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What is the purpose of conducting re-bend test of steel reinforcement?

In BS4449:1997 it species a re-bend test of steel reinforcement where
reinforcing steel is bent 45o at 100oC for an hour and then bent back by 23o.


What is the purpose of conducting bend test of reinforcement?

It is not uncommon that steel reinforcement is bent prior to installation into concrete structure. However, upon bending process steel reinforcement may fracture owing to the following reasons:

(i) The ribs on steel bars serve as location of stress concentration which is a potential weak point for fracturing.

What is the reason of grouping several reinforcement bars in concrete structure?

For too much reinforcement to be incorporated in concrete structures, the reinforcement bars are sometimes groups because:

(i) It facilitates placing of fresh concrete with more space available;

Why is acetylene gas cylinder for gas welding to be erected in upright position?

Acetylene gas is commonly used for gas welding because of its simplicity in production and transportation and its ability to achieve high temperature in combustion (e.g. around 5,000o F).


In checking the quality of weld, what are the pros and cons of various non-destructive weld inspection methods i.e. ultrasonic test, radiographic inspection and magnetic particle flaw detection test?

Currently, there are three common non-destructive testing of weld, namely radiographic inspection, ultrasonic testing and magnetic flaw detection test.