爆炸与火荷载联合作用下RC梁耐火极限的数值分析

Numerical Analysis of Fire Resistance of RC Beams Subjected to Explosion and Fire Load

偶然性爆炸荷载通常会引起建筑结构或构件的破坏和损伤.为了揭示这种损伤对钢筋混凝土(RC)梁抗火灾高温能力的影响机理和规律,本文以分层Timoshenko梁非线性动力有限元方法为基础,在已有的钢筋和混凝土应变速率型弹黏塑性材料本构模型基础上,进一步考虑了温度效应,建立了能够分析爆炸荷载作用后RC梁抗火特性的有限元分析方法,编制了有限元计算程序.采用该程序系统地分析了爆炸荷载对普通RC梁在标准火灾升温过程中耐火极限的影响规律.分析结果表明,爆炸荷载损伤会明显降低RC梁的耐火能力,且梁长度越长,影响越显著.

Accidental explosion usually causes damage to the structural components. In order to investigate the mechanism and effect of reinforced concrete（RC） beams on fire resistance after exposure to explosion, a numerical approach was proposed based on the existing layered Timoshenko beam nonlinear dynamic finite element method. The strain-rate and temperature effects of steel and concrete were included in the constitutive model, and a finite element program was compiled according to the proposed approach. Fire resistance of RC beams subjected to combined actions of explosion and fire load was investigated by the program systematically. It is demonstrated that fire resistance of RC beams was reduced by the action of explosion load, and the more reduction was observed for the longer RC beams.