The expansion of informal settlements in metropolitan areas such as Mashhad has posed serious challenges to the provision of basic infrastructure. This study aimed to identify and analyze the spatial logics of collective actions in local infrastructure provision within informal settlements of Mashhad, with a case study of the Khajeh Rabi neighborhood.

Methods: The research employed a mixed-method approach (quantitative-qualitative) with a sequential exploratory design. In the quantitative phase, 370 questionnaires were distributed and analyzed using stratified sampling and systematic random sampling. In the qualitative phase, 15 semi-structured interviews were conducted with local activists, community trustees, and residents with a history of participation in infrastructure-related activities.

Findings: The findings indicated that collective infrastructure-provision actions in the Khajeh Rabi neighborhood follow three distinct spatial logics: local reactive logic (33.8% of the sample), center-periphery logic (29.4%), and fragmented or piecemeal logic (36.8%). The center-periphery logic, which was primarily formed around social nodes such as mosques and Hussainiyas, was associated with social capital (β = 0.43) and perceived security of tenure (β = 0.29) as the strongest predictors. The regression model accounted for 51% of the variance in infrastructure-related actions (R² = 0.51). Qualitative analysis revealed the mechanism by which spatial isolation leads to collective action failure at the neighborhood edges—a mechanism that extends from reduced neighborly capacity to weakened trust, increased individualism, and the reproduction of fragmented logic.

Conclusion: The results demonstrate that infrastructure provision in informal settlements is not merely a response to service deficits but rather a reflection of the complex interaction among social structure, institutional security, and the spatial organization of the neighborhood. Therefore, urban policymakers should utilize existing social nodes as primary channels for infrastructure planning, rather than imposing top-down solutions. Furthermore, targeted intervention at neighborhood edges, prioritizing improved physical access and connectivity to social nodes, is essential.