Non-linear Analysis Of Impact Of Staircase On Lateral Performance Of Over-limit-frame-shear Wall Structure And Evaluation Of Lateral Performance Of Skip-floor Column

The frame-shear wall structure is widely used in high-rise buildings due to its flexible layout and good lateral performance.The staircase in the structure is closely connected with the shear wall of the main anti-side member,so its impact on the structural lateral performance cannot be ignored.As a vertical passageway of the building,the staircase’s own performance is also extremely important.At present,there are few studies on the influence of stairs on the lateral performance of the frame-shear wall structure.This paper takes an over-frame frame-shear wall structure as the analysis object,and focuses on analyzing the influence of stairs on the lateral performance of the frame-shear wall structure under horizontal seismic forces.In this paper,firstly through the comparative analysis of SATWE and ETABS software to verify the reliability of structural design,and then use the finite element program based on the nonlinear analysis method of the three-dimensional solid degenerate virtual laminated element to establish three finite element models of staircase opening,stair setting and elastic staircase The staircase is made of cast-in-place concrete slab stairs.Three-dimensional solid finite element analysis results show that under the action of horizontal seismic force,the staircase significantly delays the structure from entering the load-displacement curve horizontal steps,and improves the ultimate bearing capacity and deformation capacity of the structure,and the structural stiffness is more thoroughly degraded.The staircase shear wall is greatly affected by the effect of the staircase.The staircase significantly inhibits the development and yield of the reinforcement stress of the wall.The staircase shear wall is more affected than the wall of other areas;the staircase stresses the structural frame column and frame beam reinforcement.It shows a certain inhibitory effect,but the effect is weaker than the shear wall.Under the action of earthquakes,the stairs actually acted as diagonal braces,and the staircase slabs exhibited eccentric tension/compression in the early stage of bending.In terms of design,the reinforcement of the ladder section can be pulled through in both directions and double layers;the ladder beam is subjected to a large horizontal shear in the span,and the stirrups can be strengthened to improve the shear resistance of the beam section.The construction should ensure the correct retention of the construction joint.The calculation results of the elastic staircase model show that the increase of the staircase stiffness of the staircase will cause the staircase to bear greater shearing force,which leads to the structure more prone to damage.The reinforcement of the staircase needs to be designed reasonably.In order to meet the requirements of vision and modeling,high-rise buildings are often provided with skip-floor columns on the ground floor.As a key component,skip-floor columns need special attention.The finite element program based on the non-linear analysis method of the three-dimensional solid degenerate virtual laminated element is used to conduct a holistic analysis of the pierced column and the ordinary column at the bottom of the structure.The results show that the longitudinal steel bars in the pierced column yield under the action of the earthquake.The shear force distribution coefficient of the skip-floor column gradually increases with the loading process.The skip-floor column is destroyed later than the ordinary column.It can be seen that under the action of seismic force,the skip-floor column is not conducive to give full play to its role in the overall lateral resistance of the structure.In seismic design,attention should be paid to it.Measures of force and ductility of the skip-floor column to improve or strengthen the lateral resistance of the structure.The above research can provide reference and reference for accurately grasping the influence of staircase and skip-floor column in the seismic design of the over-frame frame shear wall structure,and thus help to further improve the seismic design theory of the over-frame frame shear wall structure.