结构的鲁棒性、冗余度和易损性

为进一步完善结构的鲁棒性、冗余度和易损性相关分析方法,更加准确地获取土木结构的抗力与外力关系,进而优化补强其薄弱易损部位,以减少结构因抗力不足而引发的损伤甚至是安全事故及其所造成的损失.通过综述结构的鲁棒性、冗余度和易损性分析研究进展,类比不同评价指标的表达形式,从而指出结构的鲁棒性、冗余度和易损性分析的本质含义,提出结构的鲁棒性、冗余度和易损性分析应变能评价指标,并据此对结构的鲁棒性、冗余度和易损性分析之间的关系以及基本影响因素展开研究.结果表明:结构的鲁棒性、冗余度和易损性源于不同时期、不同领域,已有文献大多是基于对其含义的不同程度理解,其评价指标也大多具有主观性、相互关联且计算较为复杂,也尚未提出可广泛接受的分析方法;结构的鲁棒性、冗余度和易损性本质均是反映结构特别是损伤结构抵抗外力作用的能力,其中结构鲁棒性、冗余度侧重结构在外力作用下安全储备或剩余容许能力,结构易损性则更直观反映了结构在外力作用下的破坏程度;结构的鲁棒性、冗余度评价指标具有相似的表达形式,并与易损性呈反比例变化;可通过提高结构构件的材料强度及截面尺寸、增加杆端约束、优化荷载路径等措施增强和提高结构的鲁棒性、冗余度,即降低结构的易损性,进而减少结构损伤甚至是安全事故及其所造成的损失.

Structural robustness, redundancy, and vulnerability

To further improve the analysis methods of structural robustness, redundancy, and vulnerability, and to obtain the relationship between structural resistance and external load effect, optimization and reinforcement measures can be implemented for the weak or vulnerable parts of a structure to reduce the loss caused by damage or even safety accident due to the lack of structural resistance. Firstly, by reviewing the research progress of structural robustness, redundancy, and vulnerability and comparing different expressions of the current evaluation indexes, the essence of structural robustness, redundancy, and vulnerability were pointed out, and a new evaluation index based on strain energy was proposed. A further study on the relationship between structural robustness, redundancy, and vulnerability, as well as the basic influencing factors was also performed. Results have shown that structural robustness, redundancy, and vulnerability are from different fields and periods, which can reflect the resistance capacity of a structure, especially that of a damaged structure. The evaluation indexes are mostly subjectively defined by a complicated calculation process based on different levels of understanding. A widely accepted analysis method has not been established so far. Specifically, structural robustness and redundancy share similar evaluation index expression, both of which can represent the safety capacity or the remaining tolerance capacity of a structure. Structural vulnerability can directly reflect the structural failure extent, and it is inversely proportional to structural robustness and redundancy in the physical sense. Moreover, the increase in the material strength, the section size, and the structural restraint, together with the optimization of the load path, can increase structural robustness and redundancy and reduce structural vulnerability. The optimization and reinforcement measures can be implemented for the weak or vulnerable parts, thus structural damage, safety accident, as well as the loss cause by them, can be further reduced.