拼合式带翼缘冷弯薄壁型钢十字形构件抗扭刚度试验研究  

Experiment on Torsional Stiffness of Built-up Cold-Formed Thin-Walled Steel Cruciform Members

作　　者：白清夫 宋振森[1,2] 缪其亮 BAI Qingfu;SONG Zhensen;MIAO Qiliang(School of Ocean and Civil Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure,Shanghai 200240,China)

机构地区：[1]上海交通大学船舶海洋与建筑工程学院,上海200240 [2]上海市公共建筑和基础设施数字化运维重点实验室,上海200240

出　　处：《建筑钢结构进展》2024年第5期84-92,共9页Progress in Steel Building Structures

摘　　要：拼合式带翼缘冷弯薄壁型钢十字形构件在轴心压力作用下的主要破坏形式为扭转失稳,其扭转失稳极限承载力取决于抗扭刚度,而拼合效应对构件抗扭刚度的影响没有明确的计算方法。为研究拼合式带翼缘十字形构件的抗扭性能及拼合效应对抗扭刚度的影响,对10个不同截面尺寸和拼合螺栓分布的带翼缘十字形冷弯薄壁构件进行了扭转试验,得到扭转全过程的扭矩-转角曲线和扭矩-应变曲线。设计了专用加载装置使构件在加载初期发生自由扭转,据此得到该拼合构件的自由扭转刚度。试验结果表明:减小螺栓间距能增强拼合效应,对于单列螺栓构件,螺栓间距的变化对拼合效应的影响更明显;拼合效应主要作用于构件的腹板,腹板尺寸增大,单位面积的螺栓数量减少,拼合效应对抗扭刚度的贡献相对减少;相较于非拼合构件,拼合构件抗扭刚度的提升可能是因为螺栓在一定程度上约束了相邻腹板的相对翘曲,提升程度可能与拼合节点间腹板的翘曲刚度有关。Torsional buckling is the dominant failure mode when built-up cold-formed thin-walled steel cruciform members are subjected to axial compression load.Its ultimate bearing capacity depends on the torsional stiffness,while there is no acknowledged method to take account of the built-up effect on torsional stiffness up-to-date.In order to study the torsional behavior and built-up effect on torsional stiffness of built-up cold-formed thin-walled cruciform members,a total of 10 specimens with different cross-section parameters and bolt distributions were designed and tested under torsion.Torque-angular displacement curves and the torsion-strain curves are fully obtained during the whole testing process.A specifically designed loading adapter was fabricated to allow the free torsion to be achieved at the first loading stage,and the free torsional stiffness of each specimen was derived accordingly.The test results indicate that the built-up effect increases while the bolt space decreases,and the influence on the built-up effect is more significant on specimens with one row of bolts than those with two rows of bolts.The builtup effect is primarily dependent on the cross-section web rather than the flange;increasement of web height leads to fewer bolts per unit area,resulting in the decrease of the proportion of torsional stiffness increased by built-up effect;compared with separate members,the enhancement in torsional stiffness of the built-up members is achieved probably due to that the relative warping of adjacent webs is to some extent restricted,and could be related to the warping stiffness of the web between bolts.

关 键 词：扭转试验 冷弯薄壁型钢 十字形构件 自由扭转刚度 拼合效应 

分 类 号：TU391[建筑科学—结构工程]