Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: RR Flat Car Bridges

[Subject Prev][Subject Next][Thread Prev][Thread Next]
> >Have you checked to see if the local county or agency will allow
> >you to place piers in the streambed?
>     It is up to the Corps of Engineers, and I have checked and it
> would not be a problem.  I think they would be glad to have the
> existing bridge removed, which is an obstruction to a navigable
> river.

How "glad" would they be?  Maybe glad enough to cover some of the bills?
Seriously, check into federal grants for removing the old obstructing bridge
(have you counted demolition into your cost estimates?) and constructing a
newer one.  Mention to them that you can't afford to do it without extra

Also, you mentioned that the bridge causes the river to get wider and
shallower.  Look into constructing abutments further out into the river and
making it deeper at that point.  Your abutment and pier foundations will get
deeper to resist scour, but your span can be reduced.  I assume that a
raised roadway is cheaper per foot than a bridge.

>    We might be able to improve the existing bridge so that it is
> more usable, but this past year it has been passable only about 6
> days from October until today.  A dam was built upstream about 20 
> years ago for flood control and it has had a negative impact on the
> bridge because high water lasts much longer.  The bridge itself is
> causing the river to become more shallow and wider at that point.
> One thing that would help is regular dredging in the vicinity of
> the bridge.  Boats would be of no use in improving our access....
> any chance a pontoon bridge would work?

A pontoon bridge is possible, but might be a maintenance problem.  A dam
upstream will help quite a bit, but trees and debris could still get caught
on and possibly damage the bridge.  Also, you mentioned this is a navigable
waterway - canoes or fishing boats can easily cross a low-water bridge, but
a pontoon bridge can be more trouble.  It can also be a safety hazard for
boats in high water.

Another option would be a military Bailey bridge:
They can clear span up to 200' with highway loads, and are often used as
temporary bridges by cities.  They're supposed to be much cheaper than a
"conventional" bridge.  The 200' clear span is really stretching the system,
though, and will be more expensive.  You'll need to discuss costs and
options (different span lengths, load limits, abutment and pier support
costs, etc.) with Bailey Bridge, Inc., and local contractors.

Also, if you're planning on building a house on this land you need to keep
construction and delivery vehicles in mind when deciding on load limits for
your bridge.

Good luck.

Jason Kilgore
Leigh & O'Kane, LLC
Kansas City, Missouri

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at:
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*   Questions to seaint-ad(--nospam--at) Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: 
******* ****** ****** ****** ******* ****** ****** ********