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Author Topic: Double tee freeway bridges  (Read 237 times)

Tom958

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Double tee freeway bridges
« on: August 06, 2022, 06:24:32 AM »

The bridge carrying Chelsea Road over the Kansas Turnpike is made of double tees, like a parking deck. It dates from 1979, 23 years after the Turnpike was opened, and was built along with several other bridges, some of them also with double tees, as part of the El Dorado Lake project. Double tees aren't well suited to freeway bridges because of their limited span lengths, but the narrow median of the Kansas Turnpike allows these to get away with spans of only 52 feet, versus the 60ish feet used on the parking decks I've worked on.

Double tees are typically used for the Miami Metrorail (note the box beam at right, where a longer span is required), but I don't know of any other freeway bridges that use them, and searching this forum for "double tee" or "double tees" turned up nothing. So, how much of a unicorn is Chelsea Road over I-35, anyway?

« Last Edit: August 09, 2022, 05:46:23 AM by Tom958 »
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Dirt Roads

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Re: Double tee freeway bridges
« Reply #1 on: August 08, 2022, 03:37:17 PM »

^^^
We use them a lot in a rail transit, mainly to straddle the existing utility corridors beneath (and sometimes to create an efficient utility corridor).  We also call them mistakenly call them straddle bents for that reason, but we also have a fair number of real straddle bents along the way.  But I'm wondering if there was an underground geological anomaly that required the use of the double column structure.  Sometimes they don't find a patch of bedrock close enough to the surface where they need to place a middle pier.  (But almost always in that case, the bridge will be designed with multiple columns that are closely spaced).  Definitely a curiosity and quite possibly a unicorn.

By the way, these two links are the same:
1979
the Miami Metrorail
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Tom958

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Re: Double tee freeway bridges
« Reply #2 on: August 09, 2022, 05:50:49 AM »

^^^
We use them a lot in a rail transit, mainly to straddle the existing utility corridors beneath (and sometimes to create an efficient utility corridor).  We also call them mistakenly call them straddle bents for that reason, but we also have a fair number of real straddle bents along the way.  But I'm wondering if there was an underground geological anomaly that required the use of the double column structure.  Sometimes they don't find a patch of bedrock close enough to the surface where they need to place a middle pier.  (But almost always in that case, the bridge will be designed with multiple columns that are closely spaced).  Definitely a curiosity and quite possibly a unicorn.

I was talking about the deck and beams, not the odd-looking bent. That's a whole separate mystery.

Quote
By the way, these two links are the same:
1979
the Miami Metrorail

Oops. Here's the real Miami link, and I've edited it into the OP, too.

https://goo.gl/maps/5k7cgsc5QD5j47pL9
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