PROBABILISTIC LIFE-CYCLE COST ASSESSMENT OF STAINLESS STEEL REINFORCED CONCRETE BRIDGE GIRDER UNDER MULTIPLE HAZARDS

Abstract

Reinforced concrete (RC) bridges are considered as the most important node for the transportation networks which play very crucial role in sustainable economic development of any nation. However, performance of reinforced concrete bridge with ordinary rebar under multiple hazards is found to be deteriorated severely. In order to maintain the performance of the bridge over a threshold value, regular inspection and maintenance actions are required to ensure their continuous service leading to higher lifetime cost. In addition to the increase in lifetime cost, the inspection and maintenance activities may also tremendously raise the indirect costs to the users due to traffic delays and loss of productivity. Furthermore, the inspection and maintenance activities may also hinder the continuous traffic movement over the bridge and the consequences in negative impact on environment and social life. Although, use of stainless steel rebar in constructing RC girder will increase construction cost, however, it will reduce the necessity of inspection and repair activities leading to lower lifetime cost. The higher construction cost of SS-RC bridge will be completely outweighed by incentives obtained from the lower repair and maintenance costs after a certain time referred as pay-off time (tpay-off) for stainless steel reinforcement economic viability which primarily depends on severity of airborne chloride hazard, price of SS rebar, and design service life of the bridge. The key purpose of this study is to determine tpay-off for SS rebar economic viability by determining the time required to obtain identical life cycle cost (LCC) value of SS- and CS-RC bridges. To fulfil this objective, two holistic flowcharts were developed to determine tpay-off for SS rebar cost efficiency. Furthermore, the proposed approach was illustrated using an RC bridge girder considering different coastal marine environments in 20 cities in Japan and the variation in SS price. The findings will assist transportation officials in deciding on selecting rebar type and cost of SS rebar to construct sustainable bridge with a nominal lifetime cost.