Monitoring the Condition of Narrow Bridges Using Data from Rotation-Based and Strain-Based Bridge Weigh-in-Motion Systems

Abstract

This study investigates the concept that when localized bridge superstructure damage is present, the weights of passing vehicles inferred from a rotation-based bridge weigh-in-motion (B-WIM) system will deviate from those predicted by a strain-based B-WIM system. Rotation measurements were gathered from a 5.4-m simply supported laboratory model bridge crossed repeatedly by a four-axle model vehicle. Damage was incorporated by bolting stiffening plates onto localized sections of the test bridge. This “negative damage” concept, consisting of local increases in stiffness, allows several damage scenarios to be investigated on the test bridge. The experimental results show that when negative damage is present, rotation-calculated gross vehicle weights decrease, while strain-calculated gross vehicle weights remain unchanged. It is also shown that the approximate location of damage can be identified.