Research On Fatigue Damage Of Tied Arch Bridge Suspender

With China's entry into the twenty-first Century, in the promotion of reform and opening up, the number of the infrastructure construction is soaring up. With the increasing traffic pressure on the highway, bridges in China are in full load operation, and the service time of more than 27 years. One can imagine the fatigue damage by vehicle bring security hidden danger bridge has become the largest. Concrete filled steel tube arch bridge with its light weight, large spanning ability, mechanical graceful bridge builders favored by the majority. The arch bridge suspender force transfer bridge structure as the main component, the health conditions related to the safe operation of the whole bridge. Therefore, this paper combined with a CFST arch bridge as the prototype which is on the state line road named number 108 Beijing to Kunming in the territory of Yunnan. By using the universal finite element calculation software MIDAS/CIVIL to simulate analysis of the arch bridge loads in the vehicle and its typical suspenders fatigue performance, and then by changing the design parameters are put forward to improve the arch bridge and the suspender fatigue design reference. The main research contents and conclusions are as follows:? By using MATLAB to generate random vehicle load spectrum which obey the logarithmic normal distribution. Then put the load spectrum random effects on the deck driveway. Based on the theory of 1860 levels of fatigue of steel strand of S- N curve analysis, and then using rain flow counting method to gain the equivalent calculation and the equivalent stress amplitude stress cycle number of each typical boom under the fatigue load spectrum. And based on the Miner linear damage accumulation theory the bearing type tied arch bridge suspender fatigue life was evaluated, the conclusion has a certain reference value to the project.? Through some fatigue design parameter change of suspenders of arch bridge, I compared the fatigue property of a total of 6 cases. Conclusion: 1)Collaborative stress of continuous bridge road layout is more conducive to the boom, it can be a good improvement suspender fatigue performance, even in a rod fracture case it will not lead to the collapse of the whole bridge. 2)And the suspender fatigue performance contrast suspender spacing will be determined according to the actual bridge span. Its distance is generally in control of 4 to 10 meters. if the suspender spacing is too large, it will do harm to the boom of anti fatigue design 3)Combined with the engineering cost, to increase the appropriate suspender sectional area favorable for fatigue design, especially the side suspenders. 4)Too large of the stiffness ratio is extremely unfavorable for suspender force, and not conducive to the anti fatigue design too. 5)Anti fatigue design influence span ratio on the boom is very small, we can make the appropriate adjustments according to the actual situation of the bridge. 6)When we only change the side hangers from the arch foot distance, this change can only enhance the edges suspender anti fatigue performance, and the fatigue performance of the other boom improve minor role.