Research On Failure-safety Design Method For Hanger Of Through Arch Bridge Based On Fatigue Analysis

The problem of the arch bridge due to the sudden break of the boom has not been solved,and when the bridge boom is broken,the traffic is paralyzed,and the cost of the boom is increased many times.Based on the theory of damage safety,this paper applies it to the tied arch bridge in order to achieve: the sudden break of the boom will not damage the components of the bridge,nor will the entire bridge collapse;and after the boom is suddenly broken,In the case of no need to interrupt the traffic,there is enough time to replace the boom,and no special support is required in the replacement boom to ensure the safety of the bridge structure.Taking the Puting River Bridge as an example,this paper discusses the factors affecting the fatigue life of the boom through finite element modeling,and proposes a damage safety design method based on stress amplitude adjustment.The behavior of the boom system is Safety performance is analyzed.Firstly,the layout forms and protective measures of suspenders of arch bridges are introduced.Then the damage safety theory is elaborated in detail,the anti-fatigue design of suspenders is summarized,and the method for estimating the fatigue life of suspenders is briefly described.Secondly,from the perspective of structural design,the influence of the distance between the boom,the distance of the boom from the arch,the area of the boom and the stiffness of the arch beam on the fatigue life of the boom is analyzed.Then using the finite element analysis software combined with the theory to demonstrate that the two so-called failure-safety double boom theory based on the area difference and the stress amplitude difference can not achieve the life difference between the two booms in the same position,and its life theory is theoretically It is roughly equal.Finally,a damage safety design method based on stress amplitude adjustment is proposed,and compared with the stress,fatigue and dynamic response of common parallel double suspenders.It is concluded that this method can greatly reduce the stress amplitude of the corresponding suspenders and realize the life difference of two suspenders located at the same suspension point.Then,the elasticity of different rubber cushions is simulated.In the case of stiffness and different area ratio of suspender,the reasonable elastic stiffness of rubber pad and area ratio of suspender suitable for the bridge are obtained.At the same time,under the condition of reasonable elastic stiffness and area ratio of suspender,the service life of suspender without considering corrosion and corrosion is analyzed respectively,and the practicability of the method is evaluated.