Elastoplastic Quasi-Static and Impact Load Response of Steel Structure Sub-Assemblage with CFRP Strips

Presented in this paper is the outcome of an experimental investigation of the elastoplastic quasi-static and impact load response of a steel sub-assemblage constructed using a pair of hollow square section members with or without Carbon Fiber Reinforced Polymer (CFRP) strips. The sub-assemblage consists of a long structural member welded to a short member, thus representing a typical combination of a column and a beam on the face of a multi-story steel building frame. The column is subjected to a lateral quasi-static or impact load. Tests are conducted on four separate steel sub-assemblages. The first two tests are conducted with a gradually increasing flexural load applied at the midspan of the column up to the collapse condition without and with CFRP strips, respectively. Additional two tests are performed with a flexural impact load applied at midspan of the column also both without and with CFRP strips, respectively. The results of the study show that CFRP strips substantially increase the quasi-static collapse load of the sub-assemblage. However, when subjected to an impact load, the steel structure sub-assemblage with CFRP strips developed smaller strains in comparison with those without the CFRP strips. The post-impact time-dependent strains also became considerably smaller for the sub-assemblage with CFRP strips.