Experimental Study on the Fire Resistance of Steel Columns Protected with Fire Boards

摘要

The thickness of the fire protection material of steel columns should be determined to guarantee the load-bearing capacity of the steel columns during a fire. In Korean standards, the strength capacity of steel columns is evaluated by measuring the axial deflection or surface temperature of only one H-section of 300x300x10x15 or similar dimensions in a fire test. Once the thickness of a fire protection material is approved, it can be applied to any section, regardless of the size and shape. However, in order to properly protect a building from a severe fire, the appropriate thickness of the fire protection material should be determined with consideration of the section factor, size and shape of steel columns in accordance with building regulations. This paper describes a series of full-scale and small-scale fire tests which were conducted on H-section and Rectangular Hollow Section (RHS) steel columns protected with glass fiber reinforced gypsum (GRG) boards and cellulose fiber reinforced cement (CRC) boards. The main factors of the fire tests were the section factor, the section shape and the thickness of the fire protection materials. Simple equations to predict the thickness of a fire protection material of steel sections, accounting for the shape factor and the required fire resistance, are proposed. A comparative study on the efficiency between the newly developed columns with two types of fire boards and the conventional columns with a combination of spray and gypsum boards was also conducted, and results are reported herein.