Near- and far-field earthquake damage study of the Konitsa stone arch bridge

This paper reports on the sensitivity of earthquake response and damage of long span masonry stone bridges to near field (impulsive type) and far field earthquakes. Towards that objective, the Konitsa Bridge is used as a case study. The particular bridge was selected for offering certain unique features such as long span, built right on an active fault, survived a recent pair of near-filed type earthquakes with minimal damage and finally, construction material mechanical properties and strength could be deduced from a recently collapsed similar bridge in the area. The multifaceted study integrated in-situ measurements of dynamic characteristics, laboratory tests on representative stone and mortar materials and a series of finite-element analyses based on non-linear modelling using a combination of discontinuous and continuous representations to capture the behavior of bridge structural component interface and interaction as well as mortar-stone interaction and failure. In addition to the ground motion records of the recent seismic activity at the Konitsa Bridge location, four additional earthquake records representing near-field and far-field families were utilized to assess the stone bridge sensitivity. The study revealed that far-field earthquakes are far more destructive than near-field counterparts, a finding in full agreement with studies on near field earthquake effects on nuclear structures. The applicability of earthquake damage indicators such as CAV, Arias intensity and energy rate, typically used for conventional and nuclear structures, was evaluated based on the numerical analysis results.