Parapet dead load deflection
Parapet dead load deflection
(OP)
I have a fairly wide bridge with 10+ girders and I'm curious how others take care of the composite deflection for the traffic rail/parapet. For strength design, I distribute the rail weight to no more than 3 beams. But what about for the deflection?
I'm waffling back and forth whether to use the parapet deflection on all the interior girders..
I'm waffling back and forth whether to use the parapet deflection on all the interior girders..





RE: Parapet dead load deflection
RE: Parapet dead load deflection
Normally this isn't an issue, but I have some really long spans so it becomes exaggerated more than a typical bridge.
RE: Parapet dead load deflection
Download a copy of NSBA G13.1 Guidelines For Steel Girder Bridge Analysis. It's a very comprehensive publication. Also, In Chapter 5 of the NYSDOT Bridge Manual there is a discussion on computing SDL deflections for steel superstructures.
Link
RE: Parapet dead load deflection
RE: Parapet dead load deflection
Remember when all else fails there's always a closure pour to set things right.
RE: Parapet dead load deflection
RE: Parapet dead load deflection
As said by Bridgebuster, we almost do that in many cases since it is out of scope/not covered in states' practice
Shoot for the Moon, even if U miss, U still land among Stars!
RE: Parapet dead load deflection
RE: Parapet dead load deflection
RE: Parapet dead load deflection
RE: Parapet dead load deflection
Unless there is a specific guideline from the state, I have always taken the barrier loads to be distributed as 60-40 between the exterior and the first interior girder. I have also found that the deflections due to the barrier loads beyond the first interior girder is almost negligible.
I would like to add another point to what 3Fan recommended. We recently did a wide bridge deck job with phasing for DDOT. At the bay where the closure pour was planned, we were not allowed to use SIP forms, even though the differential deflection between the two phases was less than 1/2 in. So we ended up using SIP forms at other bays and overhang bracket with timber forms at the closure pour bay during both phases. Something to consider for your project.