Fragility analysis of bridge pier supported on rocking shallow foundation under earthquake loading

The rocking shallow foundation (RSF) allows seismic protection of the superstructure by guiding the plastic hinge onto the soil. Fragility curves are probabilistic measures to estimate the likelihood that a structure and/or its components exceed a particular damage state for a given intensity measure. In this study, the fragility analysis of the bridge pier-RSF system is carried out to quantify the seismic damage in a probabilistic framework. The deterministic finite element model of the bridge pier-RSF system is created using BNWF modelling approach and is implemented in OpenSees platform. Five broadband and five pulse-type ground motions are selected from the PEER ground motion database and are modified to generate sixty more ground motions for the response analysis of the system. The probabilities of failure are evaluated using the Monte Carlo simulation technique considering four engineering design parameters, four model configurations and seventy ground motions for the three performance levels. Results of the analyses showed that the bridge pier-RSF system is more vulnerable in the case of pulse-type ground motions compared to the broadband-type. This study is an initial attempt to develop the fragility curves which will be helpful in the seismic vulnerability assessment of the bridge pier-RSF systems.

Automated summary

This study conducts a fragility analysis of the bridge pier-RSF system using the Monte Carlo simulation technique. The results show that the system is more vulnerable to damage under pulse-type ground motions.