火电厂钢框排架-支撑结构抗震性能试验研究

Experimental investigation on seismic performance of steel frame-bent structures with braces in thermal power plants

为研究我国高烈度大容量机组火力发电厂钢框排架-支撑结构的抗震性能,以某典型火电厂主厂房为实例,选取横向某榀结构为研究单元,设计1∶10比例模型,进行了有侧限低周往复加载试验。根据试验现象和所获滞回曲线、骨架曲线、刚度退化曲线、位移延性和等效黏滞阻尼系数等综合评价结构的抗震性能。研究结果表明:钢框排架-支撑模型结构的荷载-位移曲线饱满,结构延性和耗能能力较好,具有良好的抗震能力;结构底部支撑为最初破坏部位,塑性铰发展顺序为先梁端后柱端,最终框架柱呈压弯变形,排架柱呈弯扭变形;框架平面内加载下结构正向最大承载力比反向偏大11.3%,存在不对称性;结构第2层层间位移角达到1/22,为薄弱层所在,设计中应予以加强。钢支撑受压屈曲是局部出现平面外变形、节点连接处变形和残余变形等问题的重要原因。

Low cyclic loading tests with lateral restraint were carried out using a 1：10 scale model to investigate the seismic performance of the steel frame-bent structures with braces in domestic largecapacity and thermal power plants. The transverse roof trusses from the main building of a thermal power plant are utilized as the research object. The seismic performance is evaluated according to the observed experimental phenomena and the obtained hysterics loops, skeleton curves, stiffness degradation curves, ductility index, and the effective viscous damping coefficient. The research results show that the steel frame-bent structure with braces has good seismic performance, with a plump load-displacement curve as well as good ductility and energy dissipation capacity. The initial structural failure first appeared in the bottom-bracing part and the sequence of articulation development moved from the hinge beam to the hinge column. The failure mode of the frame-structuring columns was compression bending deformation, showed flexural-torsional deformation. The maximum bearing capacity in the positive loading higher while the bent-structuring was approximately 11.3 % than that in the negative loading by under unidirectional loading within the frame plane, so the seismic performance was asymmetric. The weak story should be strengthened in the design because the inter-story drift angle of the second floor reaches 1/22. The buckling of braces is the main reason for the out-of-plane distortion, joint deformation, and the residual deformation.