Maximum deck width?

[mike80]

I have a general question about the width of a concrete bridge deck. In the past, for a steel beam or plate girder bridge supported on steel rockers and bearings, longitudinal joints were used in the deck was to reduce the transverse movement at the bearings due to expansion and contraction. With the use of elastomeric bearings, is there a reason to limit the width of the concrete deck? (Assuming it is constructed in stages to accommodate the size of the finishing machine and the movement does not exceed the capacity of the bearings.) If so, what would a reasonable maximum width be without a longitudinal joint?

Thanks for your input.

 

[SlideRuleEra]

mike80 - I don't have a definite answer for you, but will pass on my 2 cents. Maximum width, if there is one, must be VERY wide. In the 1970's, as a bridge contractor, we bid on a bridge with 30 ft. long , cast-in-place slabs on H-pile supported caps. Each slab was fixed to the cap with dowels at one end with the other end being expansion (concrete-on-conrete, with a couple of layers of builders paper inbetween).

As a recall, the bridge carried a total of six lanes of traffic (each 12 ft. wide), two shoulders with parapet (each about 12 ft. wide), and a median (say 6 ft wide). This made each span about 30 ft. long and over 100 ft. wide. Since screeding was longitudinal, there were no construction joints needed. We did not get the job, but what I remember most was how "ridiculus" the plans looked for a bridge where the spans were over 3 times wider than they were long.

I have always assumed that temperature changes would cause both the slabs and caps to expand/contract at more or less the same rate - thus allowing one end of the slabs to be fixed. If this is true, then there would be no reasonable width limit for your situation either.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[crossframe]

Theortical limit? Probably. Practical limit? Probably not within the limits that would ever be built.

I would make sure the bearing details could handle the transverse expansion.

 

[civilperson]

112 foot width in Las Vegas I-15/Sahara overpass.