# Seismic Response of Container Crane under Near-Field and Far-Field Ground Motions
## 1 Introduction  
Container cranes are special equipment widely used at seaports to transfer containers between ships and harbors. Since they are located at the seaport where strong typhoons and earthquakes are frequent occurrences, they have received more attention recently due to the effect their damage or collapse would have on the economy. For example, after the Kobe earthquake in 1995, [PERSON] [1] showed that physical damage to the container crane occurred within a timeframe of seconds or minutes, but the ensuing economic impacts were prolonged by months or years. Despite having an important role in freight, the container crane has been one of the most vulnerable pieces of equipment at harbors, as observed in past earthquakes. It is, therefore, necessary to study the seismic response of a container crane under earthquakes to reduce seismic damage on existing and new container cranes. In past studies conducted by various researchers, the two methods used to evaluate the seismic response of a container crane are the finite element method on a prototype container crane and the shaking table test of a scale container crane. In the finite element method [2; 3; 4; 5; 6], real earthquakes or artificial earthquakes were used to analyze container crane by time history analysis. [PERSON] et al. [3] used 20 real earthquakes to evaluate the sensitivity of parameters for the ship-to-shore container crane. In their study, the 20 earthquakes were adjusted based on their response spectra by scaling the spectra value at the container crane's fundamental period to match the spectra value of an elastic response spectrum at that period. [PERSON] et al. [7] conducted a fragility analysis on a container crane using 10 real earthquakes and 10 artificial earthquakes, in which the response spectra of 10 real earthquakes were matched to an elastic response spectrum, while 10 artificial earthquakes were created from the elastic response spectrum. Then, the intensity of 20 earthquakes (10 adjusted real earthquakes and 10 artificial earthquakes) was increased according to the spectra value at the container crane's fundamental period. For the shaking table test, various authors evaluated the seismic response of a container crane by using 1/50, 1/25, 1/20, 1/15, 1/10, and 1/8 scale crane models [8; 9; 10; 11; 12; 13]. [PERSON] et al. [14] only used two earthquakes to evaluate a container crane's seismic response, including an uplift phenomenon. The two earthquakes were matched to the design spectra for the port of Los Angeles and Long Beach. [PERSON] and [PERSON] [10] used four earthquakes, which comprised three real earthquakes and one artificial earthquake, to compare a container crane's seismic response with and without the base isolator by utilizing a shaking table test. Due to time and economic limitations, a shaking table test usually uses fewer input ground motions. The selection of earthquake records used for the shaking table test is an issue of concern, affecting the seismic response of a container crane. Besides, there is a need to discuss the scale of a prototype container crane for the shaking table test to accurately reflect its seismic response. To accurately reflect the seismic response of the prototype crane, a 1/20 scale crane was designed according to the similitude law [15; 16]. The similitude law allows for conversion of the prototype crane into a lab-sized scale crane, keeping homologous dynamic properties between the prototype and scale container crane. A number of researchers have investigated the seismic response of a container crane by employing the shaking table test on a scale crane model. For example, 1/20 and 1/10 scale container cranes were built to study the seismic response of the container crane, including uplift and derailment [17]; a 1/50 scale container crane was examined to evaluate the effect of a base isolator on the strain and acceleration amplitude under earthquakes' load [10]. [PERSON] [12] used shaking table test results on a 1/20 scale container crane to build a mathematical model for the crane.