Different Piles

[roadman65]

https://maps.app.goo.gl/w6u1GTM4oqxt7rDw9
Was wondering what the application is of different pile types like in this caption of a bridge being built over a CSX rail line in Hernando County, FL.


Most piles here are concrete but some are larger and round metal piles.

[Mapmikey]

https://maps.app.goo.gl/w6u1GTM4oqxt7rDw9
Was wondering what the application is of different pile types like in this caption of a bridge being built over a CSX rail line in Hernando County, FL.


Most piles here are concrete but some are larger and round metal piles.

guide tubes perhaps?

I'm curious why there are 8 on the left side and 9 on the right...

[Scott5114]

https://maps.app.goo.gl/w6u1GTM4oqxt7rDw9
Was wondering what the application is of different pile types like in this caption of a bridge being built over a CSX rail line in Hernando County, FL.

The image isn't loading with a caption for me, just a picture of a bridge being built.

When did GSV start providing captioned images?

[Dirt Roads]

You are looking at a future bridge abutment where the cross-section is too [soft] on the north side (right side of the photo).  So in addition to the six hammered piles on this side, you have three poured columns (some states call both types "piles"; the poured columns are called "bored piles" in many other countries).  Essentially, you are seeing three steel casings (on this side) that have been [pushed] down into the soft soil; that soil inside the casings will be removed (often by standard drilling techniques) and then replaced with reinforced concrete (think very long strands of interconnected rebar).  Retailed fill will be added all the way around this whole mess, so you shouldn't be able to see anything other than the abutment cap when completed.

CSX has very strict standards for constructing bridges over active mainline, so I am surprised to see a combination of pile types here.  Poured columns have a completely different natural resonance frequency than the pre-cast concrete piles.  Ergo, one side of the abutment is going to "bounce" differently than the other.  My understanding is that is possible to stiffen the poured columns to address this issue, but I'd be concerned that one side gets weaker than the other as you approach the design life of the bridge.  It's complicated physics, so I suspect that there are situations where it is not obvious which side "bounces" more than the other.  Fortunately, there are a handful of PhD-level structural engineers out there that really love this stuff.