An in-situ online monitoring method for the stress of reinforced concrete structures

A technology of reinforced concrete and structural stress, which is applied to the measurement of the property force of piezoelectric devices, etc., can solve the problems of stress monitoring, inability to achieve in-situ monitoring, and sensors are easily affected by external factors, and achieves simple operation. Effect

Active Publication Date: 2017-01-25
SHENZHEN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The problem with this type of method is that it is impossible to realize the in-situ monitoring of the additional internal force caused by the non-load factors generated during the long-term use of the structure
However, whether it is a mechanical or electrical sensor, the sensor is placed on the surface of the measured body. The sensor is easily affected by external factors and cannot accurately monitor the stress change of the concrete member. This is very important for the long-term use of the structure. The impact of stress monitoring is particularly pronounced

Method used

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  • An in-situ online monitoring method for the stress of reinforced concrete structures
  • An in-situ online monitoring method for the stress of reinforced concrete structures
  • An in-situ online monitoring method for the stress of reinforced concrete structures

Examples

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Embodiment 1

[0056] Using the in-situ monitoring method of the concrete structure stress involved in the present invention, the linear performance of the sensors under the impact load is tested on three reinforced concrete beams with dimensions of 100mm×100mm×1200mm. The structural schematic diagram of the 1-3 type cement-based piezoelectric composite material sensor used in the present invention is shown in Figure 2, wherein, 5 is the 1-3 type cement-based piezoelectric composite material, made of PZT-51 piezoelectric ceramics (Hebei Baoding Hongsheng Acoustics Co., Ltd. equipment factory) prepared by cutting-filling method, and its final size is 10mm×10mm×1.5mm; 6 is polymer / cement packaging material, in which the polymer is AB-grouting resin, and the cement is ordinary Portland cement. The mass ratio of polymer to cement is 1:1. The mass mix ratio of the concrete beam is cement: water: sand: gravel: retarder = 1:0.49:1.65:2.19:0.009. The embedding of sensors in the beam is shown in Figu...

Embodiment 2

[0060] Using the in-situ monitoring method for concrete structure stress involved in the present invention, the concrete beam in Example 1 is tested for piezoelectric performance under impact load and cyclic load. Periodic loads are applied by electric picks, the loading frequencies are 5Hz, 10Hz, 20Hz, 30Hz respectively, and the amplitude of half-sine periodic loads is 10000N. The electric picks are bound together with the structure by belts to ensure loading stability. The piezoelectric performance of cement-based piezoelectric composite sensor in reinforced concrete structure is the key to the application of the sensor in reinforced concrete structure. For the piezoelectric performance, this example is mainly studied through the monitoring results under impact load and cyclic load. In order to study the piezoelectric characteristics of the cement-based piezoelectric composite sensor in the compression zone and tension zone of the reinforced concrete beam, impact loads were ...

Embodiment 3

[0065] Using the in-situ monitoring method for concrete structure stress involved in the present invention, the frequency response test of the concrete beam in Example 1 under different frequency cyclic loads is carried out. The frequency response of the sensor is one of the important properties to measure the dynamic response of the sensor. In this embodiment, during the loading process, the amplitude of the input sinusoidal load is kept unchanged at 10000N, and the frequency of the input load is changed, respectively inputting 5Hz, 10Hz, 20Hz, and 30Hz, and these frequencies are all included in the frequency range that includes the vibration of civil engineering structures (0.1Hz-40Hz) to test the frequency response of the sensor. The voltage waveform generated by the sensor is converted into stress, and the stress-time curve results of some sensors are as follows Figure 10 shown. Depend on Figure 10 It can be seen that under half-sine loads of different frequencies, th...

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Abstract

The invention discloses a reinforced concrete structure stress in situ online monitoring method. A sensor is pre-embedded in a concrete member. Pole direction of the sensor is consistent with detected stress direction. The sensor is used for receiving electrical signals generated by concrete stress variations. The sensor is connected through a shielded wire with a stress monitoring system which is used for recording stress monitoring information. According to the reinforced concrete structure stress in situ online monitoring method, the sensor is pre-embedded in the concrete member. The sensor can exclude influence of external factors and stress variation conditions of the concrete member are monitored accurately. The method provided by the invention is simple to operate, can be used to realize in situ, real-time and online monitoring of stress-time of the concrete structure, and is of great significance for experimental research of concrete.

Description

[0001] [technical field] [0002] The invention relates to the monitoring of concrete components, in particular to an in-situ on-line monitoring method for the stress of reinforced concrete structures. [0003] [Background technique] [0004] With the continuous emergence of important buildings such as high-rise buildings, long-span space structures, and super-large bridges, and the continuous improvement of people's requirements for the safety and comfort of civil engineering structures, the research on large-scale structural health monitoring systems has become a research hotspot in the field of civil engineering. . Structural health monitoring system is of great significance to avoiding loss of personnel and property, reducing structural maintenance costs, prolonging structural life, and ensuring structural durability and practicability. [0005] The existing stress in the concrete structure is one of the most important indicators reflecting the condition of the whole struc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01L1/16
Inventor 董必钦刘昱清洪舒贤邢锋房国豪张建超徐伟伟林立陈岸伦袁斯鸿
Owner SHENZHEN UNIV
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