STRUCTURAL MONITORING FOR SEISMIC DAMAGE EVALUATION: A CASE STUDY

Abstract

Seismic events are one of the phenomena with greater influence on the structural condition of bridges and viaducts. For this reason, its design and construction must be carried out under dynamic criteria to guarantee its resistance in a wide range of scenarios. Into the Spanish territory, these requirements are included in the Earthquake-Resistant Construction Standard – NCSE02. However, a large number of structures were built before the appearance of seismic regulations and thus, its indications were not taken into account. In these cases, it is crucial to monitor the behaviour of the structure in order to assess possible damage due to dynamic action. This work presents a case study, focusing on the Santa Ana viaduct, constructed in the Quisi ravine, in Benissa, Alicante (Spain). The rivet structure was built in the early 20th century, being unusual finding similar case studies in the literature. The viaduct, which is in the final stage of its useful life, serves as a bridge for a tram line between neighbouring towns. This work aims at studying the viaduct’s structural modal shapes and damping factor to establish its possible interaction with a seism. To this end, the viaduct was monitored with eighteen accelerometers distributed along its length. Through an acquisition system, the vibrations suffered by the structure were automatically registered after the passage of each train. The signals were subsequently processed using different operational modal analysis techniques. This allows not only to obtain the modal parameters associated with the structure, but also its temporary evolution and therefore, predictively determine the possible appearance of structural damage.