火灾下超高性能混凝土梁斜截面承载性能

为探究火灾下超高性能混凝土(ultra high performance concrete,UHPC)梁斜截面承载性能的退化与损伤演化规律,采用Abaqus建立16个UHPC梁的热-力耦合分析模型,选择剪跨比、载荷水平、配箍率、箍筋配置方式、纵筋配筋率等作为考察参数,通过与试验结果对比验证模型的正确性.火灾下UHPC梁斜截面承载性能削减严重,其破坏延性优于普通混凝土梁.载荷水平和箍筋配置方式是影响UHPC梁耐火极限的主要因素:随着载荷水平增大,耐火极限降低;配置箍筋可以提高试验梁在火灾下的延性,但降低其耐火极限.

Bearing capacity of ultra high performance concrete beam under fire

To explore the degradation and damage evolution of the bearing capacity of ultra high performance concrete(UHPC) beams under fire, the thermal mechanical coupling analysis models of 16 UHPC beams are built by Abaqus. The shear span ratio, load level, stirrup ratio, stirrup configuration and longitudinal reinforcement ratio are selected as the inspecting parameters. The validity of the models is verified comparing with the experimental results. The bearing capacity of the inclined section of the UHPC beam is seriously reduced under fire, and its failure ductility is better than that of ordinary concrete beams. The load level and the stirrup configuration are the main factors affecting the extreme limit of fire resistance of the UHPC beams: with the increase of the load level, the extreme limit of fire resistance decreases; stirrups can improve the ductility of the test beam under fire, but the extreme limit of fire resistance decreases.