基于弹性力学的钢桥面铺装层应力分析

Stress analysis of steel bridge deck pavement based on elastic mechanics

针对钢箱梁桥面易发生破损和开裂的问题,基于二维弹性力学理论,推导出常温下汽车荷载作用下钢箱梁桥面铺装层应力分布的解析表达式。以广东马房大桥的超高韧性混凝土(STC)桥面铺装新体系为例,分析了STC铺装层厚度和箱梁横隔板尺寸对桥面铺装应力和变形的影响。与文献值、有限元解以及现场实测数据进行对比,证明了本文分析模型与计算方法的合理性与有效性。结果表明:随着横隔板尺寸的增大,横隔板处铺装层的拉应力呈对数递增,而跨中铺装层的压应力呈指数递减;在横隔板刚度和强度足够的条件下,减小横隔板腹板的厚度能减小横隔板处铺装层的最大拉应力;保持STC铺装的总厚度不变,路面的最大应力随STC层厚度的减小而增大;适当增加高弹模层的厚度能有效提高桥面的刚度并减小铺装层的最大应力。研究结果为钢桥面STC铺装的设计和箱梁横隔板截面尺寸的选取提供了参考。

In order to solve the broken cracking problem of pavement layer on steel bridge deck,the stress and strain distribution expressions were established to study the mechanical properties of pavement layer subjected to mobile loads.A new super-though concrete(STC)pavement system for steel bridge had been successfully applied to the Mafang Bridge in Guangdong Province,which was used as an example for the analysis.Studies have been conducted to the mechanical properties of STC pavement layer influenced by pavement thickness and the dimension of box girder diaphragm.Study results were compared with the finite element solutions and data from on-site test to demonstrate the rationality and accuracy of the present method.Results showed that the stressσx in pavement layer at the supports increased logarithmically,however,the stressσx at the mid-span decreased exponentially with the increase of diaphragm stiffness.When enough stiffness and strength of the diaphragm were ensured,the decreasing of diaphragm thickness could reduce the tensile stress in the pavement layer at supports.When the total thickness of STC pavement remained constant,the maximum tensile stress decreased with the increase of layer thickness.The proper increase of the high-elastic sub-layer thickness could effectively enhance the stiffness of the pavement layer and reduced the maximum stress in pavement layer.Conclusions could be used as the reference for determining the diaphragm dimension and designing the pavement layer for the steel bridge deck.