Reliability-Based Assessment of Design Code Provisions for Circular CFT Stub Columns: Fid-Bau Portal

Reliability-Based Assessment of Design Code Provisions for Circular CFT Stub Columns

Lu, Zhao-Hui / Zhao, Yan-Gang / Yu, Zhi-Wu / Xu, Qing-Yuan

This paper presents a probabilistic investigation of design code provisions such as AISC, DL/T and Eurocode 4 for circular CFT stub columns. The study is based on experimental results of 250 axially loaded circular CFT stub columns published in the literature. By comparing experimental results for ultimate loads with code-predicted column resistance, the error of resistance models is analyzed and it is found that it can be described using a normal random variable. Based on the investigations, reliability analyses were performed for the three design codes with/without considering the model error random variables. It is found that the model error is quite relevant for column safety, especially for the case of small load ratios. Consideration of model error resulted in increased reliability of stub columns designed according to AISC code, due to conservative column resistance predicted by the code. While for design codes of DL/T or Eurocode 4, consideration of model error produces a reduction of reliability indexes. Finally, the safety level of code provisions in terms of sufficient and uniform reliability criteria is also evaluated. Results show that the AISC design code provided very conservative results and the scatter of reliability indexes is the smallest. Eurocode 4 provided suitable results in terms of the sufficient criteria. The paper also shows that the reliability indices of columns designed following DL/T are slightly below the target reliability levels of ISO 2394.