Building Construction and Structural Systems
Structural questions here test whether you can connect loading (Mabhas 6), geotechnical and foundation work (Mabhas 7), and the execution rules for concrete (Mabhas 9) and steel (Mabhas 10), under the seismic framework of Standard 2800.
Core rules
- Load path: dead, live, wind and seismic loads must be traced continuously from slab to beam to column to foundation; any discontinuity is a design or execution defect you must report.
- Load combinations: the code's factored combinations govern element design; service combinations govern deflection and cracking checks.
- Concrete: specified class (C20, C25, C30…), water/cement ratio, cover to reinforcement, curing duration and vibration are all inspection points, not design preferences.
- Steel: member straightness, bolt tightening, weld quality and inspection (visual, PT/UT where required) and fire protection of the frame.
Worked example
An office floor has beams at 5.0 m centres; the beam tributary width is 2.5 m. Take live load 200 kg/m² → 2.5 × 200 = 500 kg/m. Slab 150 mm thick: 0.15 × 2500 = 375 kg/m² → 2.5 × 375 = 937.5 kg/m; add partitions and beam self-weight to reach roughly 1000 kg/m dead. Factored load ≈ 1.25 × 1000 + 1.5 × 500 = 2000 kg/m. For a 6.0 m simple span, M = wL²/8 = 2000 × 36 / 8 = 9000 kg·m. Note how a small change in assumed tributary width moves the moment linearly - state your assumptions explicitly.
Traps
Using unfactored loads for member sizing; ignoring that a cantilever or opening changes the load path; accepting a concrete pour without slump and cube sampling records; treating seismic detailing (confinement, lap lengths) as cosmetic.