In this paper, a simple and innovative sandwich panel with GFRP face sheets and a foam-GFRP web core (GFFW panels) is developed. An experimental study was carried out to validate the effectiveness of this panel for increasing the bending strength. The effects of web thickness, web spacing, web height and face sheet thickness on bending stiffness and energy dissipation were also investigated. Test results demonstrate that compared to the normal foam-core sandwich panels, a maximum of approximately 640% increase in the ultimate bending strength can be achieved. Meanwhile, the bending stiffness and energy dissipation can be enhanced by increasing web thickness, web height and face sheet thickness. An analytical model was developed to predict the ultimate bending strength of GFFW panels. The formulae to calculate the equivalent bending stiffness, shear modulus and mid-span deflection were also derived. A comparison of the analytical and experimental results showed that the analytical model accurately predicted the ultimate bending strengths and min-span deflections of the GFFW panels under four-point bending. Furthermore, the finite element analysis was extended to nvestigate the effects of foam density and shear span-to-depth ratio which were not considered in the tests. The numerical results revealed that increasing foam density and decreasing the shear span-to-depth ratio can improve the bending strength and stiffness of the panels.

A composite concrete column with encased fiber reinforced polymer (FRP) confined concrete cores (EFCCC) is proposed in this paper. The cross-sectional form of the EFCCC column is composed of several orderly arranged FRP confined concrete cores (FCCCs) surrounding a filled core concrete. This novel composite column has several advantages, such as higher compressive capacity, stronger FRP confinement, and ductile response. The compressive experiment is employed to investigate the compressive behavior of the EFCCC column with deferent parameters, such as outside concrete and stirrups. Test results show that the main failure mode of the EFCCC column with and without an outside concrete or stirrups is tensile fracture of the glass fiber reinforced polymer (GFRP) tubes. Compared to a reinforced concrete (RC) column, the strength and ductility of the EFCCC column was obviously improved by 20% and 500%, respectively. A finite element model (FEM) based on the Drucker–Prager (D-P) was developed that can accurately predict the axial compression behavior of the composite column with FRP confined concrete core. The predicted results obtained by using this FEM have excellent agreement with the experimental results.

When subjected to loading or thermal shrinkage, reinforced concrete structures usually behave in a cracking state, which raises the risk of bar corrosion from the working environment. The influence of cover cracking on chloride-induced corrosion was experimentally investigated through a 654-day laboratory test on cracked reinforced concrete specimens exposed to chloride solution. The concrete specimens have a dimension of 100 mm × 100 mm × 400 mm and a single prefabricated crack at the midspan. When the percentage concentration of chloride ion (0.6%, 1.2%, 2.1%, 3.0%, and 6.0%) and crack width (uncracked, 0.2, 0.3, 0.4, and 0.5 mm) are taken as variables, the experimental results showed that the corrosion rates for cracked specimens increased with increasing percentage concentration of chloride and increasing crack width. This study also showed the interrelationship between crack width and percentage concentration of chloride on the corrosion rate. In addition, an empirical model, incorporating the influence of the cover cracking and chloride concentration, was developed to predict the corrosion rate. This model allows the prediction of the maximum allowable wcr based on the given percentage concentration of chloride in the exposure condition.