Bascule Bridge Balance
Double-leaf bascule (draw) bridge: check the balance between span and counterweight.
The Park Street Bridge in Alameda County, California is a four-lane double-leaf bascule (draw) bridge spanning 372 feet across the Oakland Tidal Canal between the Cities of Alameda and Oakland.
When rework construction modified the weight of the original lift spans the Alameda County Engineers needed to determine the proper counterweights to prevent the lift drive motors from overloading.
By measuring torque on the main pinion shafts used to lift the bridge, it was easy to determine and optimize the drive loads through adjustment of the counterweights on each span. Torque sensitive Vishay strain gages were bonded to the pinion drive shafts and two TorqueTrak telemetry systems were used to communicate the strain gage signals from both pinions simultaneously as the shafts rotated.
The County has a number of movable bridges that occasionally require adjustment due to repaving or other mechanical changes. With the Binsfeld telemetry equipment, torque and balance measurements can be made quickly and accurately, eliminating guesswork and potential drive overload problems.