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

An activity costs $10,000 for a normal 10-day duration or $14,000 crashed to 8 days. What is its crash cost slope?

• a.$500 per day
• b.$2,000 per day✓
• c.$1,000 per day
• d.$4,000 per day

Cost slope = (crash cost - normal cost) / (normal duration - crash duration) = (14,000 - 10,000) / (10 - 8) = $2,000/day. It is the cost to shorten the activity by one day.

An activity has zero total float. What does this indicate?

• a.it has the maximum scheduling flexibility of any activity in the network
• b.it is not yet scheduled
• c.it can be delayed freely
• d.any delay to it delays the whole project✓

Zero total float means the activity is on the critical path, so any slip pushes the project completion out. Critical activities receive priority for resources and monitoring.

Using the full-liquid-head assumption, what is the maximum lateral pressure at the base of a 5-ft-tall wall form for concrete weighing 150 pcf?

• a.750 psf✓
• b.600 psf
• c.1,000 psf
• d.375 psf

Treating fresh concrete as a fluid, p = unit weight x height = 150 x 5 = 750 psf. This full-liquid-head value is a conservative upper bound; ACI 347 formulas reduce it for slower placement.

Increasing the rate of concrete placement into a wall form generally does what to the maximum lateral form pressure?

• a.has no effect on form pressure
• b.eliminates the need for form ties
• c.lowers the maximum lateral form pressure
• d.raises the maximum lateral form pressure✓

Faster placement keeps more concrete fluid before initial set, so a greater depth acts hydrostatically and the peak pressure rises. Slower pours let lower lifts stiffen and carry their own weight.

A slab measures 30 ft by 40 ft by 0.5 ft thick. How much concrete is required, in cubic yards?

• a.24 CY
• b.600 CY
• c.20 CY
• d.22.2 CY✓

Volume = 30 x 40 x 0.5 = 600 cubic feet; divide by 27 to get cubic yards: 600 / 27 = 22.2 CY. Ready-mix concrete is ordered by the cubic yard, so this conversion is essential.

A continuous footing is 2 ft wide, 1.5 ft deep, and 100 ft long. What volume of concrete is required, in cubic yards?

• a.11.1 CY✓
• b.9.0 CY
• c.300 CY
• d.7.4 CY

Volume = 2 x 1.5 x 100 = 300 cubic feet; 300 / 27 = 11.1 CY. Always convert cubic feet to cubic yards (divide by 27) before ordering concrete.

A two-leg sling lifts an 8-kip load with each leg at 60 degrees from the horizontal. What is the tension in each leg?

• a.8.00 kip
• b.4.62 kip✓
• c.4.00 kip
• d.5.66 kip

Each leg carries half the vertical load (4 kip); tension = vertical share / sin(angle) = 4 / sin 60 = 4 / 0.866 = 4.62 kip. Sling tension always exceeds the shared vertical load.

A two-leg sling lifts a 10-kip load with each leg at 45 degrees from horizontal. What is the tension in each leg?

• a.5.00 kip
• b.3.54 kip
• c.10.0 kip
• d.7.07 kip✓

Vertical share per leg = 10 / 2 = 5 kip; tension = 5 / sin 45 = 5 / 0.707 = 7.07 kip. The flatter the sling, the higher the tension for the same load.

As the angle between a sling leg and the horizontal decreases (the sling flattens), the tension in each leg:

• a.tension decreases
• b.the load capacity increases
• c.tension increases✓
• d.tension stays constant

Leg tension = vertical share / sin(angle); as the angle drops, sin decreases and tension climbs sharply. This is why rigging charts warn against very flat sling angles.

For a mobile crane, the rated lifting capacity generally:

• a.decreases as load radius increases✓
• b.is independent of load radius
• c.increases as load radius increases
• d.depends only on boom length

Capacity is governed by the tipping/structural moment, so as the load radius (horizontal distance to the load) grows, the allowable load falls. Load charts list capacity versus radius.

A round concrete column is 24 in in diameter and 10 ft tall. How much concrete does it need, in cubic yards?

• a.3.14 CY
• b.1.16 CY✓
• c.0.58 CY
• d.31.4 CY

Cross-section area = pi x (1 ft)^2 = 3.14 sq ft; volume = 3.14 x 10 = 31.4 cubic feet; 31.4 / 27 = 1.16 CY. The radius is 1 ft (half of the 24-in diameter).

A road section 1,000 ft long and 24 ft wide receives a 0.5-ft-thick asphalt layer weighing 145 pcf. How many tons of asphalt are required?

• a.870 tons✓
• b.435 tons
• c.960 tons
• d.1,740 tons

Volume = 1,000 x 24 x 0.5 = 12,000 cubic feet; weight = 12,000 x 145 = 1,740,000 lb; tons = 1,740,000 / 2,000 = 870 tons. Asphalt is bid and paid by the ton.

A field-compacted soil has a dry density of 118 pcf; the maximum Proctor dry density is 125 pcf. What is the relative compaction?

• a.94.4%✓
• b.90%
• c.106%
• d.88%

Relative compaction = field dry density / max dry density x 100 = 118 / 125 x 100 = 94.4%. Specifications commonly require 90% to 95% of the Proctor maximum.

A specification requires 95% relative compaction, and the maximum Proctor dry density is 120 pcf. What field dry density must be achieved?

• a.114 pcf✓
• b.120 pcf
• c.108 pcf
• d.126 pcf

Required density = 0.95 x maximum dry density = 0.95 x 120 = 114 pcf. Nuclear-gauge or sand-cone tests verify that field density meets this target.

A sheepsfoot (padfoot) roller is best suited for compacting which material?

• a.crushed rock
• b.cohesive clay✓
• c.gravel
• d.clean uniformly graded sand placed in thick lifts

The feet knead and remold cohesive clay/silt, compacting it from the bottom of the lift up. Smooth-drum and vibratory rollers are preferred for granular soils, where kneading is unnecessary.

A crew of 4 workers places 40 cubic yards of concrete in an 8-hour shift. What is the labor productivity?

• a.1.25 CY/labor-hr✓
• b.0.8 CY/labor-hr
• c.10 CY/labor-hr
• d.5 CY/labor-hr

Productivity = output / labor-hours = 40 / (4 x 8) = 40 / 32 = 1.25 CY per labor-hour. Labor-hours, not crew-hours, are the denominator for unit productivity.

A crew costing $400 per hour places concrete at 50 CY per hour. What is the unit labor cost?

• a.$0.125/CY
• b.$20/CY
• c.$12.50/CY
• d.$8.00/CY✓

Unit cost = crew cost per hour / production per hour = 400 / 50 = $8.00/CY. Dividing an hourly crew rate by hourly production yields cost per unit of work.

A contractor's direct cost is $100,000 and applies a 15% markup on cost. What is the bid price?

• a.$85,000
• b.$117,647
• c.$15,000
• d.$115,000✓

Bid = direct cost x (1 + markup) = 100,000 x 1.15 = $115,000. Markup-on-cost adds the percentage to the cost, unlike margin-on-price which divides by (1 - margin).

A contractor wants a 20% profit margin on the selling price for a job costing $80,000. What price achieves this?

• a.$120,000
• b.$66,667
• c.$96,000
• d.$100,000✓

Price = cost / (1 - margin) = 80,000 / (1 - 0.20) = 80,000 / 0.80 = $100,000. A margin on price is not the same as a markup on cost; applying 20% to cost ($96,000) understates the price.

In a construction estimate, a contingency allowance represents:

• a.a reserve for identified but uncertain costs✓
• b.the contractor's fee
• c.guaranteed profit that the contractor keeps regardless of how the work turns out
• d.a bonus for early finish

Contingency covers foreseeable but not fully quantified risks (quantity growth, minor unknowns) within the defined scope. It is not profit and is drawn down as risks materialize.

A task has an earned value (EV) of $12,000 and a planned value (PV) of $15,000. What is the Schedule Performance Index (SPI)?

• a.0.20
• b.0.80✓
• c.1.25
• d.1.0

SPI = EV / PV = 12,000 / 15,000 = 0.80. An SPI below 1.0 means less work was accomplished than planned, so the project is behind schedule.

For a task with EV = $12,000 and PV = $15,000, what is the schedule variance (SV) and its meaning?

• a.$0 (on schedule)
• b.-$2,000 (behind schedule)
• c.+$3,000 (ahead of schedule)
• d.-$3,000 (behind schedule)✓

SV = EV - PV = 12,000 - 15,000 = -$3,000. A negative schedule variance means the work performed is worth less than what was planned, indicating the project is behind schedule.

A machine costs $200,000, has a $20,000 salvage value, and a 5-year life. What is its annual straight-line depreciation?

• a.$44,000/yr
• b.$180,000/yr
• c.$40,000/yr
• d.$36,000/yr✓

Straight-line depreciation = (cost - salvage) / life = (200,000 - 20,000) / 5 = 180,000 / 5 = $36,000 per year. Salvage value must be subtracted before dividing by the service life.

A project has a budget at completion (BAC) of $100,000 and a current CPI of 0.80. What is the estimate at completion (EAC)?

• a.$125,000✓
• b.$80,000
• c.$120,000
• d.$100,000

Assuming current performance continues, EAC = BAC / CPI = 100,000 / 0.80 = $125,000. A CPI below 1.0 projects a final cost above the original budget.

Under OSHA excavation rules, what is the maximum allowable slope for Type C soil?

• a.1H:1V
• b.0.5H:1V
• c.vertical (90 degrees)
• d.1.5H:1V (about 34 degrees from horizontal)✓

Type C (the least stable) soil requires the flattest slope, 1.5 horizontal to 1 vertical, roughly 34 degrees from horizontal. Stiffer soils (Type A, Type B) permit steeper cuts.

Per OSHA, at what trench depth is a protective system (sloping, shoring, or shielding) generally required?

• a.20 ft
• b.6 ft
• c.4 ft
• d.5 ft✓

A protective system is required for trenches 5 ft or deeper unless excavation is in stable rock. Below 5 ft a competent person may still require protection based on conditions.

In OSHA terms, a 'competent person' on an excavation is:

• a.the project owner
• b.the lowest-cost laborer assigned to the crew working inside the excavation that day
• c.any worker on site
• d.one able to identify hazards and authorized to correct them✓

A competent person can recognize existing and predictable hazards and has authority to take prompt corrective action. Excavations must be inspected by such a person daily and after changes.

A mass haul (mass diagram) plots what quantity along a roadway alignment?

• a.cumulative cut minus fill along the alignment✓
• b.concrete strength gain
• c.the crane load chart
• d.the total accumulated project cost plotted against elapsed calendar time

The mass diagram plots cumulative net earthwork (cut positive, fill negative) versus station. Its shape guides haul direction, haul distance, and balancing of cut and fill.

A road rises 3 ft over a horizontal run of 100 ft. What is the grade?

• a.0.03%
• b.30%
• c.3%✓
• d.33%

Grade = rise / run x 100 = 3 / 100 x 100 = 3%. Grade is expressed as a percentage of vertical rise per horizontal distance.

Two cross-sections 100 ft apart have end areas of 50 sq ft and 70 sq ft. Using the average-end-area method, what is the earthwork volume in cubic yards?

• a.6,000 CY
• b.222 CY✓
• c.240 CY
• d.111 CY

Volume = (A1 + A2)/2 x L = (50 + 70)/2 x 100 = 6,000 cubic feet; 6,000 / 27 = 222 CY. Average-end-area is the standard method for computing earthwork between stations.

Two sections 50 ft apart have end areas of 80 sq ft and 120 sq ft. What is the average-end-area volume in cubic yards?

• a.148 CY
• b.5,000 CY
• c.370 CY
• d.185 CY✓

Volume = (80 + 120)/2 x 50 = 100 x 50 = 5,000 cubic feet; 5,000 / 27 = 185 CY. Average the two end areas, multiply by the distance, then convert to cubic yards.

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.