Performance of recycled aggregate concrete (RAC)-filled steel tubular (FST) members and K-joints under lateral impact

Abstract

A series of tests are conducted on 26 recycle aggregate concrete (RAC)-filled steel tubular (FST) members and 25 RAC-FST K-joints on a drop hammer rig. Salient parameters considered in the experimental program include the axial load ratio, the replacement ratio of recycled coarse aggregate (RCA), the height of the hammer and the application of combined corrosion and sustained loading, et al. The shrinkage and creep deformation of core RAC is measured for 185 days, and the influence of key parameters on the structural performance of both RAC-FST members and K-joints are analyzed. A finite element (FE) model is established and verified against the test results. Considering the effects of combined chloride corrosion and sustained loading, the FE model is successively employed to investigate the behaviour of RAC-FST members and K-joints under lateral impact, including the failure mode, the time history relationships of impact load and deflection, the distribution of internal force and stress, et al. The axial compression performance of the member and the chords of K-joints after being subjected to combined loading is evaluated. On the basis of the parametric analysis, simplified models considering the effects of chloride corrosion and sustained loading are obtained to calculate the dynamic flexural capacity of the RAC-FST members and the chords of RAC-FST K-joints under impact loads.