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RE: Non-Building seimic analysis

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Chris,

The creation of Technical Subcommittee 13 is new, and our small subcommittee addresses a lot of nonbuilding structures that are structurally and dynamically quite different.  We are in the process of examining all aspects of structural design of nonbuilding structures.  We intend to revisit the R value issue for each of the listed nonbuilding structures especially in light of the new mapping and procedures for building structures.  The problem is that there is not enough research in this area, and industry has been slow to respond.  

We developed the current R values based in large part on historic values from the various industries that specialize in these types of structures and a comparison to the R value determination for buildings.  It was a lot like making sausage.

The primary difference in R values between vessels on legs and bins on legs is reflective of the uncertainty of the calculations for impulsive and convective fluid forces.  Admittedly all of the nonbuilding structure R values are conservative, again to reflect a measure of uncertainty about the accuracy of the assumptions, operating conditions, lack of damping, the critical nature of stored contents, and a lack of redundancy inherent in nonbuilding structures.

As you can see it is a work in progress.  Help is welcomed.

Harold Sprague, PE
Chairman TS 13 - Nonbuilding Structures
Krawinkler, Luth & Assoc.
4412 W. Eisenhower
Loveland, CO 80537
970-667-2426 voice
970-667-2493 fax
hsprague(--nospam--at)klaalov.com

-----Original Message-----
From:	Bill Sherman [SMTP:SHERMANWC(--nospam--at)cdm.com]
Sent:	Wednesday, September 16, 1998 8:12 AM
To:	seaint(--nospam--at)seaint.org
Subject:	Re: Non-Building seimic analysis

Chris Wood wrote:

Harold - perhaps you could shed some light on why "vessels" and "hoppers" on
braced or unbraced legs have different R-values?  It seems that the
structural system is similar, although the vessel containing fluid would also involve
"sloshing".

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