基于ANSYS的公路桥梁伸缩装置锚固区混凝土界面脱黏研究

Debonding Mechanism of Concrete Interface in Anchorage Zone of Highway Bridge Expansion Joint Based on ANSYS

公路桥梁伸缩装置受车辆荷载的长期冲击和环境因素变化极易发生疲劳破坏,锚固区混凝土和桥面铺装之间的界面脱黏尤为普遍。为防治“界面脱黏”病害,建立了桥梁伸缩装置锚固区的ANSYS有限元模型,通过计算6个不同位置公路-I级车辆荷载作用下桥面铺装与锚固区混凝土之间黏结界面拉应力和剪应力,分析了桥面铺装弹性模量、轮胎接触压力、水平力等因素对界面拉应力和剪应力的影响。结果表明,随着桥面铺装弹性模量的增大,黏结界面的应力逐渐减小,且黏结界面拉应力、剪应力与荷载压力值、水平力系数均呈现为正相关,其中水平力系数对界面拉应力的影响最明显,其次是车轮荷载大小。因此,选择弹性模量较大的桥面铺装材料、减小车辆超重情况及防止车辆在锚固区处紧急启动或刹车等均能延长伸缩装置的使用寿命。

Highway bridge expansion joints often suffer fatigue damages due to long-term vehicle impact and variations of environment,especially the interface debonding between concrete in the anchorage zone and bridge deck pavement. An ANSYS finite element model was established for the prevention and control of interface debonding. With the calculation of tensile and shear stresses of the bonding interface between concrete in anchorage zone and bridge deck pavement under six different vehicle loadings of Highway Grade one in different load positions,the influences of the elastic modulus of bridge deck pavement,the tire contact pressure and the horizontal force on tensile and shear stresses of the bonding interface were analyzed. It is found that the interface stresses gradually decrease with the increase of the elastic modulus of bridge deck pavement, and the tensile and shear stresses of bonding interface are both positively correlated with the load pressure value and the horizontal force coefficient,where the tensile stress is affected most by the horizontal force coefficient,followed by the wheel load. The service life of expansion joint can be increased by selecting bridge deck pavement with larger elastic modulus,reducing overloading situation and emergency brake or start-up at the anchorage zone,etc.