Systems Case Histories:
Sewer Overflow Basin, River Rouge, MI

Today in the U.S., Americans have water quality problems that require correction. Major cities are being troubled with low water pressure, decaying pipes blocked with sediment, broken mains and contamination. One project taking corrective action in the Detroit area is the River Rouge Combined Sewer Overflow Basin. NTH Consultants chase a sinking caisson design because existing poor soil conditions are not suitable for conventional means of earth support. A sinking caisson is a hollow concrete structure that is initially formed at the surface and is sunk into position by excavating soil from the interior of the structure. The caisson was to be sunk under very controlled conditions to bedrock. Once fully sunk, a 7'0" thick foundation slab will be poured. One facet of the design that made this project unique was the presence of artesian ground water with a pressure head of approximately 5'0" above existing ground surface. The groundwater also contains hydrogen sulfide and methane gas. As a result of this existing field condition, NTH had to incorporate rock anchors into the design to resist unbalanced hydrostatic uplift pressures expected to act upon the caisson foundation. They chose a design utilizing full Multiple Corrosion Protection Anchors (#18 Grade 75 All-Thread Bars) with an 18'0" minimum bond length. A requirement of the specifications called for each anchor to be electrically isolated tested to ensure corrosive currents could not penetrate to the steel. All the rock anchors were successfully installed and tested. Now in place, the basin is 149'0" in diameter, sunk to a depth of 75'0" and contains 7'0" thick concrete walls. These dimensions make it one of the largest sinking caisson projects ever in the U.S.

Main Reason They Chose Williams