Duplex wood hangers

[vpj]

Hello, I am working on a project that has an old steel wood hanger. It was manufactured in Cleveland, Ohio by the Duplex Hanger Company. The existing building is an old warehouse built around 1910. The interior is framed with heavy timber joists, beams and columns. One floor uses these hangers to support the floor joists. I am trying to see what information other people may have found or if they have seen these hangers before as part of my research. Thank you.

 

[RARWOOD]

Try contacting Cleveland Steel. To find their web site do a internet search on Cleveland hangers. Cleveland Steel has been around for while and may be familair with other companies in Cleveland who made hangers in the past.

If you are unable to find any inforamtion about Duplex Hangers you probably will need to analyze the hangers on your own. You probably could contact Cleveland Steel or Simpson Strong-Tie for help on assigning a design load to the existing hangers.

Another source would be to contact AITC.

Your question is an interesting one. I am always looking for older reference material on wood desing. So I am curious to see what other engineers have to say on this topic.

 

[RARWOOD]

I pulled down the wrong binder from my shelf today and discovered some photo copies from the "Handbook of Building Construction" copywrite 1920.

It has a picture of a Duplex hanger. From the picture it appears that hanger had a round bar on its back which would fit into a rout in the supporting member. In addition it had a bolt hole through the round bar.

 

[vpj]

Hello,

Did they give any indication of the capacity of this hanger? I found some information on the hanger as your copies indicated, but no loads. The older buildings have always intrigued me, even though existing conditions can get to be a headache! Thanks for the response.

 

[RARWOOD]

No just a picture. The handbook also had pictures of Van Dorn, Ideal & Falls hangers. These three hangers were all top bearing.

Unless you can find an earlier reference then the on I have, it is probably going to be difficult to obtain information on the hanger. The information I have indicates that the hanger manufacturers published test of the hangers in their catologs. The author also notes that the results of the tests should be carefully examined.

If you have the dimensions of a Duplex hanger you could estimate the allowable load. I would base the load carried into the wood on bearing of the rod, using shear plate design values as a guide.

For the capacity of the hanger itseld you would check it using standard steel design requirements. The problem you encounter is that the load you calculate based on flexural bending of the bearing seat will probably be much lower than the hanger's capacity established by tests.

For example if you look at an EG9 hanger in the current Simpson Catalog, you would find that you can support an 8 3/4" beam with a 25,000 lb reaction using a 7 gauge seat. If you did design calculations you would probably end up with a 5/8" to 1" seat.

The Simpson value is supported by testing. However for a engineer to justify the use of a 7 gauge seat, requires design assumptions. These design assumptions are only an approximation of how the hanger actually behaves.