krus1972 - I managed to contact an architect who sent me pdf's of some Macomber catalogue tables. I am in the process of getting these uploaded and placed in an FAQ so Eng-tips members can easily access them. Hopefully we can have them up within the week.
Thanks for your help. What ever information you can find would be most benificial to this Forum.
A little history to others reading this thread:
SJI can only provide only the required specifications (Loading, Material, etc..) for joists built during the time frame of the Macomber joist.
Much like today joist manufacturers can build steel joists from any shape(s) they want as long as the joist(s) meet SJI specs. Before the days of Vulcraft & Canam (1928-1960), Macomber was a widely known and widely used steel joist manufacturer. It has been a long time since Macomber went out of business but there are still many structures that exist today that have Macomber Joists. Old catalogs are very scarce and its difficult to reverse engineer these joists so they can be evaluated from any engineer. As an engineer it is nearly impossible to evaluate and design structural alterations to buildings that use the Macomber joists. Today Vulcraft & Canam has engineering departments that aid engineers when modifications/alterations to only their own joists are needed. Since Macomber no longer exists and As-built information on Macomber joists is very scarce it creates a near impossible challenge for todays engineers who have to work with existing Macomber steel joists.
Macomber had many different product lines. "V-BEAM" and "V-LOK" are only two of their many joist product lines. They also had their own decking also. On the good side the "V-BEAM" is what everyone on ENG-TIPS is looking for and their joist tags support it. The V-BEAM is what I have the info on.
On the Bad side MY project uses the V-LOK joist system and I still do not have the original Macomber product info on the V-LOK system (YET). I designed a work around where none of the joists had to be modified or touched. The V-LOK system did NOT require any welding or bolts to connect all of the joist/joist girders together. If you want to be able to spot V-LOK joist construction just look at the end connections of the joists. They are not your typical Vulcraft bearing connection that everyone is familur with. All of the joists & Girders used strange looking shear connectors that have rivets that stick out and fit into slotted holes in the girder verticals. The system was erected with no welding or bolts and fit together like the old toy erector sets we had when we were kids.
On the good side I know many old-timer structural engineers who are retired or ready to retire. Since Macomber went out of business around 32-35 years ago these retired guys will most likely have the old product catalogs. The old-timers are not internet/computer savey and thats why people are having a very hard time finding Macomber info.
I will soon change this when more (Authentic) Macomber info becomes available to me.
One thing we have done, which some may think is "scary" on old joists when you don't know exactly what you have, is to re-do the original design, doing a dead load takeoff of the floor or roof, and then apply the live load (or snow load) that was applicable at the time of the original design. In our area, years ago most engineers used 30 psf for snow. Today, with the IBC, the snow is around 21 psf so we have some extra capacity to play with.
You can build an original shear and moment diagram capacity envelope based on these assumed original design loads and then compare with your current loading condition to see where you are at. The BIG assumption in doing this is that you assume that the original engineer correctly designed the dang things.
Eight pages of information (.pdf downloads) on Macomber V-Beams (provided by krus1972 and JAE) is available at the link below. My ONLY contribution is to provide the web hosting.
"The BIG assumption in doing this is that you assume that the original engineer correctly designed the dang things."
I would think that whether the original engineer "correctly" designed the things, they almost certainly designed them differently from what you would. Stability formulas for struts and columns have changed, yield strength may have been different, factors of safety or load factors change, they may have treated all elements as pinned in the pre-computer era just to simplify the calculations. On the other hand, they could have done actual load tests to confirm a questionable design.
