Seismic probabilistic capacity models and fragility estimates for the transversal lining section of circular tunnels

This paper presents a numerical approach to construct the seismic probabilistic capacity models for the transversal lining section of circular tunnels. The influence of the lining dimension, reinforcement ratio, and properties of the concrete, reinforcement steel, and soil are considered. Two capacity measures, the bending moment M and the diametric distortion Delta d/d, are considered, and each of them is represented by a separate model. To consider the possible correlation of the two capacity measures, a bivariate moment-distortion capacity model is also proposed. As an application example, the proposed capacity models are used to estimate the fragility curves of a tunnel.