塔式起重机塔身和起重臂的风载荷特征分析

Wind load characteristics analysis of mast and jib of tower crane

定义风载荷系数表达式,完成塔机在均匀风场和B类风场下12个风向角的计算流体力学(CFD)数值计算,得到塔身和起重臂的体型系数、角度风系数和风压高度变化系数,并与国内外规范进行对比.结果表明:不同风向角下,塔身横风向风载荷可以忽略,而起重臂的横向风载荷必须考虑;塔身角度风系数计算方法与欧洲钢结构设计规范一致,但与我国起重机设计规范相差较大,建议以欧洲规范定义塔身角度风系数;塔身和起重臂角度风系数对风场特征不敏感;塔机气动外形的影响使得风压高度变化系数在不同风向角下不一致并表现出放大效应.塔机抗风设计可参考风载荷系数参数特征.

The expression of wind load coefficient was defined.The computational fluid dynamics(CFD)numerical simulation of the tower crane in twelve wind angles under uniform and B category flow field was completed.The shape coefficient,the skewed wind coefficient and the wind pressure height coefficient of the tower mast and jib were calculated and compared with the design of different countries.Results show that the crosswind load of mast could be ignored under different wind angles,while the wind load of jib must be considered;the calculation method of the skewed wind coefficient for the mast is consistent with the design of steel structures in European standard,while it differs greatly with the design rules for cranes of China,thus it is effective to define the skewed wind coefficient of mast by the European standard;the skewed wind coefficient of the jib and mast is not sensitive to the different categories of wind flow fields;the influence of the aerodynamic shape of the tower crane makes the wind pressure height coefficient inconsistent under different wind direction angles,showing the amplification effect.The characteristics of the wind load coefficient can provide reference to the wind-resistant design.