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Cable stayed bridge is the most sensitive structure because of its higher flexibility. Exact bridge behavior can be obtained by proper dynamic bridge formulation. Cable stayed bridge deck and pylon can be modelled as abeam element. Researchers used to model cables with simple truss element and letter by parabolic cable element; although they are not presenting the exact cable performance under different lateral loads. In this study, a complete comprehensive study of modelling scheme for cable stayed bridge with improved catenary cable element is adopted by Equivalent modulus approach. The Modelling strategy involved finite element modelling with a dynamic stiffness method. A real CS Bridge is modelled in Midas-civil and results are compared. This improved innovative modelling approach agrees well with the bridge analysis results of the research article.

This research aims to evaluate the dynamic interaction between a cable-stayed bridge (CSB) and operating trains during earthquakes. A three-dimensional finite element modeling approach has been used to analyze the H-shaped pylon CSB along with soil–pile interaction. The train model has been developed using a dynamic system having 10 degrees of freedom. The contact forces between the wheels and the track illustrate the dynamic interaction between the bridge and the train. A Matlab program has been built to receive train–bridge interaction responses. The nonlinear dynamic analysis was performed on CSB using the Bhuj earthquake time history. The structure’s response can then be used to assess the safety of running trains during seismic activity. The dynamic response of the train–bridge interaction system, including the derailment and offloading variables related to the train’s running safety, is evaluated using varied spectral acceleration scaling. The results demonstrate that the acceleration response of the train during seismic events is substantially higher than when there are no earthquake inputs. The operating train’s safety is influenced by both the intensity of the earthquake and the train’s running speed. The operating safety of a moving train during a seismic event is guaranteed by the threshold curve. The proposed bridge modeling technique and simulated results prove that the proposed formulation can accurately envisage dynamic train responses with acceptable computational errors.

The global acceptance of cable-stayed bridges (CSB) has increased due to their aesthetic appearance and suitability for relatively longer spans. CSBs are the most flexible structure. The behavioural study of CSB under natural disasters i.e. earthquake is a new frontier of research. The current research focused on seismic fragility assessment (SFA) of an A-shaped pylon CSB for Indian seismic zone-V using 25 ground motions. Spectral acceleration 𝑠𝑎(𝑔) is the best IM for a CSB. For the four performance criteria, the fragility curves (FC) have been built using incremental dynamic analysis (IDA). Developed seismic FC illustrates the damage probability of CSB as a function of strong ground motions. It can be used to assess the probability of damage for a specific ground motion index. The pylon drift ratio and bearing displacement have been adopted to produce component FCs. The traditional IDA approach is adopted which involves linear regression. The overall system fragility of CSB has been derived using the Riemannian Manifold Hamiltonian Monte Carlo-based subset simulation (RMHMC-SS). The bound limits exemplify the bridge behaviour under different LSs. Analysis results prove that bearings are the most fragile component; their placements and hinge formulations govern the overall bridge performance.