高强混凝土加芯柱抗震性能试验研究

Test study on seismic performance of high-strength concrete columns with central reinforcement

进行了高轴压比下7根高强混凝土加芯柱的低周往复加载试验,阐述了其主要试验现象及破坏形态,对各试件的滞回性能、延性、承载力、强度及刚度退化、耗能性能等试验结果进行研究,并分析了其主要影响因素:核心区面积、纵筋配筋率和箍筋配箍率,对其抗震性能的影响规律。结果表明:通过在普通高强混凝土柱中部配置纵向钢筋及复合箍筋,所形成的加芯柱具有良好的滞回延性和稳定的后期强度,等效粘滞阻尼系数符合弯曲破坏混凝土柱0.1～0.2的范围。在设计轴压比高达0.85时极限位移角仍不小于1/50;核心区面积较大、核心纵筋配筋率高、箍筋间距小的柱承载力高、延性好;核心纵筋配筋率高、核心区面积小、箍筋间距小的柱耗能能力强;各试件在加载初期刚度退化较快,后期较慢。

Low-cycle loading tests conducted on seven high-strength concrete columns with central reinforcement were presented in this paper,including the test phenomena and failure modes,the hysteretic performance,ductility,load carrying capacity,degradation of strength and rigidity as well as the energy dissipation characteristics.Focuses were on the size of core area,longitudinal reinforcement ratio and proportion of ties,and their effects on the seismic performance of the columns.The results indicate that with longitudinal reinforcement and composite ties imbedded at the central portion of an ordinary high-strength reinforced concrete column,the column models had high ductility and stable post-yielding strength.The equivalent viscous damping coefficients ranged from 0.1 to 0.2 for columns of normal flexural failure.Under axial compression ratio as high as 0.85,their ultimate angular displacement was not less than 1 /50.The columns with larger core area,higher central longitudinal reinforcement ratios and closer tie spacing exhibited higher ductility.The columns with smaller core area,however higher central longitudinal reinforcement ratios and closer tie spacing,dissipated more energy.Despite of the faster early stiffness degradation,the columns showed slower degradation of rigidity in later loading stages.