Safety evaluation of circular concrete-filled steel columns designed according to Brazilian building code NBR 8800:2008

摘要

This paper presents an investigation of the safety of circular concrete-filled steel columns designed according to Brazilian building code NBR 8800:2008. The investigation is based on a comparison of code provisions to column strength obtained in 32 experimental tests, and on a comparison to provisions of the equivalent American and European codes. The modeling error of theoretical code resistance models is evaluated. An analysis of covariance is performed in order to identify tendencies of these models. The study reveals that the resistance model used in the Brazilian code is compatible with foreign codes, in terms of bias and variances. The study reveals an additional safety margin of the order of 10% for the NBR8800 code, when partial safety factors are removed. Reliability analysis is performed for 3888 column configurations, resulting in reliability indexes that cover the building codes application spectrum. The study shows that the Brazilian code presents reliability indexes which are compatible with foreign codes.