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Re: Cranked Beam supported at blockwalls

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concrete beams, but thanks for input...
good to have more confidence in a design approach.
why not head it off?  i suppose i was trying to save concrete ...
never brought it up...
still not too late ...  but i think there is also an architectural
feat involved. .


2007/4/18, Jake Watson <jake.watson1(--nospam--at)gmail.com>:
I'm sure it can be done, but I haven't done it.  The torsion translates into
simple bolt shear at the wall.  Each bolt will have shear in a different
direction.  The AISC manual has a similar treatment for bolts in a
shear-tab.  All that said, why not simply header off the span?  Run a beam
from wall wall 2 to wall 3.  And then one from wall 1 to the previous beam.
You can then cantilever over the second beam (see below).

    __________________________<wall 1
> |                    |                       |
> |        _______|_____________|
> |        |            |      ^cantilever |
> |        |            | < wall 1 to beam1
> |____ |_______|____________ |
> |             ^beam 1 (wall 2 to 3) |
> ^wall 2                                    ^wall 3

You didn't give dimensions, this may not be practical.

Good luck,

Jake Watson, S.E.
Salt Lake City, UT



On 4/15/07, refugio rochin <fugeeo(--nospam--at)gmail.com> wrote:
> I have a scenario that I am losing sleep over.
> So, I think I would like some opinions from the "been there done that"
peoples.
>
> Between two perpendicular wall segments, sketch below
>
> __________________________<wall 1
> |                     |                       |
> |        _______|                        |
> |        |     ^                              |
> |        | <  cranked beam           |
> |____ |                                    |
> |                                             |
> ^wall 2                                    ^wall 3
>
> there is a cranked beam (torsion beam).  Between the cranked beam and
> wall 3 is a floor, suspended by the cranked beam and the wall.  In
> between the cranked beam and wall 2 is a stair. which lands at the
> portion of the cranked beam terminating into wall1.  total length of
> wall 1 is about 28 feet.  the stair lands about midway.
>
> the floor uses office live loading 50 psf, and is a joist and deck floor.
>
> Now, wall 2 ends just past the beam and also has a beam landing on it
> supporting one wall of load and a roof and one floor length. of the
> same joist and deck floor.  It is a 12" solid grouted block wall below
> into an 8" block wall above.  The wall 1 is an 8" block wall solid
> grouted below, into an 8" block wall above.
>
> Now, I can design a beam internally to the walls which takes the
> cranked beam ends and the torsion loads.  However, my main concern is
> what the blockwalls can take.  I can provide the beam loads tomorrow
> morning.  My calculations show it can be done, but perhaps I am
> missing some elements of surprise...  I am happy to share my calcs
> with an engineer that would be so happy to gander and give me their
> thoughts.
>
> cranked beam size:  10"x 24" with 4 #5 bars top and bott, and 4
> intermediate #5 bars spaced in pairs...  wall 1 beam is 8"x 48"beam w/
> 14 #5 bars and #3@3"o.c. stirrups.  wall 2 beam is a conjoined beam
> 12"x 26" beam + 8"x 16" beam.  The 12x 26 beam has 4 #5 bars top and
> bott and 4 intermediate #5 bars and the 8x16 portion has 8 #5 bars
> which round it out.  there are two sets of #3@3"o.c . stirrups which
> are overlapped about 8 inches.
>
> Best Regards,
> Refugio Rochin
>
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