بررسي آزمايشگاهي اثر ورق هاي سخت كننده در رفتار ستون هاي فولادي پرشده با بتن CFST

EXPERIMENTAL RESEARCH OF STIFFENERS EFFECTS ON THE BEHAVIOR OF CONCRETE FILLED STEEL TUBE COLUMNS (CFST)

Composite columns have been used in constructions for many years due to their advantages over ordinary columns. Concrete filled steel tubes, CFST are one such column. Some of the advantages of these types of column are known as; not needing molding, high ductility, rel¬atively high resistance with low volume properties, low deformation capability relative to ordinary steel columns and, most commonly, economic potential. Due to these enormous potentials, a general research program was launched to investigate CFSTʹs in an ex¬perimental manner. This program was planned and done in the IIEES structural lab in Tehran, Iran. In order to achieve the goals of the project, ten specimens were con¬structed using a 1:3 scale and were tested as cantilever columns. Specimens were loaded under a constant axial load, while laterally loading under an enhancing lateral cyclic load based on a displacement controlled condition. Three distinct geometrical shapes namely, square; cir¬cle and octagonal sections were considered and tested. Specimens were also tested using stiffeners in compari¬son to specimens without stiffeners. This paper presents the results obtained and ways and methods of achieving the goals of the project. Using stiffeners inside a steel tube in the critical zone, significantly improves column behavior and ductility