Reinforced Concrete Design / module 8
Reinforced-concrete beams
The whole design, end to end: sizing, actions, bending, bar selection, shear, curtailment and serviceability — one beam, every check, in the order a designer actually does them.
What you will understand
- Size a beam before any calculation, and say what governs the guess
- Carry a beam from actions through to a reinforcement layout
- Choose bars that fit, not just bars with enough area
- Design links and set their spacing against both strength and detailing limits
- Complete the serviceability check and know what to do when it fails
- Recognise which check governed, and what that tells you about the design
Lessons
Sizing, and the order of the checks
Why the first guess matters, and why the design is circular until you break the circle deliberately.
A complete beam design
A worked beam calculation showing how loading, bar selection, shear and serviceability interact.
Module summary
- Size first: span/depth around 15 simply supported, 20 continuous, is the starting guess
- The order matters — bending sets the bars, bars set d, d changes the bending
- K against Klim decides singly or doubly reinforced before anything else
- Bars must FIT: area is necessary and not sufficient
- Once links are needed they carry the whole shear, and spacing has two separate limits
- The serviceability check is not a formality; on long spans it governs
- Knowing which check governed tells you what to change if the beam must be smaller
Teaching basis and review status
These are educational models and exercises. Check their assumptions before using the results. The full technical content and every diagram have not yet been independently verified.
Concrete and steel calculations retain their stated first-generation Eurocode teaching basis. Use the standards and amendments specified for your project; do not mix generations without an appropriate design basis.
Read the lesson register and outstanding review notesCheck your understanding
Practice
A simply supported beam spans 6.0 m. Using the rule of thumb, what overall depth would you start with, in mm?
Practice
A 250 × 500 beam has 35 mm cover, H8 links and H25 main bars in one layer. What is the effective depth, in mm?
Check yourself
A beam's bending design passes but its span/depth check fails. Which change helps MOST?
Practice
A beam carries gk = 20 kN/m and qk = 12 kN/m over a 6.5 m simply supported span. What is the design moment, in kNm?
Practice
For that beam, what is the design shear at the support, in kN?
Check yourself
For the revised 300 × 650 mm beam, which of the reported strength and span/depth checks has the highest utilisation?