Safety of lap lengths prediction in reinforced concrete structures

The recommendations for lap lengths of steel bars in reinforced concrete as specified by CP110 (1972), BS8110 (1985) and EC2 (2008) have been reviewed and evaluated for their safety implications in the bar curtailment and detailing. Results indicate that the implied safety is not uniform especially when the bar size factor in the prevailing specified equations for lap length design is about half its value for all the codes. Also, the earlier provision of CP110 (1972) gave the best safety indices in all the cases evaluated. However, it is suggested herein that an adequate lap length of bars in reinforced concrete design could be about 50times the smallest bar size in the reinforced concrete member as opposed to the EC2 (2008) provisions of 40times the smallest bar size.