help identifying an irregular OWSJ chord 7

[andrew705]

Hello,

I am trying to analyze an open web steel joist in an existing building in Ontario, Canada.

My problem is, the top and bottom chords of the joist are an irregular shape that I have never seen before. If someone can help me identify the shape, and help me find the section properties, I will be able to analyze the joist. I have attached a picture of the cross section in question.

Some browsing around past threads has led me to the macomber v-beam series of chords. I have downloaded some information on the sizes they made, and this has been a great help. I guess I'm wondering if anyone can tell me if this was the manufacturer for sure, or if other companies were also making this shape.

 

[AVak]

Andrew,

May I suggest that you contact D. Matthew Stuart, P.E., S.E., F.ASCE, SECB

He has written a series of articles on antiquated structural systems for STRUCTURE magazine. I know that he has an extensive catalog of proprietary joist information.


Adam Vakiener, P.E.

 

[RonRoberts]

Looks like Macomber. Visit the slideruleera.net site. I think you'll find what you are looking for at:

http://www.slideruleera.net/contributions.html

 

[Ron]

RonRoberts...exactly right. SRA has one of the most helpful sites available. Glad he's an E-T member and willing to share a wealth of knowledge and info.

SRA...thanks again...from all of the "old guys" at E-T

 

[BAretired]

andrew705,

It looks similar to the Anthes Joist which was built in Toronto, Ontario until it went out of business (I forget the year). Page 27 of their catalog is attached.

If it is an Anthes joist, I would advise you to check the eccentricity of the end diagonals where they meet supports. As I recall, excessive eccentricity was the reason given for the collapse of a number of joists in several buildings. I understand this was the reason they went out of business.

BA

 

[BAretired]

andrew705, are you still with us? Why are you not responding? Get with it!

BA

 

[beton1]

Curious BA, these are cold formed? and generally not weldable/suitable for reinforcing? Had a friend of mine in structural steel fabrication look at this quickly, and he says there have been problems, as you mentioned.

 

[BAretired]

beton1,

Yes, the chords were cold formed and conformed to CSA S136-1963, which means they were or should have been weldable. I have no reason to believe they were not weldable.

Furthermore, Anthes regularly load tested their joists taken from the production line under the supervision of an independent testing company. See attached.

On the projects I looked at, because the beam spans were not consistent, the EOR selected beams with a top flange varying from 5" to 12" in width. In cases where the c/c span of joist was constant, the fabricator provided joists satisfying the widest beam flange. The end diagonal cleared the 12" flange by 1/2" but cleared the 5" flange by as much as 4" which resulted in a bending moment too high for the joist shoe to resist.

I surmise (although I do not know for certain) that the load test did not replicate this condition and that instead, the end block of the testing device was located close to the end diagonals of the joists.

I was hoping that andrew705 would see my post because in all probability, the joists he is checking were fabricated by Anthes so he would want to have a look at end eccentricities on all joists, particularly where beam flange widths are variable.

BA

 

[andrew705]

BA, sorry for not being around, I've been out of town.

thank you very very much for your very helpful response. i will look into the eccentricity on monday when i am back in the office. your post makes me feel a little bit better because i was using the macomber data for analysis, but my boss will be much happier to see me using specs from a canadian manufacturer. the buildings that i keep finding with this joist are all in the greater toronto area, so i think you're really on to something here.

i'll update you on monday when i get back to the office, thanks again!

 

[BAretired]

Thanks, andrew705. I'm glad you got my post. If you need to see load tables in the Anthes catalog, let me know the spans you have and I will post the appropriate tables.

BA

 

[BAretired]

My files reveal that two shopping centers in Alberta had partial roof collapse in about 1974. Joists for both projects were fabricated in the Winnipeg plant of Anthes Steel Products Ltd.

The two pages attached are not very clear, but illustrate the joist eccentricity. Some of the joists which did not fail had even larger eccentricities than those that did. In one case, the eccentricity was reported to be 8".

BA

 

[andrew705]

thanks again BA.

i find it very interesting that this company might have had problems with failure, as we're finding more and more of these joists that need to be analyzed. i assume by the age of these buildings that they probably dont share the same problem, but i will definitely keep the eccentricity in mind.

im trying to find more information on the company. do you have any articles about the collapses, or the closure of the company?

your help is greatly appreciated.

 

[BAretired]

I do not have any information on the closure of the company.

So far as the collapses are concerned, I believe that excessive eccentricity between the supports and the end diagonals combined with lack of fusion in the weld between the end diagonal and the top chord were largely responsible for the collapses.

BA

 

[Robbiee]

BA,
I have exactly the same issue as the one described in the OP. My building is located in Hamilton Ontario. The tag of some of the OWSJ I am interested in read " ANTHES STEEL PRODUCTS LTD M79 1751" and others read " GREAT WEST STEEL INDUSTRIES LTD N80 1751" The members of all joists are similar to the attached.
You have been a great help in identifying these joists, I wonder if you can post the load tables for 31" depth with 38' span. Thanks.

 

[BAretired]

Ailmar,

I tried to send six pages but got an error message. Here are the first three.

BA

 

[BAretired]

Here are the last three. Joist depths usually come in 2" intervals so 31" is non-standard.

BA

 

[andrew705]

BA,

Just wondering where you got this manual, and if there is any way I can see the rest of it, somehow.

The information you've posted in this thread so far has been hugely useful, but my company continues to see these joists quite frequently, and the more information I can gather the better.

Just to give you some background, the solar division of my company specializes in the design of roof mounted solar photovoltaic arrays, which is big business in Ontario right now. A huge part of what we do is analysing existing roof structures to ensure they meet current codes with an excess capacity that would suit the installation of a solar panel system... not knowing a lot about these joists we've had to take some conservative assumptions that have ruled a few buildings out, which doesnt make our clients too happy. Any more help you could lent us would be greatly appreciated.

 

[andrew705]

for example... we were assuming 33 ksi steel based on age and getting that most of the chord members arent likely up to code, thus ruling out a few rooftops for capacity. the last batch of pages you posted suggest we should be using 55 ksi, which would obviously make a huge difference.

thanks again for all the help so far!

 

[BAretired]

andrew705,

I received the Anthes catalog many years ago from Anthes Steel Products. There was the original catalog entitled "Design Manual AA3" and a smaller document entitled "Supplement to Design Manual AA3". The supplement contained two newer V-shaped chord members similar but a little thicker than the sections in the original catalog.

Counting the outside cover, the original catalog has 30 pages and the supplement has 12. I don't know offhand where you can find these documents, but there is a business card attached to the supplement under the name of:

Anthes Steel Products Limited
Campbell A. Roylance, P. Eng.
Regional Sales Manager
491 Portage Avenue, Winnipeg 2, Manitoba
Telephone 774-2535
Res. 837-3348

I have no idea whether or not Mr. Roylance is still living in Winnipeg, but if he is, you might find some luck there.

Alternatively, if there were as many structures incorporating Anthes joists in your area as you say, I would expect you could find other consultants nearby with a copy of the catalogs. Engineers wouldn't throw such things away, would they?

BA

 

[dik]

Cam Roylance... now there's a name I haven't heard in 30 plus years...

Dik