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Re: Column Base of Industrial Building

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> From: "Calvin Chang" <ccpe(--nospam--at)ms38.hinet.net>

> When designing a one-story sloped-roof industrial building with span =
> 100'~200', there are two choice for the column base, i.e., fixed and =
> pinned.
> 
> 1. considering only wind load, which is better, or both are acceptable?
> 2. considering seismic load, which is better, or both are acceptable?
> 3. if there is a crane with crane girder bracket welded at the column, =
> which is better, or both are acceptable?
> 
> Your opinions are highly appreciated.
> 
> Thanks,
> 
> Calvin Chang
>
> >> What is the height of the building?
 
> span: 100'~200'
> main frame spacing: 20'~40'
> eave height: 30'~60' 
> roof slope: 10(horizontal) : 1~2(vertical)

Base fixity decisions will be based on cost distributions and service
conditions (e.g. acceptable deflections vs cost for more steel vs cost
for more foundation) more than loads. Local variations in costs for
material and labour can be significant.

Generally, buildings with crane beams mounted on a column bracket can be
easily deisgned with a pinned base. Heavier cranes will have substantial
foundations so that a fixed base is a much smaller incremental cost
issue.

The engineer's job is to determine what economically meets his client's
requirements within all regulatory conditions.

Note: be sure that the base is actually detailed to respond
appropriately to the fixed or pinned design assumptions.

-- 
Paul Ransom, P. Eng.
Civil/Structural/Project/International
Burlington, Ontario, Canada
<mailto:ad026(--nospam--at)hwcn.org> <http://www.hwcn.org/~ad026/civil.html>