Reliability-based life-cycle-cost comparison of different corrosion management strategies

Abstract

Very limited studies have been done in the past regarding quantitative comparison of different corrosion management strategies in terms of using different materials in design and repair of reinforced concrete (RC) structures from a life-cycle-cost (LCC) point of view. In this paper, a reliability-based LCC analysis (LCCA) approach is developed to compare the long-term cost effectiveness of using six commonly-used groups of materials in design and repair of RC structures, including: normal strength concrete (NSC) with traditional black steel (BS) rebars (named as NSC-BS), NSC with epoxy coated (EC) rebars (named as NSC-EC), NSC with stainless steel (SS) rebars (named as NSC-SS), high performance concrete (HPC) containing Silica Fume (SF) with BS rebars (named as HPC-SF-BS), HPC containing Slag (SL) with BS rebars (named as HPC-SL-BS), and HPC containing Fly Ash (FA) with BS rebars (named as HPC-FA-BS). In particular, an interior T-beam of an RC bridge is used as the case study structure. First, a reliability-based design optimization (RBDO) technique is proposed and is used to achieve an optimum initial design of the T-beam for each group of materials through minimizing the initial design costs, given a target ultimate reliability index for the design. Then, reliability analysis considering prevailing uncertainties is conducted to evaluate the time-dependent serviceability and ultimate performances of the structure affected by corrosion. Next, based on the evaluated time-dependent performances, the time-to-repair and the number of repair operations are predicted for each beam. Lastly, LCCA is conducted to determine the optimum corrosion management strategy.