大跨度预应力混凝土箱梁桥开裂病害

Cracking damage of long span prestressed concrete box girder bridges

摘要:

为了研究大跨度预应力混凝土箱梁桥的开裂病害与其空间应力状态的关系,采用8节点实体退化板壳单元编制有限元软件对大跨度预应力混凝土连续箱梁桥进行空间应力分析,研究恒载、箱梁刚度、有效预应力和温度等因素对箱梁截面最大主拉应力的影响程度和影响规律;探讨设计中采用的活载应力放大系数的取值合理性;提出了控制箱梁混凝土开裂的二轴强度准则.实桥分析表明:采用板壳单元分析箱梁截面空间应力,并采用混凝土二轴强度准则进行截面主拉应力验算有利于控制大跨度预应力混凝土箱梁桥的开裂病害.

Abstract:

A FEA program using 8-node degenerated solid shell element was developed to analyze the spatial stress of long span prestressed concrete box girder bridges for the purpose of researching the relationship between cracking damage and the spatial stress state.The influences of dead load,box girder stiffness,effective prestress and temperature on the principal stress were researched,the reasonable magnification factors of live load stress were discussed and a two-axis strength criterion was proposed to control the concrete cracking of box girder.An analysis of real bridge shows that the FEA program is helpful to control the cracking damage of long span prestressed concrete box girder bridges.