# Design of a reinforced concrete beam

1. Aug 17, 2010

### mashleyk

I need help answering this question.

So theres a slab beam and column layout of a reinforced concrete structure. Beam dimensions for all beams are as follows b = 250mm and h= 400mm

(i) Determine the maximum ultimate limit state bending moment for beam b9 (it spans 6m)

(ii) From first principles determine the following for beam b9 when the beam size is as noted and the main reinforcing bars are 3H25's :
(a) The position of the Neutral axis
(b) The stress in the reinforcement at Ultimate Limit State
(c) The ultimate moment capacity of the section
(d) Is the proposed section over reinforced or under reinforced?
(e) Is the section adequate for the design actions as determined in Part (i)?

(iii) Determine the following for beam B9 when the beam size is as noted and the main reinforcing bars are 3H32's:
(a) The ultimate moment capacity of the section from first principles
(b) Is the proposed section over reinforced or under reinforced?
(c) The ultimate moment capacity of the section if the limits of 'good design practice' are applied.
(d) How is the ultimate moment capacity of the section affected by applying the limits of 'good design practice'?

It must be done using EUROCODES

I know how to do part (i) But I cant figure out the rest and I am terribly stuck! If anyone could even show me how to do a bit. I know the drawing is not up here but I jsut need to know how to work it out! Thanks!!

2. Aug 19, 2010

### sardonicus

Mashleyek, You might be better off going to someone in person for a bit of tutoring or a textbook. Short of that you might try narrowing your question(s) down to a principle or a more specific point that you are hung up on. S