discrepanze tra relazioni sperimentali e teoriche altezza ... · stato dell’arte e nuove proposte...
TRANSCRIPT
Discrepanze tra relazioni
sperimentali e teoriche altezza-
periodo degli edifici:
stato dell’arte e nuove proposte
Maria Rosaria Gallipoli and the BORA working team-
group on measurements on buildings
BORA working team- group on measurements on buildings
Co-coordinators: Philippe Gueguen and Maria Rosaria Gallipoli
Participants:
Angelo Masi, Bertrand Guillier, Christos Karakostas, Clotaire Michel,
Daniele Spina, Felice Ponzo, Manuel Navarro, Marco Mucciarelli, Vasileios Lekidis
Period-height relationship
T=C*Hα
Numerical expressions for the
fundamental periods of various
structural types
Housner and Brady (1963), Chopra and
Goel (1997; 2000), Hong and Hwang
(2000), Tremblay (2005),
Chrysanthakopoulos et al. (2006), Guler
et al. (2008), Hans et al., 2005 and
Verderame et al. (2010). Additionally,
shear-wall dominant systems have been
examined by Goel and Chopra (1998),
Lee et al. (2000), Balkaya and Kalkan
(2003), and Ghrib and Mamedov (2004).
Kwon and Kim (2010) for an extended
review for.
Experimental estimation of main
frequencies from seismic
ambient noise recordings
NATO Science for Peace project
“Assessment of Seismic Site
Amplification and Seismic Building
Vulnerability in the FYR of Macedonia,
Croatia and Slovenia” Gallipoli et al.,
(2009; 2010);
other projects (Farsi and Bard (2004);
Guler et al.(2008); Michel et al. (2008;
2010); Navarro and Oliveira (2005;
2006)
In all following slides black/grey dots
and lines are numerical estimates.
Colored dots and lines are experimental
estimates.
Comparison between numerical and experimental
period - height relationship
Estimation of building periods:
Seismic Ambient Noise vs Weak Motion
How different are the US buildings from European ones?
Numerical period-height relationships are typically provided
dependent only on the structural type (concrete frames, steel frames,
masonry, etc.), but not often they take into account other important
structural characteristics such as:
– presence/absence of infill walls (bare frame or infilled frame).
Dolsek et al. (2004); Amanat and Hoque (2006); Kose (2009);
Crowley and Pinho (2010); Ricci et al. (2011).
– flexibility of soil and soil-structure interaction effect
Stewart et al. (1999); Ghrib and Mamedov (2004); Aviles et al.(2002);
Bhattacharya and Dutta (2004); Khalil et al. (2007).
– period drop
Dunand et al. (2006); Calvi et al. (2006); Goel and Chopra (1997,
1998, 2000), Vidal et al. (2013), Ditommaso et al. (2013)
Numerical relationships ≠ Experimental relationships
such disagreement may be due
to these factors?
The effect of infill walls:
Bare Frame or Infilled Frame
bare frame bare frame with infills
The effect of infill walls: Bare Frame or Infilled Frame
Guler et al., 2008
Mucciarelli and
Gallipoli, 2007
base
free-field = foundation
top
free-field = building-foundation system
top
base = building
top
base = building
What are we really measuring on buildings?
The effect of infills and flexible bases
Rock/stiff soil
Soft soil
The effect of period elongation
1a) Variation in elastic domain
Moderate earthquake (PGA between 0.1 and 1m/s2), still in the
elastic domain (Hans et al. 2005; Michel et al. 2008, 2010).
The opening of cracks induces non-linearities, that produce a
frequency decrease reaching 35%. (Dunand et al. 2006)
2b) Frequency decrement due to damage
Goel and Chopra (1997, 1998, 2000)
It seems that a value of 60% drop in frequency is a limit
before the collapse according to data compiled by Calvi et al.
(2006).
Pollino seismic sequence - Rotonda school (Stabile et al., 2013)
Variation in elastic domain: temporary period elongation
40%
The effect of damage: permanent period elongation
Vidal et al., BEE, 2013
Ditommaso et al., NHESS, 2013
1. Objective
The main objective of this activity is to propose an extensive review of ambient vibrations
based experiences for earthquake engineering only. This review may define the first draft of
guidelines on the use of ambient vibrations experiences. After discussion, we propose also
the review be focused on European activities only, as a preliminary state-of-the-art
documents.
Several activities can be browsed:
- ambient vibrations for reducing epistemic uncertainties of fragility curves
- ambient vibrations for post-event short-term assessment of building state and integrity.
- ambient vibrations for model updating in dynamics of structures
Item 1 - Application
Item 2 - Methods and signal processing
Item 3 - Interpretation of variation of frequency
Item 4 - Damping
The first draft will be prepared for 2ECEES in Turkey (August, 2014).