Hollow-Core FRP-Concrete-Steel Tubular Columns Subjected to Seismic Loading

摘要

Synopsis: This paper describes the behavior of precast hollow-core fiber-reinforced polymer (FRP)-concrete-steel columns (HC-FCS) under combined axial and lateral loading. The HC-FCS column consists of a concrete wall sandwiched between an inner steel tube and an outer FRP tube. This study investigated two large-scale columns: the traditional reinforced concrete (RC) and the HC-FCS column. The steel tube of the HC-FCS column was embedded into the footing while the FRP tube was stopped at the top of the footing level (i.e., the FRP tube provided confinement only). The hollow steel tube provided the only reinforcement for shear and flexure inside the HC-FCS column. The FRP in HC-FCS ruptured at a lateral drift of 15.2%, while the RC column displayed a 10.9% lateral drift at failure. The RC column failed due to rebar rupture when the moment capacity dropped more than 20%. The HC-FCS failed gradually with concrete compression failure and steel local buckling followed by FRP rupture. Finite element (FE) analysis was conducted using LS-DYNA to develop a static cyclic analysis of a three-dimensional HC-FCS model. The FE results mirrored the experimental results. The bending strength of HC-FCS columns could easily be calculated with a high degree of accuracy using a sectional analysis based on Navier-Bernoulli's assumptions and strain compatibility concepts.