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

RE: Philosophy: Seismic Design Standards

[Subject Prev][Subject Next][Thread Prev][Thread Next]


Although SEAOC has been actively working at developing a performance-based
design methodology, it has been presented as a separate appendix in the blue
book.  No one is even thinking about trying to marry it into the code at
present, it is really only a research excercise and perhaps a guideline for
engineers who may be involved in unusual or "new age" projects.  Before anyone
thinks about putting it into the code we are going to have to come to grips with
the liability aspects.  Engineers who promise a level of performance are
assuming a very significant responsibility, which is likely to include the
accuracy of design, quality of construction, the details of nonstructural
elements, and perhaps even the use and maintenance of the building years after
it is built.  Heady stuff.

Future directions that ARE likely to occur include adding provisions for new
structural systems which offer good seismic performance (such as when the EBF
system was added in the past), providing a more rational method for designing
foundations for seismic effects, and improving the rationality of how the
structure actually resists the earthquake motions (such as by better definition
of what an R factor is).  As an example, the seismology committee is currently
(a) supporting an effort by a joint SEAONC and AISC group to develop a new BRBF
system, (b) watching research work at UCSD for a new prestressed concrete moment
frame system, and (c) working through an ad-hoc committee to research foundation
design methods (such as the overturning concern that Frank McClure has often
mentioned).  This is in addition to watching and trying to support IBC, NEHRP,
SAC, ACI and AISC development activities, keeping abreast of research efforts
such as the CUREe program, and watching and trying to support membership
concerns such as are frequently voiced on this list server.

regards,
Martin