| Steel box girders are widely used in long-span bridges,however,the construction of the structure is complex,a large number of welds are in this structure,and stress concentration is prone to occur at the welds.Therefore,it is necessary to predict the fatigue life of the welding seam of the steel box girder,and carry out scientific and effective visual management to ensure the safety of the welding seam details of the steel box girder.Taking the steel box girder of Hebei Taizicheng cable-stayed bridge as the research background,this paper analyzes the hot spot stress response characteristics of the weld details of the orthotropic steel deck of the steel box girder,estimates the fatigue life of the weld details,and studies the visual management of the weld information of the steel box girder.The main work and conclusions of this paper are as follows:(1)The weld details of the orthotropic steel bridge deck(deck weld root of deck to longitudinal rib weld,deck weld toe of deck to longitudinal rib weld,longitudinal rib weld toe deck to longitudinal rib weld,Longitudinal rib weld toe of longitudinal rib to transverse diaphragm weld)are selected as the research object,the sub-model technology of the finite element software ABAQUS is used to establish a solid element for simulation;the hot spot stress method is introduced to calculate the hot spot stress influence surface of the weld detail under the action of wheel load,and compare the effect of wheel loading position on weld details;establish a finite element model without longitudinal rib bulkhead for comparison,and study the influence of longitudinal rib bulkhead on the hot spot stress influence surface of weld details.The research results show that the local effect of the orthotropic steel bridge deck is obvious,and the hot spot stress influence surfaces of different weld details are quite different;number of spikes and properties of tensile and compressive stress are not affected.(2)On the basis of the hot spot stress influence surface of the weld detail,write a script to obtain the hot spot stress time history curve of the weld detail when the fatigue load model is passed,and use the rain flow counting method to convert the hot spot stress time history curve into the stress frequency value.According to the corresponding S-N curve and Miner’s linear damage accumulation theory,the fatigue life of vulnerable weld details is estimated.(3)Change the arrangement of longitudinal rib bulkhead and the parameters of the orthotropic steel bridge deck,and conduct a comparative study on the fatigue life of weld details.The research results show that: without considering the welding residual stress,the longitudinal rib bulkhead arranged in the transverse diaphragm section have the most obvious improvement in the fatigue life of the weld details;in the case of no longitudinal rib bulkhead,the fatigue life of the deck weld root of the deck to longitudinal rib weld is the shortest.and the fatigue life here can be effectively improved by setting up longitudinal rib bulkhead that fit the deck,reducing the distance between the longitudinal rib bulkhead and the transverse diaphragm,and thickening the deck.(4)Based on the CATIA software of the 3D experience platform,the "skeleton + template" modeling method is used to quickly model the steel box girder;the ENOVIA software of the 3D experience platform is secondarily developed to establish a steel box girder weld management system.The research results show that the modeling method of "frame + template" has strong applicability to the modeling of steel box girder.The steel box girder welding seam management system based on the 3D experience platform can initially realize the visual management of steel box girder welding seam information,and provides a solution to the problem that there are many steel box girder welding seams and the welding seam information is complicated and difficult to manage effectively. |
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