Modeling unknown variables and degradation effects in the assessment of stone arch bridges

In the Unites States, stone masonry arch bridges have successfully served the transportation needs of local communities and are part of the history and heritage of this country. Many of the existing bridges have exceeded their intended service life and have functional or structural issues, yet remain in service due to their critical location, cost of replacement, community involvement or historic designation. From a structural engineer standpoint, understanding the appropriate evaluation methods, analysis techniques, and repair and strengthening options is critical to the preservation and rehabilitation of stone masonry arch bridges. The chapter investigates the influence of longitudinal cracks on the arch capacity, and the effect of modeling the interaction between the arch barrel and the spandrel wall. The Bow Ridge Bridge is a six-span stone masonry arch bridge originally built to carry rail lines over the Conemaugh River, in Indiana County, Pennsylvania. The chapter presents the results for a one-hundred-year old, multi-span stone arch bridge located in Pennsylvania.