Serviceability Limit State and Crack Width Analysis of Concrete Structures inNuclear Power Plants

摘要

The paper presents the in-house design tool comprising of several independent programs that are chained to analyse and dimension three dimensional reinforced concrete structures iteratively.A specific object of the paper is to compare different design codes in the serviceability limit state design. The design codes compared are the National Building Code of Finland "B4: Concrete structures" and the European Standard "Eurocode 2: Design of concrete structures". The calculation formulas of the different design codes are compared and their differences are demonstrated by practical test examples and real structures of nuclear power plants. The results reveal that these codes lead different reinforcement even if they both are official codes in Finland presently. For example with the same crack width requirement, the amount of required reinforcement according to Eurocode 2 is about 5% less in bending and in a pure tension about 30% more than required by B4. If the comparison is made using the same exposure class, the amount of required reinforcement given by Eurocode 2 is less than according to B4 both for bending and for pure tension, as the requirement for the crack width in B4 is often stricter than the requirement in Eurocode 2. As the crack width is often a dimensioning factor for concrete structures, the reinforcement required seems to be clearly dependent on the design code applied.