[masraum]

Originally Posted by TimT

No way is something like that going to happen here...

Depending on the design of the replacement...i.e. steel truss, precast concrete, cable stayed, simply procuring and fabricating the the various elements takes time.. Evn though this project will definately be "accelerated"

Steel mills don't have stock of millions of pounds of various shapes "in-stock", with a project like this pressure will be put on the mills to "cut the line" and roll the required shapes for this bridge ahead of current orders..

Ordering bulk steels shapes usually takes months.. and certain shapes are not even rolled in the States..

Many of the jobs I've worked on have a Buy American Clause in the specs.. One job in particular the contactors detailer specified a shape that was not rolled in the States... an exception was made because of time constraints and redesign costs.. The shapes were sourced from a mill in Germany

Just some pics from the Manual of Steel Construction.. I have the Silver more recent addition somewhere..

The designer has to strike a balance of the lightest member, the most economical construction method, availability, domesticity.

Mill don't have stock of all the various weights of shapes.. Contractor need to order the shapes, then wait in line for the mills to produce the members required.. The the raw product is shipped to a fabricator to cut and drill the pieces.. mills sometimes only cut certain lengths.. So if you need a 46' member, and the mill only supplies 50 footers... you get 4' of waste on every piece...

What goes on behind the scenes to build infrastructure is really remarkable...

Originally Posted by unclebilly

Don't be so sure... I've been the professional engineer that did the failure analysis on fractured and blown high pressure lines (rated to 15,000 psi) several times. And I've written peer reviewed SPE papers on the matter, one made the JPT.

We also deal with sour gas pipelines here - not something you have much of in the US. When H2S leaks, people die. Failures involving H2S usually involve HIC but thats a different story.

Thanks for posting folks. It's great to have knowledgeable information sources available!