PE Civil (NCEES Principles and Practice of Engineering) — All Questions

Compared with the more exact prismoidal method, the average-end-area method generally:

• a.underestimates volume
• b.gives identical results always
• c.cannot be used for earthwork
• d.slightly overestimates volume✓

Average-end-area treats the volume as a simple prismatoid and typically overestimates slightly, especially where cross-section shape changes. A prismoidal correction refines the result when accuracy matters.

The learning-curve effect on a repetitive construction operation means that:

• a.quality decreases with repetition
• b.it has no effect on labor hours
• c.the unit cost rises with each successive repetition of the identical task
• d.unit labor hours fall as repetitions increase✓

As a crew repeats an identical task, unit labor hours decline in a predictable pattern as workers gain proficiency. Estimators apply learning curves to repetitive units like identical floors or spans.

For normal Type I portland-cement concrete, the commonly specified minimum moist-curing period is about:

• a.90 days
• b.1 day
• c.7 days✓
• d.1 hour

About 7 days of moist curing is a common minimum for normal concrete, allowing hydration to develop most of the design strength. Slower-hydrating cements or cold weather may require longer curing.

An S-curve on a construction project typically represents:

• a.instantaneous crane load
• b.cumulative cost or progress over time✓
• c.soil gradation
• d.rebar spacing

The S-curve plots cumulative planned or actual cost (or percent complete) against time, rising slowly, then steeply, then leveling off. It is a baseline for tracking progress and cash flow.

In precedence (activity-on-node) scheduling, the default logical relationship between two activities is:

• a.finish-to-start✓
• b.start-to-finish
• c.start-to-start
• d.finish-to-finish

Finish-to-start (FS) is the default: the successor cannot begin until the predecessor finishes. Other relationships (SS, FF, SF) are used only where the work logic requires them.

In a CPM schedule, the duration assigned to a milestone is:

• a.one day
• b.the longest in the schedule
• c.equal to total float
• d.zero✓

A milestone marks a point in time (a start, finish, or key event) and has zero duration. It consumes no time or resources and is used to flag significant schedule points.

The purpose of resource leveling in a schedule is to:

• a.remove the critical path
• b.smooth resource demand, sometimes extending duration✓
• c.increase total float to zero
• d.always shorten the overall schedule while keeping every resource demand identical

Resource leveling reallocates work to avoid peaks and valleys in resource use, which may push non-critical activities within their float or lengthen the project if resources are constrained.

A bar (Gantt) chart primarily:

• a.shows concrete mix design
• b.computes float automatically by hand
• c.shows earthwork volumes
• d.displays activities as time-scaled horizontal bars✓

A Gantt chart plots each activity as a horizontal bar against a time axis, making start, finish, and overlap easy to read. It shows timing well but does not by itself reveal logic or float.

In schedule management, 'crashing' means:

• a.delaying the non-critical activities until the very end of their available total float
• b.shortening critical activities by adding resources at extra cost✓
• c.leveling resources
• d.removing activities from scope

Crashing shortens the project by compressing critical activities, typically by adding labor, equipment, or shifts, which raises cost. The least-cost-slope critical activities are crashed first.

In earthwork payment, 'overhaul' refers to:

• a.the crane radius
• b.the swell factor
• c.haul distance beyond the free-haul limit, paid separately✓
• d.the total combined cost of all excavation and hauling on the entire project

Free haul is the distance included in the excavation price; overhaul is the additional distance beyond that limit, paid at a separate unit rate. The mass diagram quantifies overhaul.

Which laboratory test establishes a soil's maximum dry density and optimum moisture content for compaction control?

• a.the slump test
• b.the Marshall test
• c.the Proctor test✓
• d.the CBR test

The Proctor (standard or modified) compaction test yields the maximum dry density and optimum moisture content used as targets for field compaction. Field densities are compared against this maximum.

The optimum moisture content from a Proctor test is:

• a.the minimum water for cement hydration
• b.the fully saturated water content
• c.the water content giving maximum dry density for a given effort✓
• d.the water content at which the soil reaches its liquid limit and begins to flow

Optimum moisture content is the water content at which a given compaction effort produces the greatest dry density. Too dry or too wet of optimum, the achievable density falls.

For efficient field compaction of fill, the relationship between lift thickness and compaction is:

• a.thinner lifts generally achieve more uniform compaction✓
• b.lifts should equal the total fill height
• c.lift thickness does not matter
• d.thicker lifts always compact better

Compaction energy dissipates with depth, so thinner lifts give more uniform density through the layer. Specifications limit loose lift thickness (often 8 to 12 in) for this reason.

The principal concern when placing concrete in cold weather is:

• a.freezing before the concrete gains adequate strength✓
• b.too-rapid strength gain that overshoots the specified design compressive strength
• c.excessive slump loss only
• d.there is no special concern

Fresh concrete that freezes before reaching about 500 psi can suffer permanent damage from ice formation. Cold-weather practice uses heated materials, insulation, and protection to prevent early freezing.

A key concern when placing concrete in hot weather is:

• a.reduced water demand
• b.rapid moisture loss and plastic-shrinkage cracking✓
• c.delayed set with no cracking risk
• d.increased air entrainment

High temperature, wind, and low humidity accelerate surface evaporation, causing plastic-shrinkage cracking and faster slump loss. Hot-weather measures include evaporation retarders, cooling, and prompt curing.

The goal of value engineering on a project is to:

• a.increase the number of change orders
• b.maximize the total material quantities used so nothing is ever under-designed
• c.eliminate all inspection
• d.achieve the required function at the lowest life-cycle cost✓

Value engineering systematically analyzes function to deliver the needed performance at the lowest total life-cycle cost, without sacrificing quality or safety. It targets value, not merely first cost.

The main purpose of vibrating fresh concrete during placement is to:

• a.speed up curing
• b.increase the water content
• c.consolidate the concrete and remove entrapped air voids✓
• d.add entrained air

Internal vibration consolidates concrete around reinforcement and forms, expelling large entrapped-air pockets that would otherwise create voids and honeycombing. Over-vibration, however, can cause segregation.

Rebar chairs and spacers are used to:

• a.maintain proper concrete cover and bar position✓
• b.reduce the water-cement ratio
• c.increase the slump of the surrounding fresh concrete during placement
• d.entrain air

Chairs and spacers hold reinforcement at the correct height and clear cover before and during concrete placement. Proper cover protects the steel from corrosion and provides fire and bond performance.

The purpose of construction dewatering is to:

• a.lower groundwater to allow excavation in the dry✓
• b.add water to the soil
• c.cure concrete
• d.raise pore-water pressure

Dewatering lowers the groundwater table below the excavation so work can proceed in stable, dry conditions and to prevent instability such as bottom heave or piping.

Applying an efficiency factor of 0.83 (a 50-minute working hour) to ideal equipment output accounts primarily for:

• a.normal job and management inefficiencies within the hour✓
• b.machine breakdown only
• c.swell of the soil
• d.overtime pay

The efficiency (operating) factor reduces theoretical production to reflect routine delays such as maneuvering, waiting, and minor stops that occur even in a well-run operation. 50 min of work per 60-min hour gives 0.83.

Concrete intended to be pumped is typically proportioned to have:

• a.always a 10-inch-plus slump
• b.no fines at all
• c.a very low slump near zero so the mix stays stiff inside the line
• d.a moderate-to-high slump for flowability✓

Pumped concrete needs enough workability and a cohesive, well-graded mix to move through the line without blockage or segregation, so a moderate-to-high slump is used. Harsh or too-stiff mixes clog pumps.

Form ties in a wall form primarily resist:

• a.wind load
• b.vertical dead load only
• c.curing shrinkage
• d.the lateral pressure of fresh concrete on the wall forms✓

Form ties hold the two form faces together against the outward lateral pressure of fresh concrete. Their spacing and capacity are designed for the peak form pressure during placement.

One cubic yard of concrete equals how many cubic feet?

• a.27 cubic feet✓
• b.3 cubic feet
• c.36 cubic feet
• d.9 cubic feet

A cubic yard is 3 ft x 3 ft x 3 ft = 27 cubic feet. This conversion (divide cubic feet by 27) is used constantly when ordering concrete by the cubic yard.

A change order in a construction contract is:

• a.a final punch list
• b.a routine safety inspection
• c.a formal modification to contract scope, cost, or time✓
• d.the original bid document

A change order is a written, agreed modification altering the scope, price, or schedule of the contract. It documents added, deleted, or changed work and adjusts the contract accordingly.