FIRE BEHAVIOR AND FIRE-RESISTANT DESIGN OF CONCRETE-FILLED STEEL TUBULAR COLUMNS

The behavior of concrete filled steel tubular columns under ISO 834 or GB 9978 88 standard fire curve is briefly introduced in the present paper.The influences of the changing strength of the materials, sectional dimensions, steel ratio, load eccentricity and slenderness ratio on the fire resistance are discussed. The results show that the composite columns have excellent behavior under fire and high fire resistance because of the interaction between the steel tube and its core concrete, as well as the heat absorption ability of the concrete core itself. The columns can satisfy the design fire resistance that are demanded by the code named GB 50045 95 Code for Fire Protection of High Rise Building with proper spraying material protection.the fire protection thickness determination methods for pure steel structure columns are unsuitable for the composite columns. The theoretical model in this paper were used to provide data on the necessary fire protection measures for the concrete filled steel tubular columns used in a high rise building, SEG Plaza in Shen zhen City, South China.In this case 78.6% coating can be saved on the column structures of the building.And the increase of the sectional dimensions of the columns is limited.So it has a good economic profit and architectural effect.