Page 250 - Handbook of Structural Steel Connection Design and Details

Welded Joint Design and Production

Welded Joint Design and Production 235

into the available welding processes and the requirement to control
quality, in both the shop and the field, when welding any structure.
High-quality fabrication is essential for seismically resistant struc-
tures. The reader is encouraged to review these other sections, as no
attempt has been made to replicate the contents of those chapters as
they apply to seismically resistant structures.
Most fabrication work in the United States is performed in accor-
dance with the AWS D1.1 Structural Welding Code—Steel. This code
provides general requirements applicable to all welded structures. The
D1.1 code does not, however, contain any requirements unique to seis-
mic construction. Perhaps this will be done at a future date. The D1.1
code should be taken as the lower bound of acceptable fabrication prac-
tice, and the engineer can incorporate additional requirements into
contract documents to ensure that the latest requirements for seismic
resistance are employed. Section 8 of D1.1 contains the title “Statically
Loaded Structures,” and “Cyclically Loaded Structures.” This is an
improvement over the former title of “Dynamically Loaded Structures.”
Chapter provisions are specifically geared toward low-stress-range,
high-cycle fatigue-type loading, not the high-stress-range, taw-cycle
stress associated with seismic loading. It is generally recommended
that Section 8 criteria be applied for seismic applications, and appro-
priate modifications be made through contract documents as new infor-
mation becomes available.
At the time of the writing of this section, two significant earthquakes
have occurred in the recent past. In both events, significant damage
was experienced by welded steel structures, resulting in considerable
commitments of resources to research. As a result of these events and
the subsequent research, a better understanding of the expected
behavior of various structural systems and details has been achieved.
While many theories exist regarding various aspects of connection
details, some remain unproved, and more testing is required. This
section represents an accumulation of the best data available to date,
and yet recognizes that information will be emerging in the next
months and years that may render some of these recommendations
incomplete or incorrect. Before adopting these provisions, the reader
is cautioned to compare this information to the latest applicable spec-
ifications and the state of the art.
One of the best current sources of information is FEMA 267,
“Interim Guidelines for Repair and Fabrication of Steel Moment
Resisting Frames.” This document is the result of the first phase of
government-sponsored research performed by the consortium of the
Structure of Engineers Association of California (SEAOC), Applied
Technology Council (ATC), and California Universities for Research
and Earthquake Engineering (CUREe), together known as SAC. The

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