for your response. The manufacturer is designing the anchorage;
however, they are designing it for no lateral force. Their "anchorage"
consists of a stack of steel shims and a wood block. They do know that
we are in a fairly high seismic zone, but insist that their structure
floats. Which of course it will, until it collides with our
structure. Then we will have a 50 kip force (plus impact) at unknown
The latest development: we have asked that their
letter be stamped by a structural engineer with a local license. They
Any thoughts are appreciated. We will be preparing
a summary of the IBC/ASCE 7 requirements to demonstrate the magnitude of the
forces involved, although this may not help.
Original Message ----
From: Benjamin Maxwell
February 11, 2008 7:34:45 PM
Subject: Re: Moving Walkway Seismic
Maybe they don't know you are talking about lateral load due to a seismic
event. Sounds stupid, and possibly insulting, but you never know.
Unless this thing uses George Jetson technology, you're going to have a
seismic load to content with. You should get that letter from
them first though and then put it on the internet. I'd love to see
that one. Good comedy there. ;-P
On a serious note -
One way around having to extract information out of vendors who
don't really know what the heck you want is to simply ask them for diagrams of
the dead and live loads and an anchorage plan. They can usually do that
pretty readily. Then you can figure out what you need to from there.
Are you designing the anchorage of the equipment to the structure, or is
this to be designed by the vendor? Do they know they need to anchor
their equipment to the structure to meet the requirements of the building code
(assuming IBC-based code)?
Daniel Popp <drp181(--nospam--at)yahoo.com> wrote:
H. Maxwell, S.E.
A current project of ours incorporates a moving walkway on a pedestrian
bridge. The project is at the high end of Seismic Design Category C
and thus seismic forces are substantial. However, the moving walkway
manufacturer insists that the walkway will impart no lateral load to our
supporting steel structure. They are willing to put this in writing,
but I am not comfortable with a 63,000 pound piece of equipment sitting on
my structure without a defined seismic load path. Calculations using
the non-building sections of ASCE 7 indicate lateral forces on the order of
50 kips, which is quite different from zero.
Does anyone have any
experience with moving walkway installations? I am particularly
interested to know if anyone has received horizontal (seismic) reactions for
such a walkway, particularly in California or other high-seismic
areas. Any suggestions on how to extract this information from the
manufacturer would also be appreciated.
Daniel R Popp,
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