EXPERIMENTAL AND ANALYTICAL STUDIES ON THE SEISMIC RESPONSE OF BUILDING CONTENTS
This research project intends to provide a better understanding and quantitative characterization of the vulnerability of the contents of buildings subjected to ground shaking.
The dynamic behavior of building contents, such as heavy equipment, is sensitive to the characteristic of the base excitation, the friction and restitution properties of the contact interfaces, the restrainer (if present) strength and ductility, and the equipment’s structural rigidity (a thin-walled cabinet may buckle right before it sets into rocking; and may eventually slide).
The course of my research will be as follows:
The first task will be to identify typical building contents of interest and collect information of the geometric configuration and mechanical properties of their supports and contact interfaces (e.g. friction coefficient, stiffness, strength and ductility of restrainers).
The Friction Experiments (May & June 2002)
Secondly, I will select existing or generate new synthetic floor-shaking motions that will be used in the study.
Powerful computational tools such as ABAQUS, Working Model, and MSC.visualNastran 4D (and possibly UDEC, 3DEC) will be validated: analyses results obtained from these programs will be compared with the results obtained from an in-house program that was developed to analyze the rocking response of rigid blocks. After validation, simulation studies of unanchored and anchored equipment will be performed.
Some rocking simulations of block assemblies using ABAQUS
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zipped | unzipped |
| 2D simulation of a 5-drum marble column subjected to a 1-sec-long type-B pulse | 0.6 MB | 6.0 MB |
| 2D simulation of an assembly composed of two 5-drum marble columns and an architrave subjected to the Sylmar record of the 1994 Northridge Earthquake | 3.6 MB | 6.6 MB |
| 3D Simulation of a desktop computer subjected to 3-dimensional shaking (motion: Rinaldi Receiving Station 77; x: RRS-228o, y: RRS-up, z: RRS-318o) | 1.4 MB | 14.8 MB |
I will make preparations for shake table tests. Ground motions for use on tests will be established. (As there are frequency and displacements constraints of the shake table, appropriate motions that can be simulated satisfactorily will have to be selected.) In association with existing loss estimation studies, I will prepare a catalog of building contents for testing. I will then collect the building contents (mostly equipment) to be tested and make plans for shake table testing.
The shake table tests of anchored and unanchored equipment will be performed. This task will involve instrumentation, identification of structural properties, recording of equipment acceleration and displacement (including rotation) during low level shaking (“serviceability” level ) and violent bi-directional shaking, and synchronized videoscoping of the test to capture displacements that are too large to be recorded by conventional instruments.
Shake Table Experiments (September-December 2002)
More Friction Experiments (June 2003)
The experimental data will be analyzed/reduced in an effort to classify the patterns of motions and correlate them with the equipment’s geometric characteristics, interface properties, and the kinematic characteristics of the shake table motions.
Following the experimental studies, the abovementioned predictive tools will be calibrated to simulate the recorded response. This task will examine the capabilities and limitations of the predictive tools and how they can be used with confidence for future parametric studies.
The validated theoretical and numerical techniques will be used to understand response trends and lead to a probabilistic methodology to characterize equipment performance. The proposed methodology for assessing likely performance of equipment will be consistent with overall performance-based earthquake engineering criteria.
The results will be compiled and presented in a final report with detailed documentation of the experimental studies, simulation studies and the proposed performance based engineering methodology. Efforts will be directed to present the proposed methodology in the form of easy-to-use graphs for design.
See the PUBLICATIONS page for pertinent journal and conference papers that describe the findings of my research.