Metal Decking Installation 2

[loumann]

Anyone out there have experience with using powder-actuated mechanical fasteners for installing metal decking to steel joists. Are there any inherent disadvantages to this type of fastening system in lieu of the traditional puddle-welding method?

 

[Lutfi]

You can fasten steel deck to joist or any steel member via various means such as:

1. Puddle welds
2. Mechanical fasteners (i.e. TEK screws)
3. Powder driven fasteners (similar to those Hilti and others make)

Each of these systems has the good and bad. Welding is great and will have large shear capacity, if welded properly. Since welding is done on roof tops and is done by bending down and due to the thin nature of the deck, you will tend to have burn through and misalignment of the weld and the supporting steel member. Welding destroys the galvanized finish on the deck and thus promoting corrosion hence reducing the life of the deck system.

Mechanical fasteners are great. I prefer them over welding. Their weakness is s the low shear value coupled with limited published data. I use Dr. Luttrell’s manual and book published by the Steel Deck Institute for the welded and screwed decking system. They have great wealth of information. You can buy them at this link

http://www.sdi.org/manuals.htm

Since I live in Florida and most frequently I have high diaphragm loads, I do not use PDFs for metal decking because of their low shear value. Therefore, I should not comment. The following site is a good place where you can do some reading on the PDFs.

http://www.new-technologies.org/ECT/Civil/fasteners.htm

 

[dbuzz]

Hilti's "Direct Fastening" system is the only one I'm aware of. It's quite a simple way to install floor plate.

You must ensure that the surface treatment on the beam, where the stud penetrates the underside of the top flange, is touched up to avoid future corrosion problems.

http://www.hilti.com.au/holau/modules/editorial/edit_listpage.jsp?catname=/products/direct_fastening

http://www.hilti.com.au/data/editorials/-8363/au_directfast.pdf

(706kB)

 

[dbuzz]

Oops, I thought you were referring to floor plate when it seems that you are in fact referring to light-gauge decking for composite slabs and formwork...sorry.
:~/