*** 9622403 Ehsani Fiber Reinforced Composites, FRP, are fast becoming a viable new construction material. Perhaps the most suitable area of application for these materials is in the field of strengthening, repair and rehabilitation of existing civil structures. A major concern, however, is the quality control at the time of construction and the long-term behavior of these materials. The primary focus of this study is to develop a Non- Destructive Evaluation system for determining the characteristics of composites used in the construction industry. The equipment can be utilized after the completion of the construction to monitor any deterioration or delamination of the FRP which could result from environmental effects such as ultraviolet rays, moisture penetration, etc. The quality of rehabilitation will be monitored nondestructively by ultrasonic inspection of internal defects, voids and delaminations. In this research "kissing" and "slip" bonded interfaces, often dangerous for the integrity of material systems, will be investigated by exciting strong interface waves. It is expected that one will be able to successfully detect these defects by generating interface waves at the imperfect bond interfaces using an ultrasonic scanner. ***