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为了研究普通钢筋混凝土箱梁行车道板在塑性阶段的横向受力特征,得到箱梁顶板基于塑性理论的横向受力有效分布宽度的取值方法,制作了2个钢筋混凝土箱梁试验模型,对其上的2块顶板进行跨中局部加载并观测混凝土箱梁顶板从开裂到破坏的全过程,得到箱梁顶板的塑性铰线分布形式和极限荷载大小。基于2块顶板的破坏模式提出箱梁顶板的塑性分析模型;基于塑性铰线理论的极限分析推导了钢筋混凝土箱梁顶板在局部荷载作用下的极限荷载和塑性横向受力有效分布宽度的计算公式,并以试验结果验证其适用性;最后将试验结果和理论值与国内外相关桥梁设计规范的取值进行比较。研究结果表明:采用极限平衡法可以较好地确定钢筋混凝土箱梁顶板的极限承载力和塑性横向受力有效分布宽度;提出的简化破坏模式能刻化钢筋混凝土箱梁顶板在塑性阶段的横向受力特征;箱梁顶板在局部荷载作用下进入塑性阶段后,其横向受力有效分布宽度的大小与弹性阶段相比存在明显区别,极限状态下箱梁顶板基于塑性分析的横向受力有效分布宽度约为弹性解的2倍。
In order to study the transverse force characteristics of ordinary reinforced concrete box girder laneway slab during the plastic phase, the method of obtaining the effective distribution width of box girder roof based on the plastic theory is obtained, and two reinforced concrete box girder test models are made. The top two panels are loaded at mid-span and the entire roof of concrete box girder is cracked and destroyed. The distribution of plastic hinge lines and the ultimate load are obtained. Based on the failure modes of two roofs, the plastic analysis model of box girder roof is proposed. Based on the limit analysis of plastic hinge theory, the formula for calculating the ultimate load and the transverse distribution of plastic transverse force under the local load is deduced , And verify its applicability by test results. Finally, the experimental results and theoretical values are compared with the values of relevant bridge design codes at home and abroad. The results show that: the limit equilibrium method can be used to determine the ultimate bearing capacity and plastic lateral load distribution width of reinforced concrete box girder; the proposed simplified failure mode can be used to engrave the lateral deformation of reinforced concrete box girder roof in the plastic phase Force characteristics. After the roof of box girder enters the plastic stage under the partial load, the effective distribution width of lateral force has obvious difference compared with the elastic stage. In the limit state, the effective distribution width of lateral force of box girder roof based on plastic analysis About 2 times the elastic solution.