Study On Seismic Performance Of RCS Joints Filled With Grouting Material Between End Plate And Column

The RCS frame structure with end plate bolt connection form integrates the advantages of both steel and concrete materials.Its advantages for assembly are in line with the design concept of green buildings,and thus have broad application prospects.During the construction of the beam and column connection,it is found that there is a certain gap between the end plate and the concrete column due to the negative error of the component processing or the assembly accuracy limit.High-strength grouting material is generally used in the project to seal and fill the gap,but the impact of this measure on the mechanical performance of the node and whether it will become a potential safety hazard has not been studied.Therefore,the experimental research and numerical analysis on the seismic behavior of RCS joints filled with grouting material between end plate and cylinder were carried out.The main research contents and results are summarized as follows:(1)5 speciments of the RCS joints filled with grouting material between end plate and cylinder were designed and tested under cyclic loading.The parameters include: the thickness of the grouting layer,the grouting strength and the pretensioning force applied by the bolt.The test results showed that the failure mechanism of all nodes were beam hinge,the bolted connection,which was semi-rigid,had reasonable mechanical properties and deformation ability.Grouts with strengths of 60 MPa and 90 MPa can act as good medium to ensure the reliability of joint connection and force transmission.However,the high-strength grouting layer(90MPa)produces more flaking under the action of reciprocating load due to the brittleness of the material itself.(2)A finite element analysis model of the end-plate bolt connection RCS node with grouting layer was established.In the FE model,the material nonlinear problem,the geometry nonlinear problem,and the interaction among steel,high-strength bolts,concrete and grouting were considered.The analysis results show that the finite element model offered reasonable simulations on the failure mode and ultimate bearing capacity of such nodes.The prying force caused by the bending deformation of the end plate was the main cause of damage to the grouting layer.(3)The variable parameters analysis was carried out by using verification finite element model.The effects of grouting layer thickness,end plate thickness and structural measures on seismic performance of the joints were investigated.Relevant design suggestions were given based on the results of finite element analysis.