This study considers the application of object oriented programming approach to develop a Windows based program for the design of reinforced concrete T -beam bridges in accordance with the newly adopted AASHTO LRFD Bridge Specification. The program can perform both the analysis and design of the deck and beam. The program is interactive in nature and it is possible to change all input data and design parameters during execution. A series of second-degree interpolating polynomial functions were developed for representing influence line coordinates for various load effects in the deck and beam subjected to moving loads. The analysis results using the program were compared with those obtained from the commercial programs. The design results obtained from the program were compared with example problems for several test structures. Both design and analysis comparisons gave satisfactory results. The successful performance of the program demonstrates the significant advantages of the object oriented programming. It was concluded that the benefits of object oriented programming approach make this a viable technique for the development of computer applications for structural engineering. / Master of Science