# Seismic Response of Container Crane under Near-Field and Far-Field Ground Motions
## 5 Conclusions  
The container crane's seismic response was evaluated by employing a shaking table test of its 1/20 scale crane. The scale crane was designed based on the similitude law, where the cross-section of each part was scaled down by using the scale factor of the moment of inertia. Besides, added masses were applied to satisfy the scale crane's total mass. One near-field (Gazli USSR Iran) and two far-field (Nahanni Canada and Mineral Virginia) ground motions were matched to the elastic response spectrum (Z1S4_2400) and applied to the scale crane in the trolley-boom girder direction. Major findings obtained from this study are summarized as follows:  
Despite having matched the near-field and far-field ground motions to the elastic response spectrum (Z1S4_2400), which was defined as zone 1, soil type S4, and a return period of 2400 years based on the Korean standard, there was still a significant difference in the seismic response of the container crane between the near-field and the far-field ground motions, such as the internal forces in the seaside and landslide legs, and portal drift. The internal forces, the axial force and two moments, in the seaside and landslide legs when the scale crane was subjected to the near-field motions were higher than when the scale crane was subjected to the far-field motions. For example, at the top of the lower seaside legs, the bending moment \(M_{y}\) under the near-field ground motion was 37% higher than that of the far-field ground motions. The portal drift under the near-field earthquakes was also higher than that of the far-field earthquakes. For example, the seaside portal drifts under the Gazli USSR Iran earthquake were 25% and 43% higher than those of the far-field earthquakes, Nahanni Canada and Mineral Virginia.  
In the case of near-field input ground motions, which have a wider acceleration and displacement-sensitive region than the far-field ground motions, they will have a more significant effect on the seismic response of the container crane than the far-field ground motions. The maximum acceleration response of the container crane increased as compared to the peak ground acceleration when subjected to the near-field ground motion, but they decreased as compared to the peak ground acceleration when subjected to the far-field ground motions. For example, the maximum acceleration response of the location on the trolley-boom girder when the scale crane was subjected to the Gazli USSR Iran earthquake was 47% higher than its PGA, while under the Nahanni Canada and Mineral Virginia earthquakes, the maximum acceleration responses were 23% and 33% lower than their PGA.  
Conceptualization, V.B.N. and J.H.; methodology, V.B.N. and J.H.; software, V.B.N., B.K.M. and J.K.; validation, J.H. and I.-J.P.; formal analysis, V.B.N. and B.K.M.; investigation, V.B.N. and J.K.; resources, J.H.; data curation, V.B.N.; writing--original draft preparation, V.B.N.; writing--review and editing, J.H. and I.-J.P.; visualization, V.B.N. and B.K.M.; supervision, J.H.; project administration, J.H.; funding acquisition, J.H. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Ministry of Oceans and Fisheries (20160065), Korea.  
Not applicable.  
The data presented in this study are available on request from the corresponding author.  
This research is a part of the project titled 'Development of performance-based seismic design technologies for advancement in design codes for port structures,' funded by the Ministry of Oceans and Fisheries (20160065), Korea.  
The authors declare no conflict of interest.