虎门二桥坭洲水道桥纵向约束体系研究

虎门二桥坭洲水道桥为主跨1 688m的双塔双跨悬索桥。为减小该桥在汽车活载、温度作用及风荷载下的梁端位移,提出一种在塔梁连接处设置静力限位-动力阻尼装置的纵向约束体系。采用有限元软件SAP2000Nonlinear建立全桥有限元模型,分析该静力限位-动力阻尼装置的限位间隙、限位刚度对梁端位移、塔梁相对位移、限位力的影响规律,确定限位装置的合理参数取值,分析设置静力限位-动力阻尼装置前、后加劲梁应力、桥塔纵向弯矩和梁端位移。结果表明:该桥静力限位-动力阻尼装置的限位刚度取200MN/m,广东侧和东莞侧限位间隙分别取0.82m和1.05m;采用静力限位-动力阻尼体系后,静力作用和地震作用下的梁端位移大幅降低,伸缩缝规模从2 758mm降到2 106mm,减小23.6%。

Study on Longitudinal Constraint System of Nizhou Waterway Bridge of Second Humen Bridge

Nizhou Waterway Bridge of Second Humen Bridge is a double-tower double-span suspension bridge with a main span of 1 688 m. In order to reduce the beam-end displacement of the bridge under the action of live load, the temperature action and wind load, we proposed a longitudinal restraint system of setting static limit-dynamic damping device at the joint of beam and tower, and adopted the finite element software SAP2000 Nonlinear to establish a finite element model of the bridge. Moreover, we analyzed the effects of the limit clearance and limit stiffness of the static limit-dynamic damping device on the beam-end displacement, the relative displacement between tower and beam, and the limiting force, determined the reasonable parameter value of limiting device, and then analyzed the stress of stiffening girder, longitudinal bending moment of the tower, and beam-end displacement, before or after setting the static limit-dynamic damping device respectively. The results show that the limit stiffness of the static limit-dynamic damping device is 200 MN/m, the limit clearance is 0.82 m (Guangdong side) and 1.05 m (Dongguan side) respectively. After adopting the static limit-dynamic damping system, the beam-end displacement under static and seismic action decreases remarkably, the expansion joint size decreases by 23.6% from 2 758 mm to 2 106 mm.