Experimental Study On Seismic Performance Of Steel-concrete Composite T-shaped Profiled Columns

For ordinary reinforced concrete T-shaped cross section of special-shaped columns axial compression ratio limit is too low,poor torsional rigidity,easy to brittle failure occurs in the web acromegaly,bearing capacity,poor seismic performance were insufficient.In this paper,starting from the simplicity and cost control of construction,put forward a kind of both can effectively improve the special-shaped columns of the defects in stress and convenient construction of new structure forms:T section steel-concrete special-shaped columns.In combination with t-shaped section stress modes and failure characteristics of special-shaped columns,outer lining steel in the special-shaped columns web,by shear connector connect the steel and the web to ensure load carrying.In order to fastidious this kind of cross section is reasonable,through carries on the low reversed cyclic loading test,study its seismic performance.Test designed a total of 12 models,an ordinary reinforced concrete T-shaped cross-section special-shaped column(referred to as RC),11 steel-concrete composite T-shaped profiled columns(referred to as SCC).The seismic performance of the RC and SCC are evaluated synthetically by comparing the crack development,fracture morphology,skeleton curve,hysteresis curve,ductility,bearing capacity degradation,stiffness degradation and energy dissipation capacity.At the same time,the effects of different axial compression ratio and steel content on the seismic bearing capacity and seismic performance of SCC were studied,and the flat section assumption was verified.Draw the following conclusions:SCC relative to RC,its destruction began in flange and web has a good ability of deformation,the seismic bearing capacity has obviously improved,the energy dissipation of the specimens,illustrate the SCC specimen indeed improve RC specimen web acromegaly is weak,improving the seismic performance of specimens.With the increase of axial compression ratio and the ductility of the specimens,specimen of bearing capacity and the stiffness decay quickly.But the axial compression ratio is equal to the provides a vertical prestress,the increase of axial compression ratio makes the cracking load,the initial stiffness of the specimens increases,specimen fracture significantly reduced,so increasing the axial compression ratio can reduce the initial damage of the specimens;And increase of axial compression ratio can reduce the slip between steel and concrete,reduce the hysteresis curve "pinch approach" phenomenon;Late in the test,the axial compression ratio increases with the increasing of specimen aggregate internal friction energy dissipation,so the test under high axial compression ratio of specimen still has good energy dissipation capacity,the ductility coefficient can still meet the requirements of ductility of frame,indirect evidence value of axial compression ratio of SCC can improve accordingly.The higher the steel content,the specimens of the seismic bearing capacity and energy dissipation capacity have some increase,the positive and negative to the ductility of the specimen with the improvement and the ductility improvement of negative is bigger,the late stiffness of specimens and the late bearing capacity of specimens are relatively stable,show that reasonable in enhancing the steel ratio can improve the seismic performance of SCC special-shaped columns.