The Analysis And Comparison Between The Effective Length Method And The Inmaginary Horizontal Load Method For The Design Of Enbraced Frame

Much revisals were brought forward by the new edition of Code For Design Of Steel Structures (GB50017) from the current code (GBJ17-88). In order to take the influence of the internal force from translation into consideration, the design of in-plane buckling of unbraced frames adopted a new second-order elastic method to calculate the structural internal force, e.g. the imaginary horizontal loads method. These revisions can pace up with the international technical advances of design of steel structures. But when the imaginary horizontal loads method in the new code was proceeded the second" order elastic analysis, could it achieve the requirement and get the more precise results than the old effective length method? This article would analyze the two method farther in the background theory and calculate kinds of the examples of the pure unbraced frames with the effect of initial defect. At one time the same instances were analyzed by the finite element numeric method, which results were compared with the results of the three methods. The conclusions from the comparison would offer the references to the revision of the code.