الفهرس 
Introduction.Only 14 pages are availabe for public view
 |  | from | 182 |  |  |
| | | from | 182 | | |
Abstract
Cold-formed steel sections are among the most commonly used sections as purlins and girt beams due to their light weight which achieves the most economic design. The Effective Width Method (EWM) is the conventional method used in design of such sections. However, it requires multiple iterations to calculate effective section properties and it does not consider all buckling modes such as distortional buckling. On the other hand, the Direct Strength Method (DSM) which is included in AISI North American Specifications is significantly easier than the EWM. It can also predict all buckling modes by determining the critical elastic buckling load in local, distortional and global buckling modes which is then used with the aid of a series of equations to directly get the strength of the section. The major complication with the DSM is the determination of the critical elastic buckling load.
In this research, a wide parametric investigation was proceeded, where the Finite Strip Method (FSM) and the Finite Element Method (FEM) were used to model a series of beams with various dimensional parameters. A simple design procedure is proposed for the design of cold-formed lipped channel beams using the DSM by using equations to calculate the critical elastic buckling moment in local buckling mode without need of using complicated numerical procedures.