Study On Seismic Behavior Of The Joints For The Bonded Steel Anchorage Concrete Frame Structures

Bonded steel reinforced concrete structure is a new type of structural reinforcement method.In order to improve the strength or rigidity of the original structural members,a special structural adhesive is used to firmly form the steel plate and the original structure,and to withstand common forces and deformations.At present,the research on the insufficient bearing capacity of the flexural members in the positive moment region of the flexural members has been mature,and the calculation and structural measures have been relatively perfect.However,the research on the reinforcement of the negative bending moment of the concrete frame beam is not sufficient.In this paper,the joint specimens with different forms of bonded steel anchors are designed,and the seismic performance of different forms of bonded steel anchor joints in the negative moment region of reinforced concrete frame beams under reciprocating loading is systematically analyzed by theoretical analysis and numerical calculation.The main tasks completed are as follows:(1)Without considering the slippage of the steel bar,the basic mechanical method is used to analyze the force of the T-section beam and the rectangular section beam after the steel is bonded.The basic mechanical principle is used to analyze the ultimate bearing of section under the concentrated load of beam end.(2)In view of the test specimen,a spatial simulation analysis model of the adhesive bending technology of the negative bending moment zone of different forms of reinforced concrete frame beams based on ANSYS software platform is established.By setting the calculation parameters reasonably,different anchoring techniques are accurately simulated.The force of the beam under monotonic load,the numerical simulation results and the theoretical data are within 10%,which is quite consistent and has certain reference value.(3)Using the above parameter settings,the force-carrying process of the anchoring joints under different cyclic loading techniques is simulated.The seismic performance indexes such as hysteresis performance,ductility,bearing capacity and stiffness degradation were studied.The results show that the standard,coaming and back-reinforcing methods all mobilize the concrete to participate in the force,and the bearing capacity of the joint is increased by 12.52%~49.23%.The latter two are due to the increase of bearing capacity,resulting in different degrees of energy consumption.The hysteresis curves are all Z-shaped,and the energy-consuming capacity is second only to the standard reinforcement and unreinforced nodes.The results of the analysis of the two kinds of anchoring forms,such as integrated hoarding and back-reinforcing reinforcement,are only reinforced by the joint reinforcement and the beam end,which not only plays the role of the beam reinforcement,but also plays the role of anchoring the joint.The reinforcement of the coaming plate only strengthens the beam end and the column end,which leads to the early cracking of the concrete and the rapid development of the crack.Therefore,in practical applications,the anchorage of the bonded steel should ensure the integrity and coherence of the concrete columns,beams and joints.Sexuality can fully exert the good seismic performance of the reinforced steel plate.