Engineering Concepts
Engineering Concepts tests applied statics, mechanics of materials, load paths, structural systems, soil behavior, and basic mechanical and electrical principles. The exam expects conceptual safety checks, not detailed design.
Core rules
- Static equilibrium: sum of forces and moments equals zero. Use free-body diagrams and consistent units.
- Loads include dead, live, wind, seismic, snow, and construction loads. Service loads are used for deflection; factored loads are used for strength.
- Stress = force/area; strain = deformation/original length; modulus of elasticity E = stress/strain in the elastic range.
- Load path: slab to beam to girder to column to footing to soil. Tributary area determines how much load each member receives.
- Concrete is strong in compression (f'c); steel is strong in tension and compression (Fy); wood strength depends on species, grade, moisture, and grain.
- Soil capacity depends on bearing capacity, compaction, moisture, and foundation depth.
Worked example. A simply supported beam spans 20 ft and carries an 8-kip point load at midspan. Sum moments about the left support: R_right x 20 ft - 8 kip x 10 ft = 0, so R_right = 4 kip. Sum vertical forces gives R_left = 4 kip. Maximum moment at midspan is 4 kip x 10 ft = 40 kip-ft. If the load moves toward one support, that reaction increases and the moment diagram changes.
Traps
- Mixing feet and inches or kips and pounds without converting.
- Using factored loads to check service deflection.
- Assuming every load travels to the nearest column instead of following the framing.
- Confusing stress with strain or strength with stiffness.