Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: Curved Stair Stringer

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Richard,
You did not provide the radii of stringers.
I will suggest using plates for stringers, even 1/2 in
thick. If it will be not enough, go to junior
channels. Stay away from HSS, it will be extremely
difficult to roll them (check with fabricator and
rolling companies). Depending of the stair geometry,
may be the central column is not necessary at all. 
Talking about modeling, I will suggest using finite
elements, with step by tread with and adding treads
and risers. To provide enough stiffness, I will
suggest to add HSS on the landing level. 
Depend of geometry, you can have uplift on outside
stringer and vertical forces on the top landings.
BTW, maybe only struts under the intermediary landing
will do the job?
HTH

John W. Sieszycki, P.E.

--- richard lewis <rlewistx(--nospam--at)juno.com> wrote:
> I looking for some tips for modeling a curved beam.
> I have an circular
> custom stair. It is supported at the 1st floor (slab
> on ground) and 2nd
> floor. It looks something like a slotted hole in
> plan. From the first
> floor it does a 1/4 turn. Then there is a straight
> run, then another 1/4
> turn back to the 2nd floor. I am supporting it with
> a tube at the second
> floor and anchoring it to the slab at the first
> floor. The tube will give
> me torsional resistance. The tube is about 16 ft.
> long and spans to 2
> perpendicular beams, one at each end. The beams then
> span to columns
> buried in the wall. Looking at this in plan view the
> 2nd floor beams
> would form an 'H' shape. 
> I want to get feedback for modeling the stringers in
> a computer frame
> analysis. I guess my first impulse is to use short
> chord elements to
> simulate a curved member. I started doing this with
> 15 degree angles for
> the chords.  I would then uniformly load these
> members and have a fixed
> joint at the tube column at the 2nd floor. I guess
> the connection to the
> floor slab at the first floor would be pinned.  I
> would use a moment
> frame from the vertical legs of the 'H' shape to
> give me lateral
> stability. Any other suggestions for modeling this?
> I am wondering what would be the best section for a
> stringer.  Since it
> is a curved member it will have torsion.  Should I
> be using a closed
> section like a tube?  A tube might be hard to bend
> on the radius.  Should
> I make a closed section from welded curved plates? 
> Should I just use a
> single thick plate for a stringer?
> Thanks for your help.
> 
> Rich
> 
>
________________________________________________________________
> The best thing to hit the internet in years - Juno
> SpeedBand!
> Surf the web up to FIVE TIMES FASTER!
> Only $14.95/ month - visit www.juno.com to sign up
> today!
> 
> ******* ****** ******* ******** ******* *******
> ******* ***
> *   Read list FAQ at:
> http://www.seaint.org/list_FAQ.asp
> * 
> *   This email was sent to you via Structural
> Engineers 
> *   Association of Southern California (SEAOSC)
> server. To 
> *   subscribe (no fee) or UnSubscribe, please go to:
> *
> *   http://www.seaint.org/sealist1.asp
> *
> *   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any
> email you 
> *   send to the list is public domain and may be
> re-posted 
> *   without your permission. Make sure you visit our
> web 
> *   site at: http://www.seaint.org 
> ******* ****** ****** ****** ******* ****** ******
> ******** 


__________________________________
Do you Yahoo!?
The New Yahoo! Shopping - with improved product search
http://shopping.yahoo.com

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org 
******* ****** ****** ****** ******* ****** ****** ********