摘要: |
A new relationship was developed for estimating fire resistance ratings of gypsum board protected steel columns with high load ratios. The proposed formula can be used to adjust the limiting steel temperature, the commonly used 1,000°F (538℃) by the US standards, for steel columns with high load ratios. A two-dimensional finite-element analysis (2D FEA) heat transfer model, using Abaqus, was established to analyze the heat transfer of gypsum board protected steel columns exposed to the ASTM standard E119 temperature rising history. The numerical model was validated against available fire resistance ratings of protected steel columns, full-scale column fire resistance tests, a wall assembly fire test, and a column test that included a different range of steel temperatures. Results were also compared with those by SAFIR, one of the main available software packages for analysis of structures in fire. Steel temperature histories were used to extract fire endurances, and the extracted fire endurances were then used to construct a formula for predicting fire endurance for gypsum board protected steel columns at critical or limiting temperatures lower than 1,000°F (538℃). |