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Client: Northeast Ohio Regional Sewer District
Consulting Engineer: MWH Americas
Contract Amount: $16,879,059.00
Scope: 2,140 LF of 72” RCP sewer by cut and cover methods up to depths of 30 VF.
4,165 LF of 72” RCP in tunnel.
40 LF of 96” RCP in tunnel
Work Shaft 1 including drop manhole structure
Work Shaft 2 including a cast in place, baffle drop manhole structure
Work Shaft 3, an exit shaft for the tunnel boring machine.
New Flow Regulator Structure(MC31) with gates and baffles
Two cast in place diversion structures
New Plunge Type Drop Structure(14A) inside working shaft
Triad recently completed the Lee Road Relief Sewer under budget and ahead of schedule for the Northeast Ohio Regional Sewer District in Cleveland, Ohio.
Triad excavated four different circular shafts in varying soft ground conditions with some underlying rock near the bottom of two shafts. The soft ground varied from loose silts to glacial tills. All of the excavations passed below the water table. The shaft diameters ranged from 24 to 28 feet. Liner plates with circular rib bracing were used as the primary support. All were grouted in place.
The tunnel for the 72” RCP was excavated using a Lovat full face tunnel boring machine(TBM) with closing doors at the tunnel face. The TBM cut a 112” diameter. The longest tunnel run was 3,730 linear feet between Work Shaft 1 and Work Shaft 2. A second 434 linear foot run connected work shaft 14A with the new regulator structure(MC31) and work shaft 3.
After tunnel excavation was completed, the 72” RCP was installed by a pipe carrier. Each pipe was transported down the tunnel, set in place and blocked. After completion of the pipe setting of each tunnel run, the pipe was grouted in place using a cellular mix.
The contract contained a Geotechnical Baseline Report and a Dispute Resolution Board. The baseline report required the contractor to anticipate 370 boulders between 24-36” and 6 boulders between 36- 60”. The actual count was far less than anticipated. However, several boulders larger than 60” were encountered. Triad used non explosive techniques to remove the oversized boulders with minimal impact and cost.
This project had virtually no issues that required the Dispute Resolution Board’s involvement. Triad and the owner took a very proactive position to confront any issues immediately and find solutions that would quickly resolve these issues. As a result, the project moved ahead in a very quick and timely manner, finishing well ahead of schedule.