Challenges for the Next Generation of Seismic Codes - Earthquake Engineering for Structural Design - page 456

only simple constructional provisions, which do not always assure the
required plastic rotation capacity in the members.

(viii) Recognizing the need for code development based on transparent

methodology, one must also recognize that it is necessary to underline
some danger of this operation: over-simplification, over-generalization
and immediate application in practice of the latest research results,
without an adequate period of time during which these results can be
verified.

10.2 PROGRESS IN SEISMIC DESIGN CODES

10.2.1 Design Codes

Initially there were no seismic codes and, only after the first earthquakes of the 20 th
Century, the engineering community decided to implement some level of lateral
forces to avoid building collapse.
A design code is a document containing standardized requirements for the
design of most types of buildings. It is a compendium of design regulations with
the objective to guarantee that a building will be not damaged, or it will undergo
reparable damage for low and moderate earthquakes and it will not collapse after a
strong earthquake. Codes also regulate building construction and use in order to
protect health, safety and welfare of occupants. Codes address all aspects of the
construction, including integrity of structure and non-structural elements, fire
resistance, seismic resistance, equipments, etc.
The first code was elaborated in 1927 in the USA for the Californian
earthquakes. Following this code, the effort to elaborate codes was extended to all
the world's seismic zones. For these codes, the current set of seismic design factors
found in national standards is based on a measured combination of history of
seismic events, state-of-the-art of research works and engineering judgments, very
different in each country as a function of its experience of construction in seismic
areas, coming from the nature and characteristics of ground motions, traditions and
jurisdictions. Therefore, it is very important to analyze the evolution of seismic
codes in the world's main seismic areas, in the context of the above-mentioned
factors. This aspect is very important in order to know how concepts and
provisions of one code could be used for the development of other codes, without
making important errors. For this purpose, four main seismic areas are considered:
the United States of America, Japan, China and Europe. The USA and Japan are
selected, due to the very important activity in the improvement of code provisions,
according to lessons learned after the Northridge and Kobe earthquakes. China is
included as an example of special seismological aspects and high risk of
earthquake, due to the massive scale of new development in populated centers.
Europe is also selected due to the remarkable effort to unify the numerous and very
different national codes in the frame of the Eurocodes, which are valuable, with
some justified details, for all European countries (Gioncu, 2006).