allowable metal deck deflection

[structengineer]

Where can I find the allowable metal deck deflection? I am drawing a blank. I have calculated the actual deflection, but I need something to compare it to.

 

[CJJS]

The product your are using should have that information in their literature.

 

[JAE]

The Vulcraft catalog has shaded areas in their design tables that indicate when strength does not govern but rather live load deflection = L/240.

 

[structengineer]

JAE, you are talking gravity only, correct? I should clarify that I am checking shear strength from the Vulcraft tables. Even the example in the diphragm section calculates the deflection, but they never compare it to an allowable deflection.

 

[JAE]

Oh - sorry.

For diaphragm action, the deflection of the flexible diaphragm metal deck affects the lean - or sway/drift of your overall building. The combination of your main lateral bracing system deflection plus the diaphragm deflection combines to be the total lateral drift of, say, a column halfway between the braces. This drift is what you should look at in light of your maximum preferred story drift for the building.

We generally see maximum allowed drifts of between H/400 and H/500 for most buildings. AISC Journal article dated First Quarter, 1993 is a good reference for this.

 

[JedClampett]

Take a look at ICBO Reports ER-3415 (

http://www.icc-es.org/reports/pdf_files/UBC/3415.pdf)

and ER-2078P(

http://www.icc-es.org/reports/pdf_files/UBC/2078p.pdf

&

http://www.icc-es.org/reports/pdf_files/ICBO-ES/2078plan.pdf).

These have allowable deflections for different span to length cases. Note that they are very confusing to fight through.