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. SEISMIC RESPONSE OF PARTIAL-STRENGTH COMPOSITE JOINTS<br />
4.8.3 Validation <strong>of</strong> <strong>the</strong> analytical model<br />
The composite beam-to-column joint, named CJ type, is modelled using a<br />
rotational spring to simulate <strong>the</strong> connections <strong>and</strong> a rectangular articulated polygon,<br />
whose dimensions are represented in <strong>the</strong> Figure 4.30, with a non linear<br />
translational spring simulating <strong>the</strong> column web panel.<br />
136<br />
composite column<br />
b<br />
a<br />
d<br />
rigid truss<br />
composite beams<br />
CJ type – Interior Joint<br />
a = 280 mm<br />
b = 382,8 mm<br />
d = (a + b) 1/2<br />
CJ type – Exterior Joint<br />
a = 260 mm<br />
b = 382,8 mm<br />
d = d = (a + b) 1/2<br />
Figure 4.30. Dimensions <strong>of</strong> rectangular articulated polygon<br />
The mechanical properties <strong>of</strong> <strong>the</strong> rotational spring are obtained using <strong>the</strong><br />
Component Method according with ECCS - n°109 Procedure (1999); for <strong>the</strong><br />
column panel in shear <strong>the</strong> Krawinkler’s model has been used. To model <strong>the</strong><br />
rotational spring <strong>of</strong> <strong>the</strong> connection in a way that closely reproduces <strong>the</strong> expected<br />
<strong>behaviour</strong>, each component is modelled separately, taking account <strong>of</strong> <strong>the</strong> interior<br />
moments <strong>and</strong> forces in <strong>the</strong> members acting at <strong>the</strong> periphery <strong>of</strong> <strong>the</strong> web panel. The<br />
<strong>modelling</strong> <strong>of</strong> <strong>the</strong> actual <strong>behaviour</strong> <strong>of</strong> <strong>the</strong> connection is different in <strong>the</strong> case <strong>of</strong><br />
sagging or hogging bending moment. The basic components identified in this<br />
design are given in Table 4.5, for sagging <strong>and</strong> hogging bending moment<br />
respectively.<br />
The design moment resistance Mj,Rd <strong>of</strong> this rotational spring is determined for<br />
sagging bending moment from:<br />
where:<br />
M = F ⋅ z<br />
( 4.26 )<br />
j, Rd<br />
j<br />
t, j, Rd j<br />
Ft,j,Rd is <strong>the</strong> effective design tension resistance <strong>of</strong> <strong>the</strong> bolt-row j;<br />
zj<br />
is <strong>the</strong> distance from <strong>the</strong> component j in tension to <strong>the</strong> center <strong>of</strong> <strong>the</strong><br />
compression.