Civic Threshold Configurations: A Comparative Photographic Analysis of Municipal Building Entrances in Istanbul

Municipal buildings are direct architectural interfaces between public institutions and everyday urban life, yet accessibility, wayfinding, threshold, and publicness research typically addresses different parts of the arrival sequence. This study examines the civic threshold as a relational exterior sequence and asks how entrance legibility, approach structure, level condition, visible step-free access, and boundary/control conditions operate together. A rule-based comparative photographic analysis of 29 municipal buildings in Istanbul used six variables organized as a structural core, an access overlay, and boundary/control modifiers. Among 24 complete cases, six structural configurations were observed; clear–mediated–level was the most frequent (n = 7), followed by clear–mediated–stepped (n = 6) and clear–direct–level (n = 5). All seven stepped or mixed entrance conditions had mediated approaches. Step-free relations were observable in 19 cases: 16 shared the principal entrance route, and three showed no visible step-free provision within the observed principal sequence. Boundary and control conditions showed limited variation and functioned mainly as modifiers. Inter-rater agreement was 95.4% overall (Cohen’s κ = 0.822–1.000; Gwet’s first-order agreement coefficient (AC1) = 0.879–1.000). The study offers a reproducible, evidence-bounded protocol for comparing visible exterior entrance configurations, including within-profile distinctions between observable and indeterminate step-free route relationships, while keeping regulatory accessibility, user experience, and publicness outside its observational claims.