Constructing a beam from 2x10 's

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I have been watching this thread trying to keep out of it but I lost the struggle .....
Michael Daly wrote: snip

in a system will/could/might cause a failure at the "design" loads. Very obviously the entire system does need to be considered _if_ loading is going beyond the design on any given component.
What I am seeing is a debate that a single (or multiple) over designed component in a system can cause a failure else where in the system but losing sight of "designed" and as has been said several times this is untrue _if_ we are still talking at _designed_ loads.
By the virtue than one constructs a beam capable of carrying double the designed load by no means ensures that the rest of the system, posts, footings, etc, are capable of carrying this. But also this same oversided beam at the _designed_ loads will not cause catastrophic failure in any other components unless they were themselves either under designed or inadequately constructed or had a load increase beyond design.
If one constructs a structure like a beam that is, for e.g. capable of carrying 50% more loading than design but the posts used are still at designed specs loads, then for sure, if you load the beam to its increased capacity the posts and other parts are liable to fail.
This is almost an urban legend type of issue. The real item is that all parts of a structure need to be designed and constructed to meet the needs and loading requirements. Over sized/designed construction of one part will not increase the capacity of the system and is where people become misdirected like some of this discussion. The failure is always due to trying to load at a level to the specs of the over built piece rather than the original design. ... and thus results in these misconceptions that over designed beams, as in the examples in this thread, cause failures in the posts and where in reality the posts were never designed or capable of carrying these loads.

Yes, it is criminal to construct an occupancy build that does not conform to minimal standards stated in various regulations and as result incur a failure causing 3rd party losses in property, life, well-being, etc. There is absolutely nothing I have seen that says I can not exceed any building construction standards and requirements.
Ed
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But if you do not design a component to conform to standards, but merely oversize the component, you can cause the structure to behave in a manner that causes failure. Think especially in terms of statically indeterminate cases, where load distribution is a function of stiffness.
If you overdesign a component but can show that the overdesign is not a problem, then there is no risk. Columns in high rise buildings are an example - you can design several stories to use the same column even though the upper columns carry a lighter load. However, you have to _design_ it that way.
Mike
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Michael Daly wrote:

So when was the last time a high rise building was constructed from 2x10s?

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You can get drugs to treat your obsessive behavior.
Mike
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I've tried OVER and OVER to reach the local building departments. Their website is not useful, and reaching a person by phone is a 2-3 week proposition. Since the Hurricanes here (I'm in Florida in an area where 3 hit last year), there is so much building going on that it's almost impossible to speak to anyone in the building or code departments. Permits in our town are 6-12 months from the time of application.
Good suggestion though I just WISH I had a building inspector avaiable. I also talked to a clerk about the project. She said they are so backed up that projects like mine are not being permitted at this time- she basically said "have at it"..
Welcome to Florida!
IRC correctly the " steel flitch plate w/bolts may have been an alternative to either " or 3/4" ply nailed.
BX1's best bet is to check with Building/Zoning or Community Development in his town and see what they say. To overbuild is never a crime<g>
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Take a step back and make sure you're using the right material for the application. I don't know what you're up to, but when someone says "beam" I think "steel". Like I said, I have no idea what you're doing, just make sure you're doing it the right way- saving a couple of bucks does you no good if you're dead.
Aut inveniam viam aut faciam
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