Seismic Performance Study Of A New Precast Concrete Frame Structure Based On Grouted Sleeves And UHPC

The main way to promote the industrialization of construction in China is to use assembled concrete structures and steel structures,and the concrete structure systems that are now widely used in the engineering field are frame structure systems.At present,there are problems at the nodes of assembled frame that affect the mechanical properties of the nodes due to construction errors,hoop design,joints between old and new concrete,etc.Therefore,the research on the nodes is very important.This paper proposes a new type of assembled structure,prefabricated nodes first,prefabricated nodes with columns disconnected at the reverse bending point,followed by columncolumn connection through high-strength grouting sleeves,prefabricated beams connected by pouring UHPC between them,followed by concrete connection on top to form a complete frame structure,with high-strength reinforcement used for all frame bearing steel.To provide test basis for the application of this new prefabricated nodal assembled frame structure in actual engineering,this paper takes two-story assembled frame structure as the research object,and studies the seismic performance of assembled frame by conducting proposed static cyclic reciprocal loading test on twostory assembled frame and two-story cast-in-place frame,the core contents and main conclusions of this paper are as follows.1.According to the main assembled node connections in the project nowadays,this paper introduces a new design scheme of assembled frame structure.The construction form of this frame structure is introduced: that is,the nodes are prefabricated in the factory and later assembled on the actual project,and the laminated beams are poured and grouted with grouting sleeves after the assembly is completed.2.In this paper,two 1/2 scale two-story prefabricated nodal assembled frame structure specimens and one 1/2 scale two-story cast-in-place frame structure specimen were designed and fabricated,and the proposed static cyclic reciprocal loading test with the same axial pressure ratio was carried out on the three frame specimens,and the damage pattern,hysteresis curve,skeleton curve,bearing capacity,ductility,stiffness,energy dissipation,strain,etc.of the frame specimens were studied and analyzed according to the experimental phenomena.performance indexes.The results show that:the damage forms are crushed concrete at the bottom of column and dislodged concrete at the bottom of beam;the overall hysteresis performance of assembled frame is comparable to that of cast-in-place frame;the bearing capacity of assembled frame is slightly lower than that of cast-in-place frame;the ductility coefficient of assembled frame is slightly lower than that of cast-in-place frame;the energy dissipation capacity of assembled frame is similar to that of cast-in-place frame;it can be considered that the seismic performance of prefabricated nodal assembled frame structure is basically comparable to that of cast-in-place structure.It can be considered that the prefabricated nodal assembled frame structure can basically reach the same level with the cast-inplace structure in terms of seismic performance and meet the requirement of equivalent cast-in-place.3.According to the results of the framework testing study,the finite element model of the prefabricated nodal assembled frame structure is established by using ABAQUS finite element simulation software,and the numerical finite element simulation results are compared and analyzed with the actual frame test results.In addition,the finite element simulation analysis based on the parameter variation was carried out in this study to analyze the influence law of the variation of column axial pressure ratio on the seismic performance of the prefabricated nodal assembled frame structure.The results of the finite element simulation analysis show that as the axial pressure ratio of the assembled frame increases,the bearing capacity of the assembled frame at each stage of force increases correspondingly,but the displacement ductility coefficient of the frame decreases correspondingly.4.Finally,this paper puts forward further ideas for the improvement of the subsequent test of this new assembled frame structure according to the deficiencies of the conditions and operation during the frame test,as well as the idea of another new type of connection for future experimental research.