Experimental And Numerical Study On Seismic Performance Of A New-type Of Reinforced Concrete Side Retainer

Based on the study of the failure mode of the reinforced concrete retainers in the Wenchuan earthquake and the Yushu earthquake,a new type of reinforced concrete retainers is proposed for the block design of the new bridge and the retainers reinforcement of the active bridge.This paper explores the strength,deformation ability and failure characteristics of this new type of the reinforced concrete block under quasi-static experiment,and verifies the feasibility of the new structure to improve the seismic performance of reinforced concrete retainers.Finally,The paper discusses the working mechanism of new reinforced concrete retainers and plate rubber bearing,and the main conclusions are as follows:(1)12 new-type retainers specimens under the action of low-cycle reciprocating load are relative to the base of a large displacement slip shear damage.In the destruction,the retainers and the base itself almost no damage,only part of the concrete protective layer peeling,the deformation of the retainers and deformation ductility are better.This failure mode is the expected target of the test,can greatly improve the capacity of reinforced concrete retainers,and plate rubber bearings better work together.(2)The construction and reinforcement method proposed in this paper can make the new retainers have better seismic performance,in order to cooperate with the plate rubber bearing,its structure and reinforcement details are:? the constructional reinforcement of the retainers in the cover The beam/cap surface is disengaged and the shear stiffness is additionally set separately and the single row is arranged near the inner side of the retainers;?The surface of the cover/table cap is arranged in a sufficient number of horizontal bars,Single row and close to the upper surface of the cover beam/cap to prevent damage to the cover beam/cap;?a smooth dry construction joint is reserved between the retainers and the beam/cap to form a shear weak plane To promote the occurrence of sliding shear failure mode to improve the deformation capacity of the retainers;? in the actual project,the inside of the retainers can be designed in a strip of protruding block,so that the protrusions to maintain contact with the main beam and the other part of retainers is not in contact with the main beam so that the contact point of the retainers and the main beam is held at the bottom of the retainers.(3)The results of the existing strength analysis model are generally larger than the measured strength values of the new retainers.In view of this,according to the influence law of the concrete protective layer and the diameter of the shearing steel bar,the modified rigid body model is proposed.The prediction accuracy of the new type of retainers is very high,which can meet the engineering application.(4)Using OPENSEES finite element software to analyze the seismic effect of the new retainers and plate rubber bearing combination restraint system in a typical simply supported small box girder bridge viaduct,and also compared the different pier height(6m,12m,24m,30m,36m)?different initial gap(0.03m,0.06m,0.09m,0.12m,0.15m),different block strength(0.5 times,1 times,2 times,4 times,8 times the basic strength),And provides a theoretical analysis for the application of the new retainers.