Structure safety assessment under heavy traffic based on weigh in motion and simulation analysis

Abstract

This article presents a new method for structure assessment based on weigh-in-motion data and simulation analysis. The focus is particularly on the simply supported hollow slab bridges and extra-heavy truck (gross truck weight ≥ 80 t) from the right tail of weigh-in-motion data. The dynamic models of truck types are refined, and the coupling relationship between truck and multi-girder bridge are determined. A self-developed bridge–truck analysis system is established by separate iteration and is used in the simulation analysis of extra-heavy truck load cases. The truck load effect is first analyzed by a comparison with code values. The load rating index is introduced for the structure safety assessment; meanwhile, the key parameters, for example, the dynamic amplification factor, are optimized. The results show that the maximum load effect level of extra-heavy truck is obviously higher than the design vehicle load effect, and the average level is approximate to or a little higher than the latter. The displacements due to extra-heavy truck are seriously transfinite, while the structural stiffness can meet the requirement of serviceability. Both the proposed method and Chinese code method are used to assess the structure safety of hollow slab bridges. The maximum value of load rating index ranges from 0.69 to 0.78 and the average value is 0.53–0.67. The hollow slab bridges have not yet reached the ultimate limit state and have a safety redundancy under the extra-heavy truck load. The loading indices of MOCAT are close to the average values of load index of this study, but lower than those of the maximum values. Some extreme loading conditions may be thoughtless in the proposed safety assessment method by MOCAT.