STRUCTURAL C.E.

D. Slump Test

It measures the consistency of the concrete, usually at the jobsite. In this test, concrete is placed in a 300 mm high truncated cone and compacted by hand with a rod and the mold is removed from the concrete and placed next to it. The distance the concrete goes down from the original 300 mm is the measured. Too great the settlements indicate excessive water, and a very small settlement indicates the mixture will be too difficult to place properly.

A. Workability Test

B. Wash Test

C. Sieve Test

D. Slump Test

B. 25mm

A #8 rebar is reinforcement steel with a nominal diameter of ___.

A. 18mm

B. 25mm

C. 28mm

D. 30mm

B. Portland Cement

Made from materials which must contain the proper proportions of lime, silica, alumina and iron components. Four parts of limestone to one part clay are the basic ingredients. These are mixed, burned and pulverized.

A. Pozzolan Cement

B. Portland Cement

C. Hi-Grade Cement

D. Cementitious Materials

A. 414

A reinforcing steel of grade 60 has yield strength of ____ Mpa?

A. 414

B. 40

C. 248

D. 276

D. 1/5

As per Section 5.3.3 of NSCP, the nominal maximum sizes of coarse aggregate should be greater than ____ the narrowest dimension between sides of forms,

A. 1/3

B. ¼

C. ¾

D. 1/5

A. 1/3

As per Section 5.3.3 of NSCP, the nominal maximum sizes of coarse aggregate should be greater than ____ the depth of slabs

A. 1/3

B. ¼

C. ¾

D. 1/5

C. color, texture, and shape of the aggregates

Which of the following properties of aggregates has the LEAST influence to the quality of concrete?

A. grading or maximum comparative sizes of the particles

B. amounts and kinds of impurities in the aggregates

C. color, texture, and shape of the aggregates

D. durability of the aggregates, or their resistance to fire and exposure to weathering

B. 23mm

Which of the following nominal bar diameters is NOT available in the market?

A. 12mm

B. 23mm

C. 32mm

D. 8mm

C. 0.003

The maximum usable strain for concrete is ___.

A. 0.001

B. 0.002

C. 0.003

D. 0.004

D. 6”

High workability in concrete mix is observed when the slump value is __.

A. 0”

B. 2”

C. 4”

D. 6”

C. 4

The maximum number or rebar in a bundled bar.

A. 2

B. 3

C. 4

D. 5

A. 1.2 & 1.6

Based from NSCP 2010, the load factors for dead and live loads are

A. 1.2 & 1.6

B. 1.4 & 1.6

C. 1.2 & 1.7

D. 1.4 & 1.7

A. Live load

It refers to the occupancy load which is either partially or fully in place or may not be present at all.

A. Live load

B. Dead load

C. Concentrated load

D. Distributed load

A. Bars larger than 36 mm shall not be bundled in beams

Which of the following criteria for bundled bars, do NOT apply?

A. Bars larger than 36 mm shall not be bundled in beams

B. Bundle bars shall be enclosed within stirrups or ties

C. Group of parallel reinforcing bars bundled in contact to act as a unit shall be limited to four in any one bundle

D. Individual bars within a bundle terminated within the span of flexural members shall terminate at different points with at least 40 db staggered

D. 75

What is the minimum concrete cover in mm as per NSCP on concrete cast against and permanently exposed to earth?

A. 40

B. 50

C. 65

D. 75

B. 25 mm

The minimum clear spacing between parallel bars in a layer must be db but not less than? (NSCP 407.7.3)

A. 50 mm

B. 25 mm

C. 75 mm

D. 100mm

B. Retarder

The function of the admixture is to delay or extend the setting time of the cement paste in concrete. Usually used in very hot weather where hydration is accelerated by the heat, and leads the concrete to crack. This is also used for transit mix concrete that has to be hauled in long distance to ensure that it reaches its destination in a plastic and placeable condition.

A. Stopper

B. Retarder

C. Controller

D. Delayer

D. Aggregate

Concrete can be considered to be an artificial stone made by binding together particles of some inert material with a paste made of cement and water. These inert material of sand , crushed stone, burnt clay are called

A. Bill of Materials

B. Admixtures

C. Summaries

D. Aggregate

B. Curing

It is the process in which the concrete is protected from loss of moisture and kept within a reasonable temperature range. The result of this process is increased strength and decreased permeability. It is also a key player in mitigating cracks in the concrete, which severely impacts durability.

A. Slump test

B. Curing

C. Moisture test

D. Compressive test

C. 2.0 KPa

The minimum uniform live load for residential occupancy as per NSCP is

A. 1.0 KPa

B. 1.5 KPa

C. 2.0 KPa

D. 2.5 Kpa

C. structural steel

Reinforced concrete is a structural material that is a hardened mixture of cement, water, aggregates, admixtures and what other material?

A. Formworks

B. processed wood

C. structural steel

D. structural plastic

C. 40mm

Which of the following values can be used as a concrete cover for the primary reinforcement of cast-in-place concrete (non-prestressed) beams as per NSCP?

A. 20mm

B. 75mm

C. 40mm

D. 60mm

B. Brittleness

In its cracked stage, concrete has exhibited what characteristic?

A. Elasticity

B. Brittleness

C. Ductility

D. Hardness

D. Accelerators

An admixture which is used to speed up the initial set of concrete (early removal of forms).

A. Retarders

B. Hard Agents

C. Plasticizers

D. Accelerators

A. Cylinder Test

It is a test that measures compressive strength. As the concrete is being placed, samples are put in cylinder molds, 150 mm in diameter and 300 mm high, and are moist-cured for 28 days at which time they are laboratory- tested according to standardized procedures. (usually tested in 7 days)

A. Cylinder Test

B. Tension Test

C. Cube Test

D. Circular Motion Test

D. workability

Which of the following is NOT a property of hardened hydraulic cement concrete?

A. economy

B. durability

C. density

D. workability

B. Concrete strength increases, porosity decreases, solid-to-space ratio increases

What will happen to the concrete strength if the water-to-cement ratio decreases?

A. Concrete strength increases, porosity decreases, solid-to-space ratio decreases

B. Concrete strength increases, porosity decreases, solid-to-space ratio increases

C. Concrete strength decreases, porosity increases, solid-to-space ratio increases

D. Concrete strength decreases, porosity increases, solid-to-space ratio decreases

C. both I and II

Which of the following basic assumption/s for the design of a reinforced concrete beam against flexure or bending is/are TRUE? I. Design loads should be greater than or equal to actual loads II. Factored moments should be greater than or equal to actual moments

A. I only

B. II only

C. both I and II

D. neither I nor II

C. To allow the steel to reach its maximum strength and prevent slippage of bars

Development length or the development of a required length of rebar is provided in a reinforced concrete beam is for what major purpose?

A. To hold the bars in place during pouring of fresh concrete

B. To provide additional strength against torsion

C. To allow the steel to reach its maximum strength and prevent slippage of bars

D. To prevent vertical shearing of concrete

C. 1.7LL+1.4DL

In the strength design method (NSCP 2001), the ultimate load is computed as:

A. 1.4LL+1.7DL

B. 1.4DLx1.7LL

C. 1.7LL+1.4DL

D. 1.2DLx1.7LL

Which of the following is important to protect the structural integrity of reinforcing bars?

A. Fire Retardant Factor

B. Clearance from Embedded Concrete

C. Rebar Bending Requirements

D. Concrete Cover

C. 1.4

The minimum reinforcement ratio provided by the code is taken ___ / fy.

A. 1.0

B. 1.2

C. 1.4

D. 1.6

B. 0.9

The strength reduction factor for flexure is ___.

A. 0.85

B. 0.9

C. 0.7

D. 0.75

B. balanced strain

What is the condition where the tension steel strain reaches the yielding strain simultaneously with the concrete reaching the crushing strain which is usually 0.003?

A. under-reinforced

B. balanced strain

C. over reinforced

D. simply reinforced

D. 0.85

The value of ß1 if the 28 th day compressive strength, fc’ is less than 30MPa.

A. 0.7

B. 0.75

C. 0.8

D. 0.85

B. 75

The maximum reinforcement ratio provided by the code is taken ___% of pbal.

A. 85

B. 75

C. 45

D. 25

B. Under-reinforced design method

37. Which of the following design methodology gives emphasis on the premise that the steel fails first while the concrete has not yet reached its allowable values?

A. Under-designed method

B. Under-reinforced design method

C. Over-reinforced design method

D. Balanced designed method

C. Ratio of the area of steel reinforcement over concrete area

Reinforcement ratio ρ (rho) is defined as

A. Ratio of concrete area over the area of steel reinforcement

B. Product of concrete area and the area of steel reinforcement

C. Ratio of the area of steel reinforcement over concrete area

D. Product of steel reinforcement and the area of concrete

C. 75%

As per NSCP, what percentage of the balanced steel ratio is taken as the limiting value for the design of flexural members, the value of which assures that the reinforced concrete will have a ductile failure.

A. 90%

B. 85%

C. 75%

D. 50%

A. Effective depth

In USD beam section, the distance from the extreme compression fiber to the neutral axis is called

A. Effective depth

B. Compression depth

C. Elastic depth

D. Beam depth

B. m<0.5

Slab should be design as one-way slab if the ratio (m) of the shorter side over the longer side of the slab is

A. m>0.5

B. m<0.5

C. m=1

D. m=0

A. 0.85

The strength reduction factor for shear is ___.

A. 0.85

B. 0.9

C. 0.7

D. 0.75

D. Anilyo

What is the tagalong term for stirrups?

A. Barakilan

B. Reostra

C. Kilo

D. Anilyo

C. 0.7

The strength reduction factor for tied column is ___.

A. 0.85

B. 0.9

C. 0.7

D. 0.75

C. 2/3 √f’c

What is the max Vs (shear carried by the stirrups)?

A. 1/3 √f’c

B. 2/5 √f’c

C. 2/3 √f’c

D. √f’c

C. 0.650

A concrete has a compressive strength fc’=60MPa. The value of ß1 will be

A. 0.850

B. 0.635

C. 0.650

D. 0.835

B. 5pcs

How many 25mm diameter main bars are needed if the required bottom steel reinforcement is 2400 mm2?

A. 4pcs

B. 5pcs

C. 6pcs

D. 8pcs

D. 21.3 MPa

Using Sater’s formula, calculate the estimated 28-day compressive strength of concrete cylindrical sample if its 7 -day strength is 12.5MPa.

A. 25.6 MPa

B. 28.5 MPa

C. 34.1 MPa

D. 21.3 MPa

C. 21538

Compute for the modulus of Elasticity in MPa of concrete with fc’=21MPa.

A. 26812

B. 23424

C. 21538

D. 29054

D. 0.0126

A rectangular beam with a width of 200mm and effective depth of 320mm is designed to be reinforced for tension only with 4-16mm diameter rebars. If fc’=21MPa and fy-275MPa, compute the actual reinforcement ratio of the beam?

A. 0.0378

B. 0.0486

C. 0.0423

D. 0.0126

A. 0.0378

A rectangular beam with a width of 250mm and effective depth of 350mm is designed to be reinforced for tension only. If fc’=21MPa and fy-275MPa, what is the reinforcement ratio required for a balanced condition?

A. 0.0378

B. 0.0486

C. 0.0423

D. 0.0126

D. 3974 mm2

A reinforced concrete beam has a width of 300mm and an effective depth to the tension reinforcement of 618mm. If fc’=30MPa and fy=410MPa, design the steel reinforcement, As if the beam is to support an ultimate bending moment of 750KN-m.

A. 2567 mm2

B. 2927 mm2

C. 3337 mm2

D. 3974 mm2

A. 507.25

A 3m cantilever beam is to resist a service DL=25KN/m (self-weight included) and service LL=22KN/m. Given b=300mm, d=500mm, fc’=34MPa and fy=414MPa, using NSCP 2001

Which of the following gives the minimum area of steel reinforcement as per NSCP in mm2?

A. 507.25

B. 450.65

C. 550.35

D. 373.83

C. 3817

A 3m cantilever beam is to resist a service DL=25KN/m (self-weight included) and service LL=22KN/m. Given b=300mm, d=500mm, fc’=34MPa and fy=414MPa, using NSCP 2001

Which of the following gives the maximum area of steel reinforcement as per NSCP in mm2?

A. 3105

B. 3524

C. 3817

D. 4162

D. 5089

A 3m cantilever beam is to resist a service DL=25KN/m (self-weight included) and service LL=22KN/m. Given b=300mm, d=500mm, fc’=34MPa and fy=414MPa, using NSCP 2001

Which of the following gives the balanced area of steel reinforcement as per NSCP in mm2?

A. 4699

B. 4140

C. 5549

D. 5089

B. 3-30mmø

A 3m cantilever beam is to resist a service DL=25KN/m (self-weight included) and service LL=22KN/m. Given b=300mm, d=500mm, fc’=34MPa and fy=414MPa, using NSCP 2001

Which of the following gives the required area of steel reinforcement as per the given loads in mm2?

A. 2-30mmø

B. 3-30mmø

C. 4-30mmø

D. 5-30mmø

D. 4653 mm2

A reinforced concrete rectangular beam 300 mm wide has an effective depth of 460 mm and is reinforced for tension only. Assuming f’c = 21 MPa and fy = 300 MPa.

Determine the area of steel in balanced condition?

A. 3704 mm2

B. 2953 mm2

C. 4071 mm2

D. 4653 mm2

D. 3490 mm2

A reinforced concrete rectangular beam 300 mm wide has an effective depth of 460 mm and is reinforced for tension only. Assuming f’c = 21 MPa and fy = 300 MPa.

Determine the maximum area of steel?

A. 2778 mm2

B. 2215 mm2

C. 3053 mm2

D. 3490 mm2

A. 644 mm2

A reinforced concrete rectangular beam 300 mm wide has an effective depth of 460 mm and is reinforced for tension only. Assuming f’c = 21 MPa and fy = 300 MPa.

Determine the minimum area of steel?

A. 644 mm2

B. 934 mm2

C. 1289 mm2

D. 1490 mm2

B. 1.477

A reinforced concrete rectangular beam 300 mm wide has an effective depth of 460 mm and is reinforced for tension only. Assuming f’c = 21 MPa and fy = 300 MPa.

Determine the required reinforcement ratio in x10 -3 based on the ultimate moment of 25kN-m.

A. 1.060

B. 1.477

C. 1.283

D. 1.793

C. 265.57 KN-m

Determine the ultimate moment capacity of a rectangular beam having a width of 300mm and effective depth of 440mm and reinforced with 4- 25mm diameter bars with fc’=20.7MPa and fy=414MPa.

A. 209.74KN-m

B. 109.74 KN-m

C. 265.57 KN-m

D. 255.57 KN-m

A. 0.0143

A rectangular beam section with b=250mm and d=550mm is reinforced with 4-25mm tension bars in one layer. Using fc’=27MPa, fy=275MPa, 8mm diameter stirrups and 25mm concrete cover

Which of the following gives the section’s actual reinforcement ratio, ρ?

A. 0.0143

B. 0.0275

C. 0.0339

D. 0.0486

B. Under-reinforced design

A rectangular beam section with b=250mm and d=550mm is reinforced with 4-25mm tension bars in one layer. Using fc’=27MPa, fy=275MPa, 8mm diameter stirrups and 25mm concrete cover

Based from the actual ρ calculated above, what kind of beam section was given?

A. Balanced design

B. Under-reinforced design

C. Over-reinforced design

D. Over design

B. 28mm

A rectangular beam section with b=250mm and d=550mm is reinforced with 4-25mm tension bars in one layer. Using fc’=27MPa, fy=275MPa, 8mm diameter stirrups and 25mm concrete cover

Calculate the actual clear spacing between the four-25mm main bars of the given beam section?

A. 25mm

B. 28mm

C. 30mm

D. 33mm

A. 78KN/m

A rectangular beam section with b=250mm and d=550mm is reinforced with 4-25mm tension bars in one layer. Using fc’=27MPa, fy=275MPa, 8mm diameter stirrups and 25mm concrete cover

If the beam has a simple span of 5m, calculate the maximum factored uniform load that it can carry?

A. 78KN/m

B. 82KN/m

C. 84KN/m

E. 86KN/m

D. 42.06

A 6m simple rectangular beam carries a service dead load of 13.72KN/m (self-weight included) and service liveload of 13.44KN/m. The beam has an effective depth of 330 mm and base of 250 mm. If fc’ = 20.7MPa and fy = 275 MPa, use NSCP 2001 load factors

Calculate the factored uniform load on beam in KN/m?

A. 51.08

B. 37.97

C. 27.16

D. 42.06

B. 112.29

A 6m simple rectangular beam carries a service dead load of 13.72KN/m (self-weight included) and service liveload of 13.44KN/m. The beam has an effective depth of 330 mm and base of 250 mm. If fc’ = 20.7MPa and fy = 275 MPa, use NSCP 2001 load factors

Calculate the factored shear force at the critical section of the beam in KN?

A. 126.2

B. 112.29

C. 149.20

D. 130.05

B. 62.56

A 6m simple rectangular beam carries a service dead load of 13.72KN/m (self-weight included) and service liveload of 13.44KN/m. The beam has an effective depth of 330 mm and base of 250 mm. If fc’ = 20.7MPa and fy = 275 MPa, use NSCP 2001 load factors

Calculate the shear strength provided by concrete in KN?

A. 53.18

B. 62.56

C. 69.55

D. 26.59

C. 69.55

A 6m simple rectangular beam carries a service dead load of 13.72KN/m (self-weight included) and service liveload of 13.44KN/m. The beam has an effective depth of 330 mm and base of 250 mm. If fc’ = 20.7MPa and fy = 275 MPa, use NSCP 2001 load factors

Calculate the shear strength to be provided by the stirrups in KN?

A. 53.18

B. 62.56

C. 69.55

D. 26.59

B. 200

A 6m simple rectangular beam carries a service dead load of 13.72KN/m (self-weight included) and service liveload of 13.44KN/m. The beam has an effective depth of 330 mm and base of 250 mm. If fc’ = 20.7MPa and fy = 275 MPa, use NSCP 2001 load factors

Calculate the required spacing of 10mm stirrups at the critical section of the beam in mm?

A. 150

B. 200

C. 250

D. 300

B. 1872

A square tied column carries an axial service dead load of 560KN and an axial service live load of 750KN. Using NSCP 2010 load factors, fc’=28MPa, fy=275MPa and 20mm diameter main bars,

Calculate the factored load of the column in KN?

A. 2059

B. 1872

C. 1310

D. 1567

C. 350

A square tied column carries an axial service dead load of 560KN and an axial service live load of 750KN. Using NSCP 2010 load factors, fc’=28MPa, fy=275MPa and 20mm diameter main bars,

Using a reinforcement ratio of 2%, calculate the minimum required dimension of the column?

A. 250

B. 300

C. 350

D. 400

C. 2450

A square tied column carries an axial service dead load of 560KN and an axial service live load of 750KN. Using NSCP 2010 load factors, fc’=28MPa, fy=275MPa and 20mm diameter main bars,

Calculate the required total area of main reinforcement needed in mm2?

A. 1250

B. 1800

C. 2450

D. 3200

C. 8

A square tied column carries an axial service dead load of 560KN and an axial service live load of 750KN. Using NSCP 2010 load factors, fc’=28MPa, fy=275MPa and 20mm diameter main bars,

How many 20mm diameter main bars are need in the column?

A. 6

B. 7

C. 8

D. 9

A. 320

A square tied column carries an axial service dead load of 560KN and an axial service live load of 750KN. Using NSCP 2010 load factors, fc’=28MPa, fy=275MPa and 20mm diameter main bars,

Calculate the vertical spacing of 10mm diameter ties needed in the column?

A. 320

B. 290

C. 350

D. 480

B. Pascal (Pa)

What is the unit of stress in the SI system?

A. Newton (N)

B. Pascal (Pa)

C. Joule (J)

D. Meter (m)

B. Change in length to original length

Strain is the ratio of:

A. Change in force to original force

B. Change in length to original length

C. Stress to area

D. Stress to strain

B. Normal stress to normal strain

The modulus of elasticity (Young's modulus) 𝐸 is the ratio of:

A. Shear stress to shear strain

B. Normal stress to normal strain

C. Axial force to axial strain

D. Axial strain to normal stress

B. Young's modulus

Which of the following is a material property that describes how a material resists deformation under an axial load?

A. Poisson's ratio

B. Young's modulus

C. Shear modulus

D. Yield strength

C. At the top fiber

In bending of a beam, the location of maximum tensile stress occurs:

A. At the neutral axis

B. At the mid-span

C. At the top fiber

D. At the bottom fiber

D. Stress and strain are proportional only within the elastic limit

Which of the following statements is true for a material that follows Hooke's Law?

A. The material will deform plastically under stress

B. The material does not exhibit any recovery after deformation

C. The material exhibits permanent deformation when stress is applied

D. Stress and strain are proportional only within the elastic limit

A. At the mid-span

In a simply supported beam subjected to a uniform load, the maximum bending moment occurs at:

A. At the mid-span

B. Near the support

C. At the free end

D. At the neutral axis

A. At the surface of the shaft

For a circular shaft subjected to torsion, the maximum shear stress occurs:

A. At the surface of the shaft

B. At the center of the shaft

C. At the ends of the shaft

D. At the neutral axis of the shaft

B. modulus of resilience

What is the strain energy per unit volume that a material can absorb within its elastic limit?

A. modulus of elasticity

B. modulus of resilience

C. Poisson’s Ratio

D. Pascal Theory

D. Yield strength

What do you call the stress at which a material begins to deform plastically?

A. maximum stress

B. maximum strain

C. Yield energy

D. Yield strength

A. Shear force resists shear deformation, while the bending moment resists bending.

What is meant by “The shear force in a beam is the internal force that resists bending.”?

A. Shear force resists shear deformation, while the bending moment resists bending.

B. Bending moment resists shear deformation, while shear force resists bending.

C. Shear force is directly proportional to bending moment.

D. Shear force is inversely proportional to bending moment.

D. A & B only

Which of the following is TRUE about stress?

A. Normal stress acts perpendicular to a surface (tensile or compressive)

B. shear stress acts parallel to the surface, causing deformation in the form of sliding

C. Normal stress acts perpendicular to a surface, causing deformation in the form of sliding

D. A & B only

E. All of the above

D. A & C only

What is the purpose of introducing a factor of safety in structural design?

A. to account for uncertainties in material properties

B. for economy of operation and construction

C. to ensure the structure or component is safe under real-world conditions

D. A & C only

E. None of the above

C. Axial stress

What is called the internal force per unit area that resists axial loading (tension or compression)?

A. Normal stress

B. Shear stress

C. Axial stress

D. Bending stress

B. it can resist bending more effectively

90. What is the meaning if for a given area, a circular cross-section has a larger moment of inertia than a square cross-section?

A. it can absorb bending more effectively

B. it can resist bending more effectively

C. shape has no bearing at all

D. material differs accordingly

D. All of the above

Which of the following is a necessary condition for a structure to be in static equilibrium?

A. The sum of the vertical forces must be zero.

B. The sum of the moments about any point must be zero.

C. The sum of the horizontal forces must be zero.

D. All of the above

E. None of the above

B. At the mid-span

In a simple beam, the shear force is zero at:

A. At the supports

B. At the mid-span

C. At the location of applied loads

D It depends on the beam’s loading configuration

D. The difference between the number of equations of equilibrium and the number of unknowns

The degree of indeterminacy of a structure refers to:

A. The number of unknown forces or reactions in the structure.

B. The ability to predict the deformation of the structure.

C. The number of supports in the structure.

D. The difference between the number of equations of equilibrium and the number of unknowns

C. Direct Stiffness Method

Which method is most commonly used to analyze structures with internal forces (like beams and frames)?

A. Euler’s Method

B. Moment Distribution Method

C. Direct Stiffness Method

D. Virtual Work Method

A. Diagonal members

In a truss, which of the following members carry only axial forces (tension or compression) when subjected to loading?

A. Diagonal members

B. Vertical members

C. Horizontal members

D. All members carry bending, tension, and compression

C. A member that is unnecessary for equilibrium

A redundant in a structure is:

A. A joint with more than the required number of members

B. A member that is in compression

C. A member that is unnecessary for equilibrium

D. A structure that is over-constrained

B. Deflection analysis in beams and structures

In which type of analysis is virtual work commonly used?

A. Analysis of internal axial forces in trusses

B. Deflection analysis in beams and structures

C. Finding reactions in statically determinate structures

D. Analysis of EXternal axial forces in trusses

D. The relationship between bending stress and moment in a beam

The moment-curvature relationship is used to analyze:

A. The deformation of structures under axial loads

B. The rotation of beams under loading

C. The deflection of beams under shear forces

D. The relationship between bending stress and moment in a beam

C. At the free end

In a cantilever beam subjected to a point load at the free end, the maximum deflection occurs:

A. At the fixed support

B. At the mid-span

C. At the free end

D. At the neutral axis

B. Greater than the number of unknowns

In a constrained structure, the number of support reactions is:

A. Less than the number of unknowns

B. Greater than the number of unknowns

C. Equal to the number of unknowns

D. Always zero