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RE: Unfinished Business

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I used to design sign structures and the base plates
are left intentionally without grout because the
connection is designed to shear under extreme impact.
The bolted connections are designed considering they
will take the loading and not a bearing plate. This is
common for sign structures, lights, etc. where
vehicular impact is prone to occur. My thoughts.

Rob Valorio, P.E.
Cherry Hill, NJ

--- Paul Crocker <paulc(--nospam--at)ckcps.com> wrote:
> I am not sure if this is the same thing you are
> talking about, but a friend
> who engineered highway sign structures once told me
> that they often do not
> grout under the base plates intentionally.  This was
> to address the concern
> that water would wick its way between the plate and
> the grout, causing
> corrosion.  Also, this enabled the long pipe columns
> to drain out the bottom
> if water got inside.  They used what to a building
> engineer seemed like
> increadibly large bolts (2" or 3" dia., maybe
> larger?), so the shear and
> bending effects on the bolts caused by using them as
> several inch tall
> cantiveler columns was not an issue.  
> 
> Paul Crocker
> 
> 
> -----Original Message-----
> From: jwhitty(--nospam--at)itac-net.com
> [mailto:jwhitty(--nospam--at)itac-net.com]
> Sent: Wednesday, January 31, 2001 7:59 AM
> To: seaint(--nospam--at)seaint.org
> Subject: Unfinished Business
> 
> 
> I have a major problem with some of the finishing
> done on various structures
> that I've seen out in the public domain.  These
> structures usually are along
> the highways that I travel and include major
> overhead signage/signal
> structures as well as towers for cellular antennas.
> 
> It seems the structure is leveled via levelling
> bolts but is never grouted.
> In addition, there are no shear lugs on the bottom
> of these columns.  Some
> of the projections are quite large and the number of
> bolts quite few.  Going
> by the various schools of thought - some rely on
> friction between base
> plates and grout in friction against vertical load
> and some rely on shear
> lugs for lateral force transfer.  Seems to me that
> these structures transfer
> via bolt bending.  Not sure the designer intended it
> this way.  Some of
> these lateral loads could get quite large.
> 
> Am I making a mountain out of a mole hill?   Are
> contractors lazy?  Is this
> what the designer intended?
> 
> Let me know you alls thoughts.
> 
> Regards,
> 
> John Whitty, P.E.
> 
> 
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