## 4 Design  
### Car Park Building Design to Optimize Parking Efficiency  
The car park building, the subject of this study, was planned to accommodate approximately 200 vehicles. Parking buildings built in the city center must be able to handle a specific amount of parking demand and, as they are buildings with multiple floors, must secure a large number of parking spaces. The basic plan of a car park building is divided into floor and cross-section plans. First, the floor plan was based on the size of a car and the dimensions of a car's turning radius. The standard parking space in the floor plan of a car park building is 2.5 m wide and 5 m long, which are the specifications for one vehicle, with 6 m between parking spaces to allow for vehicle movement in both directions. Second, the cross-section plan of the car park building ensures that the minimum floor height for vehicle movement is 2.6 m, which is the height of one floor of the car park building. The design of a car park building that secures approximately 200 parking spaces is in progress based on the basic dimensions of the floor plan and cross-sectional plan of such a building. When planning a car parking space, the most crucial aspect is the means of vehicle movement that connects each floor. Assuming that vehicle ramps, which are commonly used in parking buildings, are placed on each floor, a four-story building is planned on a site area of 1904 m\({}^{2}\) (68 m long, 28 m wide) to accommodate approximately 200 vehicles, as assumed in this study. If people move around the car park building using elevators and stairs and vehicles move around each floor using semicircular curved ramps, the car park building can accommodate 208 vehicles (Figure 2). The semicircular curved ramp shown in Figure 2 is the most important design element for vehicle access to each floor of the building. However, the parking efficiency is reduced because parking spaces are not secured in areas where curved ramps are installed. This study aims to overcome the  
Figure 1: Flowchart of methodology. shortcomings of parking ramps and develop an architectural plan to optimize parking efficiency, which is the primary goal of car park buildings. The parking efficiency optimization design pursued in this study aims to secure the maximum number of parking spaces within a limited area. To increase parking efficiency, this study planned to use each floor as a ramp instead of using circular ramps, which serve only as vertical vehicle paths. The design of each floor connected to the top floor at a constant slope provides a vertical path for vehicles to move to each floor via the sloped floor, while also offering parking spaces on the same sloped floor. This design allows for simultaneous movement and parking of vehicles through coexisting parking spaces in the vehicle's vertical movement line. The parking lot floor slope was planned to be 2.5%. The building floor was designed to slope at 2.5% to meet the 3% barrier-free design standard. If the floor slope is less than 3%, there is no need to install rest areas every 10 m for pedestrians using wheelchairs [45]. The building floor, sloped at 2.5%, provides ease of movement for people using wheelchairs without the need for assistance, aligning with barrier-free design principles. From an architectural perspective, the entire floor was constructed with a 2.5% slope without a flat rest area for wheelchair users in the middle of the ramp, simplifying construction and achieving a high level of completion. The vertical circulation of the car park building for the general public consists of elevators and stairwells located on the south and north sides of the center of the building. Each stairwell, placed centrally in the building, ensures convenience for users and complies with building codes for fire prevention by being located within 40 m of any parking space [46]. In the event of a fire, an escape distance of up to 40 m must be secured from anywhere inside the building to a vertical staircase to facilitate quick evacuation.