摘要
文章采用ABAQUS大型有限元分析软件,建立了一榀三层底部大空间钢筋混凝土托梁转换结构模型,对该转换结构模型施加标准升温及恒定竖向荷载的共同作用,进行了九种受火工况下转换结构模型随温升时间的变形规律计算,得到了转换结构模型观测点位移与标准升温时间的关系曲线。结果表明:在常温竖向力学荷载作用下产生变形的基础上,随着不同受火工况标准升温时间的增加,转换结构模型皆产生了复杂的附加变形;随着升温时间的增加,转换结构模型中底部托梁的挠度值在升温过程前期60 min内增长较快,之后逐渐减缓,就同一升温时刻引起的底部托梁的竖向挠度变形值来看,底部大空间和上部相邻层同时受火的工况四最为显著,其次是大空间上部相邻层受火的工况二和大空间受火的工况一;随着升温时间的增加,不同受火工况下转换结构模型两侧边柱的水平侧移逐渐增大,由于受火楼层横梁受火膨胀变形的作用,受火楼层横梁位置处边柱向外凸出的侧移明显大于其他楼层;对于不对称受火房间布置的工况,两侧边柱的侧移在底层托梁以上部分产生同向侧移情形,这应是构件间约束作用的结果,表明在不对称受火情形下,结构中会产生较剧烈的相互作用和内力重分布现象。
The model of 3-story reinforced concrete structure with large space transfer floor at bottom is established. The nonlinear FEM software ABAQUS deformation of the model which is exposed to fire and coupling with vertical bearing column girder is used to analyze the loads. Based on the simulation results of 9 fire cases, the displacements of measured points and heating-up time curves are plotted. The numerical results show that based on the deformations under vertical loads at normal temperature, the transfer structure models produce complicated additive deformations with the heating- up time increasing. The deflections of the transfer girder are growing fast in 60 minutes of ignition, and then slow down gradually. As to the deflections of the transfer girder at the same moment, the fourth fire case has importance affect, followed by the second and the first fire cases. With the heating-up time increasing, the lateral disnlaeements of two side side columns of the model increase gradually in different fire cases. Because of the thermal expansion of the beam in burning floor, the lateral displacements outward of side columns in burning floors are significantly larger than other floors. In asymmetric fire room conditions, because of the constraint between members, two side columns above the transfer girder produce sway in the same direction. It shows that in asymmetric fire conditions, the structure will produce a violent interaction and the internal force redistribution phenomena.
出处
《山东建筑大学学报》
2015年第6期511-518,共8页
Journal of Shandong Jianzhu University
基金
国家自然科学基金项目(51278289)
国家自然科学基金项目(51478254)
关键词
钢筋混凝土
转换结构
火灾
承载性能
reinforced concrete
transfer structure
fire
bearing performance
