Numerical analysis of diaphragm fatigue of reinforced concrete simply supported T-beams

Diaphragms are important components of reinforced concrete ribbed beam bridges. Thus, diaphragm fatigue damage can seriously threaten the safety of in-service reinforced concrete ribbed beam bridges. In order to explore the fatigue performance of reinforced concrete beams and determine the internal relations between diaphragm fatigue life and fatigue load stress level, an entity analysis model of reinforced concrete simply supported T-beams was presented in this study. The spatial entity model was established by using the finite element software Midas/FEA. The correlation was analyzed on the basis of fatigue stress level, spacing-span ratio, width-height ratio, and fatigue performance of the beam diaphragms. The reliability of the calculation results was verified by using the traditional fatigue analytical methods of SN curve and Miner linear cumulative damage theory and the methods for Goodman and Gerber correction. Results demonstrate that the fatigue life of the model beam increases and the damage degree decreases when the spacing-span ratio decreases and the width-height ratio increases. The model is economically reasonable when the diaphragm spacing- span ratio and the width-height ratio are 3.58 and 0.17, respectively. The study can provide references for further improving the anti-fatigue design of reinforced concrete diaphragm beams. © 2018 Eastern Macedonia and Thrace Institute of Technology.