CM 2112 Midterm T&F Exam Questions
With Accurate Answers
Piles can be classified on the basis of either their use or the materials from
which they are made - ANSWER True
Sheet piles are used primarily to create a rigid barrier for earth and water -
ANSWER True
Load-bearing piles are used primarily to transmit structural loads - ANSWER
True
The friction pile transmits the load to the soil through the pile's lower tip -
ANSWER False
The end-bearing pile transmits the load to the soil through skin friction between
the surface of the pile and the soil - ANSWER False
Sheet piles are used for cutoff walls under dams, cofferdams, bulkheads, and
trenching - ANSWER True
If timber piles remain permanently wet they can have a very long service life -
ANSWER True
Untreated timber piles can have a very long service life - ANSWER False
Square and octagonal concrete piles are cast in vertical forms - ANSWER False
Precast concrete piles can be removed from the forms as soon as the concrete
has a compressive strength of 3,500 psi - ANSWER True
Concrete piles cure for 21 days or more to reach driving strengths - ANSWER
True
A way of reducing driving stresses on a pile is by inserting an adequate
cushioning material between the pile driver's driving cap and the top of the
concrete pile - ANSWER True
Pile cushions are used on steel piles or timber piles - ANSWER False
Driving stresses are not proportional to the ram impact velocity - ANSWER False
,When soil layers with low resistance are encountered, it is important to increase
the ram velocity or stroke of the hammer to have a critical tensile stresses in the
pile - ANSWER False
For cylinder piles, it is important to prevent the soil plug inside the pile from
rising to an elevation above the level of the existing soil on the outside of the
piles, thus creating unequal stresses in the pile - ANSWER True
Nondisplacement cast-in-place concrete piles require a shell or a pipe -
ANSWER False
Typical compressive strengths for the grout are 3,000 to 5,000 psi - ANSWER
True
Concrete piles are more suitable than any other type of piles for constructing
foundations that require piles driven to great depths - ANSWER False
Compared by pile length, concrete piles tend to be more costly than steel piles -
ANSWER False
Steel piles have a high load-carrying capacity for a given weight of pile than
concrete piles - ANSWER True
Compared with concrete piles, steel H piles have better driving characteristics
and can be installed to great depth - ANSWER True
Steel pipe piles can be susceptible to deflection on striking boulders,
obstructions, or an inclined rock surface - ANSWER False
Since Steel H piles do not cause large soil displacement, they are useful in urban
areas or adjacent to structures where heave of the surrounding ground may
cause problems - ANSWER True
Steel H piles are most efficient as friction piles as they have substantial surface
area that interacts with the surrounding soil to provide significant frictional load
resistance - ANSWER False
Steel pipe piles are advantageous for use on jobs where headroom for driving is
limited and short sections must be added to obtain the desired total length -
ANSWER True
For extremely hard soils or soil layers, it may be cost effective to use a concrete
and steel pile - ANSWER False
Concrete-steel composite piles are used for marine applications - ANSWER True
,Steel-concrete composite piles provide higher durability and improved
drivability - ANSWER True
Varying the amount of steel in the plastic pile core does not alter the piles'
physical properties of toughness, resilience, and specific gravity - ANSWER
False
The abrasive resistance of plastic with steel pipe core piles makes them
excellent for fender system use - ANSWER True
When the depth of support is large or when the loads are great, it is necessary to
incorporate a tieback or bracing system with the sheet piles - ANSWER True
Wakefield sheeting is a pattern used to form piles of two 1 in. x 14 in. planks -
ANSWER False
Timber sheet piles are best suited for applications where corrosion is a concern
- ANSWER False
Steel sheet piling is a rolled section that is interlocked with adjacent sections to
form a continuous wall - ANSWER True
The timber sheet piles' flat sections are designed for interlocking strength that
makes them suitable for the construction of cellular structures - ANSWER True
The Z sections of steel sheet piles are more suitable for use in the construction
of retaining walls, bulkheads, and cofferdams - ANSWER True
The total resistance of a pile to penetration will equal the sum of the forces
produced by skin friction and end bearing - ANSWER True
The relative portions of the resistance contributed by either the skin friction or
end bearing may vary depending more on the type of pile - ANSWER False
The function of a pile hammer is to furnish the energy required to drive a pile -
ANSWER True
Stiffest concrete has zero slump and the most fluid concrete have slums in
excess of 8 in - ANSWER True
Drop hammers are suitable for driving piles on remote projects that require
many piles and for which the time of completion is an important factor - ANSWER
False
A drop hammer can normally deliver 40 to 80 blows per minute - ANSWER False
, A single-acting hammer can normally deliver 40 to 60 blows per minute -
ANSWER True
The ram of the double-acting hammers is much less heavier than that of the
single- acting hammer - ANSWER True
Double-acting hammers are always suitable for concrete piles - ANSWER False
A differential-acting hammer is also known as a steam hammer - ANSWER True
It is much more difficult and complicated to move a diesel hammer than a steam
hammer - ANSWER False
A diesel pile-driving hammer is a self-contained driving unit that does not
require an external source of energy such as an air compressor or steam boiler -
ANSWER True
Diesel hammer perform especially well in cohesive or very dense soil layers -
ANSWER True
Hydraulic impact hammers have an efficiency of 90% or better delivering energy
to the pile - ANSWER True
A hydraulic hammer operates on the differential pressure of compresses air -
ANSWER False
Hydraulic pile drivers are effective when the piles are driven into water
saturated noncohesive soils - ANSWER False
The five performance factors that determine effectiveness of a vibratory driver:
amplitude, eccentric moment, frequency, vibrating weight and nonvibrating
weight - ANSWER True
Fixed leads offer good control of the pile position and keep the pile in correct
alignment with the hammer so that eccentric impacts that may cause local
stress concentrations and pile damage are minimized - ANSWER True
Swing leads is the preferred method of driving a pile - ANSWER False
Hydraulic leads are extremely useful in driving batter piles - ANSWER True
Hydraulic leads are less costly than standard fixed leads - ANSWER False
Templates or guide forms are commonly used when driving sheet piling -
ANSWER True
With Accurate Answers
Piles can be classified on the basis of either their use or the materials from
which they are made - ANSWER True
Sheet piles are used primarily to create a rigid barrier for earth and water -
ANSWER True
Load-bearing piles are used primarily to transmit structural loads - ANSWER
True
The friction pile transmits the load to the soil through the pile's lower tip -
ANSWER False
The end-bearing pile transmits the load to the soil through skin friction between
the surface of the pile and the soil - ANSWER False
Sheet piles are used for cutoff walls under dams, cofferdams, bulkheads, and
trenching - ANSWER True
If timber piles remain permanently wet they can have a very long service life -
ANSWER True
Untreated timber piles can have a very long service life - ANSWER False
Square and octagonal concrete piles are cast in vertical forms - ANSWER False
Precast concrete piles can be removed from the forms as soon as the concrete
has a compressive strength of 3,500 psi - ANSWER True
Concrete piles cure for 21 days or more to reach driving strengths - ANSWER
True
A way of reducing driving stresses on a pile is by inserting an adequate
cushioning material between the pile driver's driving cap and the top of the
concrete pile - ANSWER True
Pile cushions are used on steel piles or timber piles - ANSWER False
Driving stresses are not proportional to the ram impact velocity - ANSWER False
,When soil layers with low resistance are encountered, it is important to increase
the ram velocity or stroke of the hammer to have a critical tensile stresses in the
pile - ANSWER False
For cylinder piles, it is important to prevent the soil plug inside the pile from
rising to an elevation above the level of the existing soil on the outside of the
piles, thus creating unequal stresses in the pile - ANSWER True
Nondisplacement cast-in-place concrete piles require a shell or a pipe -
ANSWER False
Typical compressive strengths for the grout are 3,000 to 5,000 psi - ANSWER
True
Concrete piles are more suitable than any other type of piles for constructing
foundations that require piles driven to great depths - ANSWER False
Compared by pile length, concrete piles tend to be more costly than steel piles -
ANSWER False
Steel piles have a high load-carrying capacity for a given weight of pile than
concrete piles - ANSWER True
Compared with concrete piles, steel H piles have better driving characteristics
and can be installed to great depth - ANSWER True
Steel pipe piles can be susceptible to deflection on striking boulders,
obstructions, or an inclined rock surface - ANSWER False
Since Steel H piles do not cause large soil displacement, they are useful in urban
areas or adjacent to structures where heave of the surrounding ground may
cause problems - ANSWER True
Steel H piles are most efficient as friction piles as they have substantial surface
area that interacts with the surrounding soil to provide significant frictional load
resistance - ANSWER False
Steel pipe piles are advantageous for use on jobs where headroom for driving is
limited and short sections must be added to obtain the desired total length -
ANSWER True
For extremely hard soils or soil layers, it may be cost effective to use a concrete
and steel pile - ANSWER False
Concrete-steel composite piles are used for marine applications - ANSWER True
,Steel-concrete composite piles provide higher durability and improved
drivability - ANSWER True
Varying the amount of steel in the plastic pile core does not alter the piles'
physical properties of toughness, resilience, and specific gravity - ANSWER
False
The abrasive resistance of plastic with steel pipe core piles makes them
excellent for fender system use - ANSWER True
When the depth of support is large or when the loads are great, it is necessary to
incorporate a tieback or bracing system with the sheet piles - ANSWER True
Wakefield sheeting is a pattern used to form piles of two 1 in. x 14 in. planks -
ANSWER False
Timber sheet piles are best suited for applications where corrosion is a concern
- ANSWER False
Steel sheet piling is a rolled section that is interlocked with adjacent sections to
form a continuous wall - ANSWER True
The timber sheet piles' flat sections are designed for interlocking strength that
makes them suitable for the construction of cellular structures - ANSWER True
The Z sections of steel sheet piles are more suitable for use in the construction
of retaining walls, bulkheads, and cofferdams - ANSWER True
The total resistance of a pile to penetration will equal the sum of the forces
produced by skin friction and end bearing - ANSWER True
The relative portions of the resistance contributed by either the skin friction or
end bearing may vary depending more on the type of pile - ANSWER False
The function of a pile hammer is to furnish the energy required to drive a pile -
ANSWER True
Stiffest concrete has zero slump and the most fluid concrete have slums in
excess of 8 in - ANSWER True
Drop hammers are suitable for driving piles on remote projects that require
many piles and for which the time of completion is an important factor - ANSWER
False
A drop hammer can normally deliver 40 to 80 blows per minute - ANSWER False
, A single-acting hammer can normally deliver 40 to 60 blows per minute -
ANSWER True
The ram of the double-acting hammers is much less heavier than that of the
single- acting hammer - ANSWER True
Double-acting hammers are always suitable for concrete piles - ANSWER False
A differential-acting hammer is also known as a steam hammer - ANSWER True
It is much more difficult and complicated to move a diesel hammer than a steam
hammer - ANSWER False
A diesel pile-driving hammer is a self-contained driving unit that does not
require an external source of energy such as an air compressor or steam boiler -
ANSWER True
Diesel hammer perform especially well in cohesive or very dense soil layers -
ANSWER True
Hydraulic impact hammers have an efficiency of 90% or better delivering energy
to the pile - ANSWER True
A hydraulic hammer operates on the differential pressure of compresses air -
ANSWER False
Hydraulic pile drivers are effective when the piles are driven into water
saturated noncohesive soils - ANSWER False
The five performance factors that determine effectiveness of a vibratory driver:
amplitude, eccentric moment, frequency, vibrating weight and nonvibrating
weight - ANSWER True
Fixed leads offer good control of the pile position and keep the pile in correct
alignment with the hammer so that eccentric impacts that may cause local
stress concentrations and pile damage are minimized - ANSWER True
Swing leads is the preferred method of driving a pile - ANSWER False
Hydraulic leads are extremely useful in driving batter piles - ANSWER True
Hydraulic leads are less costly than standard fixed leads - ANSWER False
Templates or guide forms are commonly used when driving sheet piling -
ANSWER True
