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

Re: Lateral load statistical basis

[Subject Prev][Subject Next][Thread Prev][Thread Next]
The ASCE "Design Load on Structures During Construction" proposed standard, 5/98
draft, suggests:
6.0 Environmental Loads
The basic reference for computation of environmental loads is the 1995 edition
of ASCE7.  The requirements of ASCE7 shall be applied except as modified
herein.  During construction, the importance factor, I, shall be 1.0 for all
environmental loads, regardless of what the importance factor is for the
completed structure.
6.1.1 Design Velocity
The design wind speed shall be taken as the following factor times the basic
wind speed in ASCE7:
Construction Period                Factor
less than six weeks                   0.75
from six weeks to one year       0.8
from one year to two years       0.85

Remember, this is only a draft of a proposed standard.  Committee is not
finished, it has not been released for public comment, and should be referenced
only if you already know what you're doing.

It goes on for several pages with further discussion, and a hole nuther section
on seismic.  More than I feel like typing.  If you want the whole section email
my your fax.

Phil


Bob Hanson wrote:

> List,
> I would like to get opinions on lateral loads on a structure that is going
> to exist for only 35 days. When one looks at our building codes the wind and
> seismic are based on a probability of occurrence. So is it to simplistic an
> approach to expect to be able adjust these loads when the structure exists
> for 35 days and not the statistical base. (50 years) If any information
> sources related to this exist I would be interested. The related project to
> this is removal of framing, structural retrofitting, remove and replace
> equipment, and restore structure. This is a equipment support structure and
> not a building. The equipment is tired and needs to be replaced. The
> structure is being retrofitted for a temporary condition and it seems that
> some adjustments to code lateral loads should be allowed in retrofits for a
> 35 day life structure. The local code for normal structures is 1998
> California building code, seismic zone 4 & 70 mph wind.
> Thanks in advance,
> Bob Hanson