Expert-level structural engineering covering structural analysis, steel and concrete design, load combinations, deflection, connections, and building codes.
Determinate structures: reactions from equilibrium alone, beams, trusses. Indeterminate structures: additional compatibility equations required. Stiffness method: global stiffness matrix, solve for nodal displacements. Influence lines: show effect of moving load at different positions on member force. Second-order effects: P-delta amplification of moments due to axial loads.
LRFD: load and resistance factor design, phi times Rn greater than or equal to sum gamma_i Q_i. Tension members: yielding of gross section and rupture of net section. Compression: column buckling, effective length factor K. Beams: flexure, shear, lateral torsional buckling. Connections: bolted and welded, bearing and slip-critical bolts.
Reinforced concrete: steel rebars carry tension, concrete carries compression. Flexural design: Whitney stress block, tension-controlled failure preferred. Shear design: stirrups provide shear reinforcement beyond concrete capacity. Serviceability: crack width and deflection limits under service loads. Prestressed concrete: precompression offsets tensile stresses from loading.
Dead load: permanent weight of structure and non-structural components. Live load: occupancy loads, reducible for large tributary areas. Wind load: velocity pressure times exposure and shape factors. Seismic load: equivalent lateral force or response spectrum analysis. ASCE 7 combinations: 1.2D + 1.6L dominant combination for gravity design.
| Pitfall | Fix |
|---|---|
| Ignoring lateral torsional buckling in beams | Check unbraced length against limits |
| Wrong effective length for columns | Identify boundary conditions carefully |
| Insufficient concrete cover | Meet code minimums for durability and fire rating |
| Missing load path for lateral loads | Trace lateral loads from roof to foundation |