Module 5: Introduction to Structural Steel - Examples & Applications

Two buildings experience a major earthquake. One is an unreinforced masonry structure; the other is a properly engineered steel seismic-force-resisting system that develops substantial inelastic deformation without collapse. Explain the role of steel ductility without confusing material behavior with system-level seismic performance.

An architect requests a floor system with a very long clear span and strict vibration limits (high stiffness). The structural engineer initially specifies an ASTM A36 steel beam. The architect later asks if upgrading the steel to high-strength ASTM A992 will reduce the bouncing/vibration of the floor. How should the engineer respond?

A structural engineer is detailing a commercial building frame. They need to specify the material for the main wide-flange floor beams, the rectangular columns in the glass atrium, and the small connection plates holding everything together. Recommend the appropriate ASTM grades and shapes for these three applications.

A highway overpass requires a clear span of 45 meters. The heaviest available standard W-shape rolled by mills is a W36 (roughly 36 inches deep). Preliminary calculations show this rolled section is severely inadequate for both strength and deflection. Propose a structural solution using steel.

A column must support a dead load ($D$) of $100 \text{ kN}$ and a live load ($L$) of $150 \text{ kN}$. Calculate the required design load using both ASD and LRFD basic load combinations.

A steel roof beam must support a dead load ($D$) of $10 \text{ kN/m}$, a roof live load ($L_r$) of $15 \text{ kN/m}$, and a wind load ($W$) of $12 \text{ kN/m}$. Determine the required LRFD ultimate load ($w_u$).

Given LRFD Combinations:

1. $1.4D$
2. $1.2D + 1.6L_r + 0.5W$
3. $1.2D + 1.0W + 0.5L_r$

A steel tensile member has a nominal yielding strength $T_n=850\text{ kN}$. Determine the ASD allowable strength using $\Omega_t=1.67$.

Two candidate steel columns have similar cross-sectional area, but one has a substantially larger weak-axis radius of gyration. Which property makes it potentially more efficient against flexural buckling?

A rolled I-shape flange in uniform axial compression has $b/t=10.0$, $E=200{,}000\text{ MPa}$, and $F_y=345\text{ MPa}$. For the stated axial-compression element case, compare with $\lambda_r=0.56\sqrt{E/F_y}$.