Problem Statement: Utilization Ratio (Basic) STAAD reports an axial load $P_u = 800$ kN and a maximum bending moment $M_u = 150$ kN-m for a steel column. The column's calculated axial design strength is $\phi P_n = 2000$ kN and its flexural design strength is $\phi M_n = 300$ kN-m. Calculate the simple utilization ratio for this member ignoring specific AISC interaction formulas.

Problem Statement: AISC Interaction Equation H1-1a (Intermediate) An AISC steel member has $P_u = 1200 \text{ kN}$ and $\phi P_n = 1500 \text{ kN}$. Calculate the axial ratio. Because the axial ratio is $\ge 0.2$, Equation H1-1a applies. If the flexural ratio $(M_u / \phi M_n)$ is $0.45$, calculate the true combined Utilization Ratio.

Problem Statement: Required Flexural Reinforcement Area (Basic) A rectangular concrete beam is analyzed in STAAD. The maximum factored moment is $M_u = 250$ kN-m. The design strength of concrete is $f'_c = 28$ MPa, steel yield strength is $f_y = 414$ MPa. The beam width is $b = 300$ mm and effective depth $d = 450$ mm. Calculate the required area of steel ($A_s$) using a simplified moment arm approach to verify STAAD's output.

Problem Statement: Required Flexural Reinforcement Area (Intermediate) If the calculated required $A_s$ is $1656 \text{ mm}^2$, and you decide to use $20\text{ mm}$ diameter bars (Area $\approx 314 \text{ mm}^2$), how many bars are required, and what is the actual provided steel area $A_{s,\text{prov}}$?

Case Study: The CHECK CODE vs SELECT Command (Conceptual) You are designing a steel roof canopy. You have assigned an initial W10x30 section to all rafters. When you run the design using the CHECK CODE command, several rafters fail with a Utilization Ratio (UR) of 1.45. You then change the command to SELECT. What happens during the next analysis run?

Case Study: Visualizing Utilization Ratios (Conceptual) After a steel design run, you have a table of 500 members and their URs. How do you visually inspect the safety of the entire building instantly?