کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
284714 | 509159 | 2014 | 11 صفحه PDF | دانلود رایگان |
• Imperfections are modeled as a combination of scaled frame buckling modes.
• Statistical information of imperfections is obtained from the literature.
• A probabilistic method is used to determine the number of the buckling modes.
• A probabilistic method is used to determine the magnitudes of the buckling modes.
• The effects on frame strength of geometric imperfections are examined.
• The proposed method is demonstrated by a number of case studies.
Steel structural members and frames always indicate imperfections to various degrees. These include initial out-of-straightness and initial out-of-plumb due to manufacturing and erection tolerances. In general, the shape and magnitude of geometric imperfections may have a significant influence on the response of a structure, and hence need to be modelled accurately when determining the load carrying capacity of a steel frame by advanced structural analysis. Most conveniently, geometric imperfections can be introduced in structural models as scaled eigenmodes obtained a priori from an elastic buckling analysis. However, it remains unanswered how many eigenmodes need to be incorporated and how to choose the scaling factors of each mode.This paper presents a study of how the strength of steel frames varies with the number and magnitudes of eigenmodes. Frames with random geometric imperfections are produced using the statistics of measurements of out-of-plumb and member imperfections, and analysed using advanced geometric and material nonlinear analysis. The imperfections are then resolved into eigenmodes and a second set of advanced analysis is carried out using a finite number of modes to represent the imperfections. Conclusions are drawn about the appropriate number and magnitudes of eigenmodes to use in advanced structural analyses of steel frames.
Journal: Journal of Constructional Steel Research - Volume 98, July 2014, Pages 167–177