What does mean an essentially complete space frame?

[adarpodracir]

Hi there,

What does mean an essentially complete space frame? I know what a space frame means, but how to interpret the qualifier "essentially complete"?

In context, this is what ASCE 7-10 prescribes in page 59:

Building Frame System: A structural system with an essentially complete space frame providing support for vertical loads. Seismic force resistance is provided by shear walls or braced frames.

Thank you!

 

[gobsmacked]

Nobody else has answered, so I am suggesting that if a frame could be one of (a) deficient (b) sufficient or (c) redundant, then 'essentially complete' might be associated with (b) sufficient, meaning that it has just enough members and joints to satisfy equilibrium requirements. Most space frames are internally redundant when complete.

 

[rb1957]

maybe a complete space frame can handle loads in any direction.

i think there is (very) little loss of meaning if you delete "essentially complete" from the sentence; ie the space frame is designed to react vertical loads (only) and the lateral loads are reacted by other structure.

Quando Omni Flunkus Moritati

 

[adarpodracir]

gobsmacked, thanks for the reply.

This is what I found in the internet (

http://www.structuremag.org/article.aspx?articleid=853

):

A building frame system is said to have an "essentially complete space frame" if gravity loads are carried by columns, [and] not by bearing walls (ATC 1978).

According to the author, that definition can be found here:

ATC (Applied Technology Council) (1978). Tentative Provisions for the Development of Seismic Provisions of Buildings. ATC, Redwood City, CA.

However, I searched for "essentially complete space frame" in this ATC document and did not find the above-mentioned definition. ¿?

Thank you!

 

[RHTPE]

I suspect the real question has to do with the definition of "Space Frame".

In this context, I would define it as a "frame that completely encloses a space", think in 3D.


Ralph
Structures Consulting
Northeast USA

 

[wannabeSE]

RHTPE,

ASCE 7-10 defines space frame on the same page noted in the original post. The context of the "essential complete space frame" is to define a building frame system. I think adarpodracir has it figured-out.

Building Frame System: A structural system with an essentially complete space frame providing support for vertical loads. Seismic force resistance is provided by shear walls or braced frames.

Space Frame System: A 3-D structural system composed of interconnected members, other than bearing walls, that is capable of supporting vertical loads and, where designed for such an application, is capable of providing resistance to seismic forces.

 

[hokie66]

If that is the best ASCE can do, I am glad not to have to use their standards.

 

[adarpodracir]

Thanks all of you to reply. I think, this should be the definition of an "essentially complete space frame", after reading many papers and documents on the subject... (however, none of them explained what an essentially complete space frame meant).

An essentially complete space frame is a space frame system with adequate strength and stiffness capable of transferring all the applied forces from the point of application to the final point of resistance.

What do you think?

Thanks!

 

[Archie264]

It's stuff like this that makes people resort to essentially completely following the code.