Fragility Assessment for Horizontally Curved Reinforced Concrete Box Girder Bridges Using As-built Data

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RESEARCH PAPER

Fragility Assessment for Horizontally Curved Reinforced Concrete Box Girder Bridges Using As‑built Data Arya Zamiri1 · Mohammad‑Reza Banan1   · Mahmoud‑Reza Banan1 Received: 27 April 2020 / Accepted: 15 August 2020 © Shiraz University 2020

Abstract Damage to one or multiple components of a bridge could result in various conditions, extended from a cosmetically repairable damage to jeopardizing life safety of the users. Fragility curves are beneficial in seismic risk assessment. Due to the limitations of the transformation network, aesthetic considerations, etc., a bridge might be skewed or curved which makes the problem more complex. Fragility assessment of bridges utilizing dynamic analysis seems to be inevitable in reducing damage levels in future earthquakes. In this study, the effectiveness of adopting fragility curves in performance evaluation and risk assessment of bridges is investigated. It is done by considering a highway curved bridge with eleven piers. FEM model is developed using OpenSees platform. Time history dynamic analysis is used to obtain the displacements and forces as demands of each bridge component. Eventually, fragility curves are developed for four damage states. Pier fragility curves of this bridge depict a very appropriate behavior under various levels of excitation which could be related to the appropriate distance of the stirrups. Prevalent mode of the bridge causes torsion in the first bay of the bridge. In the other two bays, only longitudinal transfer of the deck was observed. Bearing fragility curves of the bridge depict fair results in the transverse direction due to the presence of the shear keys as opposed to the longitudinal direction. Keywords  Box girder · Bridges · Fragility curves · Horizontally curved bridges · Seismic risk assessment

1 Introduction Recent earthquakes have proven the bridges as the weakest links and more susceptible to damage in the transportation network. Severe damages to these links could result in catastrophic consequences in the aftermath of a seismic incident. In the last few decades, various studies have been done on fragility computation of the bridges, making the subject a rather novel one Ramanathan et al. (2010), Kaviani et al. (2012) and Padgett et al. (2008). However, the number of studies on horizontally curved box girder bridges is limited. There are some studies pertaining to combined effect of responses in curved bridges (Tondini and Stojadinović 2012; Monzon et al. 2013). One of the major tools at our disposal in the field of risk assessment of the structures is fragility curves. These curves represent the probability of exceeding a specific damage * Mohammad‑Reza Banan [email protected] 1



Department of Civil and Environmental Engineering, Shiraz University, Shiraz, Iran

scenario under a specified seismic excitation for a given structure. Some characteristics of a bridge such as material characteristics, damping ratio, mass, accelerations and velocity of applied loads are influential in bridge response assessment u