Transmission towers are vital channel in distributing high voltage electrical power from power plants to substations. This infrastructure is the backbone of the productive modern society. However, a number of these towers may fail due to earthquake. This failure may disrupt the electrical network, yield substantial amount of replacement cost, and more importantly, interrupts recovery efforts and business operation. This paper presents attempts to analyse seismic risk of the transmission tower by developing its fragility curve. Fragility is defined as the probability of damage exceeding a certain level given extensive range of seismic intensity. A finite element computational model was analysed under nonlinear static procedure (pushover) to obtain nonlinear response; specifically, a capacity curve. Then the fragility analysis was performed by determining certain damage states in the capacity curve. Inter-segment drift ratio (ISDR) was employed for the damage states. The result is expressed as fragility curve that provide fundamental and rational insights on the mechanical and probabilistic performance of transmission tower.
