Reliability Assessment of a New Proposal for the Design of Solid Steel Plates at Elevated Temperature

Local buckling of steel plates is a major concern, as it dominates the plastic mechanism and reduces the ultimate strength of the steel plates depending upon their slenderness. At elevated temperatures, material nonlinearities result in a further reduction in the stability, stiffness, and strength of thin steel plates. Numerical simulations have been performed on stiffened and unstiffened steel plates at elevated temperatures under uniaxial compression load for different slenderness using commercially available FE software ABAQUS. The established finite element model, which depicts the local buckling behaviour and ultimate post-buckling strength of square and rectangular steel plates, has been the basis for a number of parametric investigations, all of which have been conducted using shell finite elements. The designed specification offered by North American Standards (ANSI/AISC 360-16) and European Standards (EN 1993-1-2), which employ a stress-based method to determine the ultimate post-buckling strength of steel plates for local buckling at elevated temperature, has also been compared with the obtained results. According to this investigation, EN 1993-1-2 produces results that are excessively conservative at higher temperatures. To overcome this, an attempt has been made by replacing the normal temperature parameter by a temperature-dependent non-dimensional slenderness ratio for predicting the ultimate strength of steel plates in fire exposure conditions. Further, this study provides some critical highlights on the behavior of steel plates of two different aspect ratios at elevated temperatures under compressive loads. The design formulations have also been proposed for estimating the ultimate strength of thin square and rectangular steel plates under compression. A good correlation has been observed in predicting the strength of the new design approach compared with existing experimental and computational results. The reliability and accuracy assessments of the proposed approach have been illustrated in brief.