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.