In this paper, the incremental elasto-plastic analysis method, a plastic analysis method conventionally used for the calculation of collapse load factor of frame structures, is utilized to predict the collapse load factor of truss structures. The obtained collapse load factor is then incorporated into the scheme of truss structural optimization using a Genetic Algorithm (GA) in order to generate truss structures which can not only maintain load-carrying capacity under ordinary load conditions such as dead load and live load, but also avoid collapse under accidental load conditions such as an extremely large earthquake, drastic typhoon, or other accidental loads. In the numerical example, the designed optimization scheme is implemented to solve an optimization problem of a double layer truss structure, resulting in an optimal lightweight, safe structure under both ordinary and accidental load conditions.
