Seismic Performance Assessment of a Masonry Arch Bridge Using Finite Element Method and Retrofitting by FRP

Bridges are the most important and vulnerable crucial paths that damage them and result in significant financial disadvantages. A great part of the past technical and artistic documents are related to bridges and their construction techniques. Preservation of the historic bridges that are currently in use has particular importance. One of the historic bridges around Tehran that are located in the Firouzkuh fault zone, is Namroud Bridge. In the current study, the Namroud Stone Arc Bridge was investigated under strong ground motions to assess the weak points and to improve its behavior by retrofitting it. For this purpose, the finite element method was used for both modeling and nonlinear analyses under five near-field earthquake records. By recognizing the masonry bridge’s weaknesses, FRP material was used to retrofit the bridge. The results reveal that although the studied bridge is vulnerable to earthquakes, it can maintain its stability. Further, the vertical acceleration component has an important effect on the vulnerability of the structure. Adding FRP sheets to the bridge deck was expressively effective whereas in other parts such as piers connection with the spandrel walls, leads to the spread of damage. Also in the location of the small openings, there is no possibility of the desired performance of FRP materials. Thus other methods such as planting rebar, injection, etc. should be used for these areas. Furthermore, it is impossible to use FRP material to achieve an economical and efficient method for retrofitting all bridge parts.