Civil Engineering/over - reinforced beam
QUESTION: Hi Dear BEH,
Just wanted to understand about the over-reinforced beam. What are the characteristics of it ? Is there an easy method to find out that the RCC beam is over re-inforced by looking at the specifications like re bars used, concrete grade etc ?
I have attached the picture of a beam specifications for a 24 feet simply supported beam. Can you glace it and let me know does it come under over re-in-forced category.
If I am asking some questions beyond the scope of this forum, please excuse me. I hope you help me in understanding.
ANSWER: Dear Sudarshan
Over reinforcement depends on girder effective height and strength and amount of reinforcement and cant be qualified visually. But your detail doesnt seem to be a over reinforcement case because you have compression reinforcement where you have a concentration of tensile reinforcement.
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QUESTION: Hi BEH,
I am very happy about your quick and crisp reply as usual.
The main reason I asked you this question is because, I read in some article that over re-inforced beam will not give any warning before it fails. So, in this case i don't need to worry about such situation. is that right ? Please educate me if I am wrong in understanding this situation.
I have attached a better picture of the specification again in case you had trouble in viewing it last time.
You are right and exact. The over reinforcement make a situation for the member to fail due to compression concrete crash and thus a brittle an abrupt failure which has to be prevented. I think your girder doesnt have such a problem because you have compression reinforcement which decreases the amount of tensile reinforcement leading to over reinforcement .