火灾后波纹钢腹板组合梁力学性能研究

Research on mechanical behavior of corrugated steel web composite beams after fire exposure

建立了波纹钢腹板组合梁全过程火灾下有限元分析模型,利用持荷情况下,经历火灾升-降温全过程作用后的波纹钢腹板组合梁力学性能试验结果验证了模型的合理性。采用验证后的有限元模型对影响组合梁火灾后力学性能的参数进行了研究,其中包括:升温时间、荷载比、剪跨比及材料强度。分析结果表明:全过程火灾后组合梁有受弯破坏和受剪破坏两种破坏模式,剪跨比为1.5时,组合梁发生受剪破坏;剪跨比为2.5和3.5时组合梁发生受弯破坏;火灾后波纹钢腹板组合梁剩余承载力与剪跨比、混凝土强度及外包钢梁屈服强度成正比,与升温时间、荷载比成反比;升温时间越长,荷载比对组合梁火灾后剩余承载力影响越显著。

FEA model of corrugated steel web composite beam after fire exposure was established,and the mechanical properties of the corrugated steel web composite beam were verified by the test results.The validated model was used to investigate the parameters affecting the the residual load capacity of the composite beam,including the heating time,load ratio,shear-to-span ratio and material strength.The analysis results show that there are two damage modes which are bending damage and shear damage for the composite beam after the whole process of fire:the shear damage occurs when the shear-span ratio is 1.5,and the shear damage occurs when the shear-span ratio is 2.5 and 3.5;the residual load capacity of the corrugated steel web composite beam is proportional to the shear-to-span ratio,the concrete strength and yield strength of the outsourced steel beam,but inversely proportional to the heating time and load ratio.The longer the heating time is,the more significant the influence of load ratio on the residual load capacity of the composite beam after fire exposure will be.