In the Balkan Peninsula, the single-arched stone masonry bridge has served for centuries as an essential part of transportation infrastructure. Being exposed to the natural elements and to aging, several of these structures are in a state of disrepair that is accelerated by neglect. Nevertheless, these are important samples of the built heritage encapsulating historical materials, methods of construction and ancient craftsmanship. Still standing for over half a millennium, such bridges testify the wisdom by which the masons chose the location and form of the arch to span over torrents minimizing the wear from water scouring and floods. Preservation of the bridges that are still standing is a priority. With increasing number of bridge collapses reported in the past years under extreme flood, an immediate need emerges for methods of evaluation of the structural vulnerability and measures to enhance their resilience. Using as a case study a bridge built in fifteenth century in Greece, this paper unfolds the essential attributes of a comprehensive assessment framework that combines non-destructive evaluation techniques to reveal information about technologies and details, with a numerical investigation of the resilience of the structure to floods and seismic hazards in order to identify risks of bridge integrity.

Experiments on deformed reinforcing bar anchorages developed in strain-resilient cementitious composites (SRCCs) with high tensile deformation capacity illustrate that the bar-matrix assembly may respond in a ductile manner marked by pullout failure with no cover splitting—even in the absence of external confinement. This ductile bond-slip response is owing to the extremely high tensile fracture energy of the matrix, which is attributed to the reinforcing action of the dispersed microfibers in the cementitious matrix. This enhances the associated bond-slip law with higher strength and a slowly descending branch, very similar in form to the response curve of confined anchorages that demonstrate ductile, resilient response. To understand and model the structural response of an elastic bar anchorage in a SRCC matrix, the analytical solution of the field equations that govern the bond problem are established with reference to the entire range of the bond-slip law up to large levels of slip, including the postpeak descending branch, which quantifies the fracture energy of the matrix. The accuracy of the mathematical solution is verified through correlation with laboratory evidence, benchmark finite-element analysis examples, and numerical solutions of the discretized problem. The mathematical solution is used in order to conduct a parametric investigation that accounts both for the bond toughness and the anchorage geometry, to illustrate their significance as prerequisite for development of high-strength reinforcement.

The results of an experimental investigation of steel-reinforced beams comprising fiber-reinforced strain-hardening cementitious composites are presented. Polyvinyl alcohol fibers were used in the cementitious mix to achieve significant tensile deformation capacity, which contributed significantly to the flexural resistance. A total of 18 specimens were tested under four-point bending with shear span ratios of 2 and 3.5 to ensure flexural failure. The fiber-reinforced composite’s behavior in tension was marked by the formation of multiple cracks that resulted in strain-hardening postcracking behavior and sustained tensile strength up to large tensile strain magnitudes. Variables of the experimental program were the amount of tension and compression steel reinforcement, the availability of confinement (stirrups), and the shear span aspect ratio. Test results illustrated the beneficial action of the fibers in the tensile zone of the beam through bridging of cracks and transferring loads, while in the compressive zone of the beams, fibers restrained lateral expansion and led to ductile compressive response. Analytical expressions to estimate the flexural strength of steel-reinforced, strain-hardening cementitious composite beams were also derived and correlated with the experimental results.