粉煤灰加气混凝土砌体轴心受压构件极限承载力的研究

Study of the ultimate bearing capacity of the coal-ash air-entertaining concrete block walls subjected to axial compression with initial imperfections

本文采用适量试验结合计算机模拟的方法,对具有初始缺陷(包括砌体初弯曲和荷载初偏心)的粉煤灰加气混凝土砌体轴心受压构件的极限承载力P_u,进行了研究。 通过大小72个试件的试验,分析了轴心压力下粉煤灰加气混凝土砌体构件的工作性能、破坏特征及砂浆强度的影响,确定了砌体组成材料(砌块和砂浆)的本构关系。 利用自己编制的关于P_u的非线性全过程电算程序,首先,较全面地分析了砌体组成材料本构关系对P_u的影响;结合试验结果,确定了模拟系数;然后,运用模拟系数进行了大量的计算机模拟计算,探求构件高厚比、初始缺陷、砂浆强度等对P_u的影响。最后提出了计算P_u的纵向弯曲系数φ建议公式。

In this paper, the ultimate bearing capacity of the coal-ash air-entertaining concrete block walls subjected to axial compression with initial imperfections (including initial crook and initial eccentricity of load)is investigated by means of the method in which results of a certain number of tests combined with electronic computer simulation are used.72 test specimens are tested. The behaviour and the failure characteristics are thus analyzed. The influence of the compression strength of mortar on the ultimate bearing capacity of the block walls and the stress-strain relationships of the ingredients (block and mortar) made up the block walls are determined also.Based on theoretical analyses, a non-linear general computer program is composed by use of the numerical integral method to calulate the ultimate bearing capacity(Pu) of the block walls. Then, the influence of stress-strain relationships of the ingredients made up the block walls on the ultimate bearing capacity (Pu) are studied. Combined with the test results , a simulation coefficient is proposed. A lot of caculations by computer with the simulation coefficient mentioned above are then worked out and the effects of slenderness, initial imperfections and the strength of mortar on the Pu are analyzed. Finally, a formula of the reduction factor of the bearing capacity,ψ,of the coal-ash air-entertaining concrete block walls subjected to axial compression is recommended for design.