建筑索结构销轴耳板连接节点承载力试验研究和有限元分析

Experimental study and finite element analysis on bearing capacity of pin-connected plate joints

建筑结构中的拉索常采用热铸锚具,通过单耳式或叉耳式连接件与结构耳板销轴连接。而索节点破坏将造成拉索失效,甚至结构连续性倒塌。目前,各国标准中关于销轴连接耳板承载力的计算存在较大差异,中国标准主要参照欧洲标准,但内容尚不完善。为研究若干关键尺寸对耳板承载力的影响,对销接耳板进行单轴拉伸试验,并采用CEN双折线法求得试件承载力;采用弹塑性实体模型进行有限元分析,得到耳板应力分布基本规律。结果表明:耳板端距和中截面单宽与耳板承载力正相关;加焊贴板能有效增强耳板承载能力;耳板应力分布较不均匀,当耳板破坏时远离销孔的材料强度并未得到充分利用。与试验结果对比所得,中国标准的销接耳板承载力计算较为保守,因此在净截面受拉承载力和端部抗劈拉承载力的计算式中提出了有效宽度和有效端距的建议值,并考虑了增焊贴板的作用。

In cable structures, hot-cast anchors used for cable ends are often connected to single-ear or fork-ear connectors by pin shafts. Failure of the cable joints will cause the failure of cable and even progressive collapse of the entire structure. At present, there are differences in the calculating the bearing capacity of pin-connected plate in different countries. The domestic code generally follows the European standard, and the content has yet to be completed. Through the uniaxial tensile test, the CEN double-fold line method was used to obtain the bearing capacity of the ear plates. Nonlinear finite element analysis was also used to obtain the basic law of stress distribution of the ear plates. The results show that: the end-part distance and the mid-section side-width ware positively correlated with the bearing capacity of the ear plate;and welding plates can significantly enhance the bearing capacity of the ear plate;the stress distribution of the ear plate is very uneven, and the material strength away from the pin hole is not fully utilized when the ear plate is damaged. Compared with the experimental results, the design prediction of the strength of the pin-connected ear plate given by the domestic code is too conservative. Consequently, recommended values of effective width and effective end-distance were proposed in the formula of tensile capacity and splitting tensile capacity. Moreover, the formulas of tensile capacity and splitting tensile capacity for the mid-section were proposed as well when welding plates were added.