几何尺寸与公差论坛------致力于产品几何量公差标准GD&T (GDT:ASME)|New GPS(ISO)研究/CAD设计/CAM加工/CMM测量 - 查看单个帖子

rafters and columns required.
in the designing of water storage tank, is there a rule or method of determining if its necessary, to use columns and rafters?. i have a tank with 16 feet x 23 feet and a conical "self supported" roof of 3/16" thick, and a tan 20º of slope.
thanks.
check out our whitepaper library.
api-650 gives a formula for thickness of a self-supporting cone roof as t = d/(400 sin(theta)), where theta is the slope angle. with your tank dimensions, a self-supporting cone roof of 3/16" would work okay. this assumes dead+snow load of 45 psf or less.
this equation is in api-650 but is commonly applied to awwa tanks as well. it can generally be shown that roofs meeting this requirement will comply with the compressive stress formulas of awwa as well.

2009-09-15, 04:14 PM	#1
huangyhg 超级版主注册日期: 04-03 帖子: 18592 精华: 36 现金: 249466 标准币资产: 1080358888 标准币	rafters and columns required rafters and columns required. in the designing of water storage tank, is there a rule or method of determining if its necessary, to use columns and rafters?. i have a tank with 16 feet x 23 feet and a conical "self supported" roof of 3/16" thick, and a tan 20º of slope. thanks. check out our whitepaper library. api-650 gives a formula for thickness of a self-supporting cone roof as t = d/(400 sin(theta)), where theta is the slope angle. with your tank dimensions, a self-supporting cone roof of 3/16" would work okay. this assumes dead+snow load of 45 psf or less. this equation is in api-650 but is commonly applied to awwa tanks as well. it can generally be shown that roofs meeting this requirement will comply with the compressive stress formulas of awwa as well. __________________ 借用达朗贝尔的名言：前进吧，你会得到信心! [url="http://www.dimcax.com"]几何尺寸与公差标准[/url]