Circular Concrete-Filled Tubular Columns: State of the Art Oriented to the Vulnerability Assessment

The vulnerability of framed structures has been analyzed until recently from two different perspectives: Structural and socio-economical. For the sake of assessing the former, indexes and objective measurements have been proposed in the literature. These indexes include relatively accurate assessments of the strength, ductility, energy absorption, fire, blast response and resilience of the elements in order to define a higher-level structural magnitude. Similar approaches are performed with the latter when it comes to assessing damage, economical aspects, social and other important factors. On the other hand, concrete-filled tubes (CFT) have proven structurally efficient due to their relatively high strength-toweight ratio. Considerably complete state-of-the-art reviews are available for these members when it comes to analyzing their strength and overall or local buckling in static and/or dynamic responses. Reviews concerning important issues related to the structural vulnerability of those members are, however, scarce. In this paper, a state-of-the art dealing with the behavior of concrete-filled tubes is presented. The novelty of such approach is to present research concerning CFT but, in this case, from a structural vulnerability perspective (not socioeconomical), that is to say, summarizing references concerning seismic response, fire resistance, impact response and other main characteristics that are further used when defining the aforementioned indexes. Relevant numerical, experimental and theoretical studies presented in recent years are pinpointed as well as potential research trends.