An efficient load effect combination method based on probability density evolution method

In this paper, a new updated extreme value method based on the probability density evolution method (PDEM) is proposed for the load effect combination of structures subjected to multiple time-varying loads. The live load processes over the structure's lifetime are modeled as the compound Poisson process. Using the continuous stochastic function representation of the load model and the principle of load coincidence, the load coincidence is expressed deterministically in the combined probability space formed by all the basic random variables. To evaluate the maximum combined load effect with an increasing time domain efficiently, an updated extreme value technology is introduced to reduce the corresponding computational cost. With the help of PDEM, the time-variant probability density function of the extreme value of the combined load effect can be obtained. Taking a reinforced concrete frame as an example, the effectiveness and efficiency of the proposed method is verified.