I'm taliking about engineered lumber, technicaly all spanning structures. Most of the engineered stuff acronims are really brand names by the manufacturer.
LK was it your guy who did the work? If the guy had a bad ticker, it was only a matter of time, the straw that broke the camels back may have actually saved his life. He could have been home in bed for that eventual heart attack...
Other glue lam stories:
Security guy drills a 1/4" hole on a 12X8" lam, engineer refuses to sign off until replaced at the tune of $10+K BC.
Plumber took a notch on the side of one to get toilet to go where shown, same results...
I don't let new guys near them! And everytime I see one I brow beat it to death. Lams are an item unto themselves...
The original one we were discussing with the web between 2 2X's can be just as much hassle depending on how much the engineer is tightening the belt.
Over the years I have had several conversations with engineers about how and why these are used, sometimes with varying result. And I have a good friend who is an engineer for the Golden Gate Bridge who summed the deal out best... "Some people like to use them as a replacement for steel." Esentially you can span wider than with dimentional lumber, and its lighter than steel would be, so you dont have to over build to support the wiehgt of the span. He said most often people who do that will use them at full or close to full strength values. Holes in any lumber reduce the bearing values, and how big the hole is, and where the hole is reduce the value by so much... He also mentioned some good clues to question weather or not the Engineer was of that frame of mind, "replacement for steel"...
- Combinations of lams and wood beams used together.
- Multiple wood beams set in patterns close together.
- Or exessively wide spans.
The way all spanning structure works, is that the top portion must have a compression value, and lower portion a tention value. Each area near the supports on the ends has a shear value. And any portion within that rectangle is what he reffered to as "webbing". And any hole in the web reduces the load bearing value in multiple places at varying degrees along the span. Combinations lead to higher reduction values.
Doh, I need to draw this...
See drawing (Improved, but loads slow.)
[This message has been edited by e57 (edited 01-07-2006).]
