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

到目前为止，结构设计的大部分部分使用的技术术语只有结构专家才能理解。随着性能设计的发展，对所设计结构的性能进行清晰的说明是设计者的责任。因此，用简单明了的物理量直接表达性能，定量表达结构和荷载中包含的不确定性是很重要的。本文研究了一种结构构件极限状态再现装置。该装置可以再现包括断裂、局部屈曲、弯曲屈曲和侧向屈曲在内的极限状态。提出了一种以材料性能、截面形状和加筋材料刚度为参数的抗变形能力公式作为设计公式的形式。此外，考虑钢构件和节点屈曲和断裂的不确定性，对其抗力和变形性能进行了概率评估。采用弹塑性分析程序进行分析，考虑了材料力学性能的不确定性。分析结果与试验结果吻合较好。考虑构件和节点的影响，对整体结构的抗力和变形进行了评估。最后，考虑节点的极限变形和随机性，进行了相应极限状态的结构可靠度分析，明确了可靠度指标与阻力、变形能力的关系，提出了变形极限和塑性比作为对应性能极限的准则。从保证变形能力的角度阐明了变形要求和极限状态所对应的不确定性，并建立了不确定性数据库。

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.