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Delay in reliability index deterioration

Until C = 1

a T(a, b, c) represents a triangular distributed random variable with a = minimum, b = mode, and c = maximum.

a T(a, b, c) represents a triangular distributed random variable with a = minimum, b = mode, and c = maximum.

36.11 Life Cycle Cost Examples

Since life cycle cost analysis and reliability methods are still relatively new, the methodology and procedures are still being developed. The research is admittedly incomplete. There are many researchers who are suggesting approaches, developing techniques, and applying them to real structures. It is from these studies that standardized procedures and prescribed codes will eventually emerge. This final section briefly examines three such case studies that have attempted to apply many of the concepts discussed in this chapter to actual structures.

FIGURE 36.22 Mean and standard deviation of bridge condition and reliability index profiles considering cyclic replacement of concrete cover.

Case 36.1

Frangopol et al. (1997a,b) examined the life cycle cost design of reinforced concrete T-girders on highway bridges. The deterioration mechanism was corrosion of the reinforcing steel after sufficient chloride penetration into the concrete. The AASHTO (1992) bridge specification equations for both moment and shear capacities were used to optimize the T-girder for various life spans without the need for maintenance. Corrosion rates v of 0.0064, 0.0089, and 0.0114 cm/year (0.0025, 0.0035, and

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