Strain gage (gauge) installation on Concrete
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- Опубликовано: 30 июн 2024
- For bonding strain gages to any component, the component should have a smooth surface, free of voids, pin-holes, scratches, undulations, or other visible defects .
Concrete surfaces are porous, with voids between the sand particles and loose dust, which can prevent the gage from bonding well. Also, concrete surface will have significant variation of strain over a given area, due to its non-homogeneous nature. Due to their averaging property, small gages placed over such a surface could give varying results depending on the location, for the same load.
In this video, preparing the surface of concrete for straingage bonding is shown. After initial scrubbing, washing and rinsing of the surface, the pores, voids and uneven surface of concrete is filled with a layer of M-Bond AE-10, a slightly viscous adhesive which forms a tough base when cured. The layer of M-Bond AE-10 is sanded down until the top layer of the concrete is reached.
On this base of AE-10, strain gages can be bonded well using standard gage bonding procedure, which is illustrated in the video.
Micro Measurements Tech Tip 611 gives a complete description of the gage bonding procedure for concrete, and can be seen at :
www.vishaypg.com/docs/11091/tt...
In this video, a check on the installed gage with Micro Measurements model 1300 Gage Installation Tester is made. Gages bonded on uneven surfaces can change their resistance significantly. The Model 1300 can detect the change in terms of percent deviation from the specified resistance of the gage, which should be at least less than the resistance tolerance specified for the gage.
A well-bonded gage will show repeatability of strain readings under load, and will return to the initial balance condition when the load is removed. This is shown in the video, by connecting the gage to a System 7000 strain data logger from Micro Measurements , and loading the concrete specimen by running a vehicle over it .
Outstanding performance! A textbook gage installation! I shall refer to it during my classes
To watch more videos about strain gage installation please check our official channel: ruclips.net/channel/UCoTPJFJ7vKBBZkdKrTQM33Avideos
Thank you very much for the comment, it is very encouraging for me. I have tried to highlight the important aspects of gage installation - surface preparation, gage bonding, lead wire soldering. I hope your students will benefit from the presentation.
Vijay, Dynatec, 130 Palace Cross Road, Bangalore 560020. email: vijay.dynatec@gmail.com
Excelent video, thanks for sharing
Thank you
Very well explained sir. Thank you for sharing.
Thank you for your comment. I will be glad to provide more information on this - please contact me on vijay.dynatec@gmail.com
Thank you for sharing
Good sir great job 👌
Thank you for your kind comment. Regards, Vijay (vijay.dynatec@gmail.com)
Great
sir, do you have standard test method for measuring total strain?
and what is the standard size of beam to test it? can we use the size for creep and shrinkage test?
Sir, we allow adhesive to cure for 24 hours during surface preparation here. If I am doing it on field (i.e. bridge), it will come in contact with dust during this 24 hours. Will it create any problem? What precaution should i take in such situation?
After applying and spreading the adhesive, you may cover the adhesive area with a plastic or thick paper tray , sealing the edges with cellophane tape. The adhesive does not need air for curing, and when it is cured , it is impervious to dust or moisture. Any fine dust on the surface of the adhesive will be removed when you abrade it to get it level with the concrete surface.
@@DynatecIndia Thank you very much sir..!! For such quick response and solving my query.
@@bhumikhalani5676 I am glad I could answer your query satisfactorily.
may I ask a question, why the size of the strain gauge used is small and do we need to put a large size strain gauge to measure large sample's deformation?
Strain is ratio of deformation to original length. This is regardless of sample size. Strain gages measure only the strain, not the total deformation.
Depending on the size of the test specimen, you can choose the size of the gage to be used. Most often, the gage with 3 mm grid length is used - this is comfortable size for most applications, and the solder tabs are big enough to solder easily.
Straingages smaller than this need more skill and care while bonding, and very small straingages are difficult to manufacture and are normally more expensive.
Please see the video on Strain gage averaging effect where comparison of two different sizes of gages is shown.
I hope this answers your query, please let me know if you need more information
Suprbbb
Thank you , Best regards
How to install strain gauge for composite tensile test specimen
I have recently put up a video on bonding of strain gage on FRP material on Dynatec India channel of RUclips., please review this.
Best regards
Please see our video on straingage on CFRP material . The procedure is very similar to bonding straingage on concrete, except that initial cleaning with soap water is not necessary of the composite is clean. Regards
Where i can buy these types of strain gauge??
Please write to us about your requirement - how many gags do you need . The gages are sold in packets of 5 gages each, so you have to buy them in multiples of 5 gages. Do you also require the accessories ( cleaning chemicals, adhesives, solder etc)
@@DynatecIndia link please
@@DynatecIndia link please
@@salawudeenabdultawab4462 The link is :
ruclips.net/channel/UCWqBcaLPa5eu5SXv2AjDM7gvideos?view_as=subscriber
Hi, how to order cleaning chemicals, adhesives?