大型储罐底圈罐壁轴向应力的计算

Calculation of axial stress for the bottom shell of large-scale storage tank

为了便于钢制焊接储罐设计人员合理地选取设计规范进行储罐罐壁抗震计算,简要介绍了储罐设计规范GB 50341-2003、API 650-2013中底圈罐壁最大轴向应力和底圈罐壁许用临界应力的计算方法。分别对15×104 m3、10×104 m3双盘式浮顶油罐进行了底圈罐壁最大轴向应力、底圈罐壁许用临界应力的计算,结果表明:在计算底圈罐壁最大轴向应力时,GB 50341-2003与API 650-2013的计算结果相同;GB 50341-2003与API 650-2013在计算底圈罐壁许用临界应力方面都是安全的,但GB 50341-2003在确定罐壁许用临界应力方面相对保守。GB 50341-2003与API 650-2013中罐壁许用临界应力的计算公式可用一个公式来代替,当底圈罐壁最大轴向应力不大于底圈罐壁许用临界应力时,储罐底圈罐壁在地震作用下是安全的。

In order to facilitate the designers of welded steel tanks to calculate the seismic performance of tank wall through choosing appropriate design codes, this paper presents the calculation methods of maximum axial stress and allowable critical stress of bottom shell under GB 50341 2003 and API 650-2013. Taking the 15×10^4 m^3 and 10×10^4 m^3 dual-disc floating roof tanks as an examples, the maximum axial stress and allowable critical stress of bottom shell are respectively calculated. The results show that the maximum axial stress calculated by the method mentioned in GB 50341-2003 is the same as that of API 650-2013; both GB 50341-2003 and API 650-2013 are applicable for allowable critical stresses, but GB 50341-2003 is conservative in the calculation. The formulas for allowable critical stresses in GB 50341-2003 and API 650- 2013 can be replaced by one formula. When the maximum axial stress is not greater than the allowable critical stress, the bottom shell of tank is safe under the earthquake. （3 Tables, 10 References）