When a have a sidewalk at the edge

[jmontoya]

When a have a sidewalk at the edge of a bridge at what grade difference we need follow AASHTO Section 13.8 for pedestrian rail?, is it 2',3' or more than 4', where can I find this?

 

[ACtrafficengr]

Can you tell us more about the situation? Are you asking for the maximum height of a drop-off without a protective handrail?

The ADA doesn't cover railings other than on ramps and stairways. I'm not familiar with it, but apparently the International Building Code requires a barrier for vertical drop-offs of 30" or more. Link

Personally, I think that is too high for a sidewalk. If the drop-off is high enough to cause an injury, some sort of edge protection should be provided. Iowa DOT (see the link above) recommends railings for slopes exceeding 1 on 2 next to a sidewalk. I'd extend the rail to a point where you can provide a slope flatter than 1 on 2.

This is assuming that the vehicle barrier is between the roadway and sidewalk, since a vertical drop-off would require one.

 

[jmontoya]

I have a several culverts with sidewalks at the edge of them, grade difference varies between 3 to more than 10 feet, do I need to place pedestrian handrails following rails spacing as described on AASHTO Section 13.8 on all of them, or can I pace handrails with larger openings on some of the culverts were the grade difference is smaller 3 to 6 feet. At which grade difference in height do I need to start following AASHTO's criteria for rail spacing?, this is not clear on AASHTO, it is left to engineer's judgement.

 

[bridgebuster]

You need to discuss this with your client. As a matter of prudence you should provide railings. Someone falling from even 3' can be badly injured and you'll be first one sued. Also, AASHTO calls for a maximum clear opening of 6". However, I've worked on projects where clients have required 3 and 3 1/2 inches.