Load Spectrum and Fatigue Life Computer Analysis of Prestressed Concrete Bridges

Abstract

With respect to fatigue damage of heavy traffic on the bridge structure, this paper studied on load spectrum and fatigue simulation. The author used manual recording, live cameras, vehicle dynamic weighing system (WIM) to conduct traffic investigation in a continuous 24-hour period. Basing on these data in Hebei province, we established typical vehicle load spectrum using probabilistic and statistical methods, and deduced a standard fatigue vehicle model on this basis. Then we prepared random load spectrum by MATLAB and realized loading it on a finite element model (FEM). Next, the paper assessed the fatigue life of in-service highway bridges that in Hebei by comparing typical vehicle load and random vehicle load. Results showed that vehicle speed has significant influence on fatigue damage under typical vehicle load. Equivalent stress amplitude is small in two operational states under random vehicle load, the general operation state and intensive operation state. Fatigue damage to bridge under general operation is obvious. After verified the applicability of the standard fatigue vehicle model, we can believe that this model developed in this article can be further used as a reference to check highway fatigue damage in the entire Hebei province. Moreover, all the results showed that the bridges wouldn’t get fatigue failure under a normal operation state when there is no impact of environmental factors.