KR20100116365A

KR20100116365A - Prediction technique of temperature varying for hsc column deformation by embedded fbg sensor

Info

Publication number: KR20100116365A
Application number: KR1020090035030A
Authority: KR
Inventors: 장일영
Original assignee: (주)대우건설
Priority date: 2009-04-22
Filing date: 2009-04-22
Publication date: 2010-11-01

Abstract

PURPOSE: A temperature change prediction technique for a high strength concrete column using an embedded optical fiber Bragg lattice sensor is provided to check the deformation and safety of a structure by permanently measuring the temperature change of the structure using an embedded optical fiber Bragg lattice sensor. CONSTITUTION: A temperature change prediction technique for a high strength concrete column using an embedded optical fiber Bragg lattice sensor comprises following steps. An embedded optical fiber sensor is used. The sensor is buried underground in a long-dated and permanent manner. The varied data values are monitored. A post spot is selected in advance to install the sensor before the pouring of concrete.

Description

Prediction technique of temperature varying for HSC column deformation by embedded FBG sensor

The present invention relates to a technique for permanently burying a buried optical fiber (FBG) sensor in a high performance high strength concrete pavement, thereby measuring the temperature change of the fluid concrete before the curing of the structure from the earliest to the early age.

Embedded Fiber Optic Sensor (FBG) can measure the temperature change of fluid concrete before curing and it is waterproof structure, so it can measure internal deformation at the initial stage of curing. It also can be used for long-term strain measurement because it does not absorb moisture. That is, the sensor can measure both short and long term temperature changes.

Conventional electric resistive buried strain gauges have a large amount of noise during measurement and cannot measure small signals. In addition, the reliability of data during long-term measurement was insufficient due to the degradation of durability due to sensor damage and corrosion during construction when used as a buried type of structure. In addition, it is possible to measure the deformation by external load in the measurement of internal strain and stress of reinforced concrete and concrete after burial, but it is difficult to quantitatively measure structural physical change due to shrinkage and cracking.

On the other hand, the embedded fiber-optic temperature (FBG) sensor means a fiber Bragg grating, which can transmit signals or data without disturbing the magnetic field because it is an insulator. It has the advantage that it can be stuck or embedded in existing structures without difficulty. It has a characteristic of reflecting only a specific wavelength of pressure light by changing. The reflected wavelength changes linearly with temperature change, and the change can be used to obtain the strain value.

The purpose of this design is to examine the change and safety of the structure by measuring the temperature change permanently from the initial stage of the structure by using the buried fiber optic sensor (FBG) with various advantages.

This design uses the embedded fiber optic sensor (FBG) to select the point that can be easily measured before the concrete is placed in the early stage. Enables permanent temperature change measurement The attachment of the fiber optic sensor uses a waterproof embedded fiber optic sensor to fix the sensor in the longitudinal direction of the member by crossing two U-shaped rebars on the main rebar.

In addition, for the monitoring of permanent data, we have created an enclosure capable of storing the data logger in the field, and using this data to monitor and collect data in off-site offices, Solve the problem.

The present invention can measure the temperature change from the start to the end of the high-strength concrete column to the demolition, so that the temperature change of the structure can be continuously monitored.

Before the concrete is placed, determine the point where it is easy to measure, and select the column point where the sensor can be installed.

FBG sensor by using U-shaped reinforcement to bind to existing reinforcement

To combine. At this time, the main reinforcing bar and the sensor are sufficiently spaced apart to maximize the accuracy of measurement by minimizing the influence of the reinforcing bar when detecting the behavior of concrete.

In order to minimize the failure and change of the sensor due to the impact when concrete is placed, the sensor is tightly bound and spaced apart from the sensor installation area when placing the concrete. Minimization ensures accurate measurement.

Since the data cannot be continuously monitored at the site, the data logger connected to the sensor is placed in the prefabricated enclosure and the captain is located at the point where there is no obstacle to the construction progress.

The connected data logger uses wireless transmitters to receive data values in the office in real time, eliminating the need to remain on site.

Example

1 is a field application of the wall part by fixing the sensor to the present invention

Claims

Monitoring method of measurement change of high-performance concrete using embedded fiber optic sensor (FBG) .It is a medium to long-term and permanent technique to monitor the changing data values in the field offices and indoors away from the landfill point Technique.