Towards Thermal Requalification of a Degraded University Campus Node in Hot-Arid Climates. The Case of Biskra City, Algeria

Abstract

University campuses in hot-arid climates frequently exhibit a paradox that classical urban design theory cannot explain: a geometrically central, well-connected outdoor space remains socially empty, while an adjacent space of lesser structural prominence sustains rich voluntary activity. At the university of Biskra, Algeria, the central plaza — the primary pedestrian node of the campus, where all major routes converge — functions in summer as a mandatory crossing point only, while the adjacent central garden retains its role as a place of social gathering and extended stay. Spatial configuration theories — primarily Lynch’s node concept and Gehl’s pedestrian quality framework — were formulated in temperate climates where thermal accessibility of outdoor space could be taken for granted. Applied to hot-arid contexts, they identify the right spatial variables but cannot account for the seasonal reversal in plaza use: the plaza is socially active in winter, void in summer, with its spatial configuration unchanged between seasons. This study argues that the missing variable is thermal viability — the physiological capacity of a space to sustain voluntary presence — which functions as a threshold condition that gates all other attractiveness factors. Through a multi-method comparative study combining microclimatic investigation, behavioral observation and user perception survey, the study demonstrates the dominant role of thermal conditions in shaping spatial preference, showing that adjacent spaces can exhibit fundamentally different usage patterns due to microclimatic variation. The study contributes to climate-responsive design by emphasizing the importance of vegetation and shading in enhancing outdoor usability and demonstrating how extreme conditions suppress voluntary activity regardless of spatial quality, and that the garden’s vegetated microclimate already provides the locally validated design precedent for plaza requalification. The study extends Lynch’s node concept by proposing thermal viability as a necessary fourth condition for nodal function in hot-arid climates.