Practice Question: Minimum Size of Ties in Composite Column

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Solution

The minimum diameter of the transverse ties or hoops is 0.02 times the greater side dimension of the composite column. 
For a side dimension of 12 inches, 

\[0.02\ times\ the\ side\ dimension=0.02 (12\ in) = 0.24\ in\]

However, according to ACI-318, it should be at least No. 3 and not to be larger than #5.

Therefore, the minimum required size is No. 3 (0.375 in), which is greater than 0.24 inches.
 

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