Structural Design
Loads and the governing code
The structural items are conceptual rather than computational, but the vocabulary is exact. Governing reference: NSCP 2015. Know dead load (self-weight - reinforced concrete about 23.5–24 kN/m³), live load (occupancy-based; residential light, corridors and assembly heavy), wind, and seismic load. The Philippines is high-seismicity: expect questions on the load path (slab → beam → column → footing → soil), lateral-force-resisting systems, ductility and detailing, importance factor, and soil profile. Distinguish service (ASD) from strength (LRFD) load combinations.
Members and behaviour
A slab is one-way when the long-to-short span ratio is 2 or more; otherwise two-way. Beams carry flexure and shear; columns carry axial plus moment; footings spread load to bearing soil. Know the difference between a simply supported, cantilever and continuous member, and where tension steel goes (bottom midspan, top over supports). Deflection limits such as L/360 and concrete cover requirements are fair game.
Traps and a rule of thumb
Trap: a question describes a very long span with heavy loads and offers a deeper ordinary beam as the answer when a truss or prestressed member is intended. Another trap confuses "strong" with "stiff" - deflection, not strength, often controls serviceability. Rule of thumb for preliminary sizing: beam depth ≈ span/12 for a simply supported beam and span/8 for a cantilever; one-way slab thickness ≈ span/30 with a 100 mm minimum; column least dimension ≈ story height/15. So a 6 m simply supported beam comes out near 500 mm deep - a quick sanity check on any option offered.