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Re: Ocean transport

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Karen's response is a good one.  In addition: fatigue damage is one 
other item that is usually checked during design of tie-downs for 
"platforms" for  long voyages (such as from Japan to California.)  
Also, naval architects and oceanographers are usually involved in 
such projects, to help generate design winds, sea states, and vessel 

Dave Evans,P.E.
TNH, Inc.

> From:          Karen12959(--nospam--at)
> Date:          Fri, 16 Oct 1998 23:52:24 EDT
> To:            seaint(--nospam--at)
> Subject:       Re: Ocean transport
> Reply-to:      seaint(--nospam--at)

> I don't think there are any textbooks or official guidelines regarding the
> sway loads ... but the loads acting on the structure at ocean transportation
> mode are much, much more severe than Seismic Zone 4 loads. Construction
> companies like Bechtel, Parsons, (old) C.F. Braun have done a lot of this kind
> of construction (Alaska pipelines, Alaska chemical plants) where large
> factories (say, chemical plants) were assembled in modules on land, then they
> were placed on barges (in most cases) near New Orleans, Louisiana, and towed
> to Alaska via Panama Canal. After successfull transportation of the modules to
> the unloading dock in Alaska, the modules were driven on giant self-propelled
> dollies to be connected in situ to form one operational unit). 
> Other than contacting one of these firms and asking them what load criteria
> they are using for these kinds of interesting exercises, I have no other
> suggestions. I hope they will be cooperative and will give you some good
> advise. (But I think you need much more than good advise). 
> Who is responsible for structure breaking-up during ocean storms, or being
> damaged during "normal" ocean or land transporation ???  The structural
> engineer is responsible for all of it unless otherwise decided by the client. 
> Since I was involved in several projects of this type I can assure you that
> there are many loading conditions the structural engineer has to investigate
> before the client decides that time has come for the engineer to have enough
> guts and sign the calculation sheets and the drawings. (As I recall, on the
> average, and depending on the type of structure, there were 22 to 28 design
> load combinations for each module to be taken into account (seismic loads,
> transportation loads on dollies on the horizontal plane and at local slope
> conditions, loading and unloading loads, ocean sway loads - forward, backward
> and sideways left and right, barge tie-down loads affecting the structure, and
> many, many other loading conditions) before final sizes of structural members
> were ready to be chosen. To make things more interesting, there was no City
> Hall or other engineering authority to check the structure for its internal
> and external stability stresses. All checking had to be done in-house, by your
> own people. They have to be the best. 
> I also suggest that you and your co-workers are VERY WELL familiar with
> somewhat uncomplicated 3D-finite element computer program - as this program
> will be the real work horse for the project. 
> Two advantages of working on this kind of project:  (1) You are going to work
> on a very, very interesting project and (2)  Until the last day of your life
> you will not forget how you put the whole thing together.
> Good luck
> P.S. I would not even attempt to direct such a project without help of high
> quality key people who actually worked and completed similar jobs.
> ------->>>> I could write a book about it, but I better stop here ... for my
> own sanity.