Effect of Deflection on concrete beam capacity Question 1

[eyemeyar]

Hello Everyone, I wish to hear your ideas and experiences about these things. =)

1 - When you design concrete beams, should you always consider deflection?
2 - If the beam is adequate against shear and moment, isn't that already enough?
3 - Does deflection affect beam capacity performance?

Thank you. =)

 

[TehMightyEngineer]

1 - Yes, but often it's acceptable by inspection. ACI provides minimum thicknesses based on span and support conditions which eliminate the need for a more involved analysis.

2 - Definitely not.

3 - Not unless your deflection is so extreme to violate the assumptions used in the structural design (this is highly unlikely to happen in reinforced concrete). However, deflection of your entire structure can have P-delta effects causing increased load elsewhere (wont matter for a beam unless it's part of your LFRS).

Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries

http://www.americanconcrete.com

 

[eyemeyar]

Thank you very much. =)