Analysis and modelling of the seismic behaviour of high ... - Ingegneria
Analysis and modelling of the seismic behaviour of high ... - Ingegneria
Analysis and modelling of the seismic behaviour of high ... - Ingegneria
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4.1 Introduction<br />
4 SEISMIC RESPONSE OF PARTIAL-STRENGTH<br />
COMPOSITE JOINTS<br />
In <strong>seismic</strong> design practice, <strong>the</strong> possibility <strong>of</strong> relying appreciably on dissipation<br />
effects translates into <strong>seismic</strong> design actions lower than those called for in brittle<br />
structures, which can count on elastic resources alone. In turn, lower design<br />
actions, which st<strong>and</strong>ards provide through <strong>high</strong>er values <strong>of</strong> <strong>the</strong> <strong>behaviour</strong> factor,<br />
allow for lower design values <strong>of</strong> plastic resistance, <strong>and</strong> <strong>the</strong>refore smaller structural<br />
sections <strong>and</strong> lower weights as well. The savings in terms <strong>of</strong> structural weight, when<br />
coupled with sufficient ease <strong>of</strong> execution, may render ductile structures very<br />
competitive in <strong>seismic</strong> areas. Solutions assuring <strong>the</strong> necessary ductility can be<br />
obtained not only through careful study <strong>of</strong> building morphology, structural schemes<br />
<strong>and</strong> construction details, but also through <strong>the</strong> rational use <strong>of</strong> materials.<br />
Composite construction design, which represents a good compromise in term <strong>of</strong><br />
strength <strong>and</strong> ductility solution, has been increasingly used over recent decades<br />
(USA, Japan <strong>and</strong> some European countries) mostly in <strong>of</strong>fice buildings, commercial<br />
buildings, parking areas <strong>and</strong> bridges. However, despite <strong>the</strong> advantages it presents,<br />
composite construction is still scarcely used in <strong>seismic</strong> design.<br />
The main reasons could possibly be <strong>the</strong> lack <strong>of</strong> experience, skilled workers <strong>and</strong><br />
appropriate equipment on <strong>the</strong> one h<strong>and</strong> <strong>and</strong> <strong>the</strong> non-existence <strong>of</strong> codes for <strong>the</strong><br />
design <strong>of</strong> <strong>the</strong>se structures on <strong>the</strong> o<strong>the</strong>r h<strong>and</strong>. In fact, Eurocode 8 (prEN 1998-1,<br />
2002) sets forth general principles for designing composite structures for <strong>seismic</strong><br />
areas <strong>and</strong> imposes precise constructional <strong>and</strong> performance guidelines; however it<br />
does not provide adequate information on <strong>the</strong> use <strong>of</strong> <strong>the</strong> various structural<br />
schemes, or on <strong>the</strong> associated constructional solutions <strong>and</strong> design methodologies,<br />
for which it <strong>of</strong>ten refers designers to codes <strong>and</strong> regulations regarding non-<br />
earthquake-resistant structures.