Title: Post Earthquake Damage Repair of Various Reinforced Concrete Bridge Components
Authors: Saini, A. and Saiidi M.
Date: May 2014
Department of Civil Engineering/258
University of Nevada, Reno
Reno, NV 89557
Highway bridges are an important component of the transportation system. It is essential to restore the bridge after earthquake damage by means of repair, reconstruction, or replacement. Replacing the entire damaged bridge is cumbersome, time consuming, and expensive. Therefore, appropriate bridge repair needs to be carried out to restore the bridge. The main objective of the present study was to develop repair methods using carbon fiber reinforced polymer (CFRP) for various reinforced concrete (RC) bridge components. This study consisted of three parts. In the first part, a detailed review of damage and repair in past earthquakes was conducted and the data were compiled in tables and gaps in available repair methods were identified. In the second part simple practical methods were developed to access the condition of an earthquake damaged bridge structural components in terms of apparent damage states (DS's). For this approach to be successful, internal earthquake damage was quantified and correlated to a series of visible DS's. Because seismic performance objective varies among different bridge components, earthquake damage can vary greatly and not all DS's are applicable to every component. Because, generally bridge columns are designed to be the primary source of energy dissipation through nonlinear action, they undergo a wide range of apparent damage. DS's defined for bridge columns were used as the framework for other components. In the third part, repair design recommendations and design examples were developed to aid bridge engineers in quickly designing the number of CFRP layers based on the apparent DS. Repair methods to repair bridge components such as columns, abutments, shear keys, girders, and cap beam-column joints were developed. In cases where the extent of damage precludes an economically feasible repair, reconstruction of damaged bridge component is recommended. Because the available database for components other than columns is limited, many simplifying and conservative assumptions were made about the residual capacity of damaged components. Through this study, a new simple non-iterative method was developed for design of CFRP fabrics used in repair of concrete members. The step-by-step repair methods for bridge components that were developed as part of this study address a gap in rational and systematic repair tools that are needed subsequent to moderate and strong earthquakes.