Experimental Study On Seismic Performance Of Prefabricated Steel Recycled Concrete Frame Joints

Steel reinforced concrete structures are widely used in actual projects and have the characteristics of large bearing capacity and excellent seismic performance.It is widely used in actual projects.The concrete in the steel reinforced concrete structure is replaced with recycled concrete,and the prefabricated method is adopted,which is not only environmentally friendly but also resource-saving.It also greatly improves engineering efficiency and has broad application prospects.However,there is very little research on prefabricated steel recycled concrete structures.In this paper,a total of 5 components are designed to carry out experimental research on the prefabricated steel recycled concrete frame joints.In this experiment,different replacement rates,different axial compression ratios,different assembly forms and cast-in-place comparative components are the variable parameters.The failure modes of the components are obtained.The seismic performance of the components under each parameter is studied and analyzed,and the strains of the beam,column and core area are studied and analyzed.To analyze the force failure law of the components,evaluate whether the assembly structure is feasible,and finally put forward the calculation method of the shear bearing capacity of the prefabricated joint structure based on the test data.The main research content and conclusions of this paper are as follows:(1)The different assembly forms,different axial compression ratios,and different replacement rates designed in this paper are prefabricated and assembled steel recycled concrete frame joint components.When simulating seismic loads for low-cycle repeated loading,the failure modes of all components are shear baroclinic failure.The change of the axial compression ratio has no essential change to the failure form of the node,but the degree of bending and shear failure in the core area of the node decreases with the increase of the axial compression ratio.It can be seen from the conclusion that the replacement rate does not affect the failure mode of the nodes in the prefabricated steel-concrete frame.There is no difference in the failure modes of component nodes under the two assembly modes.(2)Under the action of different axial compression ratios,the same level of load and the same structure,the seismic performance of the prefabricated steel recycled concrete frame joint assembly is significantly different.The component with an axial compression ratio of 0.2 is lower in energy consumption than the component with an axial compression ratio of 0.1,and the strength degradation is gentler.The replacement rate of recycled aggregate also has a certain impact on the mechanical performance of the joint assembly in the prefabricated steel recycled concrete frame.The energy consumption capacity of the component with 100% aggregate replacement rate is significantly lower than that of the component with 0%replacement rate.But the ductility is about 24.86% higher than that of the component with a replacement rate of 0%,and the ultimate bearing capacity of the component with a replacement rate of 0% is larger.Under the two assembly forms,the ductility and energy consumption of the components using the converted steel plate assembly form are less than those of the other assembly form,but there is not much difference in the ultimate load-bearing capacity of the two.(3)The node components of the prefabricated steel recycled concrete frame have high ultimate bearing capacity and good seismic performance under repeated loading of the beam ends.The assembly connection method using the steel butt joint is feasible and can be used in actual projects.(4)Analyze the stress mechanism of the core area of the prefabricated steel recycled concrete frame node.The core area shear element is composed of three parts,namely the recycled concrete part,the steel part and the stirrup part.The shear capacity of each part of the node in the core area is calculated.Finally,superposition is carried out to obtain the calculation formula for the shear bearing capacity of the nodes in the prefabricated steel recycled concrete frame,and the calculation results are more consistent with the experimental results.