18963818 presentation on wind on tank
TRANSCRIPT
![Page 1: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/1.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 1/19
API 2006 Storage Tank Conference
Tulsa, Oklahoma
Preparing Tanks for Hurricanes
Presented By:Ray Penny
Prepared By:
Steven L. Braune, PETank Industry Consultants, Inc.
Katrina at Landfall August 29, 2005
You own a bunch of tanksand there is a big storm coming……
![Page 2: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/2.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 2/19
Now what?
API Standard 650 has provisions
for addressing some of the stormrelated issues that affect storage
tanks.
Storage Tanks Vulnerabilities
• Wind Issues…
–Shell Buckling
–Tank Overturning
–Roof Damage
• Flooding Issues… – Floating Off of Foundation
–Shell Buckling
![Page 3: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/3.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 3/19
Wind Loads on Tanks
• API Standard 650 has specific
requirements for shell bucklingand tank overturning
• There are no requirements in the
current Standard that address roofdamage
Shell Buckling
• In general, new tanks are designed toresist wind speeds of 100 mph
• In the absence of an owner-specifiedwind speed, manufacturer may select
shell thicknesses only for liquid loads…and then report the permissible windspeed to the purchaser
![Page 4: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/4.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 4/19
API-650 Shell Stability
• Tank is most vulnerable when empty
• API procedures originated in early 1960s
• Methods based on uniform vacuum
analogy using the maximum windpressures on shell
Shell Buckling DuringConstruction
![Page 5: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/5.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 5/19
Shell Buckling When Empty
Shell Buckling After Loss ofRoof
![Page 6: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/6.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 6/19
![Page 7: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/7.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 7/19
Buckling on Windward Side
Storage
TankWind
Empty Tank Shell Stability
Diameter, D
Check permissible
unstiffened shell height,
H1
HH1
3
1)(000,600
= D
t t H
![Page 8: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/8.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 8/19
My Tank Engineer says…
• Tanks constructed to API-12C aregenerally resistant to wind buckling forwind speeds in the range of 95 to 120 mph
• Resistance to wind buckling varies fortanks constructed to API-650. The typicalwind speeds are in the range of 80 to 105mph
• Tank diameters up to 260’ and shellheights to 48’
What if shell is not stable for theexpected wind speed?
• Hope for the best (we can do better than that)
• Fill tank with product, if possible
• Partially fill tank
![Page 9: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/9.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 9/19
Add Product to Tank to Reduce
Risk of Shell Buckling
H1
Your Tank Engineer can
determine a recommended
product depth using API-650
principles
Wind Overturning
• Primarily a problem for small diametertanks that are empty
• Doesn’t happen often, but should beconsidered
• API-650 has simplified procedures toverify
![Page 10: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/10.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 10/19
1
Wind Overturning Loads
W
D
Overturning
Moment, M
Per API-650
M max = WD/2
(Tank Empty)
Tank Industry Consultants
Knocked Over Tanks
![Page 11: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/11.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 11/19
1
Tank Industry Consultants
Toppling of Small Diameter Tanks
Tank Toppling Speed
(40 ft High Tank)
0
50
100
150
200
0 10 20 30 40 50
Tank Diameter (ft)
W i n d V e l o c i t
( m p h )
Add Product to Tank toPrevent Overturning of
Unanchored Tanks
Your Tank Engineer can
determine a recommended
product depth
![Page 12: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/12.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 12/19
1
Fixed Roof Damage• Roof uplift pressure
will occasionallydamage tanks
• Roof -to-shell jointmay tear and “peel”away roof plate
• Roof structure may be
dislodged bydistortion of shell
Wind
Peeling Off of Roof Plate
![Page 13: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/13.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 13/19
1
Plate Pulled Off Tank Roof
Floating Roof Damage• Roof uplift pressure and
wind forces may causeponded water to “shift” ona floating roof.
• Unsymmetrical load maylead to roof structuralfailure
• Water may shift awayfrom location of roofdrains… overloads withwater may result
Wind
![Page 14: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/14.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 14/19
1
Floating Roof Damage
Rolling Ladder Damage
![Page 15: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/15.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 15/19
1
Tank Flotation
• Tanks are most vulnerable to floatationwhen empty
• Minimal flood depth required to float atank off of its foundation
• Wind may displace a floating tanklaterally
Dike FloodingFlood depths of less than
two feet will float most large
diameter storage tanks when
they are empty
![Page 16: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/16.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 16/19
1
AST Displaced by Flooding
ASTs Displaced by Flooding
![Page 17: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/17.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 17/19
1
ASTs Displaced by Flooding
Avoid Tank Flotation
Your Tank Engineer can
determine a recommended
product depth
![Page 18: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/18.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 18/19
1
Avoid Tank Flotation
If tank is empty and clean,
leave the shell manholes open
Shell Buckling Due to DikeFlooding
Water pressure may cause
collapse of the shell, if it is
empty and anchored
Your Tank Engineer candetermine a recommended
product depth
![Page 19: 18963818 Presentation on Wind on Tank](https://reader030.vdocuments.net/reader030/viewer/2022021215/577d34cd1a28ab3a6b8ee389/html5/thumbnails/19.jpg)
8/8/2019 18963818 Presentation on Wind on Tank
http://slidepdf.com/reader/full/18963818-presentation-on-wind-on-tank 19/19
Summary
• Design for the expected conditions (primarilywind)
• Maintain your tanks
• A well maintained tank will fair better than aragged tank.
• Add liquid to prevent flotation, overturning,wind buckling, & shell buckling from external
pressure (rising water)• A full tank will fair better than an empty tank.
QUESTIONS?
Steven L. Braune, P.E.
804-897-7176 office
804-897-7178 fax
804-307-5609 mobile