| The United Nations Industrial Development Organization (UNIDO) has, over the past five years, sponsored a research program for the development of low-cost natural rubber isolation systems for the seismic protection of public housing in developing countries. This program has led to demonstration buildings in China and Indonesia. This dissertation describes experimental and analytical studies carried out as part of the design and construction of the Indonesian demonstration building.; The building is a four-story, eight-apartment housing block. The superstructure consists of reinforced concrete frames with infilled masonry panels, which are separated from the structural frames by seismic gaps filled with soft mortar. The superstructure is designed in accordance with the Indonesian Codes and Regulations for fixed-base buildings. The isolation system is designed using site-specific spectra, and uses multi-layer high-damping natural rubber (HDNR) bearings with recessed end connections. Two natural rubber compounds are used in the system.; An extensive experimental program using samples of full-size bearings was carried out to evaluate the dynamic properties of the isolators, and the factors that affect these properties. In addition, roll-out tests, real-time tests, and cyclic vertical tests were also performed. The test results showed that the properties of the bearings agreed with the design values, and that the bearings have a displacement safety factor of 1.3 and a force safety factor of 1.8. A one-third scale sub-assemblage of the infilled reinforced concrete frame with seismic gaps was built and subjected to gravity load and to a series of reversed cyclic horizontal loads. The results show that the soft mortar around the infill panel began to crush at about 0.1% drift, and that the infill panels remained uncoupled from the frame until the drift reached approximately 1.5%. Beyond that level, the infill panels formed diagonal compressive struts and started to influence the stiffness of the frames.; The performance of the building was evaluated for serviceability, maximum design earthquake (MDE), and maximum probable earthquake (MPE) risk levels, using both modal and time-history analyses. The isolators were modeled as a combination of an elastic spring and a viscous damper. The superstructure was modeled as a full three dimensional system in the time-history analyses, and as a lumped-mass system in the modal analyses. The composite superstructure-isolator system was subjected to a series of ground motions selected to match the site spectra in the time-history analysis, and the site spectra, the Uniform Building Code spectra, and the Indonesian Seismic Code elastic spectra were used in the modal analyses. The results from both analytical methods show that, for all cases considered, there was no amplification of the peak ground acceleration to the superstructure, and the displacements in the isolation bearings were smaller than the MPE deflection of 184 mm. The distribution of the maximum floor displacements was similar to the first mode shape of the isolated building, and the maximum interstory drifts were less than 0.3%, which would be one fifth of the interstory drift of the corresponding fixed-base building during an MDE earthquake. (Abstract shortened by UMI.)... |
