Bridges sitting on the ground

[wxfree]

This topic is about bridges with a single span and with each end on the ground, not an embankment, but somewhere nature put ground.  I thought of this topic due to this overpass, over I-10 in Texas near Roosevelt, west of Junction.

Street View

That's in a road cut where the cross road runs on the natural ground level and the freeway runs below.  Presumably to save money on cutting, they cut two narrow channels rather than a single wide one for the whole road.  This leaves rock cliffs on which to set bridges.  There's a similar one in the westbound lanes.  I'd be interested to know how these are built, since they're set directly on rock.  I would guess that each abutment is a one-piece column.  If you ever drive by there and see some idiot walking around on the elevated median, that might be me.  If you look on top of the bridge, you can see the median is easy to get to.

As a bonus topic, here's a tunnel under the Interstate.  I found the bridge location by serendipity.  I remembered this bridge on the ground, but I haven't been there in probably 15 years.  I thought it was somewhere I'd been more recently, such as west of Sonora, but when I looked there, I couldn't find it.  Then I remembered the tunnel I once saw.  I gave up looking for the bridge and started looking for the tunnel.  There are places where aerial imagery shows a gravel road disappearing under both sides of the Interstate, suggesting underpasses, but I saw this one from the side, on a public frontage road or parallel FM road.  I remembered that being farther east and a long time ago.  When I found the tunnel, I looked a little farther and found the bridges.

Street View

That's a large culvert, with metal lining.  It runs below the whole freeway and median.  If you go through, there's a Hendrix video in there.  The metal reflecting the sunlight produces interesting effects.  It's labeled as a private road, but there's no denial of access until it reaches a gate at the edge of the right-of-way.

[Big John]

Do you also mean high arches like the O'Callighan-Tillman Memorial Bridge (I-11/US 93) just south of the Hoover Dam?

[pderocco]

This topic is about bridges with a single span and with each end on the ground, not an embankment, but somewhere nature put ground.  I thought of this topic due to this overpass, over I-10 in Texas near Roosevelt, west of Junction.

Street View

That's in a road cut where the cross road runs on the natural ground level and the freeway runs below.  Presumably to save money on cutting, they cut two narrow channels rather than a single wide one for the whole road.  This leaves rock cliffs on which to set bridges.  There's a similar one in the westbound lanes.  I'd be interested to know how these are built, since they're set directly on rock.  I would guess that each abutment is a one-piece column.  If you ever drive by there and see some idiot walking around on the elevated median, that might be me.  If you look on top of the bridge, you can see the median is easy to get to.

Looking at the terrain, this looks to me like they depressed the road for reasons unrelated to the ease of building the bridge. Just 0.6 miles east, the road drops down into the Llano River valley, so it was headed downward anyway. And the rock looks pretty crumbly too.

This road was built decades ago, so I don't think this is related to the more modern techniques of building an overpass on the ground and then building the freeway under it. It's interesting to peruse the Las Vegas beltway in Google Earth historic imagery to see how that's done.

[Rothman]

Heh.  Sentinel Heights Road over I-81 south of Syracuse rested upon earth and rock in the median...until it was replaced a couple of years ago.

[wxfree]

Do you also mean high arches like the O'Callighan-Tillman Memorial Bridge (I-11/US 93) just south of the Hoover Dam?

Not exactly.  My first thought for a description was "bridges without columns."  But that isn't really accurate, since there would still be some kind of column, even if underground.  I'm interested in bridges without freestanding columns and with the roadway essentially at ground level.  This would generally be in a short span over an artificial cut or narrow natural valley.

I may have seen an embankment with vertical abutments and single span beams between them, I seem to remember one, but I'm not really interested in that, so I specified natural ground.  A bridge sitting on natural ground is more interesting than one sitting on concrete cliffs.

[1995hoo]

Are you thinking of this sort of thing in McLean, Virginia, where Kirby Road passes over Old Dominion Drive (VA-309)? You connect between the two roads either via that road to the right where the school bus is or by using other roads in the area.

[wxfree]

Are you thinking of this sort of thing in McLean, Virginia, where Kirby Road passes over Old Dominion Drive (VA-309)? You connect between the two roads either via that road to the right where the school bus is or by using other roads in the area.

Yes. It looks like it carries some kind of line that's otherwise underground.