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RE: Fwd: Positive connection

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I like it, Steve.

T. William (Bill) Allen, S.E. (CA 2607)
A L L E N   D E S I G N S
Consulting Structural Engineers
33171 Paseo Cerveza, Suite 221
San Juan Capistrano, CA 92675
V (949) 248-8588 • C (949) 374-1536
www.AllenDesigns.com

They way I see it now, the definition for the positive connection should be 
 something like: "A structural connection against all applicable forces that 
 is fully assured without the consideration of friction."

Have a good week,

Steve

______________________________
V. Steve Gordin PhD
Licensed Structural Engineer
SGE Consulting Structural Engineers
2081 Business Center Drive #105
Irvine CA 92612
949-552-5244
sgordin(--nospam--at)sgeconsulting.com

Begin forwarded message:

> From: "Solutions Center" <Solutions(--nospam--at)aisc.org>
> Subject: RE: Positive connection
> Date: April 21, 2014 5:38:02 AM PDT
> To: <sgordin(--nospam--at)sgeconsulting.com>
> 
> 
> Steve,
> 
> 
> It does not appear that the AISC Specification, or the IBC define
> “positive connection”.  In fact, the only place that I found that
> provided a definition is in the FEMA E-74 document “Reducing the Risks
> of Nonstructural Earthquake Damage, Section 6.6.1 Positive Connections. 
> There it states: “The objective of nonstructural anchorage or restraint 
> details is to provide what engineers refer to as a positive connection 
> between the item and a hard attachment point, such as a structural wall, 
> braced partition, concrete floor, or built-in countertop. Positive
> connections generally consist of some combination of screws, bolts,
> cables, chains, straps, steel angles, and other steel hardware that
> transfer seismic loads to structural framing. Positive connections do
> not rely solely on the frictional resistance produced by the effects
> of gravity. Frictional resistance between the base of an object and
> the floor or mechanical friction connections such as C-clamps or
> thumbscrew clamps are not considered positive connections. The most
> common nonstructural connection details for wall attachments, floor or
> ceiling attachments, countertop attachments, and attachments between
> adjacent items are discussed below. GENERAL INTEREST SIDEBAR
> Earthquake Forces Keep in mind that although heavy objects are hard to
> move by hand, their weight (mass) interacts with the shaking
> (accelerations) of an earthquake to produce large inertial forces.
> Those forces mostly act sideways to make the object slide or tip, and
> there are also vertical motions in earthquakes that temporarily
> "lighten" an object and reduce frictional resistance.” You can find
> this online at
> <http://cirrus.mail-list.com/seaint-seaosc/09421005.html>
> Also, the term positive connection is sometimes used in relation to
> the OSHA regulations related to rigging and lifting, though I was
> unable to find a definition supplied by OSHA or even the use of this
> exact term in the regulations – though I may have missed it. It can be
> inferred from the context in which the term is used that a positive
> connection is one which cannot accidentally become disengaged (i.e.
> slide off). For instance OSHA seems to deem a shackle through a
> lifting lug to be a positive connection, but a sling around a trunnion
> is not a positive connection. I suspect the term is typically not used
> in conjunction with the regulations related to steel erection since
> bolts provide a positive connection and regulations relative to their use 
> in steel erection are pretty explicit. This definition of positive connection 
> is also used informally in other applications. The term positive connection 
> can also refer to electrical continuity and is also used this way in OSHA 
> documents.” I hope this helps.  Please let me know if you have any 
> additional questions. Sincerely, Carlo Lini, P.E., LEED AP BD+C Staff 
> Engineer American Institute of Steel Construction 866.ASK.AISC lsm/eng How 
> did we do? Your opinion matters to
> us: www.aisc.org/TellAISC for your chance to win a free Steel
> Construction Manual! This document has been prepared in accordance
> with information made available to the American Institute of Steel
> Construction at the time of its preparation. While it is believed to
> be accurate, it has not been prepared for conventional use as an
> engineering or construction document and should not be used or relied
> upon for any specific application without competent professional
> examination and verification of its accuracy, suitability, and
> applicability by a licensed engineer, architect or other professional.
> AISC disclaims any liability arising from information provided by
> others or from the unauthorized use of the information contained in this 
> document.

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