CONSTRUCTING A CLASSIFICATION SYSTEM FOR URBAN UNDER-BRIDGE SPACES USING A TYPOLOGICAL APPROACH: A CASE STUDY OF SHANGHAI IN THE URBAN RENEWAL CONTEXT

Abstract

As cities shift from greenfield expansion toward renewal of the existing built environment, under-bridge spaces the leftover pockets beneath elevated roads, viaducts, metro lines and river-crossing bridges are being reconsidered as potential public-space resources. Existing classifications, however, rest largely on a single dimension such as bridge type or current use, and no multi-dimensional typology is available to support differentiated renewal decisions. This study examines 33 under-bridge sites in Shanghai's inner-middle ring area through a five-step typology procedure: field survey, morphological analysis, literature and document collection, spatial-attribute coding, and category construction validated through expert deliberation. The resulting six-dimensional classification system covers physical prototype (P1-P3), spatial morphology (M1-M3), spatial scale (S1-S3), spatial zone (Z1-Z5), functional orientation (F1-F6) and usage pattern (U1-U3). Standardised coding of the 33 cases makes them comparable and reveals marked distributional differences across physical prototypes. The framework, endorsed by an expert panel as complete and practically applicable, offers both a typological foundation and a decision-support reference for the differentiated renewal of under-bridge spaces in high-density cities.

Keywords: Under-Bridge Space, Spatial Typology, Classification System, Urban Renewal, Expert Validation, Shanghai