Rapid Evaluation of Load-Carrying Capacity of Long-Span Bridges Using Limited Testing Vehicles

Abstract

Load testing is usually used to evaluate the load-carrying capacity of long-span bridges in their service life. However, a large number of calibration trucks should be arranged in complicated loading patterns to deform bridges during load testing, which is labor-intensive and time-consuming. Aiming to solve this problem, this paper proposes a rapid bridge load-carrying capacity evaluation method using limited testing vehicles. The methodology includes three steps: influence line identification from limited vehicle exciting responses; influence line correction based on prior information of the bridge; and influence line–based bridge load-carrying capacity evaluation. To apply this method in engineering practice, standardized truck passage routines are designed. An application example involving a 1,280-m long-span suspension bridge is presented at the end of this paper. The truck routines, extracted bridge influence lines, and predicted load-carrying capacity of that bridge are presented based on the proposed methods. The testing results are also compared with standard load testing conducted 12 years ago to evaluate bridge performance changes. The outcomes of this paper provide a workable and economical method for long-span bridge load-carrying capacity evaluation.