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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3. SEISMIC BEHAVIOUR OF BOLTED END PLATE BEAM-TO-COLUMN STEEL JOINTS<br />
extended plate connections have been analysed. In detail, <strong>the</strong> effects <strong>of</strong> <strong>the</strong> weld-<br />
to-base metal yield strength ratio, <strong>the</strong> end plate yield-to-ultimate strength ratio <strong>and</strong><br />
<strong>the</strong> residual stress influence have been determined through detailed two- <strong>and</strong><br />
three-dimensional non-linear finite element analyses. Such analyses conducted in<br />
<strong>the</strong> monotonic regime permitted fracture toughness dem<strong>and</strong>s in terms <strong>of</strong><br />
performance indices to be evaluated. In addition, <strong>the</strong> analyses provided insights to<br />
develop a better intuitive underst<strong>and</strong>ing <strong>of</strong> fracture in <strong>the</strong> aforementioned<br />
connections.<br />
3.2 The component method<br />
Design <strong>of</strong> MR frame with semi-rigid partial strength joints is one <strong>of</strong> <strong>the</strong> major<br />
developments in <strong>the</strong> structural design <strong>of</strong> steel <strong>and</strong> composite steel-concrete<br />
buildings.<br />
The importance <strong>of</strong> joint action has been perceived since <strong>the</strong> beginning <strong>of</strong> <strong>the</strong> last<br />
century. However, only in <strong>the</strong> 80's <strong>the</strong> tools available to <strong>the</strong> practitioners, <strong>and</strong> in<br />
particular <strong>the</strong> structural analysis programs, made <strong>the</strong> new methodology ready for<br />
practical use. Since <strong>the</strong>n a number <strong>of</strong> research studies were carried on worldwide,<br />
aimed at building up <strong>the</strong> necessary knowledge to develop design tools ranging<br />
from general criteria to specific methods <strong>and</strong> rules for joints <strong>and</strong> frames (Bjorhovde<br />
et al,1988; Narayanan, 1988; Bjorhovde et al, 1992; Colson, 1992; Lorenz et al,<br />
1993; Wald, 1994; Bjorhovde et al, 1996; Maquoi, 1999; Easterling <strong>and</strong> Leon,<br />
2002).<br />
All <strong>the</strong> key facets <strong>of</strong> <strong>the</strong> problem were investigated via experimental, numerical <strong>and</strong><br />
<strong>the</strong>oretical analysis, including <strong>the</strong> <strong>behaviour</strong> <strong>of</strong> a wide range <strong>of</strong> joint types, <strong>the</strong><br />
design models to approximate joint response <strong>and</strong> <strong>the</strong> influence <strong>of</strong> joint action on<br />
frames performance. Design criteria as well as specific recommendations were set<br />
up <strong>and</strong> included in Codes (Eurocode 3, 2001) <strong>and</strong> design aids were developed in<br />
order to make <strong>the</strong> new philosophy accepted in practice.<br />
Following <strong>the</strong> recommendation included in Eurocode 3 (2001), it is possible to<br />
classify <strong>the</strong> joint by stiffness or by strength. Depending on <strong>the</strong> stiffness, a joint can<br />
be classified as rigid, nominally pinned or semi-rigid on <strong>the</strong> basis <strong>of</strong> particular or<br />
general experimental evidence or significant experience <strong>of</strong> previous satisfactory<br />
performance in similar cases or by calculations based on test evidence. A rigid joint<br />
shall be so designed that its deformations have no significant influence on <strong>the</strong><br />
distribution <strong>of</strong> <strong>the</strong> internal forces <strong>and</strong> moments in <strong>the</strong> structure or on its overall<br />
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