Question Dear Babak,
Clause 220.127.116.11 of aci 318 states: " Columns designed assuming fixed-end conditions at the foundation shall comply with 18.104.22.168 and, if hooks are required, longitudinal reinforcement resisting flexure shall have 90-degree hooks near the bottom of the foundation with the free end of the bars oriented toward the center of the column". My question is what is the reason behind this requirements ?, is it required in all codes? And where does it apply ?
Answer Dear Ayman
The provision is to make sure that the assumption of fixed end columns is correct. As I know this is a general advice in almost all codes. But an engineer may design its own way to reach to a target. They are not strict if you can think about your own situation. The codes advices are for the case no more sophisticated resolution is manipulated by the engineer.
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I am experienced in the area of earthquake engineering in electrical power industry, i.e. Lifeline Earthquake Engineering. My focus has been on structural seismic design of power installations. Recently I have got involved in project management in the category of constructional engineering.
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Education/Credentials Bs degree in Civil Engineering from Ferdowsi University ,1988, Mashhad Iran, Ms degree in Earthquake Engineering, Sharif University of Technology, 1993, Tehran, Iran