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Re: railing design

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If you are going to go to this amount of trouble guessing where the loads
are going, why don't you analyse it in a 3D analysis program with the
correct type of joints specified to take into account any fixity. It will
not take any longer and you will not have to worry about the accuracy of
your guess and should take about 15minutes total.

If you are looking for deflection criteria and cannot find one locally,
from memory, I think the Australian codes require a deflection limit of
approx 6in but I cannot check as I no longer have a copy.


At 16:43 15/02/99 -0800, you wrote:
>Presuming from the Q and A so far that the verticals are steel, and all
>alike, and cantilever up from a moment connection at the stair stringer to a
>steel flat bar at their top ends, to which all the verticals connect
>rigidly, you have a classic "beam on elastic foundation".
>
>The code horizontal load of 200 lbs. is a point load (isn't it) acting
>horizontally on the top rail "beam", which spans horizontally. The
>resistance is the whole array of verticals, each of which supports the beam
>with a springy resistance, the amount of which depends on the deflection
>imposed. The horizontal stiffness of the top rail, with respect to the
>stiffness of each vertical against horizontal load at its top end, is the
>basis of analysis.
>
>Timoshenko presents a complete solution in his texts on Strength of
>Materials, Part II, dating from 1930 and still in use at least into the
>1960's. His solution also covers the case where the applied load is
>distributed over a certain length of the "beam", or there are multiple point
>loads. There are formulas, curves, and tables.
>
>If an approximate solution is adequate, it could be done by trial and error
>as Richard Lewis suggested, keeping in mind the basic principle.
>
>There are code limits for stairway handrail dimensions that relate to a
>person being able to grasp and hang on. Lateral stiffness wants to be enough
>that subjective confidence in the sturdiness of the thing is not impaired.  
>
>Charles O. Greenlaw, SE   Sacramento CA
>********************************************
>
>Original question:
>>i have a handrail that has 1/2" X 1/2" verticals at 4" o.c. with a
>>nominal flat stock top horizontal.  in applying the code required 200 #
>>horizontal load what effective width is allowed.  another words how many
>>verticals can contribute?
>>
>>another question is, what is the codefied deflection criteria?
>
>
>

Regards  Gil Brock
Prestressed Concrete Design Consultants Pty. Ltd.
5 Cameron Street Beenleigh Qld 4207 Australia
Ph +61 7 3807 8022		Fax +61 7 3807 8422
email:	gil(--nospam--at)rapt.pcdc.com.au
webpage:	http://www.home.aone.net.au/rapt.pcdc/