Effects of Material Degradation on the Thermal Stability of Non-sway Columns

Author

Myles Andrew Scott-Stirn, Southern Illinois University CarbondaleFollow

Date of Award

12-1-2015

Degree Name

Master of Science

Department

Civil Engineering

First Advisor

Kassimali, Aslam

Abstract

The main purpose of this study is to build upon previous post buckling research by including the effects of material degradation on column strength due to temperature increase. Failure of a structure during a fire occurs in most part because of material degradation. As the temperature increases the stiffness and strength of a structural material decreases and ultimately results in failure. In this study, columns with three different types of end restraints were studied. These are: Pinned-Pinned Columns, Pinned-Fixed Columns, Fixed-Fixed Columns. For each end-restraint type three different slenderness ratios were considered: λ=50, λ=125, and λ=200. After the data was reviewed, some conclusions that can be made are Axially restricted columns with lower slenderness ratios are more affected by material degradation. This is because columns with lower slenderness ratios have a higher Tcr allowing the effects of material degradation to begin affecting the columns strength at much lower T/Tcr ratios, in some cases before the ratio even reaches 1. Axially restricted columns with a higher number of rotational end-restraints are more affected by material degradation. This can also be attributed to a higher Tcr that allows the effects of material degradation to begin affecting the columns strength at much lower T/Tcr ratios.