Module 01
How reinforced concrete works
Why two materials that behave nothing alike make the most used structural material on earth — and what happens at the moment the concrete cracks.
What this module covers
- Explain why concrete alone cannot span
- Describe how bond makes two materials act as one
- State what changes at the instant a section cracks, and what does not
- Trace a load path from slab to ground
- Distinguish material strength, member resistance, stiffness, ductility and durability
Lessons
The one property that decides everything about how concrete is used.
Start lesson →The moment a reinforced section stops behaving like a lump of concrete.
Start lesson →From a footprint on a floor to a pressure on the ground.
Start lesson →Why a stronger concrete does not fix a deflection problem.
Start lesson →
Module checkpoint
Check what you have taken in
5 questions
Question 1
Why does reinforced-concrete design assume the concrete carries no tension at the ultimate limit state?
Question 2
A plain rectangular concrete section is 250 mm wide and 500 mm deep, with a mean tensile strength of 2.60 N/mm². At what moment does it crack, in kNm?
Question 3
What does bond between steel and concrete allow the designer to assume?
Question 4
An internal column on a 7.0 m × 8.0 m grid supports five floors at an ultimate design load of 14.0 kN/m² per floor. Ignoring the column's own weight, what is the axial load at the base, in kN?
Question 5
A beam satisfies its strength checks but deflects excessively. What is the most effective change?