Engineering Structures 26 (2004) 609–618 www.elsevier.com/locate/engstruct Repair and strengthening of segmental bridges using carbon fibers G. Ramos  , J.R. Casas, A. Alarco ´n Dept. de Ingenierı ´a de la Construccio ´n, Universitat Polite `cnica de Catalunya, C/Jordi Girona 1-3—Mo ´dulo B1, 08034 Barcelona, Spain Received 7 August 2003; received in revised form 18 December 2003; accepted 18 December 2003 Abstract This work presents the results of an exhaustive experimental research carried out at the Technical University of Catalonia with the aim of studying the structural behavior of carbon fiber reinforced plastics when used for strengthening segmental bridges The study based on the ultimate strain of such composite material. Tensile and bond tests were performed on material-scale specimens and structural tests on full-scale segmental beams. The overall objective of this paper is to show the results obtained in this research project as well as to propose the bond test as an alternative for characterization of these new products in order to use them for repair and strengthening of segmental structures. # 2003 Elsevier Ltd. All rights reserved. Keywords: Bridges; Carbon fibers; Strengthening; Repair; Segmental bridges 1. Introduction Since its appearance, composite materials have attracted special attention in the construction field due to its efficient behavior under tensile loading, their great resistance against external agents and the sim- plicity of their application, among other advantageous characteristics. These properties have allowed these materials to be considered for the repair and strength- ening of concrete structures [1,2]. Since these products are new in the construction field, there is little available research on its behavior. On the other hand, the technical specifications given by the manufacturers are limited to its field of application. Then, it is necessary to establish a failure criteria for reinforcing systems based on fiber reinforced plastic sheets [3,4]. The behavior of composite materials has been stud- ied and characterization tests have been carried out at the Structural Technology Laboratory of the Technical University of Catalonia. These studies involve tests on material- and structural-scale elements [1,5,6]. The results of the study have been compared with the data given by the manufacturers [1,5,7]. Also, com- parisons have been made between the load-bearing capacity of monolithic structures in its original state and after the corresponding repair [8]. Among the different failure mechanisms, it was ob- served that concrete structures reinforced with carbon fiber meshes fail before reaching the theoretical design strength in the areas where an important cracking occurs. This fact motivated the interest for observing the behavior of carbon fiber reinforced plastics (CFRP) in dry joint segmental bridges. In which, there is a localized jointwhichwillopensimulatingacrack. Then, the fundamental objective of this research pro- ject is to study the behavior of CFRPs in concrete structures containing dry joints. Also, to propose an experimental model to quantify the strength of these type of materials when applied to the mentioned type of concrete structures. 2. Experimental program and methods Theexperimentalprograminvolvedthreemainphases: (a) Characterization of the CFRP repair systems. (b) Bond tests on 15  15  60 cm prismatic beams. (c) Full-scale tests on 7.20 m span segmental beams. Two systems of reinforcement with carbon fibers were tested; one comprising a bi-directional mesh applied according to the Freyssinet TFC procedure,  Corresponding author. Tel.: +34-93401-7356; fax: +34-93401- 1036. E-mail address: gonzalo.ramos@upc.es (G. Ramos). 0141-0296/$ - see front matter # 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.engstruct.2003.12.008