New Early Warning Indicator Based on Vehicle Load and Difference Cur- vature for Simply-Supported Beam Bridges

A new indicator called Vehicle Load Difference Curvature Indicator (VLDCI) was proposed in this paper to further study the application of difference curvature to early warning of simply supported beams. Values of VLDCI can be obtained based on the measured vertical displacement data under a novel vehicle load mode (working condition of concentrated load), which can be obtained by apply vehicle loading twice. The graph of VLDCI can indicate the damage information. Case study shows that VLDCI method can detect the occurrence and position of damage effectively and then the early warning of beam status can be realized. Moreover, the calculation process of this new indicator is simple while VLDCI values of the intact beams are not required.