Jonathan A. Knudtsen1, Petr Kabele2, and David T. Biggs3
1)  Czech Technical University in Prague, currently at KPFF Consulting Engineers
Portland, OR, USA
2)  Faculty of Civil Engineering, Czech Technical University in Prague
Prague, Czech Republic
3 Biggs Consulting Engineering
Saratoga Springs, NY, USA

Keywords: Masonry, Arch, Modelling, Finite Element, Rigid Block.

Abstract. Analytical methods for masonry arch structures have undergone significant development over the past few decades. Rigid-block and finite element analyses have largely supplanted earlier elastic-beam and graphic statics techniques. These modern analysis techniques are thought to provide better representation of arch structures. However, their range of applicability and conservativeness are still not well understood. The purpose of this paper is to compare various analysis techniques, evaluating the results from the point of view of structural response, modelling efficiency, and uncertainty in the input parameters. The techniques considered include limit analysis “by hand”, rigid-block analysis, finite element analysis using a smeared crack model, and finite element analysis using a discrete crack model. This paper is based upon a case study of a 19th-century stone masonry arch bridge in Troy, NY, USA. In 1986, the bridge underwent a significant intervention in which the infill and spandrel walls were removed and replaced. At the time, the bridge was rated using a model consisting of a series of elastic beam elements. The results of that analysis are compared with the analyses above. Based on these results, conclusions and recommendations for further study are developed.