输电塔角钢单排螺栓抗剪连接承载力中外规范差异研究

Research on the difference between Chinese and foreign norms in the bearing capacity of single-row bolt shear connection of transmission tower angle steel

螺栓连接是输电塔角钢节点设计的重要连接方式,其连接部分的承载力直接影响输电塔整体承载性能。螺栓连接共有五种破坏形式,分别是孔壁承压破坏、块剪破坏、角钢净截面拉断破坏、螺栓杆剪断破坏及螺栓杆弯曲破坏。影响螺栓连接承载力的主要因素有:角钢材质、角钢规格、螺栓等级、螺栓直径以及螺栓端距、间距及边距等。中外规范对于输电塔角钢螺栓连接节点设计存在差异性,主要体现在螺栓端距、中心距及边距的规定上。以单排螺栓连接为例,主要研究螺栓端距、间距及边距对螺栓连接承载力影响这方面中外规范的差异,并为工程实际应用提供参考。结果表明:欧标对于螺栓端距、间距和边距规定最小值比中标及美标规范要小,设计方法更具有经济性。中国规范未直接体现螺栓端距、间距和边距对螺栓连接承载力影响,美国规范将螺栓端距作为直接影响螺栓连接承载力的重要因素,欧洲规范将螺栓端距、间距和边距作为承载力系数的影响因子对螺栓连接承载力产生影响。

Bolted connection is an important connection method for the design of the angle steel node of the transmission tower, and the bearing capacity of the connecting part directly affects the overall bearing performance of the transmission tower. There are five types of bolted connection, namely hole wall pressure failure, block shear damage, angle steel net section pull failure, bolt rod shear failure and bolt rod bending failure. The main factors affecting the bearing capacity of bolted joints are: angle steel material, angle steel specifications, bolt grade, bolt diameter and bolt end spacing, spacing and margins. There are differences between Chinese and foreign specifications for the design of bolted joint nodes in transmission tower angles, which are mainly reflected in the provisions of bolt pitch, center spacing and margin. Taking a single row of bolted connections as an example, this paper mainly studies the differences between Chinese and foreign specifications in terms of the impact of bolted end spacing, spacing and margins on the bearing capacity of bolted connections, and provides reference for practical applications of the project. The results show that the minimum value specified by the European standard for the bolt end spacing, spacing and margin is smaller than that of the winning bid and the American standard specification, and the design method is more economical. The Chinese specification does not directly reflect the impact of bolt pitch, spacing and margin on the bearing capacity of bolted connections, the United States specifications take bolt end spacing as an important factor that directly affects the bearing capacity of bolted connections, and European norms use bolt spacing, spacing and margins as the influencing factors of bearing capacity coefficients to affect the bearing capacity of bolted connections.