Design and Implementation of Load Cell Bearings to Measure Dead and Live Load Effects in an Aged Long-Span Bridge

International Conference on Bridge Management, Safety and Management (IABMAS 2010),
Philadelphia, PA
July 11-15, 2010

Dubbs, N., F.L. Moon, A.E. Aktan

In the spring of 2010, the expansion bearings of the Burlington-Bristol Bridge were replaced due to a poor condition rating (that caused the bridge to be classified as structurally deficient). The replacement of these load cell bearings represented a unique opportunity to configure the new bearings to monitor the dead load and live load actions as well as their variation with environmental conditions. Towards that end, a series of trial designs were developed with various load cell bearing types, load cell configurations, etc. These candidate designs were then evaluated through a series of finite element analyses and a single design was selected. To validate the selected design, a prototype was developed and tested in the laboratory under various axial forces, unidirectional and bidirectional moments, and shear forces. Once validated, 14 “smart bearings” were fabricated and installed on the Burlington-Bristol Bridge. To verify their proper operation, a series of load tests were carried out following installation. This paper and presentation will detail the development and validation activities for the “smart bearings” as well as the results from the first few months of long-term monitoring. In addition, non-technical challenges associated with developing appropriate design and performance specifications for the load cell bearings will be discussed.

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