Construction: Scheduling, Quantities, and Field Control
Scheduling and control
Construction questions reward a working command of the critical path method, earned value, quantity takeoff, and the physical realities of earthwork and concrete. Know how to build an activity-on-node network, compute early and late start/finish, and identify total float versus free float. Total float is the amount an activity can slip without delaying the project; free float is the slip that does not delay any successor. A common trap is treating a lull in a noncritical activity as project delay, or overlooking a second critical path after a change. Watch lag/lead logic and calendar effects.
Field operations
Earthwork is a frequent source of unit errors. Track bank, loose, and compacted cubic yards separately. Loose volume equals bank volume times (1 + swell); compacted volume equals bank volume times (1 - shrinkage). Never apply a swell factor to a compacted quantity. For concrete, verify formwork pressure, placement rate, and cure time; for cranes, check capacity at radius, not just maximum rated load.
Worked example
A cut of 1,000 bank cubic yards has 20% swell and 10% shrinkage. Loose volume = 1,000 × 1.20 = 1,200 LCY. Compacted volume = 1,000 × 0.90 = 900 CCY. Haul trucks sized in loose yards need 1,200 LCY, not 1,000. A question that offers 1,000 or 1,100 as the truck volume is testing this distinction.
Contract and safety
Understand lump-sum versus unit-price contracts, change-order entitlement, retainage, and liquidated damages. Safety questions often hinge on competent-person requirements, excavation protection, and fall protection thresholds. Read whether the question asks for the controlling activity or the project duration.