Monday, November 25, 2019

Why Pull-Out test is necessary after rebaring Work? What is Standard procedure of Pull-Out Test?




In the previous blog, we got detailed information about What is rebarring and why rebarring is required? also, we discussed rebarring procedure which is using currently in the industry, but some contractor does not follow standard procedures, which is very dangerous to the strength of the structure and this is directly affected on the life of the structure. a lot of contractors are taking to much lightly when rebarring, and not follows standards procedures. for those contractors, we are providing some information about how to test rebarring work? this test is called as " Pull-Out Test".

now in this blog, we will discuss why the pull-out test is necessary and what is its procedure?


Setting time:

After rebarring of bar wait for 48 to 72 hours to execute this test. Some companies claim chemical setting time is 30 min to 1 hour, but wait up to 48 to 72 hours. because this is standard setting time for the final set of chemicals.



In meantime you can call and give order to your Chemical providing agency to provide Rebar pull-out test, those companies are offering free of cost pull out the test if rebarring quantity is more than 20 numbers. if the rebarring of the bar is less than 20 numbers companies will charge you some cost as per design, location, etc. but charges of particular companies depend on the situation.

Types of Rebarring Chemicals.

Hilti, Fischer, Wurth, Fosroc, etc are providing a wide range of rebarring chemicals.

1. Hilti: HIT RE 100, HIT HY 170, HIT HY 200R RE 500V3, etc.

2. Fischer: FIS V 360, etc.

3. Wurth: PE 500, etc.

Above mentioned chemical name and it's typed, currently in the market there are other brands are also available, but we are trying to cross-check it with pull out test.
Calculate the chemical requirements as per standards.

1. 16mm Dia. : 20mm Drill: 480mm Depth: 85ml chemical required per Hole.

2. 20mm Dia. : 25mm drill hole: 600mm Depth: 160ml chemical Required per hole.
Mark the test Bar.

Locate the test bar where you are doing pull out test, Clean the surrounding area around the bar. also, keep the leveling surface to put the Machine of Pull out the test.

Test Process

The operator will come at the site will all tools required for testing.

1 Insert Hydraulic Jack in Bar.

Insert the hydraulic Jack in the designated bar where we want to check the pull-out test. This Hydraulic jack is cylindrical shape and hollow from the middle like a pipe, which can be easily inserted in any diameter of the bar.



2 Insert the loading ring around the bar.

This ring is Square Shape or round shape depend as per the situation. which has made by heavy ms material to bare load and pressure while testing. please keep a minimum distance from hydraulic jack and rising.





3 Push Loading shoes between the loading ring and bar.

Push loading shoes are both equal shapes, which are needed to insert both sides of the ring and cover the bar. those shoes are conical shapes with zig-zag shape, which can behold any diameter of the bar tightly.




4  Press and apply load by hammer and fix this properly.

After inserting g the loading shoes in-ring and hold the bar, press and tight the loading shoes by Hamner. Loading ring, loading shoes, and bar should be tight, please check once about it, if any part of loading shoes are moving please press again by hammer and tight it.




5. Connect Hydraulic Pump to hydraulic Jack.

After cross-checking of above all setting please connect the hydraulic pump to hydraulic jack with help of a hydraulic pipe. and please tight it properly.



6. Connect Loading scale meter to pump.

Connect the Meter gauge to the hydraulic pressure pump,  which can show the exact applied load on the bar, and this will help us to measure the actual applied load on Bar. also tight pressure release valve.


                                  



7. Start the Pump by hand press.

After all, set up completed, now you can start the test by using the handle to give pressure on the bar, which rebar by using chemical. now need to focus on the meter gauge to track the currently applied load on the bar. Also, notify to push the handle on uniformly. In the meter gauge, there are 2 pointers red and Black which are located for the load applied to the bar in Kilo Newton. but Red pointer in depending on the black pointer, The red pointer is locating the highest point of black pointer the red pointer is always steady, not moving like a black pointer. that means we need to assume the red pointer reading is final. and calculate the load as per the red pointer data.






Team
CBEC India

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