With rapid urbanization, cities face immense pressures on infrastructure and resources. Uncoordinated management of transportation, energy, water and waste infrastructure leads to inefficiencies, delays and unsustainability. This paper proposes a novel IoT-enabled framework to address these challenges through holistic data-driven management of city infrastructure. While prior works have explored IoT point solutions for specific domains, our integrated framework delivers a comprehensive architecture for citywide infrastructure visibility. The edge computing-based distributed design enables scalable real-time analytics across thousands of heterogeneous assets spread city-wide. Through consolidated storage and analytics, interdependencies between various infrastructure systems can be uncovered to optimize overall city operations. The standardsbased implementation fosters seamless integration of diverse infrastructure technologies. Our unified data management layer provides a single platform for visual intelligence on city-wide infrastructure health to support data-driven planning. We demonstrate the efficacy of the proposed framework through a case study focused on transportation infrastructure management. The results showcase significant enhancements in operational efficiency, sustainability and cost savings across transport assets when managed under the IoT-enabled framework versus traditional siloed approaches. This paper provides city leaders and technologists an implementable blueprint to harness the power of IoT and analytics for transitioning to smarter, sustainable and resident-friendly infrastructure.