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RE: Effects of Transient and Cyclic Loads on Structural Elements

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Nels-
Most of the information I've seen on damage to buildings from vibrations has
been relative to blasting.  There is a book by C.H. Dowding, "Blast
Vibration and Control" that I seem to recall had some damage information
based on particle motions that could be monitored.  It might be a start.
I'm not sure whether it addresses URM or not. The two websites below have
information on blasting vibrations:
www.nrc.ca/irc/cbd/cbd063e.html <http://www.nrc.ca/irc/cbd/cbd063e.html> 

www.isee.org/catalog2.html <http://www.isee.org/catalog2.html> 

Regards,
Bill Cain, S.E.
Oakland  CA


	-----Original Message-----
	From:	Nels Roselund [SMTP:n.roselund(--nospam--at)worldnet.att.net]
	Sent:	Tuesday, August 22, 2000 9:55 PM
	To:	seaint(--nospam--at)seaint.org
	Subject:	Effects of Transient and Cyclic Loads on Structural
Elements

	I am developing a protection and monitoring program for existing
historic
	unreinforced masonry buildings directly adjacent to a project that
involves
	paving demolition, excavation, fill and compaction, and construction
	equipment traffic.

	Has there been research into the effects of construction-related
transient
	and cyclic loads of various intensities, durations and frequencies
(other
	than earthquake shaking and wind) on building components, such as
masonry
	veneers, and unreinforced  masonry walls?

	It is conventional that retrofit codes require that drilling of
holes into
	unreinforced masonry buildings be done with non-impact rotary
equipment.
	This is intended to prevent damage to the adjacent masonry.  I've
assumed
	that the basis of such a requirement is intuitive, and not based on
	research?  Is anyone aware of research?

	As an extension of the rotary drilling requirement, it is usual to
require
	that demolition on concrete slabs adjacent to unreinforced masonry
buildings
	may not be done by breaking with a jackhammer.  On my projects, I'm
used to
	requiring demolition of slabs in or adjacent to URM buildings to be
done by
	cutting them up with masonry saws into sizes that can be taken out
without
	breaking.

	On the other hand, I remember growing up near a part of town with
old brick
	buildings, and recall that jackhammers might be used to break paving
and
	excavate hard soil adjacent to old brick buildings with no apparent
thought
	of precautions to prevent impact-or-vibration-caused damage to
adjacent
	walls.    Has anyone been able to identify a part of a building that
may
	have been damaged in that way?

	With the engineers' goal to maximize effectiveness while minimizing
cost, I
	want to develop a program that is restrictive enough, without being
too
	restrictive on the types of construction activities that can be
allowed
	adjacent to, or at various distances from the buildings.  Are there
any
	references out there?

	Nels Roselund
	Structural Engineer


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