轻型木刚架抗侧力性能的参数研究

A PARAMETRIC STUDY OF RACKING PERFORMANCE OF WOOD PORTAL FRAMES

摘要:

采用通过4个足尺木刚架试验结果对比验证的有限元分析模型，对4个不同类型木刚架基本模型的抗侧力性能进行分析研究。研究中选取了刚架的高度、刚架角部竖向安装钢条的类型和位置变化、设置双层底梁板连接、覆面板在刚架竖向连接方式和覆面板与骨架钉连接模式这5个影响刚架抗侧力性能的主要参数进行对比分析。分析表明对于全部4个刚架基本模型，增加刚架高度均显著降低刚架的抗侧力刚度和承载力；刚架角部竖向安装钢条的类型和位置影响因素中，钢条本身抗拉强度对刚架抗侧力性能影响最为显著，而且钢条直接连接到骨架上比置于覆面板表面、隔着覆面板连接到骨架更加有效；设置双层底梁板和2排钉连接只能稍微增加刚架抗侧力性能；覆面板在刚架竖向采用在中部无垫块连接方式比覆面板在竖向连续的刚架抗侧承载力几无影响，而抗侧力刚度稍有降低；当覆面板两侧与墙骨柱钉连接的排数由2排改为1排时，刚架抗侧承载力没有降低，但是抗侧力刚度稍有下降。

Abstract:

The performance of different types of portal frame walls was studied using a finite element model that was verified with results from tests of four full-size portal frame walls. Parameters such as wall height, metal strip types and locations, bottom plates, sheathing and nailing pattern were investigated. Results indicate that for all the wall types, the lateral load capacities and stiffness are greatly reduced with the increase of wall height. Among the different metal strip types and locations, the tensile strength of metal strips has the greatest impact on the lateral load capacities and stiffness of portal frame walls. The walls with metal strips installed placed directly on framing members outperformed the walls with metal strips placed over the sheathing. For walls with double bottom plates and two rows of nails fastened to the bottom plate, the stiffness and lateral load capacities are slightly increased compared to the walls with single bottom plate. For walls with sheathings joined at the middle of wall height and unblocked, the lateral load capacities are the same as the walls with continuous sheathings running from the bottom to the top of the walls. The stiffness is slightly lower. The two rows of nails along end studs do not affect the lateral load capacity of the portal frame walls. However, they do increase the stiffness of the walls.