Linear Optimization of Two Stages Frame byGraphical, Big M and Lingo Software

Structural designers have always been trying to build secure and economical structuresagainst earthquakes. Since weight is one of the most important parameters in the behaviorof structures when earthquake happen, weight reduction not only increases the strengthof a structure against earthquakes but also economize the structure. There are someoptimization methods in order to reduction weight by considering the safety. Howeverthere are many optimization methods for structures in this case to check the frame basedon the plastic collapse mechanism, linear methods are capable. Therefore, linearoptimization methods are applicable in this regard. In this paper, two-stages, one-spanframe is modeled and optimized for weight by mathematical methods such as graphicaland big M simplex methods and validated by lingo software based on the plastic collapsemechanism. Finally, results show by means of this methods optimize amount of load andspan lengths obtain for resist frames in plastic collapse, and the optimum weight forbeams and frame columns was obtained based on the loading and length of the elements.

کلیدواژه ها:

sensitivity analysis ، optimization ، simplex ، frames ، plastic collapse