Analysis of Mechanical Performance of Steel Frames Composed of Non-Compact Members

To analyze the influence of the strength-weakness axis, the width-thickness ratio, the high span ratio, and the axial compression ratio on initial stiffness bearing capacity of flexible frame structure under low cyclic reciprocating load, the quasi-static test study of a single-span and double-layer steel frame was carried out, and the test results were obtained. Based on the test results, a nonlinear finite element model was established. The specific content: 1)Study the effect of the axial compression ratio of 0.1, 0.2, 0.3, 0.4 on the peak displacement, peak load, initial stiffness, and deformation capacity of the structure. 2)Study the structural performance, by changing the height of the structure layer and the span. 3)Study the effect of the width-to-thickness ratio to structural performance by changing the width-to-thickness ratio of the web and the flange. 4)Study the influence of the strength-weakness axis of the column on the members.Specific conclusions: 1)With the axial compression ratio increasing, the bearing capacity, deformation capacity, and initial stiffness were all reduced. 2)The bearing capacity, initial stiffness, and height-span ratio of the structure were inversely related, and the deformation capacity increased with the increase of the height-span ratio. 3)The width-to-thickness ratio increased the load-bearing capacity and the initial stiffness. 4)The change in the direction of the strong and weak axis had a greater impact on the overall performance of the structure. When the steel column changed from the strong axis to the weak axis, the bearing capacity decreased by 40%, the initial stiffness dropped by 65%.