Civil Engineering Exams (Principles of Structural Analysis and Design) – Page 5

#80. An 8m high retaining wall is subjected to lateral earth pressure increasing from 0 at the top to 138 kPa at the base. Flexural rigidity EI = 4.5 x 10 14 N.mm2. Analyze per meter length of wall.
To prevent excessive deflection at the free end, the wall is braced at the top. Find the force (kN) exerted at the propped end of the wall so that the resulting deflection is 0.
A 121.4 kN
B 140.1 kN
C 131.2 kN
D 110.4 kN
Answer: 110.4 kN
#81. An 8m high retaining wall is subjected to lateral earth pressure increasing from 0 at the top to 138 kPa at the base. Flexural rigidity EI = 4.5 x 10 14 N.mm2. Analyze per meter length of wall.
When the wall is propped at the top, what is the resulting moment at the base?
A -589 kN.m
B -600 kN.m
C 1472 kN.m
D -147.2 kN.m
Answer: -589 kN.m
#82. A cantilever beam 5 m long carries a concentrated load P at 3.75 m from the fixed end.
Given:
Beam moment of inertia, I = 1.6 x 10 9 mm4
Modulus of Elasticity, E= 25 x 103 MPa
Concentrated Load, P = 150 kN
What is the deflection of the beam under the load P?
A -99 mm
B -65 mm
C -56 mm
D -75 mm
Answer: -65 mm
#83. A cantilever beam 5 m long carries a concentrated load P at 3.75 m from the fixed end.
Given:
Beam moment of inertia, I = 1.6 x 10 9 mm4
Modulus of Elasticity, E= 25 x 103 MPa
Concentrated Load, P = 150 kN
What is the maximum deflection of the beam?
A -79 mm
B -109 mm
C -99 mm
D -69 mm
Answer: -99 mm
#84. A cantilever beam 5 m long carries a concentrated load P at 3.75 m from the fixed end.
Given:
Beam moment of inertia, I = 1.6 x 10 9 mm4
Modulus of Elasticity, E= 25 x 103 MPa
Concentrated Load, P = 150 kN
What upward force (kN) is to be applied at the free end to prevent the beam from deflecting?
A 99 kN
B 65 kN
C 95 kN
D 85 kN
Answer: 95 kN
#85. A cantilever beam 4 m long deflects by 16 mm at its free end due to uniformly distributed load of 25 kN/m throughout its length.
To prevent beam deflection at the free end, what force P(kN) is needed at that point?
A 36.5 kN
B 35.7 kN
C 37.5 kN
D 39.6 kN
Answer: 37.5 kN
#86. A cantilever beam 4 m long deflects by 16 mm at its free end due to uniformly distributed load of 25 kN/m throughout its length.
What force P(kN) should be applied at the mid length of the beam for zero displacement at the free end?
A 110 kN
B 120 kN
C 130 kN
D 100 kN
Answer: 120 kN
#87. A cantilever beam 4 m long deflects by 16 mm at its free end due to uniformly distributed load of 25 kN/m throughout its length.
To reduce the deflection at the free end to 10 mm, how much force is needed to be applied at that point?
A 32.2 kN
B 24.3 kN
C 30.3 kN
D 23.4 kN
Answer: 23.4 kN
#88. A hollow circular pole 3 m high is fixed at the base. It is 6 mm thick and its outside diameter is 300 mm. The pole is subjected to a torque and a lateral force at the free end.
Given:
Torque, T= 25 kN.m
Lateral Force H = 3 kN
Shear modulus of elasticity = 78 GPa
Allowable shear stress = 60 MPa
What is the max shear stress at the outside surface of the pole due to the torque, T?
A 33.2 MPa
B 30.3 MPa
C 32.1 MPa
D 31.3 MPa
Answer: 31.3 MPa
#89. A hollow circular pole 3 m high is fixed at the base. It is 6 mm thick and its outside diameter is 300 mm. The pole is subjected to a torque and a lateral force at the free end.
Given:
Torque, T= 25 kN.m
Lateral Force H = 3 kN
Shear modulus of elasticity = 78 GPa
Allowable shear stress = 60 MPa
Find the max flexural stress (MPa) at the base of the pole due to the lateral force.
A 21.2 MPa
B 23.2 MPa
C 22.5 MPa
D 25.2 MPa
Answer: 22.5 MPa
#90. A hollow circular pole 3 m high is fixed at the base. It is 6 mm thick and its outside diameter is 300 mm. The pole is subjected to a torque and a lateral force at the free end.
Given:
Torque, T= 25 kN.m
Lateral Force H = 3 kN
Shear modulus of elasticity = 78 GPa
Allowable shear stress = 60 MPa
What is the angle of twist (degrees) due to the torque?
A 0.40o
B 0.46o
C 0.64o
D 0.36o
Answer: 0.46o
#91. A column is built up from 4-300 mm x 16 mm plates, welded to form a box section having a width of 300 mm along the x-axis and a depth of 332 along the y-axis.
Unbraced column length with respect to x-axis is 12 m.
With respect to the y-axis, the column is braced at third points so that the unbraced length is 4m.
Assume pinned-ends for both axis. Sidesway is prevented.
Steel yield stress: Fy = 248 MPa
Modulus of elasticity = 200 GPa
Compute the effective slenderness ratio with respect to the x-axis.
A 90.20
B 92.40
C 94.20
D 92.20
Answer: 94.20
#92. A column is built up from 4-300 mm x 16 mm plates, welded to form a box section having a width of 300 mm along the x-axis and a depth of 332 along the y-axis.
Unbraced column length with respect to x-axis is 12 m.
With respect to the y-axis, the column is braced at third points so that the unbraced length is 4m.
Assume pinned-ends for both axis. Sidesway is prevented.
Steel yield stress: Fy = 248 MPa
Modulus of elasticity = 200 GPa
Compute the effective slenderness ratio with respect to the y-axis.
A 94.20
B 34
C 43
D 49.20
Answer: 34
#93. A column is built up from 4-300 mm x 16 mm plates, welded to form a box section having a width of 300 mm along the x-axis and a depth of 332 along the y-axis.
Unbraced column length with respect to x-axis is 12 m.
With respect to the y-axis, the column is braced at third points so that the unbraced length is 4m.
Assume pinned-ends for both axis. Sidesway is prevented.
Steel yield stress: Fy = 248 MPa
Modulus of elasticity = 200 GPa
Compute the axial load capacity (kN) of the built up column.
A 1812.5 kN
B 2812.8 kN
C 1218.5 kN
D 1521.8 kN
Answer: 1812.5 kN
#94. A beam with b = 250 mm and depth d = 450 mm is prestressed by an initial force of 600 kN. Total loss of prestress at service load is 15%.
Calculate the resulting final compressive stress (MPa) if the prestressing force is applied at the centroid of the beam.
A 10.53 MPa
B 4.53 MPa
C 6.57 MPa
D 7.85 MPa
Answer: 4.53 MPa
#95. A beam with b = 250 mm and depth d = 450 mm is prestressed by an initial force of 600 kN. Total loss of prestress at service load is 15%.
Calculate the final compressive stress (MPa) if the prestressing force is applied at an eccentricity 100 mm below the centroid of the beam section.
A 15.75 MPa
B 10.57 MPa
C 4.5 MPa
D 7.53 MPa
Answer: 10.57 MPa
#96. A beam with b = 250 mm and depth d = 450 mm is prestressed by an initial force of 600 kN. Total loss of prestress at service load is 15%.
Calculate the eccentricity (mm) at which the prestressing force can be applied so that the resulting tensile stress at the top fiber of the beam is zero.
A 85 mm
B 65 mm
C 55 mm
D 75 mm
Answer: 75 mm
#97. A 25 m long girder of the bridge is simply supported at the right end and at 3 m from the left end.
Given:
Highway live load W1 = 19.6 kN W2 = 78.4 kN Distance on center of wheels = 4.3 m. Determine the max span positive moment.
A 490.9 kN.m
B 486.7 kN.m
C 497.7 kN.m
D 477.9 kN.m
Answer: 497.7 kN.m
#98. A 25 m long girder of the bridge is simply supported at the right end and at 3 m from the left end.
Given:
Highway live load W1 = 19.6 kN W2 = 78.4 kN Distance on center of wheels = 4.3 m Determine the max shear.
A 107.5 kN
B 105.6 kN
C 117.4 kN
D 105.3 kN
Answer: 107.5 kN
#99. A 25 m long girder of the bridge is simply supported at the right end and at 3 m from the left end.
Given:
Highway live load W1 = 19.6 kN W2 = 78.4 kN Distance on center of wheels. Determine the max negative moment.
A 230.2 kN/m
B 132.5 kN/m
C 235.2 kN/m
D 135.2 kN/m
Answer: 235.2 kN/m