新旧混凝土板桥横向拼接后的收缩徐变效应分析

发布时间：2018-08-03 12:59

【摘要】：为更好地分析拼宽桥梁结构在新旧混凝土收缩徐变差作用下的受力机理,以1座钢筋混凝土简支板桥的横向拼宽为例,基于弹性力学平面应力问题的逆解法和混凝土徐变计算的按龄期调整有效模量法,推导了由混凝土收缩徐变差引起的拼宽后结构平面内应力和位移的解析表达,并与既有文献中的试验结果进行对比,验证了所提公式的适用性。实例分析结果表明:对于新旧梁跨径均为8m,宽度分别为9.5,12.5m的情形,拼接缝位置附近的新梁沿纵桥向受拉,旧梁受压,且纵桥向正应力沿梁横向呈明显的非线性分布;远离接缝界面而靠近自由边界的新、旧梁上会分别出现压应力和拉应力,新、旧梁中的最大拉应力分别为2.8,0.3 MPa;新、旧梁在拼接缝位置处4.8 MPa的剪应力和主拉应力的最大值均位于梁端部;新、旧梁混凝土强度比和宽度比主要影响旧梁自由边位置处的拉应力,对结构其他部分的应力影响较小。
[Abstract]:In order to better analyze the force mechanism of the widened bridge structure under the action of new and old concrete shrinkage Xu Biancha, taking the transverse widening of 1 reinforced concrete simply supported slab bridges as an example, the inverse method based on the plane stress problem of elastic mechanics and the age adjusted effective modulus method of concrete creep calculation are derived from the shrinkage and creep difference of concrete. The analytical expression of the stress and displacement in the plane after the widening of the structure is analyzed and compared with the experimental results in the existing literature, and the applicability of the proposed formula is verified. The results of the case analysis show that the new and old beams are both 8m and 9.5,12.5m in width, and the new beams near the joint position are pulled along the longitudinal bridge, and the old beams are pressed and longitudinal. The longitudinal stress of the bridge direction is obviously nonlinear distribution along the beam, and the pressure and tensile stress will appear separately on the old beam, and the maximum tensile stress in the old beam is 2.8,0.3 MPa respectively. The new, the maximum shear stress and the maximum tensile stress at 4.8 MPa at the joint position of the old beam are both at the end of the beam. The strength ratio and width ratio of the old beam concrete mainly affect the tensile stress at the free edge of the old beam, but have little influence on the stress of other parts of the structure.
【作者单位】：湖南大学土木工程学院;
【基金】：国家自然科学基金项目(51278182)
【分类号】：U441

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