Comparative Study on the Probabilistic Safety of Truss Structures Designed Using U.S. and Vietnamese Codes

Abstract

This study evaluates and compares the reliability of a truss designed according to the Vietnamese TCVN 5575-2012 and the American AISC 360-16 steel design codes.  The same truss configuration and applied loads are considered, with sections designed according to each standard. Their probabilistic safety levels are then evaluated to provide deeper insights into the differences between the design codes. Results indicate that, under identical loading, trusses designed with AISC are lighter than those designed with TCVN, as TCVN requires larger sections for compression members. Reliability indexes (RIs) for tension behavior are similar between codes; however, TCVN yields higher RIs for buckling, indicating a conservative approach for compression members compared to AISC. Although TCVN does not specify a target RI, its deterministic and probabilistic safety levels exceed those of AISC, suggesting a target RI above AISC’s 3.0. Consequently, TCVN-based designs generally involve higher costs, emphasizing the importance of understanding safety implications in code selection. Finally, the conservative results from TCVN are examined through equivalent safety factors, providing insights into its design assumptions.