Chloride induced corrosion is one of the main causes of premature damage in steel reinforced concrete (RC) structures such as highway bridges exposed to deicing salts. Corrosion can affect the service life performance of the RC structure by reducing the diameter and yielding strength of rebar and weakening the bond at the steel-concrete interface. These effects could change stiffness load carrying capacity and even failure mode of the structure which increases the risks of sudden failure without warning. It is reported that the costs associated with monitoring maintenance repair and rehabilitation of corroded RC bridges in the US are overwhelming. To ensure the serviceability and safety of the RC structure and reduce the corrosion related costs optimum corrosion management strategies should be utilized.Different procedures can be used to manage the corrosion related problems in RC structures (e.g. using various repair methods corrosion resistant materials and cathodic protection etc.). For existing corroded RC structures the structures are typically repaired by jacketing spraying of concrete or patching methods. These methods involve removing the deteriorated concrete beyond the reinforcing steel cleaning up the corroded rebars replacing or strengthening the corroded rebar if needed and applying new concrete. For new constructions one of the strategies to mitigate corrosion is adopting corrosion resistant materials such as fiber reinforced polymer (FRP) bars as an alternative to reinforcing steel. Although this approach can increase the serviceability of the structure in the corroded areas the initial cost of these materials can be quite expensive (about 6-8 times more expensive than steel reinforcement).In this paper we compare two different corrosion management strategies in two RC bridge T-beams designed with the same flexural strength: one T-beam designed using FRP bars and one T-beam designed using a traditional material steel rebars. A reliability-based design optimization technique is used for the design of both beams through minimizing the design costs given a target reliability index. While the FRP reinforced beam has a much higher initial cost the corrosion in the steel RC beam imposes periodic repairing associated costs which can increase the expenses in a long run. Therefore a life cycle cost analysis is conducted to compare the cost-effectiveness of these two corrosion management strategies. Particularly patch-repair is adopted as a periodic repair method for the steel reinforced beam. For a given service time the time-dependent performances of the steel reinforced beam will be assessed using reliability analysis in terms of both flexural strength and serviceability. A patch-repair will be applied when the reliability index becomes lower than given thresholds for each performance. Then the life cycle cost of the steel reinforced beam will be calculated by summarizing the initial cost with the associated repair costs. For the FRP reinforced beam it is assumed that no corrosion related the repair is needed; thus only the initial cost is considered as the life-cycle cost. The results of this study can be used for development of optimum cost-effective corrosion management strategies.

Key words: corrosion, RC bridge, GFRP, patch repair, reliability-based design optimization, lifecycle-cost-analysis