A steel column is pin-connected at the top and bottom which is laterally unbraced. It carries an axial load of 800kN and a moment of 70kN.m at the top and a moment at the bottom which is only 90% of the moment at the top. The steel section has the following properties:
A = 13000 mm2
r = 94 mm
Sx = 1200 x 103 mm3
K = 1.0
L = 3.6 m.
Yield stress Fy = 248MPa
Axial compressive stress that would be permitted if axial force alone existed
Fa = 115MPa
Compressive bending stress that would be permitted if bending moment alone existed
Fb = 148MPa
Members subjected to both axial compression and bending stresses shall be proportioned to satisfy the following requirements:
For members whose ends are unrestrained………..….Cm = 1.0
1) Which of the following gives the axial compressive stress if axial load only existed.
2) Which of the following gives the bending stress if bending moment alone existed.
3) Using the interaction formula which of the following gives the value of both axial and bending moment interaction value.
Solution:
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A flooring system consists of parallel I-beam sections spaced at 3m. on centers with simple spans of 6m. the beam support a 200mm thick slab. The flooring system is designed for a live load of 2400 N/m2 as well as ceiling load of 750 N/m2. The properties of the I=beam sections are:
d = 352mm Ix = 0.0012m4
w = 440N/m Fy = 248MPa
E = 200000
Wt. of concrete = 24kN/m3
1) Which of the following gives the uniform pressure acting on the slab.
2) Which of the following gives the total uniform load carried by the beam in kN/m.
3) Which of the following gives the max. flexural stress of the beam.
Solution:
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The implementing rules and regulations of P.D. 1594 states that for a unit price contract, quantity overruns or under runs of not more than 15% of the estimates per major pay item and 25% per minor item need not be covered by a change order provided that the same is authorized by approving authority of the contract. The quantities and contract prices of a project are as follows:
| Item |
Qty. |
Contract |
AAE |
| 1 |
120 |
P80 |
P100 |
| 2 |
50 |
P2500 |
P2400 |
| 3 |
600 |
P150 |
P150 |
| 4 |
80 |
P900 |
P1000 |
| 5 |
800 |
P45 |
P50 |
| 6 |
500 |
P90 |
P80 |
| 7 |
25 |
P1000 |
P1200 |
| 8 |
3500 |
P18 |
P20 |
| Item |
Quantity. |
Change Order |
| 1 |
120 |
150 |
| 2 |
50 |
57 |
| 3 |
600 |
420 |
| 4 |
80 |
96 |
| 5 |
800 |
900 |
| 6 |
500 |
450 |
| 7 |
25 |
30 |
| 8 |
3500 |
3150 |
Solution:
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A block weighing 100N shown at A is subjected to a horizontal force P = 100N. If the velocity of the block at A is 10m/s.
1) Which of the following gives the velocity of the block at B.
2) Which of the following gives the velocity of the block at C.
3) If the force P is released at C, which of the following gives the total distance that the block has traveled until it will stop.
Solution:
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An elevator weighing 9.8kN moves downward from rest until it attains a velocity of 20 m/s after it travels a distance of 5m.
1) Which of the following gives the acceleration of the elevator.
2) Which of the following gives the time which the elevator travels at this instant.
3) Which of the following gives the tension in the cable supporting the elevator.
Solution:
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Section 5.3.3.2 of the NSCP states that the nominal maximum size of coarse aggregates shall not be larger than.
a) 1/5 the narrowest dimension between the sides of the forms,
b) 1/3 the depth of slab
c) ¾ the minimum clear spacing between individual reinforcing bars or wires, bundle of bars or prestressing tendons or ducts.
Section 5.7.6.1 of the NSCP specifies that the minimum clear spacing between parallel bars in a layer shall be equal to “db” but not less than 25mm. When parallel reinforcement is placed in two or more layers bars in the upper shall be placed directly above the bars in the bottom layer with a clear distance between layers of not less than 25mm.
A given cross-section of a rectangular reinforced concrete beam 270mm x 600mm is reinforced with 8-20mmØ arranged as shown in the figure.
1) Which of the following gives the clear horizontal spacing between bars.
2) Which of the following gives the narrowed dimension of horizontal forms.
3) Which of the following gives the max. size of coarse aggregates.
Solution:
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A spiral column has a diameter of 600mm as shown with fc’ = 21 MPa, fy = 275 MPa.
1) Which of the following gives the minimum diameter of spiral reinforcement.
2) Which of the following gives the percentage of spiral ratio.
3) Which of the following gives the spacing of spirals.
Solution:
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From the given beam subjected to the loads in shown in the figure.
1) Which of the following gives the reaction at the roller C.
2) Which of the following gives the max. shear.
3) Which of the following gives the max. negative moment.
Solution:
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From the given frame shown in the figure, using Cantilever Method.
1) Which of the following gives the reaction of BD.
2) Which of the following gives the moment at A.
3) Which of the following gives the shear on member CD.
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Which of these is not to be considered in labor estimate?
a) Supportive work
b) Productive work
c) Non-productive work
d) Overtime work
Answer:
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Which of these does not graph a S-curve?
a) ¼ of the circle inverted upright
b) ¼ of the circle inverted downward
c) Sin curve
d) Straight line inclined from left to right
Answer:
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A tied column is subjected to axial load and end moments. The condition of the column are as follows:
Unsupported length, Lu 500m
Effective length factor, K 0.90
Flexural rigidity, EI 7500 x 109 N-mm2
Magnification factor, delta 1.20
M2 = 250 kN.m
M1 = 200 kN.m
Cm = 0.6 + 0.4 M1/M2
δ = Cm/(1-Pu/Pc)
Determine the ultimate load Pu in kN that this column can carry. Use phi = 0.70.
Solution:
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A simple beam having a span of 10m. carries a load which varies from zero at the left support to 12kN/m at the midspan. Compute the deflection at the mid-span.
Solution:
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A fixed ended beam having a span of 10m. carries a triangular load which varies from zero at the left support to 10kN/m at the right support. Compute the location of max. deflection from the left support.
Solution:
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A flat bar 50mm by 6mm in cross section is bent by a couple such that the maximum stress in the section is 162MPa. If the modulus of elasticity of the material is 200,000N/mm2, which of the following gives the radius of curvature of the bar.
Solution:
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A flat bar 75mm wide by 9mm thick and 1.2m. long is subjected to end moments of 202.5N.m. Compute the deflection of the beam at the midspan if E = 200,000MPa.
Solution:
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A beam 25m. long is simply supported at the left end and at a distance of 20m. from the left end. It carries a uniform load of 5kN/m between the two supports and a concentrated load of 20 kN at the other end. Compute the distance of maximum moment from the left support.
Solution:
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A hollow steel tube having an outside diameter of 220mm and inside diameter of 200mm. Which of the following gives the max. torque that it could carry if the allowable shearing stress is 75.5 MPa.
Solution:
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Which of the following gives the ratio of shear modulus G to the modulus of elasticity of steel if it has a poisons ratio of 0.25.
Solution:
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A suspension cable is supported at A and B, 120m. horizontally apart with B higher than A by 48m. Concentrated loads of 100kN, 200kN and 100kN were applied at a distance of 30m, 60m and 90m respectively from A. The cable sags a distance of 30m. measured from the chord AB at the point where the 200 kN is applied. Compute the horizontal reaction at the supports.
Solution:
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Which of the following the ultimate load for a simply supported rectangular section beam, breadth “b”, depth “d”, having a span L and subjected to a uniformly distributed load of intensity “w”.
Solution:
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A fixed ended beam having a span of 6m. and carries a uniform load Wu throughout its span. Compute the ultimate strength capacity of the beam in terms of its plastic moment capacity.
Solution:
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A suspension cable is supported at A and B, 120m, horizontally apart with B higher than A by 15m. The cable sags a distance of 10m. from the chord joining A and B at the midspan, compute the horizontal reaction at the supports.
Solution:
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A reinforced rectangular beam having a width of 250mm and an effective depth of 500mm carries an ultimate moment of 300 kN.m. Compute the steel area required if fc’ = 35MPa, fy = 275.8MPa.
Solution:
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A composite section consists of a slab having effective width of 1000mm and a thickness of 100mm placed on top of a wide flange section having a cross-sectional area of 10000 mm2. Which of the following gives the number of stud connectors required for the composite section if the capacity of one stud connectors required for the composite section if the capacity of one stud connector is 50Kn. Use fc’ = 27MPa, Fy = 270MPa.
Solution:
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A wide flange section is used as a column section with both ends pinned. Compute the critical load it could carry if it has the following properties.
A = 8000mm2 rx = 100mm
E = 200000MPa rv = 50mm
L = 5m.
Solution:
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A propped beam having a span of 20m. carries a triangular load which varies from 10kN/m at the fixed end to zero at the other support. Compute the maximum deflection of the beam.
Solution:
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A propped beam having a span of 20m. carries a triangular load which varies from 10kN/m at the fixed end to zero at the other support. Compute the moment at the fixed end.
Solution:
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A propped beam having a span of 6m. carries a uniform load of 60kN/m. Compute the moment at the fixed supports.
Solution:
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A propped cantilever beam (fixed at one end and simply supported at the other end) has a span of 0.6m. The beam carries a uniform load w of 600 kN/m. along the 2.0m. length of the span form the fixed end. Compute the moment at the fixed end.
Solution:
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A simply supported beam having a span of 6m. carries a triangular load which varies at 12kN/m. at the center to zero at the supports. Compute the maximum deflection of the beam.
Solution:
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A propped beam having a span of 20m. carries a triangular load which varies from 10kN/m at the fixed end to zero at the other support. Compute the location of maximum deflection from the simple support.
Solution:
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The development length (Ld) of a steel reinforcing bar with given stress (Fs) embedded in concrete anchorage bond strength (u) and diameter of bar (D) is given by the expression.
Solution:
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The development length for a 25mmØ bar with Ab = 491mm2, fy = 413.7MPa and fc’ = 20.68MPa is equal to:
Solution:
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The formula for nominal moment or resistance in concrete is:
a) Mn = bd2 fc’ w (1 – 0.59w)
b) Mn = bd2 fc’ R (1 – 0.59R)
c) Mn = bd2 fc’ w (1 – 0.59R)
d) Mn = bd2 fc’ R (1 – 0.59w)
Answer:
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