Static analysis of stay cables under the varying chord strength of the cable failure inspection in cable-stayed bridges
Authors: Ahmed Ramadan Ahmed A. , Ermoshin Nikolai A. 
Published: December 2024

Purpose of research. Bridge constructions are frequently subjected to harsh circumstances such as severe weather, earthquakes, traffic accidents, and even explosives. Bridge structures may lose some of their important structural parts (e.g., cables or piers) as a result of such intense external stresses, and further collapse is possible, as progressive collapse is often caused by the abrupt loss of one or more critical structural components. Cable-stayed bridges have very tiny crosssectional areas and are subjected to high loads. Such strong pressures can destroy anchoring zones due to large stress concentrations, resulting in cable loss.  Bridges with cable stays must be thoroughly investigated for the danger of progressive collapse induced by cable loss scenarios. Suggests considering the most common cable failure scenarios throughout the design process. To evaluate the effect of cable loss, do a static analysis with a (DAF) of two. There are two primary ways for avoiding progressive collapse. First, adopt structural or non-structural measures to provide a high level of safety against localized collapse. Second, prevent failures from spreading by establishing a solid foundation that allows for local failures.

Methods. Materials and methods. Damage to cables in the mathematical modeling of cable-stayed bridges. A continuous beam suspended from tension elements (cables) forms the basis of the conceptual model. His strength calculation plan is by comparing stiffness and flexibility matrices of intact and damaged systems. The stiffness matrix for an intact system is calculated using its reduced shape. The flexibility matrix is then calculated by inverting the reduced stiffness matrix. The conceptual model is interactive. As a result, the stiffness matrix is infinite. For direct analytical calculations, the parameter n is set as the ratio of the stiffness of the system ( = ), and a reduced form of the stiffness matrix is obtained to obtain an intact.

Results. The secant module seems to give a very good approximation, since the error remains less than 1% for cables up to 300 m long and less than 2% for cables up to 750 m long. Russians Russian Bridge has a length of 135.77 meters and the longest cable is 579.57 meters, as a result, the error rate of cables on the Russian Bridge will remain less than 1% for some cables and less than 2% for some cables. Considering that the modulus of elasticity of the steel material of the cable is rarely known with an accuracy of more than 2-3%, it is obvious that the method for determining the secant modulus would be suitable for all practical purposes. The tangent module is often easier to use than the secant module, since it is only necessary to know the voltage of the cable in its initial state. On the other hand, the tangent module can lead to erroneous conclusions with a long cable length and a large traffic-to-idle ratio, as shown in Figure 8.

Conclusion. The distance between two adjacent cables on modern bridges is significantly less than on older bridges. As a result, in the event of a car accident or explosion on the new bridge, several cables will fail. As a result, it was proposed that bridge designers take into account the rupture of all cables within a radius of 10 meters. Several studies have been conducted to find DAF in bridges. According to this study, having a father of two is not always safe. Although a recent study shows that the proposed DAD is safe for cable construction, that is, it is unsafe for structures of pylons or beams with negative moments.