混凝土箱梁桥铺装防水粘结层力学性能

为了探讨混凝土箱梁桥防水粘结层的实际受力状态,以沪杭高速公路拓宽改建工程箱梁段高架桥为研究实例,采用有限元方法和室内实验相结合的手段研究防水粘结层的层间粘结性能.建立节段整桥铺装复合结构模型,考虑刹车、超载、随机动荷载等因素对沥青混合料铺装层防水粘结层力学响应的综合影响.最后通过室内实验测得了几种典型的水泥混凝土桥防水粘结层与水泥桥面之间的层间粘结性能,并与理论分析结果进行了对比.分析结果表明,刹车超载对防水粘结层力学响应的影响大于由桥面不平度引起的随机动荷载对防水粘结层的影响.拉应力峰值出现在移动荷载接近于墩顶上方对应铺装表面,剪应力在移动荷载处于跨中时达到最大值.结合理论与试验分析结果,SBS(styrene butadienestyrene)改性沥青和橡胶沥青的防水粘结层主要粘结性能均满足理论分析结果的要求,可推荐为混凝土箱梁桥防水粘结层材料的首选.

Mechanical Properties of Waterproof Adhesive Layer on Concrete Box Girder Bridge

In order to investigate the actual stress state of waterproof adhesive layer of SMA pavement on concrete box girder bridge, the finite element method and laboratory test method were both used to analyze the interlayer bonding properties. The composite structure model of two spans of the whole bridge was established, and the influence of braking, overloading, random dynamic loading on the mechanical response of waterproof adhesive layer was analyzed. The lab shear strength and drawing strength between adhesive layer and bridge deck were carried out. Research results show that the influence of braking and overloading on mechanical response of adhesive layer is larger than that of random dynamic loading caused by bridge deck roughness. The max tensile stress appears when the load move on the pavement surface above the pier, and the max shear stress appears when the load move on the pavement surface at the center of a span. Compared calculated results with test results, lab test results can meet the theoretical requirements, and the SBS modified asphalt and rubber asphalt can be considered as the material of waterproof adhesive layer.