Moment Frame Design 2

[2meterman]

When I do structural design for residences I often find that a steel moment frame is necessary in a large window wall.

Normally I talk with the owner to discuss ways of reducing the windows so we can get wood framed shear walls to work or use a manufactured steel shear wall.

However, I would like to know how to design a steel moment frame.

So, I'm looking for a good design guide for full moment conections and moment frame design.

Any suggestions....Anyone?

Thanks for your help!

 

[csd72]

Depends on what you would normally specify. Square tube columns and w-shape beams?

Any decent steel text book should go through the basics. For more complex w to W shape connections check out AISC design guide 17.

 

[OUe]

2meterman,
I would design an "Ordinary Moment Frame" and use the Salmon and Johnson textbook as a design guide. There is a website called

http://www.engineering-international.com

that has a very useful spreadsheet for a simple moment frame. However, it is very, very easy to calculate an OMRF for a simple lateral load. It is possible to design an OMRF without even doing an indeterminate analysis. However, if you have a combination of vertical loads and lateral loads, then you will have to consider more load combinations and the structural analysis gets a little more complicated (probably requiring you to use an analysis program). If you use Ic=Ib, then the analysis gets a lot easier.
I hope I've helped a little.

Regards,
OUe

 

[strguy11]

If you are in a seismic area, check out FEMA-350 "Recommeded Seismic Design Criteria for New Steel Moment-Frame Buildings". It is available for free by downloading this pdf off their website.

http://www.fema.gov/plan/prevent/earthquake/pdf/fema-350.pdf

 

[hgallart]

You could also try using a prefabricated/preengineered steel moment frame. I've seen these offered by Hardy Frame (

http://www.hardyframe.com).

Hope this helps.

 

[msquared48]

I normally use steel tube frames - 4X_ - as 6X will not fit in a 2X6 wall.

With residential structures, normally find that lateral deflection controls the design, seldom stress of anykind. Try to limit the lateral movement to 1/2" or less per story, preferably 1/4" for the windows.

Mike McCann
McCann Engineering

 

[whyun]

The latest Seismic Design Manual from AISC has both the AISC 341-05 (for various lateral systems including Ordinary Moment Frames) and AISC 358-05 (for prequalified connections for Special and Intermediate Moment Frames).

For residential applications, where allowed by the local AHJ, try using the OMF system using the force level calculated by the lower R value (based on the wood shear wall system).

 

[csd72]

On a few occasions I have actually used steel beams top and bottom which puts the beams into double curvature.

Only appropriate if you have a good reason for the bottom beam to be there.

csd