Mechanical Behavior of Special-Shaped Reinforced Concrete Composite Columns Encased with GFRP Core Columns

In order to investigate the mechanical behavior of special-shaped reinforced concrete composite columns encased with GFRP core (EGCSSCs) subjected axial load, twenty-seven full-scale EGCSSCs were designed varying parameters: compressive strength (fcc), peripheral (fco), thickness tube (tgfrp), ratio longitudinal reinforcement (ρv), stirrup (ρs) and in cross-section (α). The three-dimensional finite element refined models established by ABAQUS software, response under load was studied based on verification modeling. influence different parameters ultimate (Nus), initial stiffness (K), ductility index (µ) obtained, typical failure mode clearly described. results showed that main bulging outward at middle EGCSSCs, yielding steel bars, crushing both ends concrete. When column damaged, reached peak stress earlier than All specimens exhibited excellent load-carrying capacity good ductility. Moreover, existence columns, Nus µ increased 11.61% 140.86%. addition, K increase fcc, fco, tgfrp α, largest increments 23.99%, 50.54%, 21.77%, 34.19%, respectively. decreased fcc which 14.05% 40.28%, By using statistical regression introducing constraint effect coefficients reduction coefficient, calculation formula for compression-bearing derived, could lay a foundation popularization application this kind practical engineering.