Service load response of masonry arch bridges

The behavior of filled masonry arch bridges under truck loading is examined by service load testing and by developing a finite-element model of a unit width of the structure. The field tests included five structures varying in span from 3 to 12 m. The structures tested included a group of three structures of similar geometry, material, age, and geographic location. The testing program demonstrated the significance of the linearity of the response to different loading levels and the importance of permanent deformations in evaluating a structure. The field tests also gave evidence of the range of responses of similar structures, and showed some evidence of the development of an incipient mechanism. The analytical model included approximation of the load distribution through the fill and the restraint to movements of the arch ring developed by the fill and spandrel walls. Reasonable approximations of the experimentally observed response of the structures were obtained using the analytical model. Guidance in selecting material properties and stiffnesses for the abutments and fill-in modeling masonry arch structures is given.