Conrad wrote:
>
> Jon, thanks for the reply.
>
> > Your fundamentals are OK. But you may find that only custom
> > steel fabrications will give you the desired headroom
> > increase, since most standard shapes gain their stiffness
> > from depth of section.
>
> I am replacing a single 7"x3" wooden beam with 2 steel beams tho. I
> would have thought I'd be able to use steel beams considerably smaller
> than 7" wouldn't I?
You still have a deflection problem in the center. The beam will bow. To
prevent that, most engineers use a standard I-beam shape which trades
weight for depth to decrease deflection. This is just a quesstimate, but
an I-beam of sufficient stiffness might be 6 inches deep. That is why I
said that a custom fab might be required to gain headroom, something
square and squat in cross section. Perhaps something that is deeper at
the ends and tapers or steps to a smaller section in the middle. Custom
steel fabs are almost always much more expensive than standard steel
shapes, and also require custom calculations, since they aren't "on the
books."
>
> > Have you considered increasing the
> > slope somehow? (new roof)
>
> I did think about jacking it up and putting another row of blocks on the
> walls, but it would look a bit silly because it kind of fits in with the
> bank it is dug into.
Since you are looking for more headroom and strength, what about using a
steel truss to support the raised leading edge and filling in the gap at
the sides with house-like siding? You'd kill two birds with one stone.
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> > I don't know where you live, but I'd strongly recommend you
> > have an architect or engineer review the snow loads before
> > you decide on a size.
>
> Ah, didn't mention I'm in the UK. Don't really have a snow problem very
> often.
I saw the UK in your addy, but I know some parts have winter. :>)
> > See 2. Sorry. As an engineer and an analyst, I'd only take on
> > something like this as a paid consultant,
>
> I understand. I'm really after something that says you can hang x weight
> from the middle of a beam of x width, y height and z length. I'm into
> overengineering everything anyway, so I'd make it much stronger than I
> need. You never know...
Yes for standard sections and supports there are such calcs. Yours
doesn't sound standard at all when you add in the gantry. I'd also hate
to see that engine come crashing down on a freshly restored body. :>)
Jon
--
Yes, I know my message date is sometime in April 2001. Welcome to
my own personal version of the film Groundhog Day!
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