Probabilistic study on ultimate deformation limit of steel frames used in performance evaluation

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Up to now, Most parts of the structural design used technical terms only understood by structural experts. With the development of performance design, it is the responsibility of designers to clearly explain the performance of the designed structures. Therefore, it is important to express the performance directly using simple and clear physical quantities and quantitative express the uncertainties contained in structures and loads. In the present study, a ultimate limit state reproduction device for structural members is developed and investigated. The device can reproduce the ultimate limit state including fracture, local buckling, bending buckling and lateral buckling. A formulation of resistance and deformation capacity is proposed as a form of design formulation with the parameters of material properties, section shape and stiffness of stiffen materials. Furthermore, the resistance and deformation performance are probabilistically evaluated with consideration of the uncertainties contained in buckling and fracture of steel members and joints. The analysis is conducted using elastic plastic analysis program and the uncertainties in mechanical properties of materials are considered. The results of analysis have good agreements with those obtained from test. The resistance and deformation of the total structures are evaluated considering the affection by the member and joints. Finally, the structural reliability analysis corresponding ultimate limit states are conducted considering the limit deformation and randomness of joints, the relationship between the reliability index and the resistance and deformation capacity is clarified, and the deformation limit and plastic ratio is proposed as the criteria corresponding to the performance limit. The uncertainties corresponding to the deformation requirements and ultimate limit state are clarified in view point of assuring deformation capacity and a database of these uncertainties are constructed.