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This can't be good... - A Suburbs Boy Living a Country Life [My Flickr Photos]
July 9th, 2006
01:55 am


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This can't be good...
I went out today and measured the span and pocket of the questionable beam up front, reviewed the floor plan to estimate the load per linear foot.

I wonder if the concrete pocket that the beam sits in counts as a cantilever?  Maybe that would lower my deflection...  I don't think so, though.  Any civil or mechanical engineers want to weigh in?

Beam Design Fails?
Beam Design Fails?

Say it ain't so...of course a lot of these parameters were civil-engineer-ese, so I'm not sure I entered them correctly.

Current Mood: worriedworried

(9 comments | Leave a comment)

Date:July 9th, 2006 06:36 am (UTC)
The graphic's not loading on my end. Problem yours, or mine?


[User Picture]
Date:July 9th, 2006 02:37 pm (UTC)


try clicking through
[User Picture]
Date:July 10th, 2006 02:41 am (UTC)

Re: hmmm

clicking through shows it's a permissions error, server-side. I can't be sure whether it's the graphic file itself, or the enclosing directory/ies.
[User Picture]
Date:July 9th, 2006 11:42 am (UTC)
You will sue if it's not to code, yes?
[User Picture]
Date:July 9th, 2006 02:40 pm (UTC)


pretty much means not moving in...

I am going to prevail upon their professional integrity...If they got it wrong, it needs to be fixed.

The "guranteed equivalent" of the W12x26 steel section originally specified is a 50% deeper LVL beem (21" instead of 14").

When I run the same loading case on even an 18" beam, or a 16" beam at 4 plies instead of 3, it passes...
[User Picture]
Date:July 9th, 2006 04:39 pm (UTC)
A cantilever load is one where the load is spread across a beam having a point of support that isn't on an end. This causes deflection to follow a more complicated curve, which is generally flatter overall than a basic catenary. I really doubt it applies in your case.

The usual approaches (assuming the beam is currently in place) depend on how the beam is expected to exceed parameters. Some failures (such as twisting) can be helped by adding steel L channel to the beam's corners. Otherwise, the beam is usually either sistered with another beam to build up an acceptable cross section (I did this in my house), supplemented with a steel I-beam underneath it, and/or additional support columns added. The I-beam approach lowers the ceiling and is therefore not generally preferred. Adding a column generally puts a post in the middle of a room somewhere, which may or may not be a problem depending on the view and whether it could be hidden inside a wall. So sistering the beam is probably your best bet.

[User Picture]
Date:July 9th, 2006 07:48 pm (UTC)
Argh! The structural is coming back to me. Must hide.

I wish I could help you, but I've purged my brain of any structural knowledge.
[User Picture]
Date:July 10th, 2006 05:22 am (UTC)
If you are really uncertain, and not sure what your builders are going to say, take it to the city/county engineer and ask them to look at it.

It is always a good idea to get a second opinion, and they would be the people to ask.

I know in commercial builds, all of those things have to be checked by the city engineer's office, but I know little about residental builds.

*remembers the days of driving rolls of plans all over the place to get them approved*
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Date:July 10th, 2006 06:18 am (UTC)
I'm surprised they didn't catch this earlier... hope it's not too hard to correct!
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