The Third Street Bridge is a vertical lift bridge that crosses the Cuyahoga River in Cleveland, OH. M&M is providing engineering services to evaluate the bridge balance condition and various operating characteristics of the span drive using the strain gage method.
The process involved attaching strain gages to the bridge's machinery to measure torque and balance on each side. Each corner of the bridge had two uphaul cables and two downhaul cables.
To check how balanced each corner was, the sag (or droop) of these cables was measured. From this, the tension in the cables was calculated using a standard formula. Additionally, spring-like devices called "snubbers" were monitored to confirm the cable tension during bridge operation.
The tension results from all three methods—cable droop, snubber displacement, and strain gage torque—were compared and confirmed the measurements were accurate.
Bridge Geometry
| Total Project Length | 123 feet |
|---|---|
| Vertical Clearance | 98 feet |
