The topic of handrail design came up yesterday, and I did a quick pole to find out what folks are up to on this front.
Interesting...
The design forces for the railing are typically indicated in the code - ASCE 7-05 [4.4.1] talks about the loads, and some exceptions for SFR.
In IBC 2006 and previous, [1607.7.1.3] used to talk about a 1/3 stress increase for members and their attachments wrt (with respect to) handrail design. In IBC 2009, this has been removed - drat! (i'm not sure that we were all taking advantage of this stress increase when we had it).
So the question came up about whether the load for handrails referred to in the code was indeed a "live" load, or more of an "impact" load? For wood design, Cd for impact is 2.0, while for live, it is 1.0. Since "common sense" would indicate that handrails loads are not likely to a sustained loading condition, it could be argued that a stress increase could be appropriate - and may be necessary - in order to come up with a reasonable solution.
Maybe we should consider getting the commentary on this section to see why they removed the section.
Any comments?
Interesting...
The design forces for the railing are typically indicated in the code - ASCE 7-05 [4.4.1] talks about the loads, and some exceptions for SFR.
In IBC 2006 and previous, [1607.7.1.3] used to talk about a 1/3 stress increase for members and their attachments wrt (with respect to) handrail design. In IBC 2009, this has been removed - drat! (i'm not sure that we were all taking advantage of this stress increase when we had it).
So the question came up about whether the load for handrails referred to in the code was indeed a "live" load, or more of an "impact" load? For wood design, Cd for impact is 2.0, while for live, it is 1.0. Since "common sense" would indicate that handrails loads are not likely to a sustained loading condition, it could be argued that a stress increase could be appropriate - and may be necessary - in order to come up with a reasonable solution.
Maybe we should consider getting the commentary on this section to see why they removed the section.
Any comments?
