Rafter and girder support and location
Rafter and girder support and location
(OP)
I am designing a steel tank of supported cone roof without column which dia is 16 m and height 12m.According to API 650 this tank requires 2 rings of rafters. No. of outer rafters and inner rafters are 28 and 16 respectly.My question is how 2 rings of different types of rafters and girders are supported if no column.Can anyone explain as I am new in this field?





RE: Rafter and girder support and location
RE: Rafter and girder support and location
Thanks for your feedback.I misunderstood the section 3.10.4.4 which refer spacing of outer ring and inner ring.
Is there any girder required to support rafters without colomn and if required how rafter and girder are arranged-slope to roof plate or horizontally?
If with column,is there any girder required and how girder is arranged(slope to roof plate or horizontally)?
Thanks
RE: Rafter and girder support and location
RE: Rafter and girder support and location
Can I use truss at roof instead of rafter at a slope of 3/32(.75 m height at centre)in case no column.
RE: Rafter and girder support and location
RE: Rafter and girder support and location
Normally, the general tank configuration is specified by the tank owner or their engineering consultants, and the details are furnished by the tank construction firm. If you are working for the tank owner or their consultant, all you really need to specify is a "fixed roof" and let the actual tank designer work out the details. If you are the tank designer working out the details, I would suggest you have somebody more knowledgeable do the design and also get a lot of input from the people that will be fabricating and erecting the tank. There are a lot of details in API-650 that are easy to overlook if you are not familiar with the standard and with common tank construction methods. And a lot of the details that are not specified by the standard are chosen to make the work easier or quicker or safer. For a tank company, it is advantageous to use similar detailing from tank to tank as well.