I am analyzing an existing steel thru girder bridge with concrete jack arches between the steel floorbeams. I'm looking for a reference. Can anyone help?
Is the jack arch (shallow arch) a single span, spanning the width of the bridge. If so, then unless there is some restraint at the ends of the jack arch, it will likely behave as a beam. If it is constrained, then it will have very high thrusts that must be accommodated.
I don't know of any publications, but the arches should be readily analised using FEM or something similar. Strut and tie also would work nicely.
I remember seeing a paper a few years ago on how to consider the composite action of jack arches. I just googled jack arch composite girder analysis and found some interesting information. The Michigan DOT Bridge manual has a chapter on jack arch analysus,
Jackcsh, I don't have a reference for you. Are the floorbeams spanning transverse between the arches with the jack arches spanning longitudinally between the floorbeams, forming the deck? If so then the jack arches are reacting against each other (and presumably an end diaphragm?). If so, care will need to be taken if you rehabilitate or replace any of the jack arch spans. You would have to allow for supporting the thrust of the adjacent arches if the floorbeams aren't stiff enough for construction loading.
Cooper, the construction is just as you described. Longitudinal steel thru plate girder with transverse steel floorbeams and concrete arches between each floorbeam. The connection of the floorbeams to the girders seem to be a custom designed moment connection near the bottom flange of the plate girders.
This is a new bridge we have been asked to review.
Jack, with more detail on the identity of the bridge (at least some of state, county, age, NBI number) we can look up the bridge on UglyBridges.com - and it doesn't have to be an "ugly" bridge. This site is just a lot more comprehensive than the original "BridgeHunter" site for pretty bridges.
