The current width to thickness ratio criteria in the Japanese standard do not allow high-strength steel to be used in practice. According to the criterion, high-strength steel results in excessive cross section since it underestimate its deflection angle at maximum strength. Considering that, it would be appropriate to consider the original yield strength retains until steel reaches a certain deflection angle. The purpose of the present paper is to study relationship between the deflection angle at maximum strength and width to thickness ration. The paper deals with plates of 490N/mm2 grade steel and 780N/mm2 grade steel and discusses their relationship by means of FEM analysis.
