连续刚构桥中跨箱梁底板混凝土局部崩裂分析与加固

根据某连续刚构桥跨中底板合龙束张拉过程中底板混凝土局部崩裂位置及形状特征,采用弹性力学应力状态原理,分析其崩裂机理,并运用ANSYS,考虑理想设计工况、预应力波纹管局部位置变化两种计算工况,模拟箱梁底板在中跨合龙钢束张拉过程中混凝土的局部应力状况。计算分析表明:理想设计工况下,各段箱梁接头处局部主拉应力较大,已接近混凝土的抗拉强度;即使预应力波纹管局部位置变化较小的范围,底板局部混凝土产生较大的主拉应力。

Analysis and Reinforcement of Local Bursting Crack in Middle Span Bottom Slab of Continuous Rigid Frame Bridge

According to the situation and shape characteristics of local bursting crack in the process of extension of closure prestressed strands in middle span bottom slab of continuous rigid-frame bridge,the theory of stress state in elastic mechanics to analyze the mechanism of bursting crack is applied.With the considerations of two kinds of calculation load cases including ideal design condition case and local corrugated pipe with its position changed,the local stress of bottom slab in the process of extension of closure prestressed strands in middle span is simulated by using the ANSYS software.The results of calculation indicate that the major tensile stress in the junction of the box girder is rather large which nearly meet the tensile strength of the concrete in the ideal design condition,while the very big major tensile stress will be occurred in the bottom slab even though the corrugated pipe change its local position in a small scope.