Research On Fatigue Characteristics Of Small And Medium-span Reinforced Concrete Arch Bridge Under The Vehicle Loads

China has a vast, complex terrain, all kinds of bridges, large and small, plays a keyrole on the development of the transport industry. Small and medium-span reinforcedconcrete arch bridges are particularly common. Over the past decade, with the blowoutdevelopment of the domestic transportation industry, the actual traffic in most parts ofChina has been far more beyond the original design traffic when the bridges weredesigned. Bridge problems caused by vehicle operation are very common, especially thebridge fatigue problems which occur from time to time. This gives the importance of theissue of bridge fatigue, which caused a great loss and painful lessons.Based on the classic principle of Palmgren-Miner linear cumulative damage, thefatigue characteristic of small and medium-span reinforced concrete arch bridge wasanalyzed. The main factors causing the highway bridge fatigue damage is day-to-daypractical random vehicle carriers. Based on the previous long-term investigation andstatistics about vehicle load, the random vehicle load flow on the roads and bridges issimulated by MATLAB and a finite element model of small and medium-spanreinforced concrete arch bridge is made by the finite software ANSYS. Through macrocommand LOAD is compiled with the ANSYS parametric design language APDL, thebridge is loaded with the random vehicle load flow generated by software MATALB,respectively in two ways of the two-lane traveling in the same direction and double lanereverse. Through making transient dynamic analysis of the arch bridge modelrespectively, the stress spectrums of arch ring’s dangerous sections in the twoconditions are obtained. The fatigue features of concrete and steel are consideredrespectively, based on the S-N curve and the principle of linear fatigue damageaccumulation. Because the vehicle impact during driving process will increase thebridge cyclic stress, considering the vehicle impact in the way of impact coefficient, thefigure damage of arch bridge under the action of random vehicle load flow is analyzedagain. The fatigue damage calculation and the remaining life prediction of the small andmedium span reinforced concrete arch bridge are realized. Finally, in order to simplifythe calculation, loading in the form of bridge fatigue load spectrum, the fatigue problemof small and medium span reinforced concrete arch bridge is analyzed.