Monday, December 25, 2017

Panama City, FL, 23rd Street Flyover

I'm saving the satellite image because it will change.
Satellite
The project is elevating US-98 and using ramps to connect to the roads that intersect with it.
nwflroads
It started by building a new US-98 just south of the existing road. The detour itself had to cost a pretty penny. The estimated cost of the project is $68m.

Screenshot (source)
Note that this post is labeled with both bridgeGirderConcrete and bridgeGirderSteel. As the following cropped screenshot from the above video shows, they use both.
-1:08
With modern cranes, the size of a girder is limited by what can be transported to the site. Notice below that many tires are used to distribute the weight across the road. States have restrictions on how many pounds an axle can carry to avoid damage to roads. One advantage of such as long load, is it spreads out the load on bridges. The girder is attached to turrets on each of the dollies so that it can turn when the truck goes around corners. Typically, the rear dolly is independently steered.
FDOT from Instagram
  • my23rdstreetflyoverSteel tub girders for U.S. 98 permanent bridge construction are being delivered to the 23rd Street Flyover project. Each girder weighs approximately 127,000 pounds.
Here is a photo from a different project that shows the rear dolly just starting to turn while the front dolly has completed the turn.
From a Facebook collection of photos showing the transport of a bridge beam.
I have concluded that they use concrete girders for spans shorter than the legal transport length. And they use steel girders for spans that are longer than the allowable transport length because they can temporarily hold beams in place and make field joints. The first photo shows the first beams temporarily held in place, and the second photo shows them lifting another girder that will be joined to the girder on the temporary shoring.
FDOT from Instagram
  • my23rdstreetflyoverThe steel girder beams used in the construction of the 23rd Street Flyover support the bridge deck (roadway surface) and are responsible for transferring the load down to the foundation. Material type, shape and weight all affect how much load a girder beam can carry.
FDOT from Instagram
  • my23rdstreetflyoverContractors set steel girder beams atop hammerhead pier caps and temporary shoring towers during the construction of the eastbound U.S. 98 bridge. Each steel beam weighs approximately 127,000 pounds.
Below we learn that the concrete beams are about 135' long.
FDOT from Instagram
  • my23rdstreetflyoverEach concrete FL U-Beam east of 23rd Street is approximately 135 feet in length. The length varies depending on the specific bridge pier span they are being set on.

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