Study on Reliability of Suspension Bridge Slings Considering Random Wind Vehicle Loads
In order to study the influence of random wind vehicle load on the reliability of long-span suspension bridge slings,a suspension bridge sling reliability analysis method considering the influence of random fluctuating wind and random traffic flow was proposed.Firstly,Kaimal spectrum is used to simulate the random fluctuating wind field,and the correlation between vehicle axle weight and wheelbase is established by copula function.The simulation method of random traffic flow distribution is established by Sobol sequence sampling.Secondly,the degradation law of the area corrosion of the suspension bridge sling steel wire is analyzed,and the sling resistance degradation model is constructed,and the structural response characteristics of the suspension bridge under random wind vehicle load are fitted by SVM.Finally,taking a long-span suspension bridge as an example,the degradation law of sling reliability under random wind vehicle load is studied.The results show that the structural response characteristics of suspension bridges under random wind vehicle loads can be accurately established by SVM;considering the random wind vehicle load,the sling reliability index presents a saddle shape distribution,and the closer to the bridge tower,the higher the sling reliability index is;the random wind vehicle load will lead to the increase of the stress amplitude of the sling,and the adverse effect on the mid span short cable is greater,after 20 years of service,the reliability index of the middle cable decreases by about 84.76％,which is faster than the degradation of the side cable;the random wind vehicle load magnifies the adverse effects of external loads and accelerates the fatigue damage process of slings.The middle cable reliability under the random wind vehicle load is only about 50％without considering the random load,and the side cable reliability is about 59.1％.
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