CN107421664B - Strain gauge for measuring bonding slippage between steel and concrete and pasting method - Google Patents
Strain gauge for measuring bonding slippage between steel and concrete and pasting method Download PDFInfo
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- CN107421664B CN107421664B CN201710371113.6A CN201710371113A CN107421664B CN 107421664 B CN107421664 B CN 107421664B CN 201710371113 A CN201710371113 A CN 201710371113A CN 107421664 B CN107421664 B CN 107421664B
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- steel
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
- G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
- G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
- G01L1/2206—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
Abstract
A strain gauge for measuring the bonding slippage between steel and concrete and a pasting method thereof, wherein the strain gauge comprises a substrate layer, the substrate layer is divided into an upper part, a middle part and a lower part, the upper part is used as a concrete substrate layer, a concrete cover layer is pasted on the front side surface of the concrete substrate layer, and the concrete substrate layer and the concrete cover layer jointly form a concrete pasting section; the middle part forms a non-sticking section and consists of a sensitive grid stuck on the front side surface of the middle part of the substrate layer, a protective sliding upper layer stuck on the front side surface of the sensitive grid and a protective sliding lower layer stuck on the rear side surface of the middle part, and the sensitive grid is provided with a lead-out wire used for connecting an external measuring device; the lower part is used as a steel base layer, a steel cover layer is pasted on the rear side surface of the steel base layer, and the steel base layer and the steel cover layer jointly form a steel pasting section. According to the strain gauge and the testing method, the steel does not need to be subjected to grooving treatment, a large amount of manufacturing cost is saved, the strain pasting method is simple and easy to operate, and the actual strength of the steel cannot be damaged.
Description
Technical Field
The invention relates to a strain gauge. In particular to a strain gauge for measuring the bonding slippage of steel and concrete and a bonding method.
Background
The bonding and sliding performance between steel and concrete is a hot problem in the research of civil construction structures and related fields, particularly, under the action of earthquake reciprocating loads, the bonding and sliding effect between the steel and the concrete seriously influences the overall anti-seismic property of the structure, so the research on the bonding and sliding of the steel and the concrete has very important significance in theory and engineering practice. The traditional bond slip effect between steel and concrete is often performed by a push-out test, and assuming that the steel does not yield, the bond stress is obtained by the equilibrium equation of steel and concrete. The steel material strain testing method is to notch the steel material and stick the resistance strain gauge inside, so as to obtain the varying adhesive stress of the steel material along the anchoring length. For the section steel concrete structure, generally, resistance strain gauges are densely distributed along the flange of the section steel with the anchoring length, and the distribution rule of the bonding stress is obtained according to the mutual relation between the bonding stress and the flange strain of the section steel. However, the method generally damages the actual strength of the steel to a large extent, and the steel sheet cutting is troublesome, so that the test efficiency is not high enough.
Disclosure of Invention
The invention aims to solve the technical problem of providing a strain gage for measuring the bonding slippage between steel and concrete without grooving the steel and a bonding method.
The technical scheme adopted by the invention is as follows: the strain gauge for measuring the bonding slippage of the steel and the concrete comprises a substrate layer, wherein the substrate layer is divided into an upper part, a middle part and a lower part, the upper part is used as a concrete substrate layer, a concrete cover layer is adhered to the front side surface of the concrete substrate layer, and the concrete substrate layer and the concrete cover layer jointly form a concrete adhering section; the middle part forms a non-sticking section and consists of a sensitive grid stuck on the front side surface of the middle part of the substrate layer, a protective sliding upper layer stuck on the front side surface of the sensitive grid and a protective sliding lower layer stuck on the rear side surface of the middle part, and the sensitive grid is provided with a lead-out wire used for connecting an external measuring device; the lower part as steel stratum basale, the steel cap coat is pasted to the trailing flank on steel stratum basale, steel stratum basale and steel cap coat constitute steel jointly and paste the section.
The bottom edge of the concrete cover layer is in adhesive connection with the upper end edge of the protective sliding upper layer, and the bottom edge of the protective sliding lower layer is in adhesive connection with the upper end edge of the steel cover layer.
The substrate layer is made of adhesive and organic resin film.
The concrete cover layer, the protective sliding upper layer, the protective sliding lower layer and the steel cover layer are all made of flexible foamed plastics.
The sensitive grid is made of one of constantan, nickel-chromium-aluminum alloy, iron-chromium-aluminum alloy, platinum and platinum-tungsten alloy.
A method for sticking a strain gauge for measuring bonding slippage between steel and concrete is characterized by comprising the following steps:
1) adopts mortar to manufacture a mortar test block for bonding the strain gauge,
2) sticking the concrete base layer, the protective sliding lower layer and the steel cover layer of the strain gauge to the polished smooth surface of the mortar test block;
3) polishing the surface of the section steel or the steel bar by using a grinding wheel or abrasive paper, cleaning the surface by using alcohol, and firmly adhering a steel base layer, a protective sliding upper layer and a concrete cover layer of the strain gauge to the section steel or the steel bar;
4) after the adhesive is solidified, firmly binding the mortar test block with the section steel or the reinforcing steel bar by using an iron wire, pouring cement mortar between the section steel or the reinforcing steel bar and the mortar test block, and simultaneously detecting whether the resistance of the two outgoing line ends of the strain gauge is the standard resistance of the strain gauge and whether the resistance between the outgoing line and the steel is infinite;
5) and pouring concrete after the poured cement mortar is solidified, and simultaneously detecting whether the line end resistances of the two outgoing lines of the strain gauge are the standard resistances of the strain gauge or not and whether the resistance between the outgoing line of the strain gauge and the steel is infinite or not.
The mortar test block manufactured in the step 1) is the mortar test block with the same strength and elastic modulus as the tested concrete, one surface of the mortar test block, which is bonded with the strain gauge, is polished by using sand paper and is cleaned by using alcohol, and the other three surfaces are roughened.
The width and the height of the test block are larger than the diameter of the tested steel bar, and the length of the test block is larger than 2 cm.
In the step 4) and the step 5), when the resistances of the two outgoing lines of the strain gauge at the line ends are deviated from the standard resistance of the strain gauge, the strain gauge is damaged, and when the resistance between the outgoing lines of the strain gauge and the steel is not infinite, the strain gauge fails.
According to the strain gage and the pasting method for measuring the bonding slippage between the steel and the steel, provided that the concrete strain of the concrete pasting section is the same as the concrete strain of the steel pasting section (or the steel strain of the concrete pasting section is the same as the steel strain of the steel pasting section), the concrete pasting section base and the steel pasting section base are firmly bonded with the concrete and the steel respectively, the free deformation can be realized between the cover layer of the concrete pasting section and the steel and between the cover layer of the steel pasting section and the concrete, and the bonding slippage between the concrete and the steel can be represented through the test result of the strain gage. According to the strain gauge and the testing method, steel does not need to be subjected to grooving treatment, a large amount of manufacturing cost is saved, the strain pasting method is simple and easy to operate, the strain testing method is the same as that of the traditional strain measurement, and meanwhile the actual strength of the steel cannot be damaged.
Drawings
FIG. 1 is a schematic front view of a strain gauge for measuring the adhesion slip between steel and concrete according to the present invention;
FIG. 2 is a schematic cross-sectional view of a strain gage for measuring the adhesion slip between steel and concrete according to the present invention.
In the drawings
1: concrete cover layer 2: concrete base layer
3: protection of the sliding upper layer 4: sensitive grid
5: protection of the lower layer 6: lead-out wire
7: steel base layer 8: steel cover
9: concrete attachment section 10: non-sticking section
11: steel material pasting section 12: base layer
Detailed Description
The following describes in detail a strain gauge for measuring the adhesion slip between steel and concrete and a method for attaching the strain gauge according to the present invention with reference to the following embodiments and accompanying drawings.
In order to make the purpose, technical scheme and effect of the strain gage for measuring the bonding slippage between steel and concrete and the pasting method of the invention clearer and clearer, the embodiment is used for further detailed description of the invention. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As shown in fig. 1 and 2, the strain gage for measuring the bonding slippage between steel and concrete of the invention comprises a base layer 12, wherein the base layer 12 is divided into an upper part, a middle part and a lower part, the upper part is used as a concrete base layer 2, a concrete cover layer 1 is adhered to the front side surface of the concrete base layer 2, and the concrete base layer 2 and the concrete cover layer 1 jointly form a concrete adhering section 9; the middle part forms a non-sticking section 10 which is composed of a sensitive grid 4 stuck on the front side surface of the middle part of a substrate layer 12, a protective sliding upper layer 3 stuck on the front side surface of the sensitive grid 4 and a protective sliding lower layer 5 stuck on the rear side surface of the middle part, wherein the sensitive grid 4 is provided with a leading-out wire 6 used for connecting an external measuring device. Namely, the sensitive grid 4 is connected with other test point strain gauges or compensation plates through an outgoing line 6 to form a Wheatstone bridge and is connected with a strain acquisition instrument; the lower part be steel stratum basale 7, steel cover coat 8 is pasted to the trailing flank on steel stratum basale 7, steel stratum basale 7 and steel cover coat 8 constitute steel jointly and paste section 11. The strain gage of the invention tests the relative slip between the steel pasting section 11 and the concrete pasting section 9 by measuring the deformation of the sensitive grid 4, and obtains the bonding slip strain between the steel and the concrete.
The bottom edge of the concrete cover layer 1 is in adhesive connection with the upper end edge of the protective sliding upper layer 3, and the bottom edge of the protective sliding lower layer 5 is in adhesive connection with the upper end edge of the steel cover layer 8.
During testing, the steel base layer 7, the protective sliding upper layer 3 and the concrete cover layer 1 are firmly adhered to the steel; the concrete base 2 layer, the protective slippage lower layer 5 and the steel cover layer 8 are bonded with the concrete.
In the strain gauge for measuring the bonding slippage between steel and concrete, the base layer 12 is made of an adhesive and an organic resin film. The concrete cover layer 1, the protective sliding upper layer 3, the protective sliding lower layer 5 and the steel cover layer 8 are all made of flexible foam plastics. The sensitive grid 4 is made of one of constantan, nickel-chromium-aluminum alloy, iron-chromium-aluminum alloy, platinum and platinum-tungsten alloy.
The invention relates to a method for sticking a strain gauge for measuring bonding slippage between steel and concrete, which comprises the following steps:
1) adopting mortar to manufacture a mortar test block for bonding the strain gauge;
the manufactured mortar test block is the same as the tested concrete in strength and elastic modulus, the width and the height of the test block are larger than the diameter of the tested steel bar, and the length of the test block is larger than 2 cm. And (3) polishing one surface of the mortar test block, which is bonded with the strain gauge, by using sand paper, the surface is smooth, the surface is cleaned by using alcohol, and the other three surfaces are roughened, so that the mortar test block is firmly fused with poured concrete.
2) Sticking the concrete base layer, the protective sliding lower layer and the steel cover layer of the strain gauge to the polished smooth surface of the mortar test block;
3) polishing the surface of the section steel or the steel bar by using a grinding wheel or abrasive paper, cleaning the surface by using alcohol, and firmly adhering a steel base layer, a protective sliding upper layer and a concrete cover layer of the strain gauge to the section steel or the steel bar;
4) after the adhesive is solidified, firmly binding the mortar test block with the section steel or the reinforcing steel bar by using an iron wire, pouring cement mortar between the section steel or the reinforcing steel bar and the mortar test block, and simultaneously detecting whether the resistance of the two outgoing line ends of the strain gauge is the standard resistance of the strain gauge and whether the resistance between the outgoing line and the steel is infinite; when the resistances of the two outgoing lines of the strain gauge at the line ends are deviated from the standard resistance of the strain gauge, the strain gauge is damaged, and when the resistance between the outgoing lines of the strain gauge and steel is not infinite, the strain gauge fails.
5) And pouring concrete after the poured cement mortar is solidified, and simultaneously detecting whether the line end resistances of the two outgoing lines of the strain gauge are the standard resistances of the strain gauge or not and whether the resistance between the outgoing line of the strain gauge and the steel is infinite or not. When the resistances of the two outgoing lines of the strain gauge at the line ends are deviated from the standard resistance of the strain gauge, the strain gauge is damaged, and when the resistance between the outgoing lines of the strain gauge and steel is not infinite, the strain gauge fails.
Claims (7)
1. The strain gage for measuring the bonding slippage of the steel and the concrete comprises a basal layer (12) and is characterized in that the basal layer (12) is divided into an upper part, a middle part and a lower part, wherein the upper part is used as a concrete basal layer (2), a concrete cover layer (1) is adhered to the front side surface of the concrete basal layer (2), and the concrete basal layer (2) and the concrete cover layer (1) jointly form a concrete adhering section (9); the middle part forms a non-sticking section (10) and consists of a sensitive grid (4) stuck to the front side surface of the middle part of the substrate layer (12), a protective sliding upper layer (3) stuck to the front side surface of the sensitive grid (4) and a protective sliding lower layer (5) stuck to the rear side surface of the middle part, and the sensitive grid (4) is provided with a leading-out wire (6) used for connecting an external measuring device; the lower part is used as a steel base layer (7), a steel cover layer (8) is adhered to the rear side face of the steel base layer (7), and the steel base layer (7) and the steel cover layer (8) jointly form a steel adhering section (11);
the bottom edge of the concrete cover layer (1) is in adhesive connection with the upper end edge of the protective sliding upper layer (3), and the bottom edge of the protective sliding lower layer (5) is in adhesive connection with the upper end edge of the steel cover layer (8); the concrete cover layer (1), the protective sliding upper layer (3), the protective sliding lower layer (5) and the steel cover layer (8) are all made of flexible foamed plastics.
2. A strain gage for measuring bond slip between steel and concrete as claimed in claim 1 wherein said base layer (12) is made of adhesive and organic resin film.
3. The strain gage for measuring bonding slippage of steel and concrete as claimed in claim 1, wherein said sensitive grid (4) is made of one of constantan, nichrome, ferrochromium, platinum and platinum-tungsten.
4. The method for bonding a strain gauge to a steel material for measuring adhesion slip between a steel material and concrete according to claim 1, comprising the steps of:
1) adopts mortar to manufacture a mortar test block for bonding the strain gauge,
2) sticking the concrete base layer, the protective sliding lower layer and the steel cover layer of the strain gauge to the polished smooth surface of the mortar test block;
3) polishing the surface of the section steel or the steel bar by using a grinding wheel or abrasive paper, cleaning the surface by using alcohol, and firmly adhering a steel base layer, a protective sliding upper layer and a concrete cover layer of the strain gauge to the section steel or the steel bar;
4) after the adhesive is solidified, firmly binding the mortar test block with the section steel or the reinforcing steel bar by using an iron wire, pouring cement mortar between the section steel or the reinforcing steel bar and the mortar test block, and simultaneously detecting whether the resistance of the two outgoing line ends of the strain gauge is the standard resistance of the strain gauge and whether the resistance between the outgoing line and the steel is infinite;
5) and pouring concrete after the poured cement mortar is solidified, and simultaneously detecting whether the line end resistances of the two outgoing lines of the strain gauge are the standard resistances of the strain gauge or not and whether the resistance between the outgoing line of the strain gauge and the steel is infinite or not.
5. The method for bonding a strain gage for measuring the bonding slippage between steel and concrete according to claim 4, wherein the mortar block manufactured in step 1) is the same as the strength and elastic modulus of the concrete to be tested, and one surface of the mortar block bonded to the strain gage is polished smooth by using sand paper, cleaned by using alcohol, and roughened on the other three surfaces.
6. The method of claim 5, wherein the width and height of the test block are greater than the diameter of the steel bar to be tested, and the length is greater than 2 cm.
7. The method for bonding the strain gauge to measure the bond slip between the steel material and the concrete according to claim 4, wherein in the step 4) and the step 5), when the resistances of the two lead-out wires of the strain gauge at the ends are deviated from the standard resistance of the strain gauge, the strain gauge is damaged, and when the resistance between the lead-out wire of the strain gauge and the steel material is not infinite, the strain gauge fails.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201710371113.6A CN107421664B (en) | 2017-05-24 | 2017-05-24 | Strain gauge for measuring bonding slippage between steel and concrete and pasting method |
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| CN201710371113.6A CN107421664B (en) | 2017-05-24 | 2017-05-24 | Strain gauge for measuring bonding slippage between steel and concrete and pasting method |
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| CN107421664B true CN107421664B (en) | 2020-05-22 |
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| CN110274872A (en) * | 2019-04-15 | 2019-09-24 | 内蒙古科技大学 | Directly measure the method for adhesive property on PEC steel reinforced concrete adhesive surface |
| CN111398164A (en) * | 2020-03-30 | 2020-07-10 | 太原理工大学 | Test device for measuring axial multi-point slippage of concrete filled steel tube |
| CN112763301B (en) * | 2021-03-19 | 2022-12-16 | 浙江循正建设工程检测有限公司 | Building concrete anti-cracking performance detection system with surface mounting function |
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| CN101819134B (en) * | 2010-04-02 | 2011-10-26 | 西安建筑科技大学 | Test method for measuring bond stress between reinforcing steel bars and concrete |
| CN102788068A (en) * | 2011-05-18 | 2012-11-21 | 厦门市宏业工程建设技术有限公司 | Sticking method of strain gauge |
| JP2013250120A (en) * | 2012-05-31 | 2013-12-12 | Ttes Inc | Damage detection method for structure |
| CN104374313A (en) * | 2014-11-26 | 2015-02-25 | 安徽省交通规划设计研究总院股份有限公司 | Resistance strain gauge under harsh environment |
| CN104792257B (en) * | 2015-04-13 | 2017-12-26 | 重庆大学 | It is a kind of to measure many places strain process inside early-age concrete simultaneously |
| CN105021522A (en) * | 2015-07-01 | 2015-11-04 | 三峡大学 | Bond-slip property detection device, reinforcing bar slotting and strain gauge protection method |
| CN106644930B (en) * | 2016-11-01 | 2023-04-21 | 长安大学 | Reinforced concrete internal bonding slip testing device and method |
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