Evaluation of Fatigue-sensitive Details in a Railway Danube Bridge by FE Analysis and SHM Measurements

Abstract

Structural health monitoring system (SHM) has an essential role in the prediction of steel bridges behavior and damage detection. Due to site difficulties and economic reasons, it is not possible to instrumenting all sensitive details within the structure. Finite element modelling is an effective tool for analyzing fatigue-sensitive details, as it enables the extension and interpretation of measured data. This study investigates the structural health monitoring (SHM) system of Southern Railway Danube bridge located in Budapest from fatigue sensitive details point of view. The research applies load testing data for the validation of finite elements models (FEM) which are to be used for specifying the sensitive details. Based on a detailed stress analysis, three fatigue-sensitive areas were identified in the bridge, as follows: 1. the cutout holes of cross girder, 2. the cope-holes, and 3. the transvers welding of bottom flange. Artificial cracks are applied in these details separately to investigate the efficiency of SHM system for crack detection. Stress values at the location of strain gauge points of the SHM system are calculated continuously as cracks size increased, simulating the propagation. The results show that the SHM strain gauges in the current placements not highly efficient to detect the cracks of the investigated details. The study extended to propose strain gauge positions to recognize the crack initiation and propagation in these details.