新型套扣式钢管脚手架节点的水平向抗压性能

Horizontal Compressive Capacity of the Joints for the New Type Nested Steel Tubular Scaffold

相比传统脚手架,新型套扣式钢管脚手架在安全、经济和便利上具有优势,但因相关理论研究尚不完备,从而影响了其进一步推广使用.文中以该新型套扣式钢管脚手架节点为对象,进行了3种不同工况下的水平受压承载力试验研究和有限元分析.结果表明:试验数据与有限元模拟值基本一致,3种工况下随着水平受压荷载的增大,套扣节点的变形均线性增加,随后节点受压屈服,表现出明显的非线性特征;其中节点在单向受压和双向非对称受压下破坏形式表现为立杆弯曲破坏和钢管截面压瘪,而双向对称受压下为节点处立杆钢管压瘪,水平杆端接头与十字套扣连接松动;表明节点的抗压刚度和受压承载能力与其受荷方式直接相关.在此基础上,对节点的抗压参数进行了系统分析,得出立杆长度对节点受压承载力影响最大,而十字套扣、水平杆端接头厚度的影响很小.由此,提出了基于立杆长度的节点水平向抗压刚度模型.

The new type nested steel tubular scaffold has advantage in safety,cost and convenience compared with traditional scaffolds,but its lack of theoretical research hinders its promotion and further application.Experimental research and finite element analysis of horizontal compressive loading cases under three different working conditions were carried out,with the joints of the new type nested steel tubular scaffold as the studying objects.The research shows that the experiment results and finite element simulation results are basically consistent.And along with the increasing of horizontal loading,the displacements of joints in all three cases increase linearly first,but later on they performs obvious nonlinearity as soon as the yield of joints appear.The failure modes of axial compression and biaxial asymmetric compression are bending failure and squashed section of standing tube.As for biaxial symmetrical compression,the failure mode is squashed section of standing tube and loose connection between wedge head of ledger and cruciform nested socket.Therefore,the compressive stiffness and compressive capacity of the joint depend on the loading method.On this basis,pressure resistance parameter of the joint was systematically analyzed.The result shows that the most influential factor is the length of standing tube,while the thicknesses of wedge head of ledger and cruciform nested socket have less influence.Thus the compressive stiffness model in term of the length of standing tube was presented.