Non-Contact Structural Monitoring for Historic Wooden Buildings
Preserving Heritage. Monitoring Structural Behavior. Reducing Intervention.
Project Overview
Monitoring the structural condition of historic wooden buildings presents unique challenges. Traditional monitoring methods often require sensors, mounting fixtures, and cables to be installed directly on structural components, potentially increasing installation complexity and introducing unwanted intervention into delicate heritage structures.
To address these challenges, Hu Entropy Tech deployed its Online Visual Tracking System for long-term structural displacement monitoring of the Nanning Wooden Pagoda.
Based on non-contact optical measurement technology, the system enables remote observation of selected structural points without requiring conventional displacement sensors or extensive wiring on the historic building itself. Detachable passive optical targets can be positioned at appropriate locations to facilitate visual tracking while minimizing intervention in the original structure.
This approach provides a flexible and reversible monitoring arrangement, helping protect the architectural integrity of historic buildings while supporting continuous structural observation.
Non-Contact Measurement Technology
The Online Visual Tracking System uses an oblique-axis Digital Image Correlation (DIC) imaging principle combined with sub-pixel positioning algorithms to track small movements of selected structural targets.
The system was configured to monitor critical elevated structural locations, including the pagoda finial and door-frame areas.
Its key advantages include:
- Non-Contact Measurement: Monitors structural displacement without installing conventional electronic sensors directly on the monitored components.
- Long-Distance Observation: Enables remote monitoring of elevated and difficult-to-access structural locations.
- Multi-Point Tracking: Observes multiple selected targets to assess displacement at different structural locations.
- Reversible Deployment: Uses detachable passive targets and flexible installation arrangements to minimize intervention.
- Continuous Data Collection: Provides long-term measurement records for structural behavior analysis.
Environmental Adaptability and Measurement Stability
The monitoring site is exposed to changing environmental conditions, including temperature variations, strong sunlight, wind, dust, and potential rain or fog interference.
To improve monitoring stability under these conditions, the system incorporates environmental sensing and image-processing technologies, including:
- Temperature and humidity monitoring
- Attitude sensing
- Auxiliary illumination for low-light conditions
- Temperature compensation
- Strong-light suppression
- Image correction algorithms to mitigate atmospheric turbulence effects
These technologies help maintain target recognition and measurement continuity under changing environmental conditions.
Monitoring Results
Through continuous observation of multiple key structural targets, the system recorded displacement variations across the monitored areas.
Maximum Horizontal Displacement: Approximately 8 mm
The largest recorded horizontal displacement amplitude was approximately 8 mm, observed in the pagoda finial area. Wind loading was considered a major influencing factor in the observed movement.
The measurement results provide valuable information for understanding the dynamic response and displacement behavior of the pagoda’s elevated structures.
Note: The recorded displacement is a monitoring result and should be interpreted in conjunction with environmental conditions, reference measurements, and professional structural assessment.
Intelligent Monitoring and Early Warning
The system was configured with a standard data sampling interval of 10 minutes, providing regular measurement records for long-term structural observation.
An adaptive monitoring mechanism can increase observation frequency and data recording intensity when displacement changes exceed predefined thresholds, subject to the configured system settings.
Measurement data is transmitted to the Hu Entropy Tech cloud-based monitoring platform, supporting:
- Real-Time Displacement Visualization
- Historical Data Comparison
- Deformation Trend Analysis
- Configurable Alarm Notifications
- Remote Monitoring and Data Management
The system also supports panoramic camera linkage. When configured monitoring conditions are triggered, associated site images and environmental information can be recorded to provide additional context for subsequent investigation and engineering assessment.
Project Benefits
The deployment of the Online Visual Tracking System provided a practical approach to long-term structural observation of the historic wooden pagoda.
Key benefits include:
1. Reduced Intervention in Historic Structures
Non-contact optical measurement minimizes the need for conventional sensor installation and extensive wiring on historic structural components.
2. Safer Monitoring of Elevated Structures
Remote observation of the pagoda finial and other elevated locations helps reduce the need for frequent manual inspections at difficult-to-access positions.
3. Long-Term Structural Data Collection
Continuous displacement records support the analysis of structural movement and changes over time.
4. Improved Environmental Monitoring Capability
Environmental sensing and image-processing functions help maintain measurement stability under changing outdoor conditions.
5. Better Support for Heritage Management
Cloud-based data access, historical comparison, alarm notifications, and associated image records provide useful information for ongoing inspection and maintenance planning.
Conclusion
Hu Entropy Tech’s Online Visual Tracking System demonstrates the value of non-contact optical measurement for structural health monitoring of historic wooden buildings.
By combining remote multi-point displacement measurement, environmental adaptability, intelligent data acquisition, and cloud-based monitoring, the solution supports long-term structural observation while minimizing intervention in valuable heritage structures.
Protect Heritage. Measure Without Contact. Monitor for the Long Term.
