新型轻钢龙骨体系桁架梁承载力试验研究

Experimental Research on Truss Beam Carrying Capacities of New Type of Light-gauge Steel System

根据12根无比钢桁架梁的承载力试验,获得了典型桁架梁在竖向荷载作用下的极限承载能力、破坏模态及抗弯刚度。无比钢桁架梁的极限承载力和竖向抗弯刚度均较小,跨中弯矩-应变基本呈直线关系。在进行设计时,应加密布置,加大受压上弦杆的截面型号,放宽梁刚度的限制数值。该体系的破坏一般经历局部破坏和整体失稳2个阶段:前者包括V型连接件局部屈曲和自攻螺丝被剪坏2种情况,可分别通过增加V型连接件的数量或自攻螺丝的直径或数量加以解决。

Based on the tests of 12 web steel truss beams, the carrying capacities, failure modes and bending rigidities of the typical truss be.ams were provided. Both the carrying capacities and bending rigidities of web steel truss beams were low. When designing web steel, the truss beams should be arranged tightly, and the allowable deflection should be loose. For the compressive chords in the truss beams, the tubes with bigger section sizes should be used. In the course of loading, the equivalent bending rigidities of the truss beam samples had small changes, while the relationships between the moments and stresses at the middle spans were generally linear. The obtained equivalent bending rigidities base on the two-point loading tests were the simplifying calculation basis of the web steel walls. The failure process of the web steel truss beam can be divided into local failures and total buckling. The local failures include the buckling at the end of V-shape clips and shear failure of the self tapping .screws, which can be avoided separately by increasing the amount of V-shape clips at two ends of the truss beams and the number or diameter of the self tapping screws.