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
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
4. SEISMIC RESPONSE OF PARTIAL-STRENGTH COMPOSITE JOINTS<br />
Component (1) (2) (3)<br />
End plate <strong>and</strong> column<br />
flange in bending (1)<br />
Concrete slab in<br />
compression (2)<br />
Web panel in shear (3)<br />
--- FRd .2 ≥ 1.3F<br />
Rd.1<br />
( + )<br />
Rd.1 = Rd.3<br />
F F<br />
FRd .2 ≥ 1.3F<br />
Rd.1<br />
--- FRd .2 ≥ 1.3F<br />
Rd.3<br />
F ≥ 1.3F<br />
---<br />
( + )<br />
FRd .3 = F Rd.1<br />
Rd.2 Rd.3<br />
Table 4.2. Joint capacity design for sagging bending moment<br />
Component (1) (2) (3)<br />
Reinforcing bars <strong>and</strong> I<br />
bolt-row in tension (1)<br />
Beam flange in<br />
compression (2)<br />
Web panel in shear (3)<br />
( + )<br />
--- FRd .2 ≥ 1.3F<br />
Rd.1<br />
FRd .1 = F Rd.3<br />
FRd .2 ≥ 1.3F<br />
Rd.1<br />
--- FRd .2 ≥ 1.3F<br />
Rd.3<br />
( + )<br />
FRd .3 = F Rd.1<br />
Rd.2 ≥ 1.3 Rd.3<br />
Table 4.3. Joint capacity design for hogging bending moment<br />
F F ---<br />
As far as resistance is concerned, particular attention must be paid for <strong>the</strong><br />
definition <strong>and</strong> calculation <strong>of</strong> <strong>the</strong> strength <strong>of</strong> <strong>the</strong> concrete slab in compression<br />
(component 2 in <strong>the</strong> Table 2) <strong>and</strong> <strong>of</strong> <strong>the</strong> column web panel in shear (component 3)<br />
4.5.1 Concrete slab resistance<br />
Eurocode 8 Annex C (2002) contains some formulas that refer to <strong>the</strong> design <strong>of</strong> <strong>the</strong><br />
slab <strong>and</strong> <strong>of</strong> its connection to <strong>the</strong> steel frame in moment resisting frames in which<br />
beams are composite T-beams comprising a steel section with a slab. The Annex<br />
has been developed <strong>and</strong> validated experimentally in <strong>the</strong> context <strong>of</strong> composite<br />
moment frames with rigid connections <strong>and</strong> plastic hinges forming in <strong>the</strong> beams; it is<br />
clearly stated that <strong>the</strong> expressions in <strong>the</strong> Annex have not been validated for cases<br />
with partial strength connections in which deformations are more localised in <strong>the</strong><br />
joints. According to this Annex two conditions have to be fulfilled to ensure that a<br />
<strong>high</strong> ductility in bending is obtained:<br />
• early buckling <strong>of</strong> <strong>the</strong> steel part shall be avoided;<br />
• early crushing <strong>of</strong> <strong>the</strong> concrete <strong>of</strong> <strong>the</strong> slab shall be avoided.<br />
The first condition imposes an upper limit on <strong>the</strong> cross-sectional area AS <strong>of</strong> <strong>the</strong><br />
longitudinal reinforcement in <strong>the</strong> effective width <strong>of</strong> <strong>the</strong> slab. The second condition<br />
imposes a lower limit on <strong>the</strong> cross-sectional area AT <strong>of</strong> <strong>the</strong> transverse<br />
reinforcement in front <strong>of</strong> <strong>the</strong> column.<br />
111