Resilient Renewal of Aging Parks in High-Density Cities: Integrating Performance-Based Design and the Environmental Overlay Method in the Wuxi Case

Climate change exacerbates challenges for old urban parks in high-density cores, intensifying urban heat islands and overcrowding hazards and causing limited extreme weather resilience. These parks face climate maladaptation, urban health risks, and reduced adaptive capacity. This study applies performance-based urban design through an “environmental analysis Overlay method,” integrating space syntax, CFD-Phoenics wind simulation, and solar analysis to translate climate adaptation, urban health, and urban resilience dimensions into measurable indicators including ventilation efficiency, crowd dispersion comfort, and flexible space capacity. Using Chengzhong Park in Wuxi as a case study, the method employs a diagnosis–optimization–validation process. Results demonstrate substantial improvements: (1) Climate: Problematic wind areas (>4 m/s or <0.5 m/s (stagnant)) decreased from 30% to 11%, while comfortable wind zones (0.5–1 m/s) increased to over 30%, achieving optimal microclimate conditions 89% of the park; (2) Health: Pedestrian circulation capacity increased by 25%, and activity areas with under 3 h of winter sunlight reduced from 26% to 19%; (3) Resilience: Spatial units consolidated from 155 to 115, with global-local integration improving from R2 = 0.39 to 0.64, significantly enhancing network coherence and adaptive functionality. The findings confirm that this method provides a scientifically rigorous, replicable pathway for climate-adaptive renewal of old urban parks, supporting urban resilience agendas.