Lifting Trunnion Common Practices 1

[CW3]

I am looking for some direction in finding documentation regarding lifting trunnion design for pressure vessels. In particular, I'm trying to educate myself on the common practices involving lifting trunnions. My company generally utilizes lifting "lugs" when practical, however, we have a client whose spec requires "trunnions" on all vessels over 5 metric tonnes in weight. An example of one of their vessels is a 72"I.D. vessel, 20' long, approx. 56,000 lbs. with 16"-Sch80 trunnions. Reasonable or overkill? Now, this vessel will be hoisted onto an offshore rig from a barge and the lifting devices are to be designed with an impact factor of 4. Where can I go for information regarding good/standard engineering practice for lifting trunnions. I'm not doing the design on this project, I just want to gain some insight for my own piece of mind. Books? Website? Applicable ASME Code?

Thanks,
CW

 

[codeeng]

Pressure Vesssel Design Manual (Third Ed.) by Dennis Moss has a detailed section on lifting devices and design of same.

 

[LSThill]

TEMA MEMBER

LIFTING TRUNNION new release of CODEWARE COMPRESS.

CHAPTER 7
TRANSPORTATIONI AND ERECTION OF PRESSURE VESSELS, 365
Procedure 7-1: Transportation of Pressure Vessels, 365
Procedure 7-2: Erection of Pressure Vessels, 387
Procedure 7-3: Lifting Attachments and Terminology, 391
Procedure 7-4: Lifting Loads and Forces, 400
Procedure 7-5: Design of Tail Beams, Lugs, and Base Ring Details, 406
Procedure 7-6: Design of Top Head and Cone Lifting Lugs, 416
Procedure 7-7: Design of Flanges Lugs, 420
Procedure 7-8: Design of Trunnions, 431
Procedure 7-9: Local Loads in Shell Due to Erection Forces, 434
Procedure 7-10: Miscellaneous, 437

TECHNICAL NOTE:
EVALUATION OF LOAD UNDER ERECTION CONDITION
LIFTING TRUNNION
1. CALCULTIONOF LIFTINF FORCES
2. SUMMARY OF LIFTEING FORCES IN VARIOUS ANGES OF LIFTING (UNITS: kg, kg-mm)
3. MAX. FORCES SUMMARY AT TRUNNION AND TAILING LUG (KG)
4. STRENGTH OF TRUNNION LUG
4-1. GEOMETRIC AND MECHANICAL PROPERTIES OF TRUNNION
4-2. STRESS CALCULATIONS
4-4. WELDMENT STRENGTH (AT TRUNNION TO PAD)
4-5. WELDMENT STRENGH (AT PAD TO SHELL)
5. STRENGTH OF TAILING LUG
6. BASE BLOCK UNERR ERECTION CONDITION
6-1. SECTIONAL PRPERTIES OF BASE BLOCK
6-2. EFFECTIVE LENGTH OF SKIRT
6-3 SECTION AREA, A
6-4 CENTROID, C
6-5 MOMENT OF INERTIAL OF AREA, I
6-6 MIN. SECTION MODULUS, Z
6-7 STREESS IN BASE BLOCK DUE TO TV
a). BENDING MNENT (Ma) & TANGENTIAL FORCE (Ta) AT BASE BLOCK
CASE NO BRACING: ROARK 4th ED CASE 25

b). BENDING MNENT (Ma) & TANGENTIAL FORCE (Ta) AT BASE BLOCK
CASE five bracing; ROARK 4th ED CASE 24 & 25
5-8 STRESS CHECK AT BRECING
a) Max Loads at Tailing Lug
CASE FIVE BARCING
b). Max. Allowable Stress of tension Flange
c). Max Allowable Stress of Compression Flange (AICE Eq.1.5-7)

*Beam-1 (Assuming Bending +Tension)
1) Bending Moment (Mb), Bending Stress (Sb), Tensile Stress (St)
2) AISC Criteria’s Bending Moment (Mb), Bending Stress (Sb), Tensile Stress (St)

*Beam-2 (Assuming Bending +Tension)
1). Bending Moment (Mb), Bending Stress (Sb), Tensile Stress (St)
2). AISC Criteria’s Bending Moment (Mb), Bending Stress (Sb), Tensile Stress (St)

*Bear-3 (Assuming always Compression only)
1). Allowable Compressive Stress (Sba) (AISC EQ. 1.5-1,2)
2). Compressive Stress in Beam-3

MOMENT & SHEAR FORCE CALCULATION
[1] LIFTING TRUNNION
[2] LOAD
[3] REACTION FORCE
[4] RESULT

SHELL STRENGTH CALCULATION

LOCAL STRESS ANALYSIS BASED ON WRC-107
LIFTING TRUNNIION OD
LIFTING TRUNNIION OD + PAD
LIFTING TRUNNIION (0°)
LIFTING TRUNNIION (15°)
LIFTING TRUNNIION (30°)
LIFTING TRUNNIION (45°)
LIFTING TRUNNIION (60°)
LIFTING TRUNNIION (75°)
LIFTING TRUNNIION (90°)


Best Regards, Tokyo, Japan

 

[waskillywabbit]

I have the latest build (6247) of COMPRESS and I see NO lifting trunnion application for the program.



Brian

 

[MJCronin]

CW3...

Lifting trunions have a geometric advantage over "lugs" when lifting tall pressure vessels.

While most short tanks I have encountered use lifting lugs or ears, they do not require the more precise rotation enabled by two lifting trunions as a tall tower is lifted into place. (I am assuming that the trunion has a lubricated "wrap" of wire rope that slides along the surface as the lift is made)

Trunions are also typically more "robust" than lugs or ears, giving the client a warm feeling during the rigging and placement of his expensive equipment.

-My opinion only


-MJC

 

[CW3]

MJC,

I agree. We're just getting a lot of "deer in the headlight" looks from drafting and design on these in particular. I mean, 16", on a six-foot diameter shell does, indeed, look "robust". The calcs for shear, bending, and weld stresses are WELL within limits using an impact factor of 4. I was just trying to find some reference or source of information from which I can make some broad generalizations. Thanks for your input.

CW3

 

[LSThill]

Brian: waskillywabbit (Mechanical)

IS NOT RELEASED IN 6247

 

[waskillywabbit]

Isthill,

I've often wished COMPRESS did lifting trunniong calcs...so please, tell me where it is released or when it will be released? I was curious about your post so I spoke directly with CodeWare today via email and they said that COMPRESS has no lifting trunnion calculations and has no plans to incorporate it anytime soon.

I'd like to see it incorporated regardless.




Brian

 

[DSB123]

waskillywabbit,
Looks like you have done your homework and checked with the Software providers for Compress. Do you think lsthill has got it wrong or perhaps the software supplier does not know whats in his package??

 

[waskillywabbit]

DSB123,

I spoke with TomBarsh...straight from CodeWare COMPRESS...so I would think he would be in the know.


Brian

 

[arto]

How about swivel hoist rings:

http://americandrillbushing.com/eztorque.htm

they go up to 250000#

 

[pennpoint]

Back in the early 1970's I was involved in lifting vessels of various types and attachaments for a top rated design build firm. Top Flange mounts were really neat, simple, but still scary. Saddle clips with spreader bar were more confortable. Hince, I've been so far removed from this technology in the last 30 years or so I can only comment that you should be clear upon the bending moments of the top flange attachment trunnion if thats your lift point. Otherwise investigate the shell at truncation and spreader bar which seemed to be far safer. Calculate for buckling of shell at mid length points along the vessel and skirt buckling. Be sure not to just drag the skirt of the vessel along the grade, have a skirt ring support along with a cherry picker (crane) of capacity to follow in to the vertical position. Should I add that you must have very stable soil during the erection process of any vessel if not you must provide ample dunnage.

Best regards
pennpoint

 

[LSThill]

REFERENCE PAPER:

Reference to ASME PAPER in the Note Book for Professional Development Pressure Vessel ASME South Texas Section Design of LIFTING AND TAILING LUGS/ LIFTING TRUNNION. (1998) Reference (Bechtel)