Design Standard Strength and Nominal Strength
By T. Ayano and K. Nakura
Concrete Journal, Vol.63, No.3, Mar. 2025
- Synopsis
- The Standard Specifications for Concrete Structures published by the Japan Society of Civil Engineers adopted the allowable stress design method until the 1980 Edition. For construction under this method, concrete with a compressive strength that had no more than a 25% probability of falling below the design standard strength in a single test was required. With the introduction of the 1986 Edition of the Standard Specifications for Concrete Structures [Design], the design method was revised to the limit state design method. Under this method, concrete with a compressive strength that has no more than a 5 % probability of falling below the design standard strength in a single test is required. In civil engineering, both the allowable stress design method and the limit state design method are currently used for design. This paper explains how to specify the nominal strength of ready-mixed concrete used in the construction of structures designed under each method, based on the 2023 Edition of the Standard Specifications for Concrete Structures [Materials and Construction].
- Keywords:
- Design standard strength, Material factor, Defect rate, Producer risk, Characteristic value, Acceptance criteria value, Nominal strength
