Measurement specimen and measurement method for interface characteristic of embedded rib reinforced concrete beam

A technology of concrete beam and interface characteristics, which is applied in the direction of testing material strength by applying a stable bending force and preparation of test samples, and can solve problems such as not considering the influence of dense strain gauge interface characteristics

Inactive Publication Date: 2015-03-25
HUNAN INSTITUTE OF ENGINEERING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] 4. The influence of dense strain gauges

Method used

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  • Measurement specimen and measurement method for interface characteristic of embedded rib reinforced concrete beam
  • Measurement specimen and measurement method for interface characteristic of embedded rib reinforced concrete beam
  • Measurement specimen and measurement method for interface characteristic of embedded rib reinforced concrete beam

Examples

Experimental program
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Example Embodiment

[0052] Example 1

[0053] See attached figure 1 , 2 , The present invention is a sample for measuring the interface characteristics of a concrete beam reinforced with embedded reinforcements. The sample includes a combined reinforcement 11, and a through groove 13 is provided along the axis direction at the center of the cross section of the combined reinforcement 11; On the inner wall of the through groove 13, strain gauges 12 are uniformly distributed along the axial direction of the through groove;

[0054] The combined reinforcing ribs are carbon fiber reinforced plastic ribs, the reinforcing ribs are produced by Nanjing Haituo Composite Materials Co., Ltd., and the product name is Lica-200;

[0055] The cross section of the through groove 13 is square.

Example Embodiment

[0056] Example 2

[0057] The difference between the second embodiment and the first embodiment is that a row of strain gauges 12 is attached to a set of opposite inner surfaces of the square through groove 13, and the positions of the same row of strain gauges 12 are on the same straight line along the axial direction of the through groove.

[0058] The preparation method of a specimen for measuring the interface characteristics of reinforced concrete beams with embedded reinforcement is briefly described below: two CFRP bars are processed on a planer to obtain two CFRP bars with a semicircular cross section; on the cross section of the semicircular bar , Slotting along the CFRP ribs; Paste strain gauges on one side of the slot or take the axis of the slot as the axis of symmetry, and paste two rows of strain gauges evenly on the inner wall of the slot, and the positions of the same row of strain gauges are on the same straight line; then , Re-bond two semicircular CFRP ribs into ...

Example Embodiment

[0059] Example 3

[0060] A method for measuring interface characteristics of reinforced concrete beams with embedded reinforcements, including the following steps:

[0061] (1) Design and manufacture of test beams.

[0062] The specification of the concrete beam is 150mm×300mm×2600mm, and the longitudinal reinforcement at the bottom of the beam is 2 14. The erecting rib is 2φ8(A s ′=101mm 2 ), the thickness of the net protective layer of the longitudinal bars c=30mm, a s =30+8+7=45mm, the net protective layer thickness of the vertical bars c′=25mm, a s ′=25+8+4=37mm, then the effective height of the concrete beam is h 0 =255mm, choose φ8@150 stirrups at the 1 / 3 length of the beam span, choose φ8@100 stirrups at both ends of the beam near the 1 / 3 of the support for shear resistance, the concrete strength grade is C30, and a total of 12 concrete beams are poured root.

[0063] (2) Contrast group concrete beam test.

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Abstract

The invention discloses a measurement specimen and a measurement method for an interface characteristic of an embedded rib reinforced concrete beam. The specimen comprises a combined reinforced rib, wherein a through groove is formed in the center of the section of the combined reinforced rib in the axial direction; strain gauges are uniformly distributed on the inner wall of the through groove along the axial direction of the through groove. The method comprises the following steps that the combined reinforced rib is embedded into the concrete beam, and according to the conventional four-point bending static load test, an automatic static strain acquisition instrument records data epsilon f of the strain gauges and the cracking load Pcr, the yield load Py and the ultimate load Pu of the beam in real time; according to the strain data measured actually, the shearing strength of an interface of the combined reinforced rib or a CFRP rib with a glue agent is obtained by calculation; the Pu theory value is obtained by calculating according to the calculating method of the concrete reinforcing strength in the concrete reinforcing theory. By comparing the errors of the Pu theory value with the Pu, the result shows that the specimen can be used for improving the measurement precision of parameters of the interface characteristic of the reinforced concrete beam, and the strain measurement is convenient and easy.

Description

technical field [0001] The invention discloses a measurement sample and a measurement method for the interface characteristics of a concrete beam reinforced with embedded ribs, in particular to a measurement sample and a measurement method for the interface characteristics of a concrete beam reinforced with embedded carbon fiber reinforced plastic bars; it belongs to the composite interface of concrete The field of characteristic measurement technology. technical background [0002] Reinforced concrete structure is the most widely used structural form in engineering practice. There are many reinforced concrete structures that need to be reinforced due to poor construction quality, changes in building use, structural overloading, exposure to harsh environments, etc. Carbon fiber reinforced plastic (Carbon Fiber Reinforced Polymer English abbreviation is CFRP) has been widely used in the maintenance and reinforcement engineering practice of engineering structures due to its s...

Claims

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Application Information

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IPC IPC(8): G01N1/28G01N3/20
Inventor 任振华曾宪桃
Owner HUNAN INSTITUTE OF ENGINEERING
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