The NTH and Turn-Key Tunneling Team has been working closely with the NEORSD since May 2017 to design and construct the project to the NEORSD’s needs. The project design will provide a new conduit for the stormwater to drain through and return the site to pre-existing drainage conditions or better. NTH evaluated existing studies including a previous subsurface investigation, closed-circuit televising information, and historical geotechnical data, and determined that the existing culvert collapsed due to excess overburden placed on the pipe over time from development that had occurred over the years. NTH performed the hydraulic analysis to confirm flow capacity and to evaluate the proposed modifications to the project, to verify that all modifications meet the NEORSD’s design criteria, and to identify opportunity for optimizing the stormwater conveyance system. Our design approach is optimized to reduce both risk and cost. As part of this project, NTH is assisting with collaboration of other entities to ensure successful completion of the project in a timely fashion. When complete, the area will be restored to prior conditions or better.
Designed and built to date are the following:
- Geotechnical instrumentation, consisting of inclinometers, surface settlement points, and structure monitoring points.
- 24-foot diameter temporary shaft at the interface of the collapsed portion and intact portion of the culvert, for the construction of the tunnel alignment and temporary drainage flumes.
- One of two temporary flumes constructed via 36-inch auger bore that is drilled and cased about 230 feet from the shaft to the retained water. One flume is strategically placed in the upper tunnel portion, while the other flume will be below the tunnel – this way allowing stepped dewatering of the retained water, in turn allowing for worker safety.
An Open face digger shield in combination with hand mined tunneling will be used for the construction of the initial support system towards the upstream of the alignment. Initial support system consists of steel ribs and wood lagging. HOBAS pipe will be used as the final tunnel liner.
This project is a unique design-build project – the first ever tunnel design-build project by the NEORSD. It has involved collaboration with property owners / stakeholders, including ODOT, Cleveland Hopkins International Airport, and two major hotels who have critical adjacent infrastructure.