Fire Resistance of Concrete-Filled Square Hollow Section Columns in Two-Adjacent-Side Fire

Fire resistance is required to sustain the structural stability when building elements are exposed to a severe fire condition. To evaluate the fire resistance of structural members such as columns and beams, fire engineers can apply either prescriptive methods or performance-based fire design. These two kinds of fire resistance evaluation methods have been developed independently and performance fire design consists mainly of an advanced and simple methods. The simple method stipulated in New Zealand and the U.K. use the limiting temperature. The values of the limiting temperatures of structural steel members were shown in the BS, SNZ, etc but the temperatures of individuals were not classified. In general steel columns were made of H-section but recently the hollow section is inclined to increase for its higher resistant of structural stabilities than any other sections. But the hollow section shows different pattern when it carry out the loads in the cold and is expected to show different behavior when it is exposed to fire. Therefore the limiting temperature of the hollow section is required for evaluation of fire resistance. The paper is to make the limiting temperature of the circular hollow section (CHS) with or without filling of concrete and variance of applied loads.

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EXPERIMENTAL STUDY ON BEHAVIOR OF UNPROTECTED FOAMED CONCRETE FILLED STEEL HOLLOW COLUMN UNDER FIRE

Journal of Civil Engineering Science and Technology ◽

10.33736/jcest.3983.2021 ◽

2021 ◽

Vol 12 (2) ◽

pp. 189-202

Author(s):

Bishir Kado ◽

Shahrin Mohammad ◽

Yeong Huei Lee ◽

Poi Ngian Shek ◽

Mariyana Aida Ab Kadir

Keyword(s):

Fire Resistance ◽

Applied Load ◽

Fire Test ◽

Lightweight Concrete ◽

Steel Tube ◽

Load Level ◽

Exposure Test ◽

Hollow Section ◽

High Rise ◽

Foamed Concrete

Reduction in self-weight and achievement of full fire resistance requirements are some of the important considerations in the design of high-rise structures. Lightweight concrete filled steel tube (CFST) column provides an alternative method to serve these purposes. Recent studies on lightweight CFST columns at ambient temperature have revealed that foamed concrete can be a beneficial and innovative alternative material. Hence, this study investigates the potential of using foamed concrete in circular hollow steel columns for improving fire resistance. A series of nine fire test on circular unfilled hollow and foamed concrete filled hollow section column were carried out. ISO 834 standard fire exposure test were carried out to investigate the structural response of these columns under fire. The main parameters considered are load level and foamed concrete density; foamed concrete density used are 1500 kg/m3 and 1800 kg/m3 at 15%, 20%, and 25% load level. All the columns tested are without any external fire protection, with concentrically applied load under fixed-fixed boundary conditions. The columns dimension was 2400 mm long, 139.7 mm diameter and steel tube thickness of 6 mm. The fire test result showed that foamed concrete increases the fire resistance of steel hollow column up to an additional 16 minutes. The improvement is more at load level above 15%, and the gain in fire resistance is about 71% when 1500 kg/m3 density foamed concrete is used. Generally, foamed concrete filled steel hollow column demonstrate a good structural fire behavior, based on the applied load and foamed concrete density. Also, inward local buckling was averted by filling the steel hollow column with foamed concrete. General method for composite column design in Eurocode 4 adopted to calculate the axial buckling load of 1500 kg/m3 foamed concrete filled columns. These type of columns can be used for structures like airports, schools, and stadiums; taking the advantage of exposed steel for aesthetic purpose and high fire resistance. It can also be used for high rise structures; taking advantage of high fire resistance and reduction in self-weight of a structure.

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