Yes, it is basically a "giant pontoon". The IFC manufacturer claims that that it is designed for a buoyancy 5 times of that required by API 650. There is nothing inside the panels, other than aluminum extrusions to provide support. These are NOT honeycomb sandwich panels.
Jorge, Jr.
The IFC is made of aluminum 3003. Panels are hollow with a 0.023" thick skin, no honeycomb style. Prior to fill the tanks with gasoline, client insisted on hydrotesting the tanks once the IFC were installed. They were in contact with water for more than 60 days, from filling up to emptying...
The ATG and gauging cone penetrations are at 36" from the tank wall. Both are at 180 deg. apart. Here's the IFC section drawing. The panels are actually less than 4" thick. Jamming by an obstruction is hardly possible, but by thermal expansion could be a possibility.
Jorge, Jr.
Hi ALl,
We recently installed internal floating roofs (IFR) of the full-contact type in two new 150,000 bbl. regular gasoline tanks (145' diam. by 56'high). The IFRs were hydro tested per the request of the client. They were floated to the tanks critical height with successful results...
We are rehabilitating a tank as per API 653 and when the door sheet (cut by others) was re-installed, the welding produced a localized deformation (banding) on the top horizontal seam of the door sheet of 3/4". The project inspector claims that the banding should be not more than 1/2" as per API...
Adding a repad around the anchor chair is an economic alternative to increasing the fisrt shell ring size. I have a tank in which the fisrt shell ring is 1/4" thick. If I were to increas it's thickness to comply with the 25,000 psi requiremeent, I would need to increase it to 5/8".
Jorge L...
Shahin71,
I have had the same question. I'm still looking for a good reference that will direct me in the design of these repads. CHeck out this thread I posted a long time ago.
http://www.eng-tips.com/viewthread.cfm?qid=180411&page=1
Jorge L. Ramos, Jr., MSCE, PE
Alonso & Carus Iron...
Thank you all for your replies. When I present this situation to the owners/designers, the most common response we are getting is "use UBC 1997 requirements." But, my engineeering judgement always tell me to use the the current design standard (API 650 Ed. 11th or AWWA D100-05) and that's waht...
I have come across this situation many times lately and I would like to hear your opinion. Most of the designers, when writing specs for steel tanks, use "generic" specs just becasue they are not familar with API 650 or AWWA D100-05 Standards. When specifying the seimic design requirements...
Per Appendix E, the tank must be anchored.
Jorge L. Ramos, Jr., MSCE, PE
Alonso & Carus Iron Works, Inc. (www.alonsocarus.com)
Euro-American Steel Co., Inc. (www.euroamericansteel.com)
I'm currently designing an API 650 tank to Appendix E. This tank will be set on top of and existing conrete base. The client is proposing the use of HAS rods with an epoxy adhesive (no welded nut nor hooked). However, section E.7.1.2 states that anchorage systems based solely on bond fricton...
I'm currently using ITS Design, which is pretty easy to use, plus it includes Add. 4. In a few weeks they will issue the AWWA D100-05 module. We also have ETank, but it has not been updated to App. 4. Regardless of the software you choose, you need to be familiar with the code to be able to...
I wonder why API 650 App. 4 did not include the same table as in ASCE 7-05. Why have they chosen to left out the condition for SDS >= 0.5g? Does anyone know?
Jorge L. Ramos, Jr., MSCE, PE
Alonso & Carus Iron Works, Inc. (www.alonsocarus.com)
Euro-American Steel Co., Inc...
What reference/book can I use to design the repad?
Jorge L. Ramos, Jr., MSCE, PE
Alonso & Carus Iron Works, Inc. (www.alonsocarus.com)
Euro-American Steel Co., Inc. (www.euroamericansteel.com)
Thanks JStephen. I checked teh ASCE 7-05 and you are correct.
Jorge, Jr.
Jorge L. Ramos, Jr., MSCE, PE
Alonso & Carus Iron Works, Inc. (www.alonsocarus.com)
Euro-American Steel Co., Inc. (www.euroamericansteel.com)
doct9960,
Thanks for the reply. However, the last column on Table 3-21b clearly states that the allowable shell stress at the anchor attachment is 25,000 psi when seismic loads are considered. This is the stress occurring just above the top of the chair. I'll check with ASME Section VIII...
When designing the anchor chairs in the API 650 tank that I'm currently designing, the stress in the shell (around the anchor chair location) exceeds the allowable stress (25,000 psi, per Table 3-21b). Options to decrease the stress are to increase the shell thickness, add more bolts or...
Hi,
I'm currently designing an API 650 tank that has been assigned to SUG I. Per Table E-7, the minimum required freeboard is 0.7d if SDS < 0.5g. What happens if SDS >= 0.5g? The table does not specify what to use if SDS >= 0.5g. Should the freeboard be equal to the wave height should this...