The issue of sustainability regarding the environment, resources, and nature is deepening, and even in the public sector, consideration is being given to sustainable cycles. Despite the advantages of plastic, such as its lightweight and versatility, t...
The issue of sustainability regarding the environment, resources, and nature is deepening, and even in the public sector, consideration is being given to sustainable cycles. Despite the advantages of plastic, such as its lightweight and versatility, there are environmental pollution issues, and with mixed plastics, continuous recycling is difficult, making the use of single plastics important. The public bench recycling in Korea have an experimental nature aimed at improving citizens' awareness of the environment. Moreover, since mixed plastics and concrete mixtures are common, there are limitations to continuous recycling.
From this perspective, this study proposes the design of a public bench using a single recycled plastic material that meets the existing public bench guideline conditions for sustainable plastic recycling and the sustainability of public goods. To achieve this, domestic and international public bench guidelines were analyzed using a universal design evaluation system. As a result, five key criteria—maintainability, simplicity, accessibility, safety, and convenience—were identified, and the priorities of these criteria were determined.
The status of recycled plastic application in public benches was assessed through case studies both domestically and abroad. The results showed that mixed plastics were used in domestic cases, while abroad cases included examples of public benches made from single recycled HDPE plastic. To identify suitable materials for single recycled plastic public benches, the properties of HDPE used in abroad cases and PET, PP, and PS, which were confirmed to be recyclable, were compared through preliminary research. PP and HDPE were chosen as relatively easy-to-recycle materials. Subsequently, a comparative experimental study on the properties of PP and HDPE was conducted, confirming that HDPE is more suitable for public benches.
Furthermore, basic design considerations, including functionality, form, structure, material, color, and size, were proposed to establish a basic design for recycled plastic public benches while meeting existing guideline recommendations and considering recycled plastic material application. Simulation tests using FUSION360 were then conducted on the components forming the basic design—legs, seat, and connecting structures. Based on the safety factor of the derived structure, improvements were made to enhance structural stability.
The simulation validation results suggested that an H-shaped structure for the legs was suitable for distributing loads, and an additional H-horizontal beam was added to the seat to distribute applied forces. This design conforms to the guideline recommendation of concealing structural joints. The thickness of the seat was determined to be between 30 to 50T, and a rib structure with minimal strength difference and economic benefits compared to solid seat was applied to the legs and seat.
Additionally, to meet the guideline recommendation of easy drainage and drying during rain, a drainage structure was applied to the seat panel. The leg structure was divided into two parts for injection molding, with a cantilever snap-fit adopted for their connection, while an annular snap-fit connection method was applied to the connection between the seat and legs, ensuring sustainability by using recyclable materials for all components without the need for additional components made from different materials.
This study proposes a structurally stable design using single recycled plastic, meeting the guidelines of existing public benches within the scope of sustainable circulation of public goods, without mixing with other materials. It is hoped that the results of this study will serve as fundamental data for public bench design using various recycled materials.