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Re: vibrations from railroad

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Donna,

Did you draw the 2 H :1 V line from the edge of a standard 8'-6" tie or from the
centerline of track?  If the former, it would appear that you have a VERY short
canal wall   [(10'-4.25')/2=2.9'].  One way of computing the lateral earth
pressure from the train is to apply the weight of the train plus impact as a
surcharge (see AREA Chapter 8) at bottom of tie and based on the geometric
configuration, use a Boussinesq distribution to calculate the lateral force on
the wall (see "Foundation and Analysis Design" by Joseph Bowles or any other
comparable book) .    We did this once for some temporary walls during a bridge
replacement.  The railroad entity did not like this method (they weren't paying
for the tab so they could be as conservative as they wanted to be but we still
had to follow their requirements) and just gave us a blanket surcharge
(something like 15 feet of surcharge) to apply to the wall.  You might want to
consult the railroad entity involved because they may have some control over
what you use for your design.

Hope this helps.

Hector






"Friis, Donna" <FriisDL(--nospam--at)cdm.com> on 10/14/99 03:53:24 PM

Please respond to seaint(--nospam--at)seaint.org

To:   "'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>
cc:   "Verwey, Timothy" <VerweyTA(--nospam--at)cdm.com> (bcc: Hector
      Morera/NYC/AmmannWhitney)
Fax to:
Subject:  vibrations from railroad





I am designing a concrete lined storm water channel/canal, which has a
railroad track running parallel to the channel.   I have been searching for
design procedures/formulas to account for the vibration induced from the
train or to prove that the channel is far enough away that the effect is
negligible. The nearest edge of the channel is 10' off the center line of
the track. This is far enough away that the dead, live (Cooper E 80) and
impact loading of the railway cars does not effect my channel (based on the
2:1 method). This seemed sufficient to me at first because the channel was
beyond the live load (and thereby impact load) lateral distribution length.
But I have been within 15' of  a train and felt the vibration through a slab
on grade.

 I  have the 1995 AREA (American Railway Engineering Association) manuals
for railway engineering, which have design loading information and minimum
structure offsets.
I could not find info regarding the frequency calculations of the railway
system.

Have any of you designed structures for similar types of vibrations or know
of sources of vibration design info? Any info would be greatly appreciated.

Sincerely,
Donna Friis, EIT

> _____________________________________
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> Donna Friis
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