Hollow Steel Columns Research Articles

Strengthening of slender hollow steel columns by filling with concrete

The long hollow steel columns that support the roof of the oil storage tanks at Lennox generating station required strengthening to resist bending moments in addition to axial load. The results of a theoretical analysis indicated that pumping these columns full of concrete would provide the necessary increased capacity. However, present standards ignore the stiffening effect of concrete for columns where the slenderness ratio is high. Also, there are no test data available to confirm the theoretical analysis. Therefore, tests were conducted on two 47 ft (14 m) long, 13 in. (33 cm) diameter pipe columns, one empty and the other filled with concrete. The results of these tests confirmed that the concrete significantly increased the load and moment capacity of the columns.

Temperature Distributions in Fire-Exposed Building Columns

A procedure based on a finite difference method is described for calculating the temperature history of fire-exposed protected steel columns with rectangular cross section and heat generation or absorption in the insulation. Comparison with results of tests and those obtained from an analytical solution of the heat transfer equations indicates that the accuracy of the method is adequate for fire engineering purposes. The method is also suitable for the calculation of temperatures in monolithic building components such as solid concrete columns, beams, and walls. It can also be used for the calculation of temperatures of any system in which a perfect conductor or well stirred fluid is enclosed in an encasement, for example, water-filled hollow steel columns or beams, and exposed to a radiative heat source of varying temperature.