The Influence Of Local Slots And Their Distribution In Floor Slab On The Seismic Performance Of RC Frame Structures

Existing studies have shown that the cast-in-place floor slab is an important reason for the plastic hinge of the column end of the RC frame structure under the action of earthquake.The slot structure of the RC frame cast-in-place floor slab proposed in response to this phenomenon can effectively improve the yield mechanism of the RC frame structure.Taking into account the practical problems that this structure may bring,this article discusses the local distribution of two kinds of cast-in-place floor slab slots,aiming to reduce the number of slots on the cast-in-place floor slab as much as possible based on the the effect of the slots.Based on the theory of finite element analysis and elastoplastic analysis,the following researches are carried out in this paper:（1）The ABAQUS and SAP2000 finite element models are compared and verified with reference to experimental data;（2）Based on SAP2000 finite element software,through modal analysis and Pushover Analyze and study the influence of slots in cast-in-place floor slabs on the seismic performance of RC frames;（3）Considering the vertical local slots of cast-in-place floor slabs,it is suggested that some floors of cast-in-place floor slabs shall be set up slots.Through dynamic elasto-plastic time history analysis,IDA analysis and vulnerability analysis,the influence of the structure on the seismic performance of the RC frame is studied,and the value of the number of floors with slots is studied;（4）Considering the horizontal partial slots of the cast-in-place floor slab,the center column is proposed The cast-in-place floor slab is located nearby.Based on ABAQUS,the structure is used to study the stress of steel reinforcement and concrete damage;based on SAP2000,the effect of the structure on the torsion and seismic performance of the L-shaped frame is studied.The main conclusions of this paper are as follows:（1）The full-floor slots of the cast-in-place floor slab have less influence on the structural stiffness weakening and inter-story displacement,which improves the yield mechanism of the structure;（2）The partial floor slots of the cast-in-place floor improve the yield of the structure.The mechanism reduces the maximum inter-story displacement angle and failure probability of the structure under earthquakes,improves the seismic collapse reserve coefficient CMR,and can achieve an enhancement effect close to the seismic performance of the cast-in-place floor slab with full-floor slots;the calculation examples for the 6th and 8th floors of this section When the number of seam layers is 1/2 of the total number of floors,and when the number of seam layers is 3/4 of the total number of layers in the10-story calculation example,the effect of setting seams on some floors to reduce the number of plastic hinges at the column ends is more significant;（3）There is a spot near the center column.The placement of slots in the cast floor slab reduces the stress of the longitudinal reinforcement of the center column,and the stress of the longitudinal reinforcement of the side column and corner column increases after yielding,and the yield is advanced,which is not conducive to the realization of the "strong column and weak beam" yield mechanism of the side column;（4）Near the center column The slolts of the cast-in-place floor slab reduces the torsion period ratio and the interstory torsion angle of the L-shaped frame,and improves the torsion performance of the structure.In rare earthquakes,the number of hinges at the integral column end of the structure is reduced,and the number of hinges at the beam end is increased to a certain extent.Improved the overall yield mechanism of the structure.