Construction Engineering
Construction Engineering tests how field operations are planned, measured, and controlled: earthwork balance, compaction, concrete placement and curing, temporary structures, CPM scheduling, and construction safety under OSHA 29 CFR 1926. The exam favors quantity calculations and code-based safety decisions over general management theory.
Earthwork volume states
Soil volume changes among bank (in-place), loose, and compacted states. Swell increases loose volume relative to bank; shrinkage reduces compacted volume relative to bank. Track the state of every quantity before adding or subtracting.
Schedule and excavation safety
In CPM, the critical path has zero total float; a delay on it delays the project unless the logic changes. Under OSHA Subpart P, a protective system is required at 5 ft depth (and may be required in weaker soils at less depth), a competent person must inspect daily, spoils and equipment must be kept at least 2 ft from the edge, and trench boxes must be installed without workers inside the protected area. Excavations 20 ft or deeper need a registered professional engineer's design.
Worked example
A project has 10,000 BCY of cut and needs 9,500 CCY of fill. The soil shrinks 12% when compacted. Compacted volume from the cut is 10,000(1 − 0.12) = 8,800 CCY. The deficit is 9,500 − 8,800 = 700 CCY. Borrow must be measured in bank yards and will also shrink, so borrow = 700 / 0.88 = 795 BCY. Buying 700 BCY would be short because that is a compacted-state quantity.
Traps
Do not apply swell to a compacted-fill deficit; use shrinkage. Do not mix BCY and CCY in the same balance. Confirm whether a unit weight is dry or total. For trenching, the 5 ft trigger and 2 ft spoil setback are commonly inverted or misremembered.
Key points
- Convert every soil quantity to one state before balancing cut and fill.
- Swell applies to loose volume; shrinkage applies to compacted volume.
- Zero-float activities form the critical path.
- OSHA requires a protective system at 5 ft in excavations.
- Keep spoils and surcharge loads at least 2 ft from excavation edges.