Abstract— The method of strengthening concrete structures with FRP composites has existed for over a decade in civil engineering rehabilitation projects; the most common way to strengthen structures is in bending, but also wrapping of girders and beams is quite common. A time dependent reliability analysis of RC girders shear strengthened by CFRP wraps and subject to both pitting corrosion and FRP degradation is conducted. Based on environmental harshness classified in relevant literature, three levels of corrosion vulnerability, and correspondingly surface chloride concentration as a random variable, are considered for chloride ion attack to steel reinforcement. The FRP degradation progress due to the environmental effects was modeled as two range of FRP's retention in strength according to existing studies. Monte Carlo simulation (MCs) was used in time dependent reliability model to consider uncertainties in vulnerabilities and calculate the reliability indices (βti) during the extended lifecycle of strengthened beam. The model was applied to a worked example designed based on ACI440.2R-08. Delamination and debonding of FRP sheets roughly parallel to the concrete surface are the most predominant mechanisms which results in premature fracture of the strengthened beam. Therefore in this paper the premature fractures limit state function is defined in reference to the provisions of ACI440.2R- 08 and its corresponding time dependent probability of failure during the extended lifecycle is calculated using Monte Carlo simulation method. Since the target reliability index according to ACI440.2R-08 is 3.5, the proposed method can precisely predict the time of deviation from code provisions. As the mechanism of shear fracture in beam elements is catastrophic, by estimating the deviation time, this model can denounce the onset of the brittle and premature fracture likelihoods in different environmental aggressiveness. Furthermore via sensitivity analysis of different strengthening configurations and material characteristics, the influence of design variables on probability of different fracture modes is assessed. Also it is shown that the trend and inclination of time-β diagram after the onset of the brittle fracture and probability of premature fracture modes can predict approximately the governed fracture mode and related time. Index Terms— Shear fracture, Fiber Reinforced Polymer, Time dependent reliability analysis, Deterioration models. Afshin Firouzi. Department of Construction Engineering and Management, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran., Tehran, Iran (Corresponding author to provide phone: +98-021-44868428; e-mail: firouzi@srbiau.ac.ir). Amirmasoud Taki. Department of Construction Engineering and Management, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran. (e-mail: masoud.taki07@srbiau.ac.ir). Saeed Mohammadzadeh. School of Railway Engineering, Iran University of Science and Technology Tehran, Iran. (e-mail: mohammadz@iust.ac.ir). I. INTRODUCTION Over the last decades, FRPs have emerged as a noteworthy rival to the more conventional civil engineering materials for rehabilitation of as-built infrastructures [1].This applicability has been due to the well-known advantages of FRP composites including their high strength- to-weight ratio, excellent fatigue resistance in cyclic loading, good corrosion resistance, and versatility in coping with different sectional shapes [2-4]. Therefore, many researchers and related associations such as American Concrete Institute (ACI) provided practical design guidelines for all aspects of application FRPs for strengthening structural elements [5]. In these guidelines, the provisions specified for bending design are more well-understood than for shear because the shear equations have been developed by semi-empirical background [6] and aren't quite comprehensive or are treated very briefly [7]. The reason for this is that the interaction of concrete and reinforcement is complicated and difficult to describe in terms of mechanical properties. When a strengthening material like FRPs is added to the concrete, the shear mechanism will be even more complicated [7]. Shear strengthening of RC members with CFRPs is a research problem with no consensus understanding and agreement amongst subject matter experts [8]. Moreover, the brittle shear fracture of RC beams is catastrophic compared to the flexural mode [9] that takes the shear capacity of an RC beam as its critical strength. The source of the existing disagreements are mainly related to uncertainties have been recognized as the role of materials properties and degradations in long term operation [10], [11], the effect of design parameters such as the size of the beam section, fiber orientation, strip width and spacing between FRP strips [12- 14] and governed fracture mechanism among probable failure modes [6], [15]. In spite of all these efforts accomplished so far, there are still limited and some gaps in the knowledge base and hence definite rooms for improvement to reach a holistic and sustainable solution. There are several modes of deterioration affecting FRP strengthened structures. Chloride induced pitting corrosion of steel stirrup and FRP's degradation are known as the more effective deterioration mechanisms which are considered in this work. Although several reliability analyses have been developed so far to assess the flexural strengthened RC beam, [16- 18] the application of reliability based evaluation of shear strengthened RC beam with FRPs is scarce [13]. Since environmental uncertainties make the governed Time Dependent Reliability Analysis of Concrete Transportation Infrastructure Shear Strengthened by CFRP Wraps Afshin Firouzi, Amirmasoud Taki, Saeed Mohammadzadeh Proceedings of the World Congress on Engineering and Computer Science 2016 Vol II WCECS 2016, October 19-21, 2016, San Francisco, USA ISBN: 978-988-14048-2-4 ISSN: 2078-0958 (Print); ISSN: 2078-0966 (Online) WCECS 2016