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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5. SEISMIC BEHAVIOUR OF RC COLUMNS EMBEDDING STEEL PROFILES<br />
By considering <strong>the</strong> prescription both <strong>of</strong> Eurocode 2 <strong>and</strong> Eurocode 8, within <strong>the</strong><br />
critical region <strong>the</strong> most restrictive <strong>of</strong> <strong>the</strong> following conditions should be satisfied.<br />
Eurocode 2<br />
LCR (critical regions length): 720 mm<br />
Hoops spacing in <strong>the</strong> critical regions: 180 mm<br />
Eurocode 8: to satisfy plastic rotation dem<strong>and</strong>s <strong>and</strong> to compensate for loss <strong>of</strong><br />
resistance due to spalling <strong>of</strong> concrete cover<br />
LCR (critical regions length): 700 mm<br />
Hoops spacing in <strong>the</strong> critical regions: 150 mm<br />
5.3.5 Design <strong>of</strong> <strong>the</strong> fully encased composite columns<br />
To ease <strong>and</strong> promote <strong>the</strong> utilisation <strong>of</strong> composite columns in <strong>seismic</strong> geographical<br />
areas in order to obviate <strong>the</strong> S<strong>of</strong>t Storey type <strong>of</strong> building failure, <strong>the</strong> steel pr<strong>of</strong>iles<br />
for strong <strong>and</strong> weak axis bending have been chosen by matching simple design<br />
criteria developed at <strong>the</strong> University <strong>of</strong> Liege. This constructional measure should:<br />
• provide ductility;<br />
• maintain axial strength, (plastic) shear <strong>and</strong> moment resistance, <strong>and</strong> stiffness<br />
190<br />
similar to those <strong>of</strong> <strong>the</strong> RC column at <strong>the</strong> ultimate stage when concrete is locally<br />
crushed.<br />
The following design criteria have been defined, in order to allow <strong>the</strong> achievement<br />
<strong>of</strong> <strong>the</strong> mentioned target.<br />
1. The steel section should at least be able to take alone <strong>the</strong> design axial force <strong>of</strong><br />
<strong>the</strong> <strong>seismic</strong> loading case:<br />
NRd > NSd (γgG + γqQ) ( 5.10 )<br />
with:<br />
γg = 1<br />
γq = 0.3<br />
2. The steel section alone (not acting composedly) should be able to substitute<br />
<strong>the</strong> deficient concrete section:<br />
MRd,steel > MRd,concrete ( 5.11 )<br />
VRd,steel > VRd,concrete ( 5.12 )