胶合木-混凝土组合梁斜交螺钉连接件抗剪刚度计算方法研究

Calculation method of shear stiffness for inclined cross screws connectors in glulam-concrete composite beams

为了研究胶合木-混凝土组合梁斜交螺钉连接件抗剪刚度计算方法,进行了7组共计21个胶合木-混凝土组合梁斜交螺钉连接件的推出试验,得到了斜交螺钉连接件的荷载-滑移曲线,分析了混凝土强度等级、螺钉直径、螺钉嵌入角度对胶合木-混凝土组合梁斜交螺钉抗剪连接件抗剪刚度的影响,探讨了斜交螺钉连接件在胶合木-混凝土组合梁中的受力机理。基于弹性地基梁理论,提出了斜交螺钉连接件抗剪刚度计算公式。研究结果表明:增大螺钉直径可以有效提高斜交螺钉连接件的抗剪刚度;随着斜交螺钉连接件嵌入木梁角度逐渐减小,斜交螺钉连接件的抗剪刚度逐渐降低。抗剪刚度计算公式反映了螺钉直径、螺钉嵌入角度、螺钉抗剪刚度、木材顺纹刚度系数以及木材横纹刚度系数的影响,且计算结果与试验结果吻合较好。

In order to develop the calculation method of shear stiffness for inclined cross screws in glulam-concrete composite beams, seven groups of the inclined cross screws, a total of twenty-one push-out tests were carried out. Based on the push-out test result, the load-slip curves of inclined cross screws were achieved, the influences of concrete strength, screw diameter, embedded angle of screws on shear stiffness of inclined cross screws were analyzed, the mechanical behavior of inclined cross screws in glulam-concrete composite beams were discussed in detail. Based on the theory of a beam on a two-dimensional elastic foundation, a model for calculating the shear stiffness of the inclined cross screws was proposed. The results show that the shear stiffness is improved effectively with increased screw diameter. The shear stiffness is reduced with the decrease of angle of the inclined cross screws to the beam. The calculation method indicates that the screws diameter, embedded angle of screws, shear stiffness of screws, and foundation modulus of timber parallel and transverse to the grain are the main influence factors of shear stiffness. The calculated results were in good agreement with the experimental results.