部分填充混凝土矩形钢管组合桁梁桥车激振动响应分析

为研究部分填充混凝土钢管桁梁桥车激振动响应,以陕西某部分填充混凝土矩形钢管组合桁梁桥为工程背景,基于分离迭代法原理,采用APDL语言自编车桥耦合振动系统求解命令流实现其车激振动响应计算；对比分析了不同填充系数、桥面不平度等级、车速等因素对桁梁桥动力响应的影响。结果表明：部分填充混凝土能有效提高钢管组合桁梁桥的竖向动力刚度,降低桁梁桥的动力响应,提高桁梁桥在车辆荷载作用下的抗疲劳性能；随着填充系数增加,主桁跨中下弦杆相对刚度先减小后增大,轴力最大值呈现先减小后增大变化趋势；桥面不平度是部分填充混凝土矩形钢管组合桁梁桥车激振动的主要影响因素,桥面不平度等级越低,桁梁桥动力响应增幅越大；部分填充混凝土矩形钢管组合桁梁桥动力响应最大值并不随车速增加而单调递增,当车速为60 km/h或120 km/h时,桁梁桥动力响应值最大。部分填充混凝土矩形钢管组合桁梁桥填充系数推荐取值范围为0.35 ~ 0.5。

Analysis of Vehicle-induced Vibration Response of Partially Concrete-Filled Rectangular Steel Tube Composite Truss Bridge

In order to study the vehicle-induced vibration response of partially concrete-filled steel tubular truss bridge, a partially concrete-filled rectangular steel tubular truss bridge in Shaanxi was taken as the engineering background. Based on the principle of separation iteration method, vehicle-bridge vibration system was developed by APDL language, and the calculation of vehicle-induced vibration response was realized. The influences of different filling coefficients, bridge deck roughness levels and vehicle speed on the dynamic responses of truss bridge were compared and analyzed. The results show that partially filled concrete can effectively improve the vertical dynamic stiffness of steel tube composite truss bridge and reduce the dynamic response of truss bridge, which could improve the fatigue resistance of truss bridge. With the increase of the filling coefficient, the relative stiffness of lower chords of the middle span in main truss decreases first and then increases, and the maximum axial force of lower chords of the middle span in main truss decreases first and then increases. The bridge deck roughness is the main influencing factor of vehicle-induced vibration of partially concrete-filled rectangular steel tube composite truss bridge. The lower the bridge deck roughness level is, the greater the increase of bridge dynamic response is. The maximum dynamic response of partially concrete-filled rectangular steel tube composite truss bridge does not monotonically increase with the increase of vehicle speed. When the vehicle speed is 60 km/h or 120 km/h, the maximum dynamic response of the bridge is obtained. The recommended filling coefficient of partially concrete-filled rectangular steel tube composite truss bridge ranges from 0.35 to 0.5.