钢管火炬塔架设计中径厚比限值对用钢量的影响

火炬塔架抗震设计标准给出的钢管径厚比限值远小于非抗震要求的限值。然而,通常情况下火炬塔架设计的控制荷载是风荷载,是否仍然需要满足抗震规范径厚比限制要求缺乏足够的研究。本文以某150m高火炬塔实际工程为背景,考虑常用基本风压情况,分别按抗风和抗震要求的径厚比确定构件,比较满足抗风设计与抗震设计要求时用钢量的差别,并找出对应的大震作用下处于弹性状态的设防烈度。分析结果表明,在基本风压不大于0.55 MPa时,按抗风要求径厚比确定的构件比按抗震要求确定的构件可节省用钢量20%左右,且在7度设防烈度大震作用下,塔架可保持在弹性范围;基本风压超过0.55 MPa后,径厚比改变对用钢量的影响不明显。综合考虑,火炬塔架设计宜先以抗风要求为主进行优化设计,然后进行抗震验算。

Influence of Diameter Thickness to Steel Quantity Ratio in the Design of Circular Steel Tube Torch Tower

The diameter thickness ratio （DTR） of circular steel tube according to the anti-seismic design standard for torch towers is far smaller than the value according to the non-seismic＂ design standard. However, the design of circular steel tube torch tower is always controlled by wind load, and no sufficient research have been carried out about whether the anti-seismic DTR have to be met in this condition. Based on the 150m high actual project, considering common basic wind pressure, choosing members according to anti-seismic design standard and non-seismic design standard respectively, the difference of steel consumption and the large fortify intensity under which the torch tower retains in elastic status are analyzed. The analytical outcomes indicate that as long as the basic wind pressure not larger than 0.55 MPa, the steel consumption according to the non-seismic design standard is smaller average 20% than that according to the anti-seismic design standard and the torch tower retains in elastic status under large 7 degree fortify intensity ; if the basic wind pressure larger than O. 55 MPa, altering DTR do not affect the steel consumption evidently. Synthetically taking into account torch towers should be designed according to anti-wind load design standard at first and then checked again according to the anti-seismic design standard.