| The Orthotropic steel bridge deck has been widely used in the construction of long-span bridges due to its advantages of light weight,strong bearing capacity,rapid construction and strong integrity.However,with the increase of the age of the orthotropic steel deck bridge,the shortcomings of the structure gradually appear.One of the most prominent problems is the fatigue cracking of orthotropic steel deck.For this reason,the bridge researcher of various countries have done a lot of research on the fatigue cracking problem of the orthotropic steel bridge panel and perfected the structure continuously,which made the fatigue performance of the orthotropic steel bridge deck greatly improved.However,in order to eliminate the fatigue problem more thoroughly,it is necessary to further study the fatigue problem of orthotropic steel deck.In this paper,the finite element analysis method of the orthotropic steel bridge deck at home and abroad is summarized and analyzed,and the force mechanism of each subsystem of the steel bridge panel is analyzed.Finally,the UHPC layer is laid on the pure steel bridge deck o explore the efifect of the UHPC layer on the fatigue performance of the steel bridge deck.The main research work and results are as follows:1.Taking a flat steel box girder bridge as an example,the finite element model of local steel box girder is established,and the finite element fatigue analysis method of various fatigue details is carried out.The mesh size of different concerned fatigue details and the way to determine the most unfavorable details are determined.For different fatigue details,the amplitude analysis procedure is:First,the longitudinal loading position corresponding to the maximum stress is determined.Then,lateral loading is carried out at the longitudinal position to determine the most unfavorable lateral position of the details and the corresponding unfavorable loading position.Finally,the longitudinal stress history curve of the most unfavorable details is obtained by longitudinal loading at the most unfavorable lateral loading position,and the stress range of the detail is calculated by the stress history curve.2.The whole orthotropic steel bridge panel system is divided into different subsystems.Through the finite element modeling,the force behavior analysis and parameter influence analysis are carried out separately to each subsystem.The force behavior of each subsystem and the influence degree of each parameter on its force are understood,and the most obvious parameters that affect the detail fatigue performance involved in each subsystem are obtained.3.Taking a flat steel box beam as an example,the Finite element model of local steel box girder segment with pure steel and with UHPC layer.The stress amplitude of each fatigue detail was computed and compared respectively.The results showed that the UHPC layer greatly increased the rigidity of the steel bridge deck,and then greatly reduced the stress level of the fatigue details,result in the reduction the probability of fatigue cracking in every detail.The UHPC layer has a great influence on the fatigue stress range of the details of the longitudinal rib-to-deck connection,and the stress range is reduced from 60%to 78%;for the rest of the details,the degree of influence is relatively small,and the maximum range of the stress range is only 46.9%. |
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