Chapter 7 - RC Columns

Question 1

What are the dimensional requirements for a column?

Answer 1

h < 4b

Where:
h = the longer edge.
b = the shorter edge.

Question 2

What impact does axial load have on an RC column also under bending?

Answer 2

The higher the axial load, the further the neutral axis moves into the tension zone.

Question 3

What are the normalised axial load and bending moment eqautions for rectangular RC columns?

Answer 3

M = MEd/(bh^2fck)

N = NEd/(bhfck)

Question 4

What are the normalised axial load and bending moment eqautions for circular RC columns?

Answer 4

M = MEd/(h^3*fck)

N = NEd/(h^2*fck)

Question 5

What does the balance point represent on an RC column interaction diagram?

Answer 5

The point of highest moment resistance.

Question 6

What does it mean if a section is above and below the balance point of an interaction diagram?

Answer 6

Above - over-reinforced section.

Below - under-reinforced section.