Abstract: The reliability of reinforced concrete (RC) aqueduct structures that suffer the influence of various random factors is crucial to the safe operation of water diversion projects. For a large hydraulic RC aqueduct or important water conveyance structure, it is of great practical significance to ensure its water conveyance function reliability under the influence of various random factors. Based on the latest achievements in the field of structural random dynamics and damage failure analysis, a random dynamic analysis method of aqueduct structures is presented in this paper, which considers reasonably the randomness of structural parameters of a large RC aqueduct and the randomness of its seismic excitation. Reliability indexes are formulated according to its water conveyance function requirements; a method is developed to calculate its water conveyance function reliability under combined random conditions. A comparative analysis of the reliability is made systematically in a case study of an aqueduct in operation under the influence of different random factors. The result shows that for an RC aqueduct under combined random conditions, its random dynamic response has more significant variability than that of only the randomness of its seismic excitation considered, and its reliability level is lowered considerably. This reveals the influence of seismic excitation randomness on the response and reliability of an aqueduct structure is obviously greater than that of material parameter randomness. Thus, it is very necessary to consider comprehensively the combined influence of the above two random factors in calculation of the water conveyance function reliability of aqueduct structure.

Key words: reinforced concrete aqueduct, structural parameter randomness, seismic excitation randomness, combined randomness, water conveyance function reliability