9402196 Soong The objective of this joint research program with researchers in PRC is the full-scale implementation of passive and active control technology to structures against wind and earthquake loads. While several structures in PRC are being considered for structural control, the focus of the project is on the Nanjing Tower, which has been chosen not only for control implementation but also as a test-bed where multiple systems will be installed and their performances observed, analysized and compared. During the first phase of this project the research, development and installation of suitable control systems for the Nanjing Tower will be carried out in collaboration with PRC researchers. The systems under consideration include tuned liquid dampers, viscoelastic dampers, and tuned, semi- active, and hybrid mass dampers. One of the direct benefits to the structural control research community derived from this joint research program is new information about some of the important implementational issues in connection with structural control. Some of the issues to be addressed in the second phase of this project include: system optimization, fail- safe measures, reliability and maintenance, operational issues, diagnostics, and cost benefit analysis. ***