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 />
The force reactions are measured by two load cells located under <strong>the</strong> extreme<br />
faces <strong>of</strong> <strong>the</strong> concrete beams, whereas <strong>the</strong> specimen displacements, slopes, <strong>and</strong><br />
deformations are derived from <strong>the</strong> inclinometers (giving as measure absolute<br />
angles in respect to <strong>the</strong> vertical axis) <strong>and</strong> from <strong>the</strong> digital displacement transducers<br />
described above.<br />
In order to underst<strong>and</strong> <strong>the</strong> <strong>behaviour</strong> <strong>of</strong> <strong>the</strong> joint under cyclic loading, it is important<br />
to underline <strong>the</strong> rotation capability <strong>of</strong> <strong>the</strong> panel zone. For this reason, <strong>the</strong> angular<br />
distortion was monitored during <strong>the</strong> test through <strong>the</strong> measures <strong>of</strong> diagonal<br />
transducers TR500-2D, TR500-1D fitting <strong>the</strong>ir values in <strong>the</strong> Krawinkler (1978)<br />
equation:<br />
γ<br />
( )<br />
( U U )<br />
−1 2<br />
2 ∆ TR500−2 D − ∆ TR500−1 D<br />
conn tg ( hj ) bj<br />
= + ( 5.69 )<br />
2 *<br />
( hj bj<br />
)<br />
Where hj <strong>and</strong> bj are <strong>the</strong> net height <strong>and</strong> breadth <strong>of</strong> <strong>the</strong> panel zone subjected to<br />
shear given by hb-2cc <strong>and</strong> bc-2cc. ∆UTR500 represent <strong>the</strong> diagonal LVDT joint<br />
measures. In this manner it is possible to underline <strong>the</strong> panel energy absorption<br />
<strong>and</strong> its performance in terms <strong>of</strong> ductility due to <strong>the</strong> plastic deformation.<br />
The rotation <strong>of</strong> <strong>the</strong> beam in respect to <strong>the</strong> connection, ϕconn, gives <strong>the</strong> relative angle<br />
between <strong>the</strong> deformed joint panel <strong>and</strong> <strong>the</strong> concrete beam in <strong>the</strong> deformed shape.<br />
The following equations, based on <strong>the</strong> measure <strong>of</strong> <strong>the</strong> horizontal displacement<br />
transducers TR500 3O, 4O, 5O, 6O, can be utilised:<br />
∆U − ∆U<br />
TR500−40 TR500−30<br />
ϕCONN . SX<br />
hj<br />
= ( 5.70 )<br />
∆U − ∆U<br />
TR500−50 TR500−60<br />
ϕCONN . DX<br />
hj<br />
= ( 5.71 )<br />
Ano<strong>the</strong>r way to derive this quantities is to purify <strong>the</strong> measures from <strong>the</strong> “vertical”<br />
inclinometers attached to <strong>the</strong> two sides <strong>of</strong> <strong>the</strong> concrete beam by <strong>the</strong> reading <strong>of</strong> <strong>the</strong><br />
“horizontal” inclinometer at <strong>the</strong> joint <strong>and</strong> adding <strong>the</strong> panel zone distortion, Equation<br />
[6.17], where panel = connection:<br />
ϕ = Incl − Incl + γ<br />
( 5.72 )<br />
CONN . DX 3 2 panel<br />
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