Interface to Support Seismic Retrofit Kenneth Hanson Cerritos College
Jan 03, 2016
Data Acquisition Interface to Support Seismic Retrofit
Kenneth Hanson
Cerritos College
Overview- Retrofit Project
Long Beach Public Safety BuildingCSULB Involved in Unique Project Data collection during seismic retrofit Correlate data with construction progress Identify changes in structural characteristics as
construction progresses
Critical facility-Down Town Long Beach Fire station Police station City jail Emergency response services
Overview- Retrofit Project
6-story, Steel-FrameUndergoing a $30M seismic retrofitDense Instrumentation
Data Collection Before retrofit During retrofit After retrofit
Acceleration Measurements
Project: Automate Ambient Vibration Measurements Very important, especially during
construction
National Instruments NI-4472 PCI data acquisition 24-bits Synchronized timing
Acceleration Measurements
K-2 Data Recorders Kinemetrics Inc. Automatic recording when
earthquake event happens Threshold-based recording
Structural Health Monitoring
Measurements of building structural responseCompare model predictions to measured responses Modeling
Finite element model Linear Nonlinear
Model response to earthquakes Historical earthquake records Pre-retrofit Post-retrofit
Statement of the Problem:
Ambient vibration data must be acquired before, during and after the retrofit. Presently stored data is manually taken twice a week at the building location. To perform real time data measurements the output of the existing system does not interface with the National Instruments Data Acquisition (DAQ) system.
Solution to the problem:
Design and fabricate an interface that would allow data to be routed around existing hardware to provide real time data acquisition, measurement and display.
Instrumentation
Vibration measurements Accelerometers
Strain measurements Strain gages Fiber-optic strain sensors
Displacement measurements Laser based displacement
Acoustic Emission Sensors
Instrumentation: Installation Time Line
2-axis EPI Sensor
STRONG MOTION ACCELEROMETERS. Installed pre-retrofit
K2 recorderK2 recorder DATA ACQUISITION . Pre- and Post-retrofit installation.
SGSTRAIN GAGES. Installation during retrofit.
AE ACOUSTIC EMISSION SENSORS. Post-retrofit installation.
FOSG
FIBER-OPTIC STRAIN GAGES. Post-retrofit installation.
LFD LASER-BASED FLOOR DISPLACEMENT. Install during retrofit.
EPI Sensor
STRONG MOTION ACCELEROMETERS. Post-retrofit installation.
2-axis EPI Sensor
6th Floor
3-axis EPI Sensor
5th Floor
EPI Sensor
EPI Sensor
2-axis EPI Sensor
4th FloorEPI Sensor
2-axis EPI Sensor
3rd FloorEPI Sensor
3-axis EPI Sensor
2nd FloorEPI Sensor
2-axis EPI Sensor
1st FloorEPI Sensor K2 recorder
K2 recorder
K2 recorderK2 recorder
K2 recorderK2 recorder
PC
RS232
RS232
Basement Instrument cabinet on 1st floor
SG
AE
SG
SG
SG
SG
SG
FOSG
LFD
LFD
LFD
LFD
LFD
LFD
AE
Modified System Diagram
Interface Hardware
Retrofit Project
The Long Beach Public Safety Building
Starting from Scratch
LBPSBRetrofitPhase
Fig. 1. Three Dimensional Numerical Model ofPre-retrofit Long Beach Public Safety Building
LocationsSensor
Post-Retrofit Measurements
New Shear Wall
Strain Gages to be Installed
Acceleration Measurements
FBA - Accelerometer
3-axis
Installed in LBPSB
2nd Floor
Acceleration Measurements
K2 Recorders
Instrument cabinet
Acceleration Measurements
Computer Cabinet
Installed in LBPSB
Acceleration Measurements
0 2 4 6 8 10-1
0
1x 10
-3
Acc
el.
(g)
Baseline Measurements: Roof Center - Oct. 1999
0 2 4 6 8 10-3.5
-3
-2.5x 10
-3
Acc
el.
(g)
0 2 4 6 8 100.01
0.012
0.014
0.016
Time (sec)
Acc
el.
(g)
Typical
Acceleration
Measurements
Time History
Post-Retrofit Activities
Remote CapabilitiesLong Term Role of CSULB