| With the increase of carbon emission,the demand for green buildings is getting higher.The development of low-carbon economy has become a new growth point of economy in China and even the world.Hollow slab-column structure system(HSCSS)has great seismic performance as frame structure,and with the advantages of slab-column structure,such as low storey height,large column grid and flexible space,etc.In addition,this structure system can save land resource,cut carbon emissions and greenhouse effect as a green architecture.However,the research on HSCSS is not comprehensive enough.The punching shear performance of slab-column connection and the seismic performance of slab-column structure is not explicit.There is also no seismic design standard of HSCSS.Based on the above research,a series of experiments were conducted to study the mechanical property of slab-column connection and slab-column structure.The computing methods of slab-column connection were proposed according to the experimental results and parameter numerical results.Further,the formula for calculating the equivalent beam width of HSCSS was presented based on numerical analysis and theoretical research.Finally,on account of the design concept of equivalent solid,the seismic design method of HSCSS was put forward to.The main conclusions of this paper are as following:(1)Slab thickness,direction of pipe,width of rib,hole sizes and reinforcement ratio were the main study objects.The experimental study on eleven slab-column connections under vertical load were conducted to study the punching shear performance,such as crack distribution,bearing capacity,failure mode,strain distribution,etc.;(2)The numerical analysis of failure mode of slab-column connections under vertical load were conducted.With reference of calculation formulas of punching shear strength of slab-column connections from other countries and based on the semi-experiential and semi-theoretical research method,the calculating method of punching shear capacity was proposed under vertical load;(3)Hollow ratio,moment direction and two-way unbalanced moment were the main study objects.The experimental study on six slab-column connections under vertical load and unbalanced bending moment were conducted to study the punching shear performance,such as stress mechanism of the connections under unbalanced moment,crack distribution,failure mode,etc.In addition,the parameter numerical analysis on slab-column connections was conducted on hollow ratio,unbalanced moment,tension reinforcement ratio and the concrete strength,etc.;(4)On the basis of experimental research and numerical analysis,the proposed calculating formula of punching shear capacity of slab-column connections under vertical load and unbalanced moment were in agreement with test values based on yield line theory;(5)Based on the test results of punching resistance capacity of slab-column connections,seismic experimental study on a two-storey hollow slab-column structure under low-period cyclic loading was conducted.The hysteretic energy dissipation capacity,spine curve,strength degradation and stiffness degradation of slab-column structure were studied.Numerical simulation of slab-column structure under whole loading history was analyzed.The analysis results were in good agreement with experimental results.In addition,parametric numerical analysis of column section,hidden beam,slab thickness and pipe diameter were conducted;(6)Simplified formula of stiffness along and perpendicular to pipes were proposed.Further,the effect of geometrical parameter on width of equivalent beams was studied based on numerical analysis.Finally,the formula to calculate the equivalent beam width of inner frame and side frame was presented based on numerical analysis and theoretical research;(7)The HSCSS can have the same mechanical property with solid slab-column structure system by the means of appropriate solid area and tube arrangement.Finally,on account of the design concept of equivalent solid,the seismic design method of HSCSS was put forward to. |
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