Factored load for handrails and traffic barriers?

[Logan82]

Hi,

Is it required to factor the horizontal loads applied for pedestrian handrails and for traffic barriers for LFRD calculations? In other words, is it required to multiply that load by the live load factor?

 

[ProgrammingPE]

They are considered live loads, so I don't see why they would be treated any differently. I would include the live load factor when using LRFD.

Structural Central

http://www.structuralcentral.com

http://www.youtube.com/channel/UCOj2mXXf3ZbZtgxTc6BtkGg

 

[Logan82]

I am wondering about this because I have verified by calculation a few existing standard handrails from some engineering firms, and so far they are all designed without live load factor on LFRD.

One thing I found on this topic was this OSHA letter saying "The standard does not require any specific safety factor applied to the required 200 pound force.":

https://www.osha.gov/laws-regs/standardinterpretations/2017-10-27

I'm wondering if it's the same thing for traffic barriers.

 

[Logan82]

In CSA S6-14, Canadian Highway Bridge Design Code, in the Table 3.1 Load factors and load combinations section it says the live load on which the live load factors are applied includes the barrier loads.

 

[phamENG]

Logan82 - I wouldn't try to mix OSHA with AASHTO. It's hard enough to mix OSHA and building codes for buildings when OSHA standards have to be met in the building...trying to apply an interpretation of a construction safety regulation to fixed guardrail design on a bridge probably won't work. The analysis and design theory behind OSHA's is very much NOT LRFD.

As to why some standard details don't work...couldn't tell you. But I've seen it in the building world, too. It's 'how it's always been done' and nobody stops to consider if it works or not. It might have under a very old code edition, but under new requirements it falls short.