Spatial Design Strategies for Public Open Spaces as Tsunami-Responsive Infrastructure: A Study of Coastal Cities in Sri Lanka

Public Open Spaces (POSs) are fundamental to sustainable urban development, yet their planning and design potential as resilience-generating infrastructure in coastal cities remains insufficiently explored. In tsunami-prone contexts, POSs can be reconceptualized as multifunctional spatial systems that integrate environmental sustainability with disaster-responsive urban design. This study investigates how POSs can be planned and designed as tsunami-responsive infrastructure to enhance coastal urban resilience. Using a grounded theory approach supported by a focused literature review, data were collected through 72 unstructured interviews with tsunami-affected communities, urban planners and designers, disaster resilience experts, sociologists, and coastal environmental planners, etc. The findings identify three resilience-oriented POS typologies: (1) evacuation-integrated open spaces structured as spatial corridors and elevated assembly landscapes; (2) protective and mitigative landscapes employing topographic modulation, vegetative buffers, and water-sensitive design; and (3) adaptive shelter-embedded open spaces designed as flexible civic grounds capable of rapid transformation into temporary refuge infrastructure. The study proposes an architectural and urban design framework that positions POSs as adaptive coastal infrastructure simultaneously serving everyday civic functions while supporting evacuation, mitigation, emergency response, and climate adaptation. This approach advances resilience-focused architecture and risk-informed coastal urbanism.