Long-term structural health monitoring of the Crowchild Trail Bridge

2008 ◽  
Vol 35 (2) ◽  
pp. 179-189 ◽  
Author(s):  
Tim R. VanZwol ◽  
J. J. Roger Cheng ◽  
Gamil Tadros

Steel-free deck design is a relatively new approach to bridge deck construction. Several steel-free deck bridges constructed in Canada exhibited satisfactory behaviour immediately after construction. However, the long-term health of many of these structures has not been investigated. Significant cracking has been observed in many of these structures after only a few years in service. Long-term structural health monitoring of these structures is key in determining their long-term performance and future adoption of this new technology. Structural health monitoring data were obtained from the steel-free deck of the Crowchild Trail Bridge during its first seven years in service. Field monitoring included ambient vibration tests, static and dynamic load tests, and deck crack mapping. Despite significant amounts of cracks in the concrete deck and barriers, the overall behaviour of the Crowchild Trail Bridge has remained satisfactory and consistent. Future steel-free deck designs should consider crack control to meet serviceability requirements.

Inge CUC ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. 52-65
Author(s):  
Alvaro Viviescas Jaimes ◽  
Wilmer Julián Carrillo León ◽  
Laura Andrea Vargas Carvajal

Entropy ◽  
2020 ◽  
Vol 23 (1) ◽  
pp. 60
Author(s):  
Tzu-Kang Lin ◽  
Dong-You Lee

This study proposesd a novel, entropy-based structural health monitoring (SHM) system for measuring microvibration signals generated by actual buildings. A structural health diagnosis interface was established for demonstration purposes. To enhance the reliability and accuracy of entropy evaluation at various scales, composite multiscale cross-sample entropy (CMSCE) was adopted to increase the number of coarse-grained time series. The degree of similarity and asynchrony between ambient vibration signals measured on adjacent floors was used as an in-dicator for structural health assessment. A residential building that has been monitored since 1994 was selected for long-term monitoring. The accumulated database, including both the earthquake and ambient vibrations in each seismic event, provided the possibility to evaluate the practicability of the CMSCE-based method. Entropy curves obtained for each of the years, as well as the stable trend of the corresponding damage index (DI) graphs, demonstrated the relia-bility of the proposed SHM system. Moreover, two large earthquake events that occurred near the monitoring site were analyzed. The results revealed that the entropy values may have been slightly increased after the earthquakes. Positive DI values were obtained for higher floors, which could provide an early warning of structural instability. The proposed SHM system is highly stable and practical.


2013 ◽  
Vol 778 ◽  
pp. 757-764 ◽  
Author(s):  
Francesca Lanata

Structural design, regardless of construction material, is based mainly on deterministic codes that partially take into account the real structural response under service and environmental conditions. This approach can lead to overdesigned (and expensive) structures. The differences between the designed and the real behaviors are usually due to service loads not taken into account during the design or simply to the natural degradation of materials properties with time. This is particularly true for wood, which is strongly influenced by service and environmental conditions. Structural Health Monitoring can improve the knowledge of timber structures under service conditions, provide information on material aging and follow the degradation of the overall building performance with time.A long-term monitoring control has been planned on a three-floor structure composed by wooden trusses and composite concrete-wood slabs. The structure is located in Nantes, France, and it is the new extension to the Wood Science and Technology Academy (ESB). The main purpose of the monitoring is to follow the long-term structural response from a mechanical and energetic point of view, particularly during the first few service years. Both static and dynamic behavior is being followed through strain gages and accelerometers. The measurements will be further put into relation with the environmental changes, temperature and humidity in particular, and with the operational charges with the aim to improve the comprehension of long-term performances of wooden structures under service. The goal is to propose new improved and optimized methods to make timber constructions more efficient compared to other construction materials (masonry, concrete, steel).The paper will mainly focus on the criteria used to design the architecture of the monitoring system, the parameters to measure and the sensors to install. The first analyses of the measurements will be presented at the conference to have a feedback on the performance of the installed sensors and to start to define a general protocol for the Structural Health Monitoring of such type of timber structures.


2021 ◽  
Author(s):  
Ainulla Khan ◽  
Krishnan Balasubramaniam

Abstract The continuous Non-Destructive Evaluation of assets for long-term assurance of performance has led to several developments over the deployment of a Real-Time Structural Health Monitoring (SHM) system. Considering the challenges involved under the implementation of an SHM system for the applications working under harsh environmental conditions with limited access to power sources this work is aimed to contribute towards overcoming those challenges by using the noise from the structure’s machinery or any ambient source as an alternative energy source and employing Fiber Optics based sensing, for its applicability under harsh environments. The required SHM system is realized with the cross-correlation of a fully diffused noise field, sensed using the Fiber Bragg Grating (FBG) sensors at two random locations. With no control on the input received as noise, to this end, a method is developed based on a Deep Learning framework, which is aimed towards a Universal Deployment of the passive SHM system. The methodology is designed to perform the health monitoring of the system, independent of the input perturbations. The validation performed on simulation data has demonstrated the feasibility of the developed technique towards the required kind of passive SHM system.


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