交错桁架延性段双槽钢组合截面弦杆往复弯曲性能试验研究

Experimental study on behavior of steel double-channel built-up chords of special staggered truss steel frame structure under cyclic loads

为研究交错桁架钢框架结构中采用双槽钢组合截面的桁架弦杆延性区段的抗震性能,对8个双槽钢组合截面足尺试件进行往复弯曲荷载作用下的滞回性能试验。重点研究了填板间距、侧向支撑设置、加劲肋设置等因素对该类型截面构件滞回性能的影响。试验结果表明:减小填板间距可减小单肢槽钢平面外长细比,防止组合截面试件发生单肢槽钢失稳,保证双肢槽钢共同工作;塑性铰处设置侧向支撑可有效限制塑性铰区域槽钢发生平面外变形,保证试件不发生整体弯扭失稳,提高构件耗能能力;在塑性铰区域设置加劲肋可限制板件的局部屈曲,保证试件在循环加载过程中的耗能机制为"屈服耗能",提高构件的耗能及转动能力。研究成果可为交错桁架钢框架中双槽钢组合截面桁架弦杆的工程应用提供参考。

In order to study the seismic behavior of the special segment when the chords of special staggered truss steel frame structure use double-channel built-up members, quasi-static tests on eight full-scale double-channel built-up members under reversed cyclic bending were conducted. The main parameters were stitch spacing, lateral support settings and stiffener settings. Experimental results indicate that the reduction of stitch spacing can reduce out-of-plane slenderness ratio of the individual channel, preventing lateral-torsional buckling of the individual channel, thus can make sure that the two channels work together. The lateral support adjacent to the plastic hinge region is very effective in restricting out-of-plane deformation of channels at the plastic hinge region, and preventing the lateral-torsional buckling of the member, thus can improve energy dissipation capacity of the member. Stiffeners which are located at the plastic hinge region can fully eliminate local buckling of plates, and the member yields and dissipates energy instead of buckling, thus leads to some increases in energy dissipation capacity and rotation capacity of members. The study enriches the achievements on the seismic behavior of special staggered truss steel frame structure, and also offers reference for other engineering applications of double-channel built-up members.