Just because it was built that way and has been around for 30 years does not
mean it was adequate for the original design loads. Plenty of (inadequately
designed)retaining walls/buildings/roofs... have been around for a long time
and have never seen a design loading. When they do get a design loading,
either the factor of safety is infringed on and they remain standing, or
they fail. Also, building uses change, codes change, design values change
(most notably decrease in wood design values). All of these things lead to
differences in design over the years.
I've seen several buildings built in the 'good old days' that have wood
joists sitting on damp soil, joists over beams with no blocking to prevent
rotation (with corresponding rotation), beams unattached to supports that
could shift in a wind/seismic event.... In those cases, I'm glad they don't
build them like they used to.
Hope this helps.
Conrad Guymon, P.E.
----- Original Message -----
From: "Mitchell J. Sklar, MBA, P.E." <mitchsklar(--nospam--at)alumni.psu.edu>
Sent: Monday, January 29, 2001 5:09 PM
Subject: Yesterday's Comments
> As a young engineer, I often find my self in a situation where the owner,
> developer, or the contractor responds with some of the following:
> "We built things this way thirty years ago, why are your designs so much
> "I've never seen designs like this in all my life."
> "This 8" retaining wall has worked for thirty years and you want to
> it with a 12" wall."
> Does any one have a good tactful and polite answer?
> Mitchell J. Sklar, PE
> fax 413-383-1615