NCHRP Report 485 contains the findings of a study to develop a process for validating bridge design and analysis software. The report describes the research effort leading to the recommended process and discuses the application of this process to software evaluation, design comparisons, and specification review. The material in this report will be of immediate interest to software developers, bridge-design specification writers, and bridge engineers.

Computer software is needed to permit a full adoption of the AASHTO LRFD Bridge Design Specifications as the standard specification. AASHTO is addressing this issue through joint development of AASHTOWare BridgeWare Products, and others are also developing software systems. Because of the complexity of the specifications, designers and bridge owners need a way to ensure that the software is valid and reliable. A standard validation process is needed to achieve this goal.

The objective of this project was to develop a methodology for bridge-design software validation. This objective has been achieved with the development of "Process 12-50", a systematic method of comparing and evaluating bridge design and analysis software. Process 12-50 also provides a standardized report format for presenting and comparing results for a specific bridge design and a powerful method for formally reviewing specification changes.

Michael Baker Jr., Inc., assisted by BridgeTech, Inc., Modjeski and Masters, Inc., and Paul D. Thompson, performed the research. The report fully documents the methodology used to develop the validation process and provides specific instructions on implementing the process. The accompanying CD ROMs contain the testbed of bridges with well-defined parametric inputs and outputs developed in this research. All common tables necessary to implement Process 12-50 and software to aid in viewing the databases also are included on the CD ROMs.