Axial compressive behavior of PBL-stiffened double-skin composite walls considering local buckling: Experimental and theoretical investigation

Double-skin composite walls (DSCWs) stiffened with perforated ribs (perfobond leiste in German, abbreviated as PBL) has gained popularity in large-scale structures due to their industrial construction potential. This study aims to explore the axial compressive behavior of PBL-stiffened DSCWs, considering the post-local buckling effect of the faceplates. Six PBL-stiffened DSCWs underwent an experimental investigation under axial compressive loads to evaluate their failure mode, load-axial behavior, ductility, and local buckling behavior. The study also examined the effect of the spacing of transverse and longitudinal PBLs and the introduction of headed studs on the axial compressive behavior of DSCWs. Results reveal that decreasing the spacing of transverse PBLs enhances the confining effect on the infilled concrete, increasing the axial compressive resistance of DSCWs. The introduction of studs delays local buckling and results in strain-hardening of the faceplates, improving the axial compressive resistance of DSCWs. However, increasing the longitudinal PBL spacing weakens the out-of-plane restraint of the faceplates, decreasing both local buckling load and compressive resistance. Assuming the longitudinal PBLs as out-of-plane continuous elastic supports, the elastic critical local buckling coefficient of PBLstiffened plates with unilateral restraints was derived using the Ritz method. Based on this, the critical relative stiffness of the PBL can be determined, which helps in identifying the local buckling mode of the PBLstiffened plates. To estimate the post-local buckling behavior of PBL-stiffened plates with unilateral restraints, an effective area method was proposed. Finally, a formula was proposed to predict the axial compressive resistance of PBL-stiffened DSCWs, considering the post-buckling effect. A suggested design procedure for PBLstiffened DSCWs was also provided.