FATIGUE RELIABILITY ASSESSMENT OF ORTHOTROPIC STEEL BRIDGE DECKS BASED ON PROBABILISTIC MULTI-SCALE FINITE ELEMENT ANALYSIS

摘要

The orthotropic steel deck (OSD) has been utilized successfully for thousands of bridges worldwide; however, fatigue cracking of the OSD has been observed frequently due to the complicated welded details combined with stresses that can be difficult to quantify, and the uncertainties in fatigue damage accumulation. In this paper, a fatigue reliability assessment method is proposed based on a comprehensive vehicle load model and probabilistic multi-scale finite element (FE) analysis. The vehicle load model, obtained from statistical data of toll stations, consists of probability distribution functions regarding the number of axles, axle weights, and transversal positions of vehicles, etc. The multi-scale finite element model not only captures the main features of the entire bridge but also gives an accurate description on local stress responses of the OSD in a relatively efficient way. Based on the probabilistic FE analysis combined with the developed vehicle load model, the fatigue reliabilities of the OSD could be obtained. Application of the proposed method is made in the fatigue reliability assessment of the OSD of the Runyang Cable-stayed Bridge for demonstration.