剖分T-型钢三角形钢屋架的次应力分析

Secondary Stress Analysises on Triangular Steel Truss with Hot-rolled Cut-T-section Chord

编制国家标准图集06SG517—2时,弦杆采用剖分T型钢。与弦杆采用角钢的屋架相比,采用剖分T型钢比较经济。采用ANSYS有限元分析软件,分析了弦杆采用剖分T型钢时,杆件之间刚性连接时次应力的影响。结果表明,上弦杆的次应力较大。出于安全考虑,设计时需要计及次应力的影响。对于下弦杆,次应力的最大值均不超过主应力的20%,影响较小,设计时可不考虑。腹杆虽次应力较大,但设计时规范考虑了单角钢单面连接强度折减,设计时也无需考虑。

Cut-T-section chords were adopted when compiling the national standard of architecture drawing 06SG517—2.It is more economical comparing with chord adapting angle section steel.The effect of secondary stress with hot-rolled cut-T section chords is analyzed when the connection is rigid by software ANSYS.The results show that the secondary stress of upper chord located isbigger and it should be considered in design due to the safety.As the end panel of chord controlled the design of upper chord due to the largest axial force in this panel and the same section of all panels,so the effect of secondary stress is not remarkable.For lower chord,the maximum secondary stress is less than 20 percent of the primary stress and the effect is small.The secondary stress of web member is not considered despite it is relatively large because the code considered strength reduction when single-angle section adopted with one leg connection.