Analysis of UCS
by OpenSees
GSR Tae-Hyung Lee
PI
Khalid M. Mosalam
May 23rd, 2002 Meeting at RFS
Objectives
• Conduct and verify a 2-D nonlinear time history
analysis of UCS using OpenSees
• Develop floor responses to be utilized for the
UCB and UCI shake table tests of the building
contents
• Assess the importance of the different sources
of uncertanties on the structural response
• Extend investigation to 3-D modeling including
multi-directional ground motion
Current Status
• 2-D structural model completed for the UCS
building
• Time history results (as absolute and relative
floor displacements and accelerations and
mid-points of all floors) are available for two
levels of seismic hazard (50% and 10% in 50
years)
• Similar results will be available for the third
level of seismic hazard (2% in 50 years) by
the end of July.
Future Tasks
1) Verification:
A similar shear wall
building where response
data are available will
be analyzed using the
same modeling
approach in OpenSees
An example is the 9 story
Robert A. Millikan
Library Building at
Caltech [McVerry 1979]
Future Tasks
(Cont.)
2) Assess Importance of Uncertainties:
The following five sources will be considered
a) Spectral acceleration
b) Mass
c) Damping
d) Force-deformation characteristics of the different
elements, e.g. in terms of moment-curvature
relations
e) Soil/foundation properties
Future Tasks
(Cont.)
2) Assess Importance of Uncertainties (Cont.):
The objective is to conduct similar study to that of
(Porter et al. 2002, Earthquake Spectra) with
focus on structural response parameters (rather
than costs) and their sensitivity to modeling
issues and input intensities.
The importance of uncertainties will be assessed by
developing a “tornado diagram” using the idea of
“swing” estimation.
Future Tasks
A methodology has
been developed
using SFEM to
generate
probabilistic
moment-curvature
or interaction
diagrams of RC
elements [Lee and
Mosalam, 2002,
Computers and
Structures]
(Cont.)
Future Tasks
(Cont.)
Several verification
studies were
conducted
Future Tasks
(Cont.)
Some results of
interaction
diagrams
Future Tasks
(Cont.)
3) Extension to 3-D:
Modeling structural elements in longitudinal as well
as transverse direction.
Subject the building to simultaneous components of
the ground motions.
Investigate variations of floor response parameters
within the floor space.