钢筋混凝土偏心受压构件增大截面加固后可靠度分析

RELIABILITY ANALYSIS OF REINFORCED CONCRETE MEMBERS STRENGTHENING BY AUGMENTED SECTION UNDER ECCENTRIC COMPRESSION

偏心受压构件增大截面加固后的可靠度与初始偏心距、荷载比和纵筋配筋率有密切的关系。该文首先推导了大、小偏心受压构件在对称配筋下增大截面加固后的计算公式和Nu-Mu相关曲线方程,并在此基础上建立其极限状态方程。采用蒙特卡罗法,分析了四组不同截面的构件在不同初始偏心距、不同荷载比和不同纵筋配筋率下,偏心受压构件增大截面加固后的可靠度。结果表明:截面尺寸大小对可靠指标的影响不是很显著,可靠指标随着初始偏心距和荷载比的增大而减小,随着纵筋配筋率的增大而增大。

When calculating the reliability of eccentric compression members which is reinforced by augmented section, it would be of significance to take into account parameters such as initial eccentricity, load ratio as well as the ratio of longitudinal reinforcement. In this paper, formulas to calculate the ultimate bearing capacity of symmetrically reinforced members along the Nu-Mu interaction curve equation are deduced. Then, the limit state equation is developed. Monte Carlo method is adopted to calculate the reliability of eccentric compression members reinforced by increasing section area. Furthermore, the effects of initial eccentricity, load ratio and ratio of longitudinal reinforcement on the reliability of four column sections are studied. It can be concluded that reliability index is significantly affected by initial eccentricity, load ratio and ratio of longitudinal reinforcement, while the influence of section area is much less pronounced compared with the other three parameters. Reliability index increases with the ratio of longitudinal reinforcement, but decreases with the initial eccentricity and load ratio.