Numerical Analysis for Earthquake Response of Polar Crane

To evaluate seismic properties of polar crane in nuclear power station, the earthquake responses of polar crane are analyzed. The first order frequency of polar crane fixed on containment wall is 2.44 Hz. The first order mode shape of polar crane is transverse horizontal deformation of two horizontal parallel main girders. El Centro earthquake loading and Los Angeles earthquake loading are used as input loadings on bottom the containment wall. The maximum accelerations of time histories of earthquake loading are normalized. The numerical simulation investigation shows that the maximum Mises stresses in mid-span of girder of polar crane under the action of El Centro earthquake loading and Los Angeles earthquake loading are 131 MPa and 133 MPa respectively, and they are less than permissible stress of material. The numerical simulations indicate that the wheels on polar crane don’t derail during earthquake process because the wheel pressure is always compressive state. Considering the El Centro earthquake loading, the maximum vertical acceleration on polar beam of containment wall is 3.3 m/s2 and less than gravity acceleration (9.8 m/s2).