风荷载作用下圆形三开孔烟囱的受力性能研究

Study on the performance of the chimney with three circular holes under wind load

随着工艺发展,国内一些发电厂将多台火力发电机共用1座烟囱或将输煤栈桥从烟囱中穿过,这导致烟囱外筒在同一截面处开设多于2个孔道。对于此类烟囱外筒,我国现行《烟囱设计规范》(GB 50051—2013)中并未有相关设计规定。本文依托实际工程,以钢筋混凝土烟囱有限元模型为研究对象,在模型同一水平截面处设置了3个圆形孔,以孔洞角、孔洞中心标高和风向角为参数,研究了在风荷载作用下各参数对烟囱外筒结构受力性能的影响规律。研究结果表明:外筒结构的混凝土最大等效应力和结构最大水平位移随孔洞角的增大而增大,孔洞中心标高为10 m、25 m和40 m,且孔洞角分别达到70°、70°和80°时,混凝土发生破坏;当孔洞角分别为30°、50°与70°时,改变孔洞中心标高,模型中的混凝土均未发生破坏,且环向钢筋与纵向钢筋均未屈服;改变风向角对模型受力性能影响不显著;当烟囱孔洞角不超过70°时,可以采用在孔洞处设置环向钢筋和纵向钢筋的方法对孔洞进行补强。最后,基于分析结果,给出了相关设计建议,以供类似工程参考。

In some power plants,several power generators using one chimney and coal transporting trestles going through the chimney are normal,which may result in more than two holes being set up at the same horizontal cross section in the chimney.However,there are no design requirements for these chimneys in Code for design of chimneys(GB 50051—2013)in China.In this paper,the finite element model(FEM)of the practical RC chimney was established and three circular holes were carried out at the same horizontal cross section.The circular holes angles,elevations and direction wind angles were considered as the parameters to study their effects to the performance of the FEM under wind load.The results indicated that the stress of concrete and horizontal displacement of FEM increased with the increment of the rectangular hole angles.When the hole elevations were 10 m,25 m and 40 m,the concrete damaged when the hole angles reached 70°,70°and 80°,respectively.When the hole angles were 30°,50°and 70°,respectively,changing the hole elevations did not result in the concrete and rebars in the FEM.The different direction wind angles had no obvious effect to the performance of the FEM.The annular and longitudinal rebars can be considered to reinforce the holes in chimney.Finally,some design suggestions were given based on the finite element analysis results.