The Using of Container For Earthquake Mitigation Shelter In West Jawa

Bandung is a city in West Java. Bandung has unique topography because it is surrounded by volcanoes. This condition causes Bandung to become an earthquake prone area. It is necessary to plan the disaster mitigation if an earthquake occurs. One thing that needs to be planned is a refugee shelter. The shelter must be strong enough to resist the aftershocks and quick to install.and disassemble. Container can be one of the best option for the shelter. This research uses container material as the existing structure that will be tested for resistance to seismic loads (Bandung). Seismic load testing is carried out using the ETABS software following the design requirements according to SNI 1726:2019. There are six variations of the containers arrangement tested for stiffness and strength. All variations of the modified container arrangement meet the requirements for stiffness and strength against earthquake forces according to SNI 1726:2019 regulations.


Introduction
House has a very important role in providing stability to human life.[1] Natural disaster damaged houses and disaster victims were forced to settle in temporary shelters or shelters provided by the local government.[2] Problems often faced by people in areas with high earthquake rates are the high cost of construction and the lack of insurance against natural disasters [3].
Indonesia prones to natural disasters such as earthquakes, volcanic eruptions, and tsunamis.[4] This is also supported by the fact that Indonesia has three active tectonic plates and is located in the Pacific Ring of Fire [5].The consequences of this disaster could be in the form of material and physical lost in the form of residences, buildings and public facilities [6].Disaster victims were forced to live in refugee camps for a long period of time.[7] Temporary shelter is needed because emergency tents were temporary and were the initial phase of post-disaster evacuation [8].
This study was conducted on the Province of West Java, especially in the city of Bandung.[9] Bandung is one area in Indonesia that has high potential risk of disaster such as earthquake.[10] Judging from the previous mitigation measures [11], temporary shelters were only posts made up of tents so that there were problems with cleanliness and diseases [12].In this research, the planning of a postearthquake temporary shelter for the city of Bandung used a modified container structure so it was suitable to be used as a temporary shelter considering its ease of mobility and short implementation time.[13]  Temporary shelter (shelters) must be carried out as effectively as possible [14].One effective work was to use containers or containers as material.[15] By using containers, we could develop the concept of green housing because containers were easy to mobilize and use repeatedly.[16] By using containers, there were several advantages such as easy workmanship, ready to use because it had been formed before mobilization, ease of transportation and can be reused [17].

Research Methodology
This research begins with collecting data that will be used for analysis.The data collected consists of earthquake data, container parameters and applicable design standards.Followed with structural modeling using ETABS software where the results of ETABS will be analyzed using manual calculations.
The analysis reviewed consists of checking the deviation between levels, structural stability and structural strength.The analytical method used follows the guidelines of SNI 1726:2019.The results of the analysis will determine the strength of the structure in overcoming earthquake loads.
The area reviewed for the application of this shelter structure is the city of Bandung.The city of Bandung was chosen because it has higher earthquake parameters than other areas in the West Java region.In this study, there are parameters used in the analysis of earthquakes.The parameters used consist of container structural parameters, earthquakes and information about containers according to existing conditions.The parameters collected will be presented in the following Table 1.Analysis of the container structural resistance in overcoming earthquake loads is carried out by following some applicable guidelines.The stages of analyzing the deviation between levels, stability and strength using the SNI 1726:2019 guidelines, determining the loading value following the SNI 1727:2020 guidelines, as well as information on container specifications following the ISO 668:2020 standard.
In research on container structure analysis, several stages of analysis were carried out in accordance with the guidelines of SNI 1726:2019.These stages consist of determining earthquake parameters, checking the period of the structure, checking the load ratio by elements, analyzing the basic seismic shear force, force scaling, deviation control, stability control, and strength control.Determination of earthquake parameters is obtained through the PUSKIM website [18].Followed by the determination of other parameters in accordance with the provisions of SNI 1726:2019.The earthquake parameters used in this study can be seen in the Table 2.
The loading combination applied to the design follows the stages according to Indonesian National Standard procedures for earthquake resistance planning for building and non building structures [19] and Indonesian National Standard procedures for minimum design loads and related criteria for buildings and other structures [20].The load that is input into the ETABS consists of a uniform load value and a combination of loads.The following is a load combination used:1,4D; Analysis of the container structure was carried out on 6 variations of the container arrangement.The arrangement of this container is chosen by considering the arrangement of the container in the existing condition.The arrangement of the containers used can be seen in Figure 1 and Figure 2.

Results and Discussion
The period of the structure is a parameter that will be used in analyzing the seismic base shear forces.The period of the structure consists of a period in the X direction and a period in the Y direction.In determining the period of use, it is necessary to pay attention to the condition that it does not exceed the maximum period that occurs.Table 3 consists of the period results used for each variation.This inspection aims to determine the structural elements with the greatest earthquake loads.This value can also be used as a factor that influences the determination of the structural system which is continued to determine the value of the seismic response coefficient.Examination of the load ratio for all variations can be seen in Table 4. From Table 4, it is concluded that the appropriate structural system according to table 12 SNI 1726:2019 is the supporting wall system (A17).
Seismic base shear forces are analyzed according to SNI article 7.8.The seismic base shear is used to determine how much shear value is caused by the earthquake.In this study, the value of the entire basic shear force can be seen in the following Table 5.The deviation between the design levels is calculated as the difference in the deviation at the center of mass above and below the level under consideration.In conducting analysis of deviation control, there are limit requirements for deviations between levels which are regulated in accordance with SNI 1726:2019 article 7.12.1.The following Table 6 is the results of the analysis of the deviation control for all variations.it is necessary to pay attention to the P-delta effect.The P-delta effect is a condition where the lateral displacement due to earthquake loads produces additional loads that occur by gravity loads, this condition occurs in flexible building structures.Analysis of stability control can be seen in the following Table 7. Capacity control is done by finding the value of the internal force acting on the element.The ratio of the capacity obtained from the value of the internal force must be less than or equal to 1 so that it can 6 be stated that the structure is strong to withstand combined loads.If the capacity ratio is greater than 1, then the structure is deficient in strength to withstand earthquakes, or can be called overstressed.The results of the ETABS analysis for the structural capacity can be seen in Figure 3.

Figure 3. Capacity Control
The capacity ratio for each element in each variation is still below the critical limit (blue).If the capacity ratio exceeds the permit limit (red), then the elements used must be modified.The conclusion obtained from this capacity control is that the structure can hold combined loads.
The research was conducted with the building structure system is the supporting wall system (A17).Therefore, it is necessary to check the capacity of the wall to withstand all combinations of loads.In this case, the maximum stress values, obtained through ETABS and are summarized in the Table 8 below.

Figure 1 .Figure 2 .
Figure 1.Variant I, II and III of Container Arrangement

Table 1 .
Container Structural Parameters

Table 3 .
Period Used

Table 4 .
Ratio of Load By Element

Table 5 .
Shear Force Variation Shear X dir.Shear Y dir.

Table 7 .
Stability Control

Table 8 .
Checking Wall Capacity