Chi Ming Wong

Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Civil Engineering and Engineering Mechanics


W.K. Tso


Access floor systems have been widely used to support equipment in telecommunications central offices. In this thesis, the seismic response of equipment supported on access floors in telecommunications central offices is studied. There are two major issues for equipment supported on access floor under seismic condition. First, the access floor tends to amplify the motions from the building floor; as a result, the equipment supported on it is subjected to a more severe shaking than if it were supported directly on a building floor. Second, most access floor systems are designed for gravity load only. Their seismic performance depends on their lateral stiffness and strength. Such information is not generally available. The objective of the study is to address the first issue and to provide guidelines for the seismic analysis, design and qualification of equipment installed on access floors. This is achieved by a systematic study on the dynamic response of combined equipment-access floor systems by experimental and analytical approaches.

The experimental work is carried out using commercial access floors of two different floor heights and a typical switching equipment unit commonly used in telecommunications central offices as test specimens. There are three phases involved in the experimental work. First, static tests are performed to investigate the stiffness and strength properties of the access floors. Second, dynamic exploratory tests are carried out to study the dynamic characteristics of the access floors, the telecommunications equipment and the combined equipment-access floor systems. Lastly, seismic tests are performed for the equipment alone and the combined equipment-access floor systems to evaluate the effect of the access floor on the seismic response of the equipment.

Based on the observations and results of the experiment, an analytical model is developed. The reliability of the model to predict the dynamic properties and the seismic response of combined equipment-access floor systems is checked by experimental results. A parametric study is then carried out using this model to provide insight into the dynamic properties of equipment-access floor systems. The model is also used to study the seismic response of equipment supported on access floors in telecommunications central offices. Finally, design spectra for telecommunications equipment supported on access floors are generated for the purposes of seismic analysis, design and qualification.

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