The objective is the development of a cost-effective dynamic monitoring system for steel bridges and other steel structures with permanently instrumented sensors and computer integrated signal processing techniques. The theoretical basis of this monitoring system is the "Vibrational Signatures Analysis:. In addition to hardware and software development, this monitoring system will be implemented on a 2/5 scale five story steel structure and a 1/6 scale model bridge cooperatively with the NY State DOT. These two tasks are designed to evaluate the effectiveness of the proposed system subject to a variety of loading and environmental conditions. //