In order to study the concrete damage characteristic of pelton turbine distributor and its effects on the dynamic behaviors of the hydropower house,nonlinear static analysis of the distributor and powerhouse was carried out using concrete plastic-damage model by finite element method.Based on the concrete damage state,the natural vibration properties and the response to generating unit vibration were calculated subsequently.The results showed that though the concrete surrounding the distributor is poured after steel pipe carrying parts of the internal pressure alone,the concrete in some regions is still apt to damage.These regions include the top of the pipe,the inside waist of pipe and the branch acute angle region.Usually the damage originating from the top and waist of the pipe will extend to the concrete surface.Because of the concrete damage,the steel pipe and rebar take most of the internal pressure especially in the branching region,but the stresses of steel pipe and rebar are still in the allowable range due to the small diameter and large pipe shell thickness. Simultaneously the concrete damage leads to the reduction of local structural stiffness and the increase of uneven uplift and vibration response of unit pedestal. However the effect of damage is local and small,the static and dynamic bearing capacity of the whole structure can be maintained.
