Girder extension effect on earthquake resilience of ship unloader crane: A numerical study

Girder of a ship unloader crane (SUC) with a rated capacity of 1250 t/h has to be extended in order to follow jetty upgrading. The girder extension is limited by the railway span of gantry crane and the capacity of belt conveyor, which are maintained. This simulation aims to determine the effect of girder extension on the vulnerability of SUC to earthquake shocks in Indonesian region. A new method is proposed to evaluate earthquake resilience of crane structure that is not anchored to the ground, based on an equivalent static load of earthquake shock. The equivalent static simulation is carried out using ANSYS Mechanical APDL R18 on the 3d-truss model of SUC, which is generated based on the general arrangement drawing. To investigate the influence of earthquake shocks on the SUC structure, three variations of girder extension is applied, i.e. 3m, 6m, and 9m. The applied load consists of the SUC operating load and the earthquake load that works on the SUC structure’s supports. The earthquake resilience of SUC after girder extension is evaluated by comparing the reaction forces that occur in the supports. The simulations indicated that the girder extension can reduce the earthquake resilience of SUC, depending on the direction of the earthquake propagation.