Seismic Behavioural
study of A-Shaped Pylon Cable-stayed Bridge through Seismic Fragility Assessment
Variyavwala Jigar P. and Desai Atul K.
Disaster Advances; Vol. 15(10); 18-27;
doi: https://doi.org/10.25303/1510da018027; (2022)
Abstract
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.
