全装配式桁架檩条力学性能试验研究

EXPERIMENTAL RESEARCH ON MECHANICAL PROPERTIES OF TOTAL-PREFABRICATED TRUSS PURLIN

针对螺栓连接装配式桁架檩条的力学性能,进行了7组不同工况的足尺静力加载试验,研究压力及风吸力作用下结构的荷载-位移、荷载-应变等变化规律,分析各部件的工作机理及破坏形式。结果表明:装配式桁架檩条的试验破坏模式与理论破坏模式基本一致,但其试验承载能力明显高于理论值,且构件挠度试验值也远大于理论值;压力荷载作用下弦杆和腹杆螺栓连接节点强度不足是导致试件破坏的主要原因,而风吸力作用下试件的主要破坏原因是下弦杆的局部受压承载力不足。建议实际设计中,对螺栓连接节点进行改进以增加其刚度或对檩条整体刚度进行适当折减,并适当增大端腹杆截面,提高其承载能力。

For the mechanical properties of total-prefabricated truss purlins, 7 full-scale static loading experiments of different working conditions were designed and carried out. The relations of load-displacement, load-strain of the structure under pressure load and wind suction were studied. The working mechanism and damage mode of each specimen were analyzed. It was shown that the experimental failure mode of the total-prefabricated truss purlin was basically the same as the theoretical failure mode, but its experimental bearing capacity was obviously higher than the theoretical value. The experimental deflection value was also much larger than the theoretical value. The main reason of the failure of the specimen under the pressure load was the insufficient strength of the joint between the chord and the web member. The main failure reason of the specimen under wind suction was the insufficiency of the local compressive capacity of the lower chord. It was suggested that the bolt joint should be improved to increase its stiffness, or the overall stiffness of the truss purlin should be reduced properly. At the same time, the bearing capacity of the end web member should be increased appropriately by enlarging cross-section.