| With the rapid development of traffic construction in China,the research on bridge has been further improved.Because of its beautiful shape and its applicability to long-span structures,tie arch bridge has been widely used.This paper takes Boguan Bridge in Hunnan District,Shenyang City,Liaoning Province as the engineering background.Based on the analysis model of the whole bridge,the mechanical characteristics of the steel box arch rib of the long span arch bridge with tumbling-in type steel box arch rib as the representative are studied.In this paper,the finite element software Midas/civil was used to carry out numerical analysis of the bridge,the construction process of the suspender was simulated,the stress and displacement of the steel box arch rib in the key construction stage and the bridge state were analyzed under three kinds of suspender tension construction schemes,and at the same time,the mechanical characteristics of the arch rib were studied by comparing it with one time tension of suspenders.The results show that the stress of the arch ribs is affected equally by the tension sequence of different suspenders in the key construction stage and in the state of bridge formation;the stress distribution of the steel box arch rib is not uniform when the suspender is tensioned one time or in batches,some adjacent nodes suddenly change,the stress of the arch rib is larger than that of the suspender which is tensioned in batch than that of the suspender which is tensioned in batch,and the maximum stress value of II and III steel box arch rib is increased by 12.34% and 16.46% respectively;one-time tension of the suspender has a great influence on the vertical displacement of II steel box arch rib and the longitudinal displacement of III steel box arch rib,and the batch tension of suspenders has a great influence on the lateral displacement of II steel box arch rib.The force characteristic of steel box arch ribs under the action of live load and eccentric load are analyzed,and the influence of different lateral strut arrangement between arches on the stress of arch ribs under the action of eccentric load was studied.The results show that in a comparative analysis of stress and displacement of the live load and the eccentric load,the stress of steel box arch rib under live load is larger than that under eccentric load,the difference of maximum stress of II and III steel box arch rib is 10.79% and 10.28% respectively,and the effect of eccentric load on the lateral displacement of II steel box arch rib is the more obvious;for II and III steel box arch rib,the stress and displacement of the affected by own lateral brace layout.The dynamic characteristics of the bridge are discussed through modal analysis,three kinds of combined seismic loads are performed on the bridge,the horizontal and vertical elastic response spectra are analyzed respectively under the action of E1 and E2 earthquakes so as to study the seismic performance of the arch bridge.The results show that with the increase of mode order,the deformation of the structure increases,and the more complex modal,the stronger the couplingbetween the modes;the lateral stiffness of the deck system is small,and the lateral stiffness of the arch rib is larger than the vertical stiffness;the constant load and seismic load combination one have the greatest influence on the longitudinal and vertical displacement of the arch rib,the constant load and seismic load combination two have the greatest influence on the lateral displacement of the arch rib;the stress of steel box arch rib caused by E2 earthquake is larger than that caused by E1 earthquake,and the displacement deformation of E2 earthquake and E1 earthquake occurred in different forms.Through the above research contents,it can provide basis and reference for such bridges. |
