Reinforced concrete beams at ultimate flexural limit state: comparison of BS 8110 and Eurocode 2

Abstract

BS 8110, the British Code for structural concrete design has been implemented as the code of practice in Malaysia since its first inception. However, the British Standards Institution will cease to revise this structural concrete design code after year 2008. Eurocode 2 will be implemented as the structural concrete design code in the United Kingdom thereafter, with the additional Nationally Determined Parameters (NDP'™s). It is envisaged that Malaysia will gradually implement Eurocode 2 in lieu of BS 8110 as the standard code of practice. This paper presents a parametric study on flexural strength of singly- and doubly-reinforced rectangular beams based on BS 8110 (1985) and Eurocode 2 (1992). It was found that both codes give almost similar flexural strength for beams reinforced with either mild or high yield steel if the relationship of concrete cube strength and cylinder strength is taken into account. The difference in calculated strength is merely 1% for singly-reinforced beams within the maximum limit for neutral axis depth; and about 2 % of maximum difference. These differences are considered negligible in consideration of steel reinforcement provision. The maximum difference in flexural strength encountered in this study is 7% for doubly-reinforced beams. This may also be considered as insignificant in provision of steel reinforcement. Therefore, it can be concluded that flexural design based on both codes of practice are similar and the structural designer will arrive at the same design following either code. The charts presented in this parametric study can serve as nomographs for the design of singly- and doubly-reinforced rectangular beams and basis for the structural designer to compare the design based on two different codes of practice.