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Bridge Life Cycle Cost Analysis

 

Life Cycle Costs Analysis (LCCA) is a method of analyzing infrastructure investment cost options over a design lifetime and includes the initial construction cost and the costs of downstream repairs adjusted back to a present value using a real discount rate (which accounts for both the nominal interest rate less the inflation rate). For bridges, life cycle costs are computed from the time at which corrosion of the rebar starts to where patching and overlay of the deck surface is no longer viable, so that replacement of the deck is required.

 

Wiss, Janney, Elstner Associates, Inc. (WJE) has applied a sophisticated computer model to assess the service lives and associated life cycle costs for a bridge deck constructed using 1) black bar, 2) MMFX-II rebar, 3) epoxy coated rebar ECR), 4) solid Type 304 stainless steel rebar, 5) NX Type 316L clad stainless rebar [NX-SCRTM)] and 6) solid Type 316L stainless steel rebar. The analysis is based on 100 years design life and considers the differing levels of corrosion resistance inherent with each of these alternative reinforcing bars. The model assumes severe chloride contamination of the bridge deck surface, using a surface chloride content of 26 lb/yd (based on measurements on three bridges in Iowa).

 

For the major conclusions of the WJE study, click here.