Performance Analysis Of A New Type Of Anchor Bolt Connection Between Isolation Support And Lower Support Pier

At present,there are many anchor sleeve connections between seismic isolation bearings and concrete lower piers.In the design of seismic isolation layers in many building structures,it is necessary to consider bearing more anti overturning capacity.However,in the traditional form of anchor sleeve connection,the concrete around the sleeve collapses,making the mechanical performance of the anchor bolt connection unable to be fully utilized.Therefore,in order to improve its connection performance,this article proposes a new connection method by improving the traditional anchor bolt connection form.In order to study the excellent performance of the new connection method and the traditional connection,an experimental model of horizontal shear deformation of the pier under the isolation bearing was established using ABAQUS finite element software,to study the stress state of its various components,analyze its mechanical behavior,and further study the shear resistance performance of the new anchor bolt connection and its influencing factors.The main research content of this article is divided into the following parts:(1)Based on the four failure modes of anchor bolt connection,the design of connecting anchor bolts and lower connecting plates for traditional anchor bolt connections is theoretically analyzed,and the maximum compressive stress for local failure of concrete is analyzed.The reinforcement calculation for complex components such as concrete lower piers is performed using a tension compression model(STM).The concrete dimensions,foundation reinforcement cage reinforcement,and reinforcement stirrup arrangement for both LRB600 and LRB700 specifications are designed.(2)Relevant specifications and documents are cited to provide reference for setting up the constitutive models of six materials involved in finite element simulation.With the help of ABAQUS finite element software,a finite element model is established based on the size of the test specimen in the literature.The simulated hysteretic curve of the support and the tensile force curve of the anchor bolt in the tension zone are well fitted to the test results.Then establish a model of the lower pier of the isolation bearing connected with a new type of anchor bolt,and set up the deformation of the bearing with horizontal load displacement of 100%,150%,200%,250%,300%,and 350%.Analyze the stress state of each component,and find that under the same displacement and load deformation,the stress of each component in the new type of anchor bolt connection decreases significantly and is more evenly distributed,which can withstand greater load effects.(3)Based on the verification of the test and finite element model,the finite element model was simplified using the above method for establishing the finite element model.66 finite element models were established,and a large number of numerical simulations were conducted for different parameters.The effects of multiple parameters such as buried depth h,anchor bolt diameter d,concrete strength,steel strength,stirrup spacing l,and anchor bolt preload F on the bearing capacity performance of the component were analyzed.Compared with the formulas for calculating the shear capacity of anchor bolt connections proposed by domestic scholars,the finite element simulation results fit well.