In this project experimental and analytical studies are underway to examine the seismic vulnerability of free standing and anchored equipment located within buildings with several floor levels. The equipment of interest are low-temperature refrigerators, freezers, incubators and other heavy equipment of the Life Science Addition (LSA) building on the UC Berkeley campus.

The dynamic behavior of either free-standing or anchored equipment is very sensitive to the characteristics of the base input (mainly acceleration amplitudes and frequency content), the frictional characteristics of the equipment-base interface, the restrainer strength and ductility and the structural rigidity of the equipment.
In this project we concentrate on three heavy pieces of equipment of various size and slenderness that we are able to obtain from the LSA building administration. The reader can view the equipment that have been tested and analyzed at: http://www.ce.berkeley.edu/~dakon/shaketests/

After having experimentally identified the mechanical properties of their support (flexibility of legs/pads and coefficient of friction) we conducted extended shake table studies to better understand the response patters of free-standing and anchored equipment. The experimental data will be used to validate commercially available software (Working Model) that we have used during summer 2002 for simulation of the anticipated response. Upon validation of the Working Model software, extensive simulation studies will be conducted to produce fragility curves on the seismic response of building contents.

The methodology employed combines experimental and analytical studies. Early numerical simulation offered indications on the anticipated response. Subsequently, the shake table studies have been planned to generate strong shaking of the equipment in an effort to reach response levels that correspond “life safety” of failure. Because of the many nonlinearities that govern the mechanical behavior the response appears initially chaotic. Efforts are under way to order the recorded data using formal dimensional analysis. The study is concerned with what are the most meaningful intensity measures (IM) and how the engineering demand parameters (EDP) of interest depend upon.

The seismic response of building content is of interest to major facilities such as hospitals and companies that use sensitive computer equipment. Recently, the International Conference of building Officials (ICBO) has issued acceptance criteria for seismic qualification testing of non-structural components. The criteria were developed and adopted following public hearings conducted by the Evaluation Committee (ICBO Evaluation Service, INC). This project will generate data that will enhance the evaluation of the acceptance criteria.

ABS Consulting, INC, contact: Farzin Beigi, PE.

Validation of simulation procedures with experimental data. Calibration of predictive analytical and numerical tools to simulate the recorded response. Development of a methodology to characterize equipment performance in probabilistic terms. The proposed methodology for assessing likely performance of equipment will be consistent with the overall PEER performance-based earthquake engineering evaluation methodology.

Compilation of results and preparation of final report with detailed documentation of the experimental studies, simulation studies and the performance based engineering methodology. Continuous updating of the web site: http://www.ce.berkeley.edu/~dakon/shaketests/