大悬臂钢-混凝土组合脊骨梁扭转效应分析

TORSIONAL EFFECTS OF STEEL-CONCRETE COMPOSITE SPINE GIRDER WITH LONG CANTILEVER FLANGES

带波形钢腹板大悬臂挑梁的组合脊骨梁在偏载作用下的扭转效应十分明显。该文提出了组合脊骨梁扭转效应的分析模型和考虑大悬臂翼板影响的乌氏第二定理计算方法,并利用模型试验和空间有限元分析对理论计算方法进行验证,三种方法所得到的结果对比表明:提出的理论计算方法能够满足工程精度要求、结果偏于安全。进一步的计算分析表明,偏载作用下组合脊骨梁的翘曲正应力和扭转附加剪应力所占弯曲应力的比例较大,结构扭转计算时考虑大悬臂的影响更为合理,设计时应以单点扭矩的加载方式来进行扭转验算,组合脊骨梁的畸变应力较小,可以不予考虑。

Under eccentric loads, the torsional effects of steel-concrete composite spine girder with long flanges supported by cantilever beams with corrugated webs （SCCSG） are significant. An analytical model and a calculation method are proposed in this study, which are based on the Second Theory of A.A.Umanskii for the torsional behaviors of the SCCSG structure considering the influence of the cantilever flanges. The theoretical calculation method is verified through an experimental test and spatial finite element （FEM） analysis. The comparison of results from theory, test and FEM indicates that the analytical model and theoretical method can generate conservative results satisfying design requirement. The further investigation shows that 1） The warping stress and the additional torsion shear stress of the SCCSG structure contribute a large proportion of the total flexural stress, and should be taken into account in engineering design; 2） It is more reasonable to consider the influence of cantilever flanges for torsion analysis; 3） Single-point twist moment should be used as loading pattern for torsion checking of structural design; 4） The distortional stresses of composite spine girder are negligible.