It is the opinion of AASHTO and FHWA engineers that U.S. engineers are in need of new, advanced tools and protocols to help them assess and assure safety and serviceability of highway bridges. These tools include an overall, integrated approach to bridge analysis, design, evaluation and determination of load carrying capacity (load rating). Present-day design Specifications (LRFD) have assured safety by analyzing the effect of heavy, legal trucks throughout the United States, and applying a calibration protocol utilizing limited but very reliable Canadian site statistics. However, the calibration did not include serviceability calibration to assure bridge serviceability and performance, and it did not utilize comprehensive statistics available in the U.S., such as weigh-in-motion (WIM) data, as it was deemed unreliable. Therefore, it is desirable to identify design practices, design truck assessments, and detailed code calibration procedures utilized in other countries to assure the safety and serviceability in the design of new bridges. The AASHTO Manual for Bridge Evaluation was developed to assist bridge owners by establishing inspection, evaluation, load rating and posting practices and procedures. The Load and Resistance Factor (LRFR) load rating section of the manual is based on reliability theories to assure a certain level of safety for members and systems against truck traffic. However, certain serviceability checks, i.e. crack control and deflection, were left optional as they are perceived to restrict the movement of goods. It is unclear as to whether or not making these checks optional reduces the service life of the aging U.S. bridge infrastructure. Therefore, it is desirable to identify evaluation (load carrying assessment) practices and quantify the required level of safety and performance utilized in other countries to avoid failures, serviceability concerns, unnecessary expenditures and traffic restrictions.
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