Applications in Civil Engineering
Automated Model Updating using Ambient Vibration
Data from a 48-Storey Building in Vancouver
One of the purposes of conducting ambient vibrations
tests on large civil engineering structures is to use the
modal information obtained from these tests to improve the
finite element model of the structure being investigated.
The building considered in this study is called Heritage
Court Tower (HCT) and it is located in downtown Vancouver,
British Columbia in Canada. It is a relatively regular 15-story
reinforced concrete shear core building. In plan, the building
is essentially rectangular in shape with only small projections
and setbacks. Typical floor dimensions of the upper floors
are about 25 m by 31 m. (see figure 1).
Figure 1: View of HCT building and
typical floor plan dimensions (m).
The
modal identification from a series of ambient vibration
tests was performed using the ARTeMIS Extractor software.
For more information see
http://www.svibs.com/documentation/case_hct.htm
A finite element model of the
HCT building was made and solved with FEMtools. FEA. Properties
of the beams, columns, shear walls, floor slabs and cladding
panels were estimated and used to compute the first 6 modes
of the building. These modes are then overlaid and compared
with the experimentally obtained mode shapes. Figure 2 shows
the result for the first 3 modes by reducing the FE model
to the same number of degrees of freedom as used in the
test model. This provides easier graphical interpretation
of the results.
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Figure 2: Comparison of reduced FE
mode shapes of updated model and experimental mode shapes
of HCT building.
Considering the uncertainty on the initial
estimates of the input data, a number of parameters were
selected to update the finite element model, including Young's
modulus, mass density, moment of inertia and panel thickness
of various components. The resulting improvement of mode
shape correlation is shown in figure 3.
Figure 3: MAC matrices for six mode
shapes of HCT building before (left) and after (right) model
updating.
This case study showed that is it possible
to accomplish an effective model updating of a large civil
engineering structure using the results from ambient vibration.
The use of FEMtools Model Updating greatly facilitates determining,
which are the model parameters that can be modified in order
to achieve a good correlation between experimental and analytical
results. The interpretation of the changes obtained by the
modal updating program requires knowledge of background
information on the test and FE modeling assumptions.
For more information:
J.-F. Lord, Carlos E. Ventura, Eddy
Dascotte, Automated Model Updating using Ambient Vibration
Data from a 48-Storey Building in Vancouver. Proceedings
of the 22th International Modal Analysis Conference (IMAC),
January 2004, Detroit, Michigan.
Download (PDF, 174 KB)
J.-F. Lord, Carlos E. Ventura, Eddy
Dascotte, Rune Brincker, and Palle Andersen, FEM Updating
using Ambient Vibration Data from an 48-Storey Building
in Vancouver, British Columbia, Canada. Presented at
the 32nd International Congress and Exposition on Noise
Control Engineering (Internoise 2003), August 25.28, South
Korea.
Download (PDF, 472 KB)
Carlos E. Ventura, J.-F. Lord and
Robert D. Simpson, Effective Use Of Ambient Vibration
Measurements For Modal Updating Of A 48 Storey Building
In Vancouver, Proceedings of the 3rd International Conference
on Structural Dynamics Modeling - Test, Analysis, Correlation
and Validation - Madeira Island, Portugal, June 2002.
Download (PDF, 280 KB)
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