Research On The Seismic Performance And Design Method Of The Structure With Mild Steel Energy Dissipation Bearing In Staircase

For a long time,the seismic design method for stairwells has not been deeply studied in structural engineering field,neither considering the seismic performance of staircase members,nor considering the influence of staircases on the seismic performance of the whole structure.Seismic damage survey shows that the failure degree of stairwell is much more serious than other parts of structure under earthquake load.Due to the collapse of stairwell,the escape routes are interrupted or blocked,resulting in grave consequences.To solve the above problems,in this paper a new kind of mild steel energy dissipation bearing is proposed.By seting mild steel energy dissipation bearing in staircase,The Brace effect of gangboard can be weaked,the force of the staircase members are decreased.At the same time,the mild steel energy dissipation bearing can dissipate energy by plastic distortion and provide additional damping ratio for the structure and improve the characteristics of the structure,.Then achieving the target of shock absorption effectively.The main research contents and results are as follows:(1)In order to ensure the energy dissipation effect of the soft steel energy dissipation bearing,the section form of the energy dissipation core plate is designed through theoretical analysis and finite element simulation.On this basis,four specimens were designed and tested for obtaine the mechanical properties parameters.The test results show that the soft steel energy dissipation bearing has good mechanical properties,it has small yield displacement and good deformation ability and energy dissipation capacity.It can meet the requirements of staircase use.(2)The finite element model of three patterns of reinforced concrete frame respectively set with non-stairs,normal cast-in-place stairs and mild steel energy dissipation bearing stairs was established.The the dynamic response of the structure is analyzed.The parameters such as natural vibration period,acceleration response,floor shear force,interstory displacement angle and internal force of staircase components are compared.this paper obtained the following conclusions: in the earthquake,the stair will enlarge the stiffness of frame structure,and enhance the effect of the earthquake;After setting the mild steel energy dissipation bearing in staircase,it can significantly weaken the influence of stairs on the structure.The acceleration response of the structure and the shear force of the layer are reduced,The force of staircase ladder,ladder beam,slab column is decreased significantly.The staircase with mild steel energy dissipation bearing has good shock absorption effect,It can significantly improve the overall structure and safety of staircase under earthquake.(3)Based on the characteristics of the stairwell’s force and the design method of energy dissipation structure,This paper presents a design method of mild steel energy dissipation bearing and a design process of whole structure.Thus it provides an effective new way and new method for aseismic design of staircases.