冻融循环作用下偏心受压柱承载性能分析

Analysis on the bearing capacity of eccentric compression column under freeze-thaw cycle

本文通过冻融循环试验,观测不同冻融程度下构件状态,分析质量、动弹性模量、抗压强度、抗拉强度变化规律。通过钢筋混凝土柱偏心受压静载试验,分析不同冻融循环程度、偏心距下构件破坏形态、挠度、开裂及极限荷载变化规律,分析大偏心、小偏心受压构件承载力规范公式计算的适用性。结果表明:构件剥蚀程度随着冻融次数逐步加深,质量、动弹性模量、抗压强度、抗拉强度均随着循环次数增加非线性减少;偏心距不大于36mm时构件柱为小偏心脆性破坏,偏心距大于36mm时为大偏心延性破坏;构件柱挠度随着冻融循环程度以及偏心距增大而增大;开裂荷载、极限荷载随冻融循环程度增加呈降低趋势;极限荷载规范理论值与实测值对比表明,规范公式适用于冻融后偏心受压柱承载力计算。

The state of components under different freezing-thawing degrees is observed through the freezing-thawing cycle test in the paper,and the variation rules of mass,dynamic elastic modulus,compressive strength and tensile strength are analyzed. Based on the static load test of eccentrically loaded reinforced concrete columns,the variation rules of components of under different freeze-thaw cycles and eccentricities in the aspect of breaking state,deflection,cracking and ultimate load are analyzed. The applicability of the formulas for calculating the bearing capacity of large and small eccentrically loaded components is analyzed. The results show that the denudation degree of the components is increased gradually with freeze-thaw cycle frequency. The mass,dynamic elastic modulus,compressive strength and tensile strength are decreased nonlinearly with the cycle frequency. The component column suffers from small eccentricity brittleness damage when the eccentricity is not greater than 36 mm,and the component column is broken by large eccentricity ductility when the eccentricity is greater than 36 mm. The deflection of component column is increased with the increase of freeze-thaw cycle and eccentricity. The cracking load and ultimate load are decreased with the increase of freezing-thawing cycle. It is concluded that the formula is applicable to the calculation of the bearing capacity of eccentrically loaded columns after freeze-thaw by comparing the theoretical and measured values of the ultimate load specification.