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

RE: Unfinished Business

[Subject Prev][Subject Next][Thread Prev][Thread Next]
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.