INFLUENCE OF CABLE TENSION ON THE DYNAMIC STABILITY OF A LARGE MULTI-SPAN CABLE-STAYED BRIDGE

Large-span cable-stayed bridges are increasingly becoming a vital component of modern bridge infrastructure due to their efficiency in load distribution, aesthetic appeal, and ability to span significant distances. This study examines the structural and dynamic performance of Azerbaijan’s largest multi-span cable-stayed bridge, which is currently under construction along the Muganly-Ismayilli-Gabala road. With a total length of 1100 meters, the bridge is located in a region of high seismic activity, making stability and structural integrity paramount concerns in its design and construction. A detailed load analysis was conducted, considering both permanent and temporary loads. These include the self-weight of the bridge, vehicle loads, environmental forces such as wind, snow, and ice, as well as the influence of seismic effects. The bridge features multiple cable configurations - with specific cross-sectional areas and tension forces that ensure structural stability. To mitigate seismic impact, the bridge is equipped with kinematic roller supports between the stiffening beam and its supporting structures, allowing controlled movement during seismic events. The study also focuses on the dynamic behavior of the bridge under various forces, particularly wind loads that induce oscillations in the cables and the stiffening beam. Through finite element analysis, the vertical and horizontal vibration frequencies were calculated, ensuring that resonance conditions are avoided. The results demonstrate that the bridge remains within safe limits for aerodynamic stability, with no risk of excessive oscillations due to wind or traffic loads. Furthermore, the analysis of cable strength and durability confirms that the maximum tension forces are within acceptable limits, with safety margins that comply with international engineering standards. The bridge’s stiffness conditions were verified using deformation calculations, showing that maximum deflections remain within allowable limits, ensuring long-term serviceability. This study provides crucial insights into the design and performance of large-span cable-stayed bridges in seismically active regions. The findings highlight the importance of advanced structural analysis and innovative engineering solutions to enhance stability, durability, and safety. The research contributes to the broader understanding of bridge engineering, offering valuable guidelines for the construction of future large-span cable-stayed structures in challenging environmental conditions.