Initial Situation and Motivation:
The maintenance and rehabilitation of buildings and infrastructure, particularly bridges, are resource-intensive processes. Timely and accurate condition assessment is essential to implement targeted measures early and avoid costly reconstruction. Currently, structures are mostly monitored through visual inspections or surface sensors, which provide limited insights into the internal structural condition. Integrating sensors within the interior of structurally relevant components (e.g., beams, columns) is technically challenging, as active sensors require their own power supply and have limited lifespans. Therefore, the development of energy-efficient, wireless, and durable sensor solutions is a pressing need to ensure sustainable structural monitoring.

Objectives and Innovation:
The research project MON-Net addresses these challenges by utilizing passive Surface Acoustic Wave (SAW) sensors, which can be embedded directly into concrete or attached to existing bridge structures. These sensors do not require their own power supply and can be wirelessly read by external readers. The readers act as communication nodes, creating a robust and self-organizing sensor network. The vision of MON-Net is to develop an innovative bridge monitoring tool that continuously transmits sensor data to a central evaluation station. There, the data is analyzed using a digital twin to derive precise maintenance strategies. By combining SAW sensor technology, wireless sensor networks, and digital twins, a new energy-efficient and scalable solution for accurate bridge condition assessment is created.

Expected Results and Insights:
MON-Net will demonstrate a functional proof-of-concept (TRL 4) in which the SAW sensors, wireless sensor network, and digital twin are validated in a realistic environment. The expected results include:

1. Further development of SAW sensor technology for robust and precise structural monitoring.
2. Optimization of reader technology for efficient wireless communication.
3. Development of an energy-efficient, self-organizing sensor network that utilizes alternative data routes and has multipath capabilities.
4. Integration of sensor data into a digital twin to enable continuous real-time monitoring.
5. Sustainability and economic analysis to evaluate the benefits of the technology for infrastructure operators and public institutions.

MON-Net makes a significant contribution to the sustainable transformation of transportation infrastructure by extending the lifespan of bridges, reducing maintenance costs, and promoting circular economy principles. More precise condition assessment will also minimize material waste by reducing excessive safety margins during renovations. The project results will not only strengthen the scientific relevance of the participating research institutions but also open new business opportunities for companies in the field of IoT-based structural monitoring.