Physical Nonlinear Model Adaptation in Long-Term Structural Health Monitoring: Proposals of Experimental Studies on a Reinforced Concrete Beam

2010 ◽  
Vol 97 (8) ◽  
pp. 32-38
Author(s):  
Martina Schnellenbach-Held ◽  
Bjoern Karczewski
Keyword(s):  
Reinforced Concrete ◽  
Structural Health Monitoring ◽  
Nonlinear Model ◽  
Health Monitoring ◽  
Concrete Beam ◽  
Experimental Studies ◽  
Reinforced Concrete Beam ◽  
Model Adaptation ◽  
Structural Health

scholarly journals Smart RFID Sensors Embedded in Building Structures for Early Damage Detection and Long-Term Monitoring

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5514 ◽  
Author(s):  
Christoph Strangfeld ◽  
Sergej Johann ◽  
Matthias Bartholmai
Keyword(s):  
Reinforced Concrete ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Radio Frequency Identification ◽  
Civil Engineering ◽  
Cement Matrix ◽  
Term Operation ◽  
Structural Health ◽  
Passive Rfid

In civil engineering, many structures are made of reinforced concrete. Most degradation processes relevant to this material, e.g., corrosion, are related to an increased level of material moisture. Therefore, moisture monitoring in reinforced concrete is regarded as a crucial method for structural health monitoring. In this study, passive radio frequency identification (RFID)-based sensors are embedded into the concrete. They are well suited for long-term operation over decades and are well protected against harsh environmental conditions. The energy supply and the data transfer of the humidity sensors are provided by RFID. The sensor casing materials are optimised to withstand the high alkaline environment in concrete, having pH values of more than 12. Membrane materials are also investigated to identify materials capable of enabling water vapour transport from the porous cement matrix to the embedded humidity sensor. By measuring the corresponding relative humidity with embedded passive RFID-based sensors, the cement hydration is monitored for 170 days. Moreover, long-term moisture monitoring is performed for more than 1000 days. The experiments show that embedded passive RFID-based sensors are highly suitable for long-term structural health monitoring in civil engineering.

scholarly journals Toward Structural Health Monitoring of Civil Structures Based on Self-Sensing Concrete Nanocomposites: A Validation in a Reinforced-Concrete Beam

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Diego L. Castañeda-Saldarriaga ◽  
Joham Alvarez-Montoya ◽  
Vladimir Martínez-Tejada ◽  
Julián Sierra-Pérez
Keyword(s):  
Reinforced Concrete ◽  
Damage Detection ◽  
Direct Current ◽  
Health Monitoring ◽  
Electrical Resistance ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Structural Member ◽  
Rc Beam ◽  
Electric Resistance

AbstractSelf-sensing concrete materials, also known as smart concretes, are emerging as a promising technological development for the construction industry, where novel materials with the capability of providing information about the structural integrity while operating as a structural material are required. Despite progress in the field, there are issues related to the integration of these composites in full-scale structural members that need to be addressed before broad practical implementations. This article reports the manufacturing and multipurpose experimental characterization of a cement-based matrix (CBM) composite with carbon nanotube (CNT) inclusions and its integration inside a representative structural member. Methodologies based on current–voltage (I–V) curves, direct current (DC), and biphasic direct current (BDC) were used to study and characterize the electric resistance of the CNT/CBM composite. Their self-sensing behavior was studied using a compression test, while electric resistance measures were taken. To evaluate the damage detection capability, a CNT/CBM parallelepiped was embedded into a reinforced-concrete beam (RC beam) and tested under three-point bending. Principal finding includes the validation of the material’s piezoresistivity behavior and its suitability to be used as strain sensor. Also, test results showed that manufactured composites exhibit an Ohmic response. The embedded CNT/CBM material exhibited a dominant linear proportionality between electrical resistance values, load magnitude, and strain changes into the RC beam. Finally, a change in the global stiffness (associated with a damage occurrence on the beam) was successfully self-sensed using the manufactured sensor by means of the variation in the electrical resistance. These results demonstrate the potential of CNT/CBM composites to be used in real-world structural health monitoring (SHM) applications for damage detection by identifying changes in stiffness of the monitored structural member.

Modeling the operation of structures made of dispersed-reinforced concrete with an alternating dynamic load of high intensity

2021 ◽  
Vol 14 (3) ◽  
pp. 36-44
Author(s):  
S. Nikolenko ◽  
Svetlana Sazonova ◽  
Viktor Asminin
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Load ◽  
High Intensity ◽  
Concrete Beam ◽  
Static Load ◽  
Dynamic Compression ◽  
Experimental Studies ◽  
Reinforced Concrete Beam ◽  
Beam Elements ◽  
Laminated Structures

A study of the properties of dispersed-reinforced concrete and a study of the effect of dispersed reinforcement on the operation of structures was carried out, mainly with a static load of the same sign. Based on the results of experimental studies, a comparison was made of the work of dispersed-laminated structures under alternating dynamic action of high intensity with the work of reinforced concrete beam elements under similar influences. The results of experimental studies of cubes and prisms for static and dynamic compression are also presented. The results of experimental studies allow us to conclude that there is a significant effect of dispersed reinforcement on the operation of structures under the investigated influences and the feasibility of combined reinforcement of structures. The use of dispersed reinforcement in structures will increase the resistance of structures to such influences.

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