Shipping Spiders
Shipping Spiders
(OP)
Can anyone recommend a resource for the design of shipping spiders? Anyone have some rules of thumb? Or even a go by?
My vessel's D/t approaches 150.
A previous tower of similar size arrived out of round after road shipment, even with weld-in rings every 2' for the field-installed trays. Between our inspector and the AI, we take it that the vessel was round once upon a time.
My vessel's D/t approaches 150.
A previous tower of similar size arrived out of round after road shipment, even with weld-in rings every 2' for the field-installed trays. Between our inspector and the AI, we take it that the vessel was round once upon a time.





RE: Shipping Spiders
And I hope you refused delivery of that column. With trayrings spaced that often, somebody mishandled it after hydro. No reputable [or semi-reputable] AI would sign off a hydro & Code Stamping for a misshapen vessel. The Code allowable out-of-round and crookedness are fairly stringent.
RE: Shipping Spiders
http://www.nsrl.ttu.edu/personnel/JCCokendolpher/C...
MJCronin
Sr. Process Engineer
Venture Engineering & Construction
www.VentureEngr.com
RE: Shipping Spiders
Cheers,
gr2vessels
RE: Shipping Spiders
This go around we have called for some spiders to be force fit and tacked in by the vessel fabricator. What these spiders look like is the problem. 2 lengths of small angle forming four 90deg pie pieces? 4 lengths of wide flange keeping the slices down to 45 degrees?
Figuring the compressive forces on these spiders is the problem I suppose. Is anyone willing to share some ideas on how to approach this?
RE: Shipping Spiders
RE: Shipping Spiders
RE: Shipping Spiders
Thanks for the recommendation. I have the 4th edition through Knovel and read through chapter 10 "Transportation and Erection of Pressure Vessels." The only mention of temporary support for transportation loading says that a spider might be employed if a shipping saddle cannot be located near a naturally occurring stiffening element (page 633). Searching the entire book, that's the only mention of spider and appears to be the only relevant mention of "temporary."
Where in the book is spider design covered?
RE: Shipping Spiders
Try Megyesy's "Pressure Vessel Handbook." That's another extremely useful reference for items such as this. Usually one of the older engineers will have a copy.