Spalding DeDecker Associates, Inc., Jay Dee Contractors Inc., and the city of Detroit Water & Sewerage Department successfully tested a newly constructed stop gate for the Garfield Road Interceptor Tunnel project.
The stop gate, the largest in the DWSD sewer interceptor system, is 11 ft wide by 15 ft high and was designed to close the 11 ft diameter Romeo Arm Interceptor located 62 ft below ground surface at 15 Mile Road and Garfield Road. The gate will be used for flushing sediment and inspecting the interceptor condition downstream of the stop gate.
The gate was lowered in the morning and the flow was allowed back up throughout the day and night. By evening, the flow had still not reached the top of the stop gate. However, the flow was pouring over the top of the gate on the next morning. The gate was designed to hold back flow without overloading the sanitary system or flooding basements upstream. With flow backed up to the top of the stop gate, the force of the sewage on the 6.5-ton stop gate exceeded 50 tons.
One design feature was the use of a space age urethane seal that reduced the co-efficient of friction through the addition of Ultra High Molecular Weight particles. Reducing the coefficient of friction lowers the force required to break the gate free of the static load from 57 tons to 15 tons. This allowed the use of a smaller crane resulting in a cost saving to DWSD.
The project was recently awarded the Construction & Design Award from the Engineering Society of Detroit.