5 - Modern Steel Construction

• earthquake can produce rather
than code level forces. This has
been a requirement of seismic design
codes in the United Sta tes for
man y years. The observed buckling
failure of columns in the Mexico
Earthquake has led to revisions
in recent editions of the Ulliform
Bllildillg Code. Those revisions require
columns in braced frames to
be designed for seismic axial loads
approximating those actually expected
rather than the much lower
"code level" forces used to proportion
the balance of the frame.
Adoption of this practice should
prevent similar failures from occurring
in steel frames in the future.
Unfortunately, design requirements
for other construction
materials, with less capacity to resist
inelastic demands, do not yet
require consideration of this failure
mode.
1987: New Zealand
Earthquake
• In March 1987, the north island
of New Zealand was struck by the
magnitude 6.25 Edgecumbe Earthquake.
That quake produced
ground surface rupture along a
distance of 15 kilometers, with vertical
offsets in excess of 2 meters.
The resulting ground motions
caused wood-frame homes to slide
off their foundations; overturned
diesel locomotives and trucks; destroyed
many light-gauge stainless
steel tanks at a large milk-processing
facility; ripped apart a shopping
center constructed of tilt-up
concrete; and severely damaged
the Matahina Dam, a major earthfill
structure located about 10 kilometers
away, requiring the reservoir
to be drained to allow repairs.
The region around Edgecumbe
is predominantly agricultural and
as a result contains relatively few
major structures. However, there
are three large pulp and paper
mills in the epicentral region. The
Caxton and Tasman mills are lo­
•
cated about 5 kilometers from the
fault rupture and are esti mated to
have experienced peak ground accelerations
in excess of O.35g. The
Whakatane mill, located about 15
II'T LET
YOUR REPUTATI
H BYA
THREAD
The quality of your construction fasteners can make or break
your reputation. At Dyson we have more than a full line of bridge
pins, clevises, turnbuckles, rods, nuts and bolts. We have the
engineering staff, the QA and calibration laboratories, and the
complete in-house manufacturing facilities to design and produce
full-integrity fasteners. Special or standard. To ASME, military,
Navy nuclear and commercial specifications. For reliably joining
together any type construction ... bridges, bulkheads, piers,
towers, dams and foundations. And we've been doing it for almost
100 years. The next time you 're faced with a fastener challenge,
let Dyson produce forged fasteners that protect your reputation.
For more information call TOLL FREE 1-800-321-7058. In Ohio call
1-800-537-2658. Or write Dyson, 53 Freedom Road , Painesville,
OH 44077. FAX: 216-352-2700. TELEX: 980-508.
DYSen
FORGED FASTENERS FOR THE BIG JOBS