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Re: Moving Walkway Seismic Restraint

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This is also my experience in dealing with ME's and Building Code issues.
Breaking out dead and live loads for reactions is sometimes foreign to
manufacturers. The issues usually boil down to mistaken assumptions about
scope and common practice (e.g. who is responsible for the connections, what
level of seismic event must the device withstand and remain operable).
Arrange to talk to the manufacturer's designer or engineer rather than
through the letter writing chain via sales people and project coordinators.
Send the designer a copy of the Building Code clauses about anchorages of
non-structural elements.

The mechanical code only establishes the minimum load and performance
conditions that their product must achieve. However, your structure has to
resist the effects that are developed according to the Building Code
procedure and applied at the supports. The response and performance
expectations may be wildly different.

The biggest barrier that you will probably have is getting people to look
past the notion that you are asking the manufacturer to redesign their
product to suit your Building Code forces. That's not required. Ultimately,
you may find that their product will behave in a complex, non-linear manner
and have no ability to transfer the maximum Building Code effects to the
anchors (e.g the assembly will fail in wildly unpredictable ways and bang
against all manner of obstructions, killing and smashing everything in its
path ... but it meets ASME). ;)

After that, maybe there really is an issue that needs to be resolved by the
project design team.

Paul Ransom, P.Eng.
ph 905 639-9628
cell 905 802-3707
fax 905 639-3866

> From: "Chris Slater" <chris(--nospam--at)>
> To: seaint(--nospam--at)
> Subject: Re: Moving Walkway Seismic Restraint
> Daniel,
> I have a Master's Degree in Mechanical Engineering, and I can tell you
> that I never learned about lateral forces until I started working in
> the structural engineering field.
> My guess is that they just don't understand what it is you're talking
> about.  It seems to me that the highest priority is just being sure
> that the project gets designed safely - and I think the way to make
> that happen is to educate the manufacturer on seismic design and then
> work with them to figure out what type of anchorage is needed to make
> it safe in an earthquake.  Ideally, they'll come back to you to tell
> them what needs to be done.
> Chris

> On Feb 12, 2008 4:34 PM, Daniel Popp <drp181(--nospam--at)> wrote:
>> An update:  the walkway manufacturer has provided a "total horizontal force"

>> still have two problems: the difference in expected force level and the lack
>> of a load path.

>> Speaking of which:  if anyone has access to the ASME A17.1 code (2000
>> version or newer), I would appreciate an excerpt from the seismic force
>> section (8.5, I believe).
>> Daniel

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