Alabama Foundations, Pilings and Cofferdams with Retaining Walls Contractor Examination

Under OSHA excavation rules commonly tested for foundation work, a protective system is generally required when an excavation is how deep or greater, unless entirely in stable rock?

• A2 feet
• B3 feet
• C5 feet
• D8 feet

How far must excavated spoil and other materials generally be kept from the edge of an excavation to reduce surcharge loading?

• AAt least 6 inches
• BAt least 2 feet
• CAt least 10 feet
• DNo setback is required if the soil is Type A

For simple sloping of Type C soil in excavations 20 feet or less deep, what is the maximum allowable slope (horizontal:vertical)?

• A3/4:1
• B1:1
• C1-1/2:1
• DVertical (90°) banks

Who is responsible for classifying soil and inspecting excavations for cave-in hazards on a construction site?

• AAny laborer who has watched a safety video
• BA competent person designated by the employer
• COnly a licensed professional engineer on every cut under 5 feet
• DThe utility locate technician

In a trench 4 feet or deeper, OSHA generally requires a means of egress (such as a ladder) so that workers need not travel more than how far laterally to reach it?

• A10 feet
• B15 feet
• C25 feet
• D50 feet

Which soil classification is generally the most stable among OSHA Types A, B, and C for sloping purposes?

• AType A
• BType B
• CType C
• DType D

What is the primary purpose of compacting fill under footings and slabs?

• ATo increase soil organic content
• BTo reduce settlement and increase bearing capacity by densifying the soil
• CTo permanently lower the water table below sea level
• DTo eliminate the need for any foundation reinforcement

A Standard Proctor or Modified Proctor test is used primarily to determine which property of soil?

• AThe maximum dry density and optimum moisture content for compaction
• BThe exact pH of groundwater only
• CThe color of paint for utility marking
• DThe tensile strength of reinforcing steel

When excavating for a footing, what is the usual reason to avoid leaving soft, disturbed, or frozen soil in the bottom of the excavation?

• AIt improves form release
• BIt can cause excessive settlement or reduced bearing capacity under the foundation
• CIt automatically increases concrete compressive strength
• DIt is required only for decorative landscaping walls

Benching is generally NOT an allowed protective method in which OSHA soil type when used alone as the protective system?

• AType A only when short-term
• BType B in all cases without exception
• CType C soil
• DStable rock only

What is a common purpose of a cofferdam on foundation and marine-adjacent work?

• ATo permanently replace all structural concrete
• BTo create a temporary dry or controlled work area by excluding water while foundation wor…
• CTo paint underground utilities yellow
• DTo eliminate the need for any shoring design

Which condition most strongly suggests that an excavation side wall is becoming unstable?

• AUniform vertical faces in solid stable rock with no cracks
• BFissures, sloughing, bulging, or tension cracks near the edge after rainfall
• CA dry, lightly dusted surface on Type A clay with no free water
• DProperly placed trench shields fully covering the work zone

For foundation grading, finish grades around a structure are typically sloped away from the building to:

• ADirect surface water toward the foundation wall
• BPromote positive drainage away from the structure and reduce water intrusion
• CMaximize ponding against basement walls
• DEliminate all need for gutters and downspouts permanently

A trench shield (trench box) protects workers primarily by:

• APreventing all soil movement anywhere on the site
• BWithstanding cave-in loads so workers inside the shield are protected if walls fail
• CReplacing the need for a competent person
• DActing as permanent formwork for the foundation wall

When backfilling against a foundation wall, which practice is most appropriate?

• ADump full height of wet clay in one lift against an unbraced green wall
• BPlace approved material in controlled lifts, compact as specified, and avoid overloading…
• CUse only organic topsoil for structural backfill
• DFlood the excavation with water instead of compacting

If an excavation will be deeper than 20 feet and sloping is proposed, OSHA generally requires that the protective system be:

• ASelected by any crew member using freehand sketches only
• BDesigned by a registered professional engineer
• CLimited to Type C tables without engineering
• DOmitted if the soil looks firm

What is the primary structural purpose of a deep foundation pile?

• ATo transfer structural loads through weak upper soils to deeper competent strata or by fr…
• BTo decorate the building facade
• CTo replace all horizontal bracing in the superstructure
• DTo serve only as a temporary form for sidewalks

Which pile type is commonly driven with an impact or vibratory hammer and often made of steel H-section, pipe, precast concrete, or timber?

• AAuger-cast pile only poured without casing always
• BDriven displacement or driven pile
• CHelical pile installed only by hand tools
• DMicropile drilled only with dental equipment

In pile driving, “refusal” generally means:

• AThe crew refuses to work overtime
• BThe pile has reached a driving resistance criterion where further penetration is impracti…
• CThe pile is still moving freely with every blow
• DThe hammer has run out of fuel only

What is a major advantage of steel H-piles for foundation work?

• AThey cannot be spliced
• BThey penetrate dense layers relatively well, can be spliced, and have high structural cap…
• CThey are always lighter than timber for the same length without exception
• DThey never require corrosion protection considerations

Drilled shafts (caissons) differ from driven piles mainly because they are:

• AAlways timber
• BConstructed by excavating a hole (often cased or slurry-supported) and placing reinforced…
• CInstalled only by vibratory hammers without excavation
• DUsed exclusively above grade as columns

During pile installation, keeping a continuous driving log is important primarily to:

• ADocument depth, blow counts, hammer energy, and interruptions for capacity and quality co…
• BReplace the need for any geotechnical report
• CSatisfy only landscaping permits
• DAvoid marking the pile locations

Sheet piles used for cofferdams and retaining excavations are primarily designed to resist:

• AOnly roof snow loads on buildings
• BLateral earth and water pressures, often with wales and struts or tiebacks
• COnly vertical column loads without lateral pressure
• DInterior furniture loads

Pile heave of previously driven piles when nearby piles are driven most commonly indicates:

• AImproved capacity of every pile automatically
• BPossible displacement of soil that may reduce capacity or require redriving/evaluation
• CThat the site has no groundwater
• DThat timber piles should replace steel without analysis

Concrete compressive strength is most commonly verified on site work using:

• APaint adhesion tests
• BStandard cylinder specimens cast, cured, and tested in compression
• COnly visual color matching of the truck chute
• DWood moisture meters

A slump test measures primarily which property of fresh concrete?

• A28-day tensile strength of rebar
• BConsistency/workability of the fresh mix
• CAir content of hardened concrete only
• DExact cement brand name

Why is curing important after placing foundation concrete?

• AIt only changes the color for architectural reasons
• BIt maintains moisture and temperature so cement hydration can develop strength and durabi…
• CIt permanently freezes the concrete to stop all chemical reactions
• DIt is only required for precast plants, never field concrete

Adding uncontrolled water to a ready-mix load on site after batching typically:

• AIncreases compressive strength reliably
• BIncreases water-cementitious ratio, which can reduce strength and durability
• CHas no effect on any concrete property
• DConverts the mix to prestressed concrete

Cold-weather concreting precautions are needed mainly to prevent:

• AOverheating of steel only
• BFreezing of fresh concrete and slowed strength gain at low temperatures
• CExcessive solar radiation only
• DAll need for formwork

Hot-weather concreting concerns include rapid setting and plastic shrinkage. A common control measure is:

• ALeaving concrete uncovered in full sun with no moisture
• BCooling materials, placing promptly, and protecting surfaces from rapid drying
• CAdding random organic debris for shade
• DEliminating all curing

Segregation of concrete during placement is best avoided by:

• ADropping concrete freely from excessive heights without trunks or tremies
• BUsing proper placement methods so coarse aggregate and mortar stay uniformly mixed
• CVibrating from a single point for an extremely long time until paste boils away
• DAdding extra water until rock sinks and paste floats

Air-entrained concrete is specified for many exterior foundations and walls primarily to improve:

• AResistance to freeze-thaw damage
• BMagnetic properties of rebar
• CElectrical conductivity of the mix
• DColor matching to brick only

A cold joint in a foundation wall typically results when:

• AFresh concrete is placed against concrete that has already stiffened so the layers do not…
• BForms are perfectly tight and continuous pours are maintained
• COnly plasticizers are used within open time
• DCuring blankets are applied on schedule

Mass concrete in large footings or mats requires temperature control mainly to reduce:

• AThermal cracking from heat of hydration differentials
• BAll need for reinforcement
• CPaint adhesion on steel only
• DWind loads on the finished roof

Before placing concrete for a footing, the subgrade should typically be:

• ACovered with loose trash for cushioning
• BAt correct elevation, firm, free of standing water, debris, and frozen material as specif…
• CLeft with deep mud ruts to key the concrete
• DSaturated with oil to reduce bond

Vibration of concrete in walls and footings is performed primarily to:

• ARemove entrapped air and consolidate the mix around reinforcement without segregation
• BDrive all air-entrainment bubbles out of exterior mixes intentionally
• CReplace the need for proper mix design
• DCut rebar to length

In reinforced concrete foundations, reinforcing steel is provided primarily to resist:

• AOnly compressive stresses, which steel cannot carry
• BTensile stresses and to control cracking, since concrete is weak in tension
• COnly architectural surface texture
• DMagnetic fields for surveying

Clear cover over reinforcing steel in concrete is important mainly to:

• AExpose bars for easy inspection after casting
• BProtect steel from corrosion and fire and develop bond with surrounding concrete
• CReduce concrete strength intentionally
• DEliminate the need for chairs or supports

Bar supports (chairs, bolsters, dobies) are used to:

• AHold reinforcement at the correct elevation and cover during concrete placement
• BReplace all lap splices
• CCut bars to length on site
• DMeasure slump of the mix

A lap splice in reinforcing bars is used to:

• APaint the bars for corrosion only
• BTransfer force from one bar to another by overlapping them a specified length in concrete
• CReduce cover below minimum
• DEliminate all development length requirements forever

Epoxy-coated reinforcing steel is typically specified to:

• AIncrease magnetic attraction for layout
• BImprove corrosion resistance in aggressive environments
• CAllow zero concrete cover
• DMake bars weaker in tension by design

On reinforcing bar marks, a #5 bar has a nominal diameter of approximately:

• A1/4 inch
• B5/8 inch
• C1 inch
• D1-1/2 inches

Hooks and bends on rebar are provided mainly to:

• AImprove anchorage and development of the bar in concrete
• BDecorate the end of the bar
• CReduce steel grade automatically
• DAllow bars to be left completely outside the form

Before concrete placement, oil, mud, ice, and loose rust should be cleaned from rebar because they can:

• AImprove bond strength
• BReduce bond between steel and concrete and create weak planes
• CIncrease specified yield strength
• DSubstitute for epoxy coating completely

Dowels projecting from a footing into a wall are intended to:

• AProvide a construction joint key only without steel continuity
• BTransfer forces and provide structural continuity between footing and wall reinforcement
• CHold form ties exclusively
• DMeasure concrete temperature

Welding of reinforcing bars in the field is generally:

• AAlways permitted on any bar without procedure control
• BRestricted and only allowed when specified, with proper weldable steel, procedures, and q…
• CPreferred over all mechanical splices in every code without exception
• DUsed to reduce cover requirements to zero

When operating excavators near open trenches, a key safety practice is to:

• APark equipment on the spoil pile at the very edge for convenience
• BKeep machines set back to avoid surcharge and edge collapse, and use spotters as needed
• CIgnore overhead power lines if digging below grade
• DRemove all seat belts to allow quick jumps