الفهرس 
chapter 1Only 14 pages are availabe for public view
 |  | from | 167 |  |  |
| | | from | 167 | | |
Abstract
This thesis presents an efficient and simplified numerical model for the analysis of plane-framed steel structures at elevated temperatures. Large deformations and second-order effects are included. The material and geometrical nonlinearities as well as the non-uniform profile of temperature across the section of frame members are taken into account. Additional refinements to allow for the gradual spread of yielding on the member are included, by means of stiffness reduction factors and the tangent modulus concept. The determination of the internal force vector in the presence of temperature is detailed. The proposed model is validated by comparing its results with previous experimental tests and more complex finite element models. The comparison shows good agreements with lower computational times. Based on the proposed numerical model, a computer program is developed and used to perform critical temperature and stability analyses for plane frames. Moreover, the study is extended to investigate the behavior of common structural steel systems subjected to mechanical loads and various heating regimes, including; rectangular frames, trapezoidal frames, and parabolic arches. The obtained results confirmed the efficiency, accuracy, and reasonability of the proposed model for tracking the behavior of steel frames up to the critical temperatures. .