The Dynaseis experiment
ELSA, JRC
Ispra Italy
2003
Monitoring of the dynamic
behaviour of a building at
Parque das Nações
Lisboa
Maria Ana Baptista
Instituto Superior de Engenharia de Lisboa
The Dynaseis experiment
DYNASEIS - DYNAMIC BEHAVIOUR OF A
RE–INFORCED CONCRETE STRUCTURE
UNDER SEIMIC LOAD
Project funded by the
Portuguese Science Foundation (FCT)
MAIN OBJECTIVES
• Study of dynamic response of a re-inforced concrete
structure using ambient vibrations (“output only”)
•Experimental study of natural frequencies
•Implementation of numerical modelling of the structure
ELSA, JRC
Ispra Italy
2003
The Dynaseis experiment
TARGET
ELSA, JRC
Ispra Italy
2003
The Building of
Portugal Telecom Offices
Built in 1998
Area 11 000 m2
Located at the newly
residential and office area
of Lisboa, called
Parque das Nações
(Expo98)
The Dynaseis experiment
TARGET
ELSA, JRC
Ispra Italy
2003
The Tower has 12
floors above ground
and four basement
levels, and is
responsible for the
entire
telecommunications
network in the
“Parque das Nações”
complex (Expo ’98).
Two floors are entirely occupied by the telecom central,
being the remaining floors used by Marconi (PT
subsidiary) as their head-office.
The Dynaseis experiment
TARGET
ELSA, JRC
Ispra Italy
2003
The Dynaseis experiment
WHY AMBIENT VIBRATION TEST ?
ELSA, JRC
Ispra Italy
2003
1. Forced-vibration tests are more difficult to perform
and require heavy equipment and logistics;
2. State-of-the-art vibration generators do not have
the capability to excite to resonance all significant
modes of all structures (Çelebi,2000);
3. Different vibrational modes can be detected from a
single measurement;
4. Forced vibrations can damage the structure.
However,
1. Modal characteristics corresponding to low amplitude
vibrations may be different from large higher levels
of shaking (Ventura & Schuster, 1996).
The Dynaseis experiment
AMBIENT VIBRATION TEST
ELSA, JRC
Ispra Italy
2003
The Telecom Tower is located close to the Gare do
Oriente railway station (designed by Santiago Calatrava)
and is one source of ambient noise).
Others are urban traffic,
wind, etc...
The Dynaseis experiment
DYNAMIC MODELLING
ELSA, JRC
Ispra Italy
2003
Dynamic analysis was performed by the designers of the
structure but the information available is scarce.
The building is a reinforced concrete structure consisting
of “boat shape” flat plate slabs.
•floor slabs are 0.25 m thick (floors 5 to 11), 0.30 m
(floors 1 to 4) and 0.40 m (ground floor);
• floor slabs are directly support by columns;
• analysis were conducted up to 8 modes but only the
first 6 were considered relevant;
• fundamental frequency: 0.55 Hz;
Exterior Support beam
For lifts and windows
The Dynaseis experiment
INSTRUMENTS - SENSORS
ELSA, JRC
Ispra Italy
2003
1
Triaxial Acelerometer Episensor FBA ES-T:
Dynamic Range
155 dB
Frequency Band
DC to 200 Hz
Scale Amplitude
0,25g a 4,00g
6
Uniaxial Acelerometer Episensor FBA ES-U:
Dynamic Range
140 dB
Frequency Band
DC to 200 Hz
Scale Amplitude
0,25g a 4,00g
The Dynaseis experiment
INSTRUMENTS - ACQUISITION
ELSA, JRC
Ispra Italy
2003
Acquisition System: Kinemetrics Altus K2 Digital Recorder:
Dynamic Range
> 114 dB
Sampling Rate
20 a 200 Hz
Output
Acquisition Mode
Clock
24 bit
Contínuous/Trigger
GPS (accuracy 0,5 ms)
The Dynaseis experiment
FIRST TEST
ELSA, JRC
Ispra Italy
2003
Field Operations: 30 December 2002
Triaxial: Top Floor (fixed)
Continuous 10 min observations in all even floors with
the following geometry:
Reference Sensors
Roving Sensors
The Dynaseis experiment
FIRST TEST
Sampling Rate – 250 Hz
Channels
• 1,2,3 – (x,y,z) triaxial reference acelerometer
• 4 – y direction south tower
• 5 – x direction south tower
• 7 – x direction north tower
Time base – TU (sinal GPS)
ELSA, JRC
Ispra Italy
2003
Scale 2,5 V/1g
The Dynaseis experiment
FIRST TEST
ELSA, JRC
Ispra Italy
2003
Cables were deployed along the floors ...
The Dynaseis experiment
FIRST TEST
ELSA, JRC
Ispra Italy
2003
Successive setups (30.12.2002):
•Floor_10
•Floor_08
•Floor_06
•Floor_04
•Floor_02
To maintain a good quality
control the sensor layout was
kept the same when moving
from setup to setup.
The Dynaseis experiment
FIRST TEST
ELSA, JRC
Ispra Italy
2003
Example of event record from setup 6.
The Dynaseis experiment
ELSA, JRC
Ispra Italy
2003
ESD obtained by FFT
y direction
Triaxial record on the top
floor
x direction
z direction (vertical)
The Dynaseis experiment
ELSA, JRC
Ispra Italy
2003
ESD obtained by FFT
A
Event recorded at the
6th floor:
A – transversal
B – longitudinal
C – longitudinal
B
C
The Dynaseis experiment
FIRST TEST
ELSA, JRC
Ispra Italy
2003
Field Operations: 24 January 2003
Triaxial: Top Floor (fixed)
Continuous 10 min observations in all uneven floors with
the following geometry:
Successive setups 24.012003:
•Floor_11
•Floor_07
•Floor_05
•Floor_03
•Floor_01 - closed
The Dynaseis experiment
ELSA, JRC
Ispra Italy
2003
6 HOUR CONTINUOUS ACQUISITION
10 February 2003 and 11 February 2003
• free-field station: it is impossible to locate a free-field
station at a distance greater than 1.5 - 2 times the height of
the nearest/tallest building (Çelebi, 2000);
The Dynaseis experiment
ELSA, JRC
Ispra Italy
2003
6 HOUR CONTINUOUS ACQUISITION
10 February 2003 and 11 February 2003
Data Acquisition – 6 hours
Sampling rate 100Hz
Data is stored in a PCMCIA 64 MB
• continuous observation can
be achieved only in the
following places: 11th, 6th, 0th
floors
• triaxial accelerometer at
floor – 4 (foundation level)
The Dynaseis experiment
ELSA, JRC
Ispra Italy
2003
6 HOUR CONTINUOUS ACQUISITION
10 February 2003 and 11 February 2003
Data acquisition
system K2 was
installed at 6th floor
Connection of the transverse and
logintudinal sensors to the junction box
that is connected to k2 and after that
The sensors were oriented
parallel to the tranverse (x) and
longitudinal (y) axes of the
building
The Dynaseis experiment
ELSA, JRC
Ispra Italy
2003
NEXT ACTIVITIES
• Conclusion of the Finite Element Modeling (FEM) of
the building – SAP2000 in order to avoid definitive
installation at nodal points of the structure;
• Experimental data analysis: Modal analysis –
ArteMis;
• Validation of dynamical analysis
• Improvement of the methodology:
- in earthquake prone areas
- different building typology
The Dynaseis experiment
ELSA, JRC
Ispra Italy
2003
ACKNOWLEDGMENTS
The author wish to thank the Portuguese Telecom Board
of Administration and LNEC (Laboratório Nacional de
Engenharia Civil) for all support.
DYNASEIS TEAM: M. A. Baptista, A. Campos Costa, A.
Afilhado, C. S. Oliveira, P. Mendes, M. Vasques
This project was funded by Portuguese Science
Foundation (FCT) project POCTI-36071-ECM
The Dynaseis experiment
REFERENCES
ELSA, JRC
Ispra Italy
2003
Çelebi M., 2000 Seismic Instrumentation of bulidings, USGS OF report 00157
Ventura & Schuster, 1996 d Structural dynamic properties of a re inforced high rise building
during construction. Can. J. Civil Eng 23,950-970.
The Dynaseis experiment
STRUCTURAL RESPONSE
ELSA, JRC
Ispra Italy
2003
Frequency
range
Hz
Displ.
range
µm
Velocity
Range
mm/s
Accel.
Range
µg
1 - 80
1 - 200
0.2 - 50
2 - 100
Wind
0.1 - 10
10 - 105
Earthquakes
0.1 - 30
10 -105
0.2 - 400
2 - 200
Acoustic: traffic and
machinery outside
10 - 250
1 - 100
0.2 - 30
2 - 100
Machinery inside
1 - 1000
1 - 100
0.2 - 30
2 - 100
Vibration
Excitation
Traffic: road, rail
Adapted from ANSI: S247 - 1990