Problem: A 300mm thick concrete wall carries a dead load of $150 \text{ kN/m}$ and live load of $100 \text{ kN/m}$. The allowable soil bearing capacity is $q_a = 200 \text{ kPa}$. The footing base is at $1.5 \text{ m}$ below grade. Soil unit weight $\gamma_s = 18 \text{ kN/m}^3$, Concrete $\gamma_c = 24 \text{ kN/m}^3$. Determine the required width $B$.

Problem: A $2.0 \text{ m} \times 2.0 \text{ m}$ square footing supports a $400 \times 400 \text{ mm}$ column. The effective depth $d = 350 \text{ mm}$. The factored soil pressure $q_u = 250 \text{ kPa}$. Check one-way shear capacity. $f'_c = 28 \text{ MPa}$.

Problem: For the same footing in Example 2 ($q_u = 250 \text{ kPa}$), check two-way (punching) shear.

Problem: For the same footing in Example 2 and 3 ($2.0 \text{ m} \times 2.0 \text{ m}$, $d = 350 \text{ mm}$, $q_u = 250 \text{ kPa}$, $400 \times 400 \text{ mm}$ column), calculate the required flexural reinforcement in one direction. $f_y = 420 \text{ MPa}$, $f'_c = 28 \text{ MPa}$.

Problem: An isolated square footing ($3.0 \text{ m} \times 3.0 \text{ m}$) supports a $400 \text{ mm} \times 400 \text{ mm}$ square column at its center. The flexural steel requires a tension area of $4000 \text{ mm}^2$ in each direction, provided by 13-20mm bars. The required basic development length for a 20mm bar is $l_{db} = 650 \text{ mm}$. The clear cover to the edge of the footing is $75 \text{ mm}$. Determine if the bars have sufficient length to develop their yield strength ($f_y$).

Problem: A large, isolated, unreinforced concrete spread footing was used to support a heavy column load. Soon after the building was fully occupied, the column punched entirely through the center of the footing, resting deep in the soil while the broken footing halves tilted upwards around it. Explain the structural failure mechanism.

Problem: A combined rectangular footing was designed to support two closely spaced columns. Column A carries $500 \text{ kN}$ and Column B carries $2000 \text{ kN}$. The footing was proportioned correctly for total bearing capacity, but a year later, large vertical cracks appeared on the top surface of the footing between the two columns, and the building began leaning towards Column B. Explain the causes of this distress.