倾斜对砌体结构构件承载力的影响研究

Influence of inclination on bearing capacity of masonry members

倾斜会引起砌体结构构件的竖向荷载偏心距增大,从而对其受压承载力造成不利影响。研究了国内外标准中,砌体受压构件计算高度取值方法以及荷载偏心距与侧向弯曲附加偏心距组合方式对构件受压承载力的影响。以我国GB 50003—2011《砌体结构设计规范》的无筋砌体受压承载力计算公式为依据,提出了倾斜对受压承载力影响系数的算式,并分析了平面外、平面内倾斜对砌体结构构件受压承载力的影响。结果表明:平面外倾斜会对砖墙承载力产生明显的不利影响;倾斜率相同时,砖墙高厚比越大,其承载力降低幅度越大;当倾斜率超过0.003时,应考虑平面外倾斜对砌体结构构件承载力的影响;平面外倾斜率γ为0.003、0.007、0.01、0.02和0.03时,高厚比为9.6的砖墙的受压承载力影响系数λ分别为0.95、0.88、0.83、0.67和0.50;平面内倾斜对砖墙承载力影响很小,一般可不予考虑。

Inclination of masonry members can increase vertical load eccentricity, thereby weaken the compressive bearing capacity of the members. The calculation method of the effective height of masonry compressive members was discussed according to different design codes at home and aboard. The influence of the combination of load eccentricity and additional bending eccentricity to the compression bearing capacity were also analyzed. The influence coefficient equations for calculating the effect of inclination on the compression capacity was established based on the compression bearing capacity calculation equation in the GB 50003—2011 ‘Code for design of masonry structures’. A parametric study was conducted based on the so-established equations to further investigate the effects of in-plane and out-of-plane inclination on the compression bearing capacity of masonry members. The calculation results indicate that the out-of-plane inclination has a negative effect on the compression bearing capacity of masonry members. The compression bearing capacity of the members under the same inclination rate decrease with the increase of height-to-thickness ratio. The negative effect of out-of-plane inclination should be considered when the inclination rate is over 0.003. The influence coefficients of the compression bearing capacity of the wall with its height-to-thickness of 9.6 are 0.95, 0.88, 0.83, 0.67 and 0.50, respectively, when the out-plane inclination rate was chosen as 0.003, 0.007, 0.01, 0.02 and 0.03. The effect of in-plane inclination is small, and can be ignored.