Temperature Rise of a Protected Steel Column Exposed to Fire from Two Adjacent Sides

摘要

Current design equations in EN1993-1-2 for calculating the temperature rise of a protected steel column assume the uniform temperature distribution across the section in a fire, which ignore the difference in heating rate at different parts of the column. The temperature rise and the temperature distribution across the column section at a given fire exposure time were studied through finite element analysis for a column exposed to fire from two adjacent sides. Studied parameters included the section dimension and the fire protection thickness. Modification factors were proposed to the current EN1993-1-2 design equations for calculating the temperature of the un-exposed flange and the web. Differences between temperatures obtained from the modified calculation method and from the finite element simulation were less than 20A degrees C. Temperature distributions across the two flanges and the web were assumed to be linear and methods were proposed to calculate the temperature gradient. With the increase in fire exposure time, differences between the simplified method and the finite element simulation decreased. At the fire exposure time of 120 min, differences in temperatures of the un-exposed flange and the web were less than 10%; and the differences in temperatures of the exposed flange was less the 5%.