1. A 'short', 'braced', 'axially-loaded', 'fix-ended' reinforced concrete square column is 3 m high. It supports a load of 1250 kN (dead) and 200 kN (imposed), which it transmits to a soil with an allowable bearing pressure of 250 kN/m² through a square pad footing. The footing concrete is cast against murram blinding.

(I) Determine:

1. The suitable dimension (s) for the column.
2. The area of the longitudinal steel reinforcement, hence the size and number of the bars required in the column. Check whether or not the steel area lies within the specified limits as stipulated by the code of practice.
3. The size and centre-to-centre spacing of the links.
4. The centre-to-centre spacing of the longitudinal bars in the column for mild exposure conditions.
5. The suitable dimensions (i.e., base breadth and depth) for the pad footing based on the serviceability limit state. Assume a footing weight of 10% of the dead load (inclusive of self-weight of column).
6. The earth pressure on the footing based on the ultimate limit state.
7. The shear stress at the face of the column. State any assumptions made.
8. The bending moment at the face of the column, hence, the area of the steel reinforcement, the size, number and centre-to-centre spacing of the bars required in the footing (state assumptions made). Check if the steel area lies within the specified limits as stipulated by the code of practice.
9. The punching shear force and the punching shear stress, hence check the suitability of the depth of the footing.
10. The shear stress at the critical section (1.0d) from the face of the column.

(II) Draw a sketch of the elevation view of the column and pad footing showing all reinforcement details.

Answer rating: 100% (QA)

Answer a i d L7 60007 857 mm take d 860 mm h 860 50 910 mm b 05h 455 mm take b 460 mm ii Ultimate lo... View the full answer