Objective  In the context of the new normal of economic development in China, urban construction has transformed from incremental expansion to stock optimization, and the growing demand of the public for public life has led to the gradual exploitation of urban space. In the process of urban renewal, there still exist various remaining spaces that are abandoned or idle or fail to be efficiently utilized. The potential tapping and utilization of remaining space is of significant significance, as it is a systematic and complex issue in urban governance, and also an important issue for urban stock renewal during the “14th Five-Year Plan” period. Due to economic, management, historical and other reasons, it is often impossible to achieve the most scientific and reasonable allocation of urban spatial resources, thus giving birth to remaining space. At present, with the structural change in urban development from incremental construction to stock renewal, there are various problems with remaining space. Utilizing remaining space reasonably in a problem-oriented manner is of great significance for current urban renewal in China.

Methods  Following the principle of being problem-oriented and people-based, this research, starting from the actual situation of remaining space, analyzes and evaluates the conceptual category, type characteristics and renewal means of remaining space. Taking underbridge space, a representative remaining space, as an example, the research systematically proposes a comprehensive renewal approach for urban remaining space. Before the actual utilization and renewal of urban remaining space, it is necessary to conduct potential research that involves problem extraction, point selection and value judgment. Specifically, field surveys should be conducted on various remaining spaces, especially the five types of representative ones, to identify potential targets for exploration; then the representative remaining spaces identified should be marked and sampled by block and community to clarify their key role in urban design; finally, the approaches for utilization and renewal of such remaining spaces should be proposed based on the potential research.

Results  This research proposes the following renewal approach for remaining space: place research and spatial analysis (careful analysis of space problems and types) − space identification and research assessment (evaluation of space status in combination with public participation) − space restructuring and design intervention (formulation of development strategies for space renewal). Taking the underbridge space as an example, the research proposes several specific renewal strategies. Strategy 1: Plan in coordination with surrounding areas to repair the fragmented environment. Connect underbridge land plots nearby to integrate the utilization of land resources; strengthen the design of spatial entrances and exits, and use diverse methods for spatial connection; strengthen the guidance of space through guiding signs, cultural installations, artistic walls, etc.; set up functional spaces, strengthen spatial features, and use terrain, plants, sound, color and other means to eliminate unfavorable factors. Strategy 2: Fix the slow moving system to ensure a safe passage. Enhance pedestrian accessibility through slow traffic channels; set up safe slow traffic lanes at intersections through special ground signs, color paving distinguishing and indicating signs, traffic lights, etc; use special marking systems, isolation devices or plants to isolate the safety interference of motor vehicles, set up refuge island waiting for passage, etc., and shape the overall slow traffic system of the area. Strategy 3: Expand the service sector and make up for functional shortcomings. Complement the functions of surrounding cities to meet diverse needs such as parking, bus hub and human activity; pay attention to residents’ needs for underbridge space in such aspects as passage, safety and activity, and improve service shortcomings through renewal. Strategy 4: Integrate and summarize human activities, and make reasonable use of spatial resources. Integrate the types of crowd activities and available resources in the underbridge space, namely diverting and guiding spontaneous activities according to the types and characteristics thereof, and combining factors such as light, air and temperature to set up appropriate functional and activity spaces. Strategy 5: Protect historical culture and tap into potential resources. To highlight the urban image, it is necessary to deeply improve the quality and taste of underbridge space. The specific techniques for creating cultural characteristics need to be moderate and authentic without being overly designed.

Conclusion  The renewal of urban remaining space, as an important issue in the stage of urban stock development, needs to be reality-based and problem-oriented, and entails multidisciplinary and multi-specialty cooperation, scientific and objective analysis of different remaining spaces, specific analysis of specific issues in combination with internal and external factors, and dynamic coordination of the renewal approaches and strategies for spatial planning and design by virtue of innovative concepts and methods. It is crucial for current urban renewal and refined governance to intervene in the comprehensive role of multiple disciplines such as landscape architecture, urban planning, and architectural design, and to reasonably and sustainably renew and improve the potential remaining spaces, which also reflects the concept of “design for people” in the sense of people’s city.