Demoltion of prestressed concrete bridges

[GHJ]

I am looking for guideline "best practice" documentation for the demolition of post-tensioned concrete box-girder bridge spans in an urban motorway environment, including demolition over live traffic. Any assistance would be welcomed!

 

[BillRoosa]

Generally speaking the 5.25 series will have all this info. If you can get one of the old ones (pre 1950) they have a wealth of data on such things. Be prepaired to use good old engineering though.
Alternatly, box gurders are hollow right? That solves the traffic problem. and they are made of 2 side beams and a top and a bottom beam. Think of the top and bottome beams as the flanges on an "I" beam and the side beams as the web protion of the "I" beam. The attack the beam as usual
William Roosa
CPT, SF
got my freedom

 

[stresshead]

Thank you for the info. I'm involved in a demolition project with large overhead box beams with similar concerns. Can you please give me more detail about the series 5.25? Thanks.

Paul Purmort

 

[estimator79]

Type USAPA in your browser. You go to the Army publications site. Go to the Corps of Engineers section. That is the "5-series". Surf around, there is, to quote my old CO, "all kinds of good stuff". As a last resort, find 5-34. In this pub you will find a conservative blasting solution to your project. In other words, you will use a bigger charge than you would probably nedd, but the bridge will be down.

Hooah!

 

[Ayuir]

The 5.25 manual has changed - it's now '5-250 Demolitions'. It provides good guidance for a wide variety of demolitions (usually military in nature). While the 5-34 is also very useful (and somewhat abridged) it's downloading is now restricted.
Before you cut the box beams, try to find the original design/manufacturing specs (if they're available) since you can assume steel reinforcing. Without steel, cutting the concrete beam is trivial, but with the steel you'll want to ensure you cut it (the steel) as well so you don't have large hanging or jambed portions of bridge to deal with (much more dangerous and time consuming).
David Larson
CPT, EN/EOD