Pedestrian Railing Height on a bridge 1

[OSUCivlEng]

Section 13.8 says that a pedestrian railing has to be a minimum of 42" tall. If you have a traffic rail that separates the sidewalk from the traffic lanes (as opposed to a 8" barrier curb) does the traffic rail between the sidewalk and the lanes need to be 42" tall as well? Would the traffic rail between the traffic lanes and the sidewalk be considered a pedestrian railing even though it is a traffic rated barrier? I can't find anything in the AASHTO bridge code that specifically states the minimum height required. However the commentary on section 13.4 does seem to indicate that it needs to meet the minimum height for pedestrian railings. But the commentary isn't the code...

 

[BridgeEI]

Never paid attention to it and have used shorter traffic barriers as the means of separation. Hasn't been an issue with the local DOT.

 

[OSUCivlEng]

This owner is fine with a shorter barrier as well. It appears that you can just use whatever the owner desires.

 

[cvg]

pedestrian hand railings are for preventing the pedestrian from falling off the bridge, not from falling off a curb into traffic. many bridges with pedestrian railings on the outside of the sidewalk have no traffic barrier at all

 

[bridgebuster]

Typically, a barrier along the sidewalk is used when it's a high speed roadway. In which case the barrier along the curb is the main barrier and has to be traffic rated (TL-1, 2, ...). As a matter of policy, the owner would probably want it high enough to protect bicyclists. The outer railing would just be for pedestrian loads.

This is a project I worked on a few years ago.

 

[OSUCivlEng]

Yep cvg I agree. Here is one I did with just a raised sidewalk. You only really need the separation if the speed limit is more than 45.

 

[ACtrafficengr]

If the walkway will carry bike traffic like in Bridgebuster's pic, you need a 54" high railing due to a cyclist's higher c_m.

I can think of one situation where a higher barrier is needed between the vehicle lanes and sidewalk. The (way overcapacity) bikeway/walkway on the Brooklyn Bridge is above the vehicle lanes, so it needs a higher barrier, too. I saw a proposal recently to add bike lanes on the beams spanning over the roadways. I don't know if it would work but the added capacity is certainly needed.

What would you call those members, anyway? Ceiling beams?

 

[bridgebuster]

ACtrafficengr - I know where they should put those bicyclists but decorum prevents me. Moving them off the walkway would be a good idea. That is one arrogant bunch of people, they'll run someone over for crossing the line.

 

[Lomarandil]

AC -- you could call them top struts, or portal frames (may or may not be technically accurate, I don't know the geometry of the Brooklyn Bridge).

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