升温下钢构件的强度设计标准

通过与非线性有限元模拟比较,对结构钢构件在升温下的设计公式进行了评估。比较美国钢协与欧洲标准委员会对温度在800℃侧向无支撑的Ⅰ型柱、梁、柱-梁的设计规定。欧洲规范3的规定与有限元模拟的结果相差10%～20%。另一方面,美国钢协的规范预测的强度与模拟结果相差高达2倍。对于温度超过300℃的中细构件,相差最大。提出了对美国钢协规范计算公式的修正建议,修正后的精度与模拟的结果误差在20%～30%。最后讨论了结构防火工程基于构件评估的局限性、未来的研究以及发展方向。

Strength Design Criteria for Steel Members at Elevated Temperatures

Design equations for structural steel members at elevated(fire)temperatures are evaluated through comparisons with nonlinear finite element simulations.The study includes comparative analyses of the American Institute of Steel Construction(AISC)and European Committee for Standardization(CEN)design provisions for laterally unsupported I-shaped columns,beams,and beam-columns at temperatures between ambient to 800℃.The Eurocode 3 provisions are shown to predict the simulated finite element results within about 10%~20%.On the other hand,the AISC specification predicts strengths that are up to twice as large(unconservative)as the simulated results.The discrepancies are largest for members of intermediate slenderness and temperatures above 300℃.Modifications to the AISC equations are proposed that provide improved accuracy with calculated strengths typically within 20%~30% of the simulated results.Limitations of the member-based assessments and future research and development needs for structural fire engineering are discussed.