基于裂缝分布的开裂钢筋混凝土梁抗弯刚度计算

Flexural Stiffness Calculation of Cracked Reinforced Concrete Beams Based on Crack Distribution

为了准确描述开裂钢筋混凝土梁的抗弯刚度,提出了一种综合考虑裂缝分布的刚度计算方法.基于裂缝的数量和位置信息,确定裂缝的影响范围;基于裂缝的深度信息,建立裂缝附近梁截面的非线性应变分布模型.利用内力平衡方程求解模型中的未知量,得出整个钢筋混凝土梁的应变分布,进而得到全梁的等效惯性矩分布.利用梁单元有限元法计算带裂缝钢筋混凝土梁在外荷载下的响应.算例中位移计算结果同实验数据吻合良好,提出的抗弯刚度计算方法能够准确反映开裂钢筋混凝土梁刚度随裂缝分布的变化.

In order to accurately describe the flexural stiffness of cracked reinforced concrete beams,a stiffness calculation method considering crack distribution was proposed.Based on the number and position information of cracks,the influence range of cracks was determined.Based on the depth information of cracks,the nonlinear strain distribution model of beam section near cracks was established.Using the internal force balance equation to solve the unknown quantity in the model,the strain distribution of the whole reinforced concrete beam was obtained,and then the equivalent moment of inertia distribution of the whole beam was obtained.The beam element finite element method was used to calculate the response of reinforced concrete beams with cracks under external loads.The displacement calculation results in the example are in good agreement with the experimental data,and the proposed bending stiffness calculation method can accurately reflect the change of stiffness of cracked reinforced concrete beams with crack distribution.