ABSTRACT
On-site inspection of concrete strength plays an important role in reliability assessment of existing concrete structures, and the sample size has a direct influence on estimation accuracy of concrete strength. The optimum sample size of eccentric compressive members decreases with the increasing ratio of reinforcement in compressive region and/or with the decreasing ratio of reinforcement in the tensile region. This chapter examines the influence of sample size on the sample average and standard deviation. Based on the probability distribution model of concrete strength and inspection error, the process of on-site inspections of concrete strength is simulated by Monte-Carlo method. The chapter considers influencing factors of optimum sample size for flexural members Flexural members with single-side reinforced rectangular section, double reinforced rectangular section and T-shape sections. For a rare-reinforced single-reinforced section, the flexural capacity depends on tensile strength of concrete so that the sensitivity of flexural capacity to concrete strength is relatively higher, resulting in a larger optimum sample size.
