Seismic Behavior And Damage Analysis Of Steel Reinforced Concrete T-shaped Columns Loaded Along The Flange

Steel reinforced concrete special-shaped column structure refers to a new structure formed by adding steel and configuring appropriate amount of longitudinal reinforcement and stirrups in the section.It not only inherite the advantages of reinforced concrete special-shaped columns structure,such as high room rate,flexible and beautiful architectural design,but also bring into full play the advantages of high strength and good seismic behavior of steel reinforced concrete structures.It has a good promotion and application prospects.Based on the research on the special-shaped column structure of steel reinforced concrete columns in the early stage of the research group,this article continues to study in depth,and analyzes the seismic behavior and damage behavior of the solid-web steel reinforced concrete T-shaped columns loaded along the flange,and the damage evolution rules are clarified.In this paper,10 solid-web steel reinforced concrete T-shaped columns were designed and tested for seismic behavior by "parallel four-linkage" loading device The failure modes,load-apex displacement curves and skeleton curves of each test specimen were obtained.The variations of strength attenuation,stiffness degradation,displacement ductility,and energy dissipation capacity of T-shaped columns under different axial compression ratios,different steel ratios,and different loading regimes were studied.The results show that the solid-web steel reinforced concrete T-shaped columns with shear span ratio of 2.5 has obvious bending failure when loaded along the flange.The hysteresis curve of the specimen is full of shuttle shape,and symmetrical in both positive and negative directions.Compared to the monotonous loading,the hybridcontrol loaded test specimens have different degrees of reduction in bearing capacity,deformation ability and energy dissipation ability after experiencing different displacement amplitudes and cycle times.The strength attenuation coefficients of all specimens are greater than 0.85,the ductility coefficients are all greater than 5,the limit displacement angles are between 1/10 and 1/16,and the equivalent viscous damping coefficients are between 0.358 and 0.417.All exhibite good seismic behavior.The finite element model was established by OpenSees to analysis the solid-web steel reinforced concrete T-shaped columns loaded along the flange.The calculated results were in good agreement with the experimental curves.Based on the calculation results,the internal steel stress of solid-web steel reinforced concrete T-shaped columns was analyzed,and the stress distribution and change law of solid-web steel reinforced concrete T-shaped columns under horizontal load was clarified.The influence of P-Δeffect on the hysteretic behavior of solid-web steel reinforced concrete T-shaped columns was researched.The influences of factors such as axial compression ratio,concrete strength,yield strength of steel and steel distribution ratio on the elastic stiffness,bearing capacity,and displacement ductility of solid-skin reinforced concrete T-shaped columns were analyzed.The shortcomings of the existing damage models are summarized,and combine the results of the experimental study on solid-web steel reinforced concrete T-shaped columns,a non-linear combined damage model based on deformation and cumulative hysteretic energy was established by introducing a combination coefficient.This model can better reflect the damage evolution process of solid-web steel reinforced concrete T-shaped columns.By analyzing the variation law of the damage index of each test piece and combining with the test phenomenon in the loading process,the damage state and the corresponding damage index range of the solid-web steel reinforced concrete T-shaped columns are given,which provides reference for the post earthquake damage evaluation of this type of component.