Introduction – Virtual City Model

Within the scope of this work, an integrated infrastructure configuration is analyzed with a particular focus on the evaluation of maintenance strategies and life cycle assessment, in which individual subsystems are combined to represent a complete and realistic operational system. The system includes a sewer pipeline, road infrastructure, an overhead storage tank, a warehouse building and a residential building. Integration is achieved by explicitly modeling the physical and functional interfaces between these components. Through the system’s interactions, maintenance decisions are no longer evaluated locally, but within a shared decision space defined by system-level constraints.

Maintenance planning is a central challenge in the long-term management of civil infrastructure. Infrastructure assets are expected to operate reliably over extended service lives while being subject to deterioration, changing operational demands, and external constraints. Decisions regarding maintenance timing, frequency, and coordination influence not only asset condition, but also service continuity, environmental performance, and economic efficiency. As infrastructure systems become more spatially constrained and functionally interconnected, maintenance planning increasingly requires a system-level perspective in which trade-offs between competing performance objectives must be considered explicitly rather than resolved independently.

The performance of the integrated system is evaluated using a combined life-cycle and decision-oriented framework. Life-cycle assessment is used to quantify environmental impacts and costs over the system lifetime, while maintenance strategies are assessed in terms of their influence on service availability through total interruption time. These criteria are inherently conflicting, and improvements in one dimension may lead to compromises in another. To address this, multi-objective optimization is applied to explore sets of feasible solutions and to identify maintenance strategies that achieve balanced performance across environmental, economic, and service-related objectives. This approach supports informed decision-making by revealing how different coordination strategies perform under competing system-level demands.