Girder Longitudinal Movement and Its Factors of Suspension Bridge under Vehicle Load

Abstract

Vehicle load may not only cause vertical deformation and vibration of suspension bridge but also lead to longitudinal deformation and vibration. And the longitudinal behavior is closely related to the durability of the girder end devices and the bending fatigue failure of suspenders. In this study, the longitudinal deformation behavior and longitudinal vibration of suspension bridge under vehicles, as well as the related influencing factors, are investigated. The underlying mechanism of girder longitudinal movement under the moving vehicles is revealed. Based on the simplified vehicle model of vertical concentrated force, the characteristics of main cable deformation and girder longitudinal displacement under vertical loads are analyzed first. Then, the longitudinal motion equation of the girder under vertical moving loads is derived. Finally, a single long-span suspension bridge is employed in the case study, and the girder longitudinal response and influencing factors are investigated based on both numerical simulation and field monitoring. Results indicate that the asymmetric vertical load leads to cable longitudinal deflection owing to the geometrically nonlinear characteristic of the main cable, leading to longitudinal movement of the girder. The results of field monitoring and numerical simulation indicate that the girder moves quasi-statically and reciprocates longitudinally with centimeter amplitude under normal operational loads.

Research on the longitudinal movement and influence of restraint parameters of the long-span suspension bridge’s main girder

“…The existing studies have shown that support friction also has a certain inhibitory effect on girder end displacement, and its effect cannot be ignored (Huang et al, 2021). In order to further obtain the influence of support friction resistance on the displacement of the That is, when the friction coefficient is within the range of 0~0.03, the increase of the friction coefficient has an obvious control effect on the main girder in the longitudinal displacement; While after the friction coefficient is greater than 0.03, the increase of the friction coefficient has little effect on the main girder in the longitudinal displacement, and the cumulative displacement of the girder end only fluctuates slightly, as shown in Table 5 In addition, it is observed that after the friction coefficient of the support is greater than 0.03, the displacement of the girder increased.…”

“…Current research shows that, in the bridge operation stage, the traffic load causes constant reciprocal movement of the longspan suspension bridge's main girder end, and the massive cumulative displacement will cause fatigue damage, insufficient durability, and other problems of the restraint devices such as expansion joints, dampers, and supports. In addition, the girder end displacement is also an important parameter for the design and selection of the key restraint device for the suspension bridge (Zribi et al, 2006;Huang et al, 2021). Therefore, it is of great necessity to study the longitudinal motion characteristics, influencing factors, and control methods of long-span suspension bridges' stiffened girders under traffic loads to ensure their safe operation.…”

Correlation model of deflection, vehicle load, and temperature for in‐service bridge using deep learning and structural health monitoring

“…As mentioned above, the bridge deflection monitoring data mainly includes temperature-induced component, vehicle load-induced component, and test noise. [5][6][7] Effectively separating the components of temperature and vehicle load of deflection monitoring data is one of the important problems in bridge structure health monitoring. Most of the existing studies used filtering or time-frequency analysis methods.…”

“…[1][2][3][4] The analysis of monitoring data has revealed that vertical deflection of bridge structures is mainly induced by vehicle loads and environmental temperature. [5][6][7] The monitored deflection is found to correlate with site-specific vehicle loads and environmental temperature. The database collected by monitoring systems can be used to establish the correlation model of vehicle loads, temperature, and bridge deflection.…”

“…During the past decades, deflection monitoring and assessment for in‐service bridges have attracted lots of attention and been well developed 1–4 . The analysis of monitoring data has revealed that vertical deflection of bridge structures is mainly induced by vehicle loads and environmental temperature 5–7 . The monitored deflection is found to correlate with site‐specific vehicle loads and environmental temperature.…”