A simply supported steel beam has a span of 6m. and is subjected to a vertical concentrated load of 150 kN acting at midspan. An allowance of 100% for impact is made for the concentrated load only. The beam is laterally supported only at the supports. The 1992 National Structural Code of the Philippines States that the allowable tensile stress for laterally unsupported members subject to bending is 0.60 Fy while the allowable compressive stress for laterally unsupported members subject to bending is given by the equation.
Where Cb maybe taken as 1.0 since the maximum moment does not occur at the supports, rt is the radius of the compression web area, taken about the axis in the plane of the web.
Steel is A 36 steel with yield strength Fy = 248MPa. Which of the following most nearly gives the most economical (lightest) section that will limit the flexural stress to the allowable value.
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The preliminary design of a roadway established two tangents meeting at the point of intersection at station 200 + 130. The first tangent has an azimuth equal to 169° while the second tangent has an azimuth equal to 118°. A simple horizontal curve with radius equal to 100m. is to be provided. Which of the following gives the tangent distance “T”.
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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 the approving and contract prices of a project are as follows.
| Item |
Quantity |
Unit Price (Pesos) |
|
1
|
100 |
1,000 |
| 2 |
50 |
10,000 |
| 3 |
500 |
5,000 |
| 4 |
60 |
6,000 |
| 5 |
1,000 |
3,000 |
| 6 |
400 |
1,500 |
| 7 |
3,000 |
2,000 |
| 8 |
20 |
25,000 |
Which of the following quantity need not be covered by a change order.
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A projectile is fired upward and to the right at an initial slope of 4 vertical to 3 horizontal and hits the ground at a point 2m lower than the origin. The maximum height is attained 8m away from the origin. Compute the value of the total horizontal distance.
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The approved agency estimate (AAE) of a Gov’t. project is 500M. The bids are:
Bidder A : P354,000,000
Bidder B : P639,000,000
Bidder C : P483,000,000
Bidder D : P583,000,000
Bidder E : P295,000,000
Bidder F : P385,000,000
The implementing rules and regulation of Pres. Decree No. 1594 states that no award of contract shall be made to a bidder whose bid price is higher than Allowable Government Estimate(AGE) or the Approved Agency Estimate(AAE) is defined as one half the sum of the (AAE) and the average of all responsive bids. For the purposes of determining the average of responsive bids, bids higher than 120% of the AAE or lower than 60% of AAE shall not be considered. Which bidder wins the contract for the Gov’t. project?
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A 50mm diameter split barrel sample is driven into the ground and the load of a cased burbale by means of blows form 65kg mass hammer falling freely through a distance of 760mm. The sample is driven a total of 450mm into the soil. Which of the following is the test best described by this procedure?
a) Dutch Cone Penetration Test
b) Standard Proctor Test
c) Standard Penetration Test
d) Vane shear test
A block weighing 200 N rests on a plane inclined upward to the right at a slope of 4 vertical to 3 horizontal. The block is connected by a cable initially parallel to the plane passing through a pulley which is connected to another block weighing 100N moving vertically. The coefficient of kinetic friction between the 200N block and the inclined plane is 0.10, which of the following most nearly gives the acceleration of the system.
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A beam 8.5m. long is fixed at the left end and supported by a roller at a point 1.5m from the right end. There is an internal hinge at a point 2.5m. from the fixed end. The beam is loaded by a clockwise couple equal to 50kN.m at a point 4.5m to the right of the fixed end and a downward uniform vertical load equal to 5kN/m starting at a point 4.5m. from the fixed end up to the right end of the beam. Which of the following most nearly gives the maximum moment.
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A floor is made up of 150mm thick concrete slab and 50mm thick finish both of which has a unit weight of 24kN/m3. The floor also carries ceiling whose weight is 720Pa and a live load of 2400Pa. The floor is supported by simply supported steel beams with a span of 10m spaced at 4.6m on centers with compression flange rigidly attached to the concrete floor. The steel is A36 with yield strength (Fy) = 248MPa. The allowable shear stress specified in the 1992 NSCP is 0.40Fy. Considering the weight of the beam, which of the following sections is the most economical (lightest) section for the given load assuming that shear stress governs the design.
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A steel plate is 360mm wide and 20mm thick with four bolt holes cut into the plate as shown in the figure s-3. The general expression for the specification method for computing the net area is:
Where: T = thickness of plate
B = width
H = diameter of holes
S = pitch
g = gage
Which of the following most nearly gives the critical net area (An) of the section in accordance with the 1992 NSCP.
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A simply supported beam has a span o f4.5m. The beam is subjected to an axial tensile force of 250kN. And a vertical concentrated load P acting at its midspan. The member is fully laterally supported for its entire length. The effect of any bolts can be neglected. The beam consists of 2-150×90x12mm angles with long legs back to back spaced at 10mm apart. For this problem the properties of one 150×90x12mm angles are:
Area (A) = 2751 mm2
Section modulus (Sx) = 0.000063m3
Steel is A36 with yield strength (Fy) = 248MPa
Allowable tensile stress = 0.60Fy
Allowable flexural stress = 0.66Fy
Neglecting the weight of the beam, which of the following most nearly gives the maximum value of the load P that the member can support.
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A beam is fixed at both ends and has an internal hinge along the span. Classify the beam as either unstable, statically indeterminate or statically determinate and degree of indeterminacy. Assume all loads can act anywhere in any direction of the beam.
a) Statically indeterminate to the first degree
b) Unstable
c) Statically indeterminate to the second degree
d) Statically determinate
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A 2 N weight is swing in a vertical circle of 1m radius and the end of the cable will break if the tension exceeds 500N. Which of the following most nearly gives the angular velocity of the weight when the cable breaks?
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In accordance with sections 5.4.7.2.3 of the 1992 NSCP, strength level of an individual class of concrete shall be considered satisfactory if both of the following requirements are met.
a) Average of all sets of three consecutive strength tests equal or exceeds fc’
b) No individual strength test (average of two cylinders) falls below fc’ by more than 3.5MPa.
The required fc’ for a project is 28MPa. The results of four sets of cylinder tests with 5 samples are as follows.
| |
Set A
|
Set B |
Set C |
Set D |
| Sample # 1 |
24.0 |
28.5 |
32.0 |
21.0 |
| Sample # 2 |
23.5 |
28.0 |
30.5 |
24.5 |
| Sample # 3 |
25.0 |
32.0 |
25.0 |
20.5 |
| Sample # 4 |
35.0 |
25.0 |
25.0 |
22.0 |
| Sample # 4 |
30.5 |
29.0 |
28.0 |
20.0 |
Which of the following set is acceptable for the project requirements?
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The result of standard Proctor Test is as follows:
| Water content (%) |
Weight (W) of moist soil in Proctor mold (grams) |
| 10 |
1.485 |
| 12 |
1.606 |
|
14
|
1.696 |
| 16 |
1.755 |
|
18
|
1.741 |
| 20 |
1.651 |
The volume of the mold for this test is 1/30cu.ft. (946,000 cubic millimeters). Which of the following most nearly gives the value of the optimum moisture content of the soil?
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Section 5.10.11.5 of the 1992 NSCP, discuss the provisions for moment magnification. Compression members shall be designed using the factored axial load Pu from a conventional frame analysis and a magnified factored moment Mc defined by:
Mc = δs M2b + δb M2s
Where:
M2b = the value of larger factored end moment on compression member due to loads that result in no appreciable sideways, calculated by conventional elastic frame analysis.
M2s = value of larger factored end moment on compression member due to loads that result in appreciable sideways, calculated by conventional elastic frame analysis.
∑Pu and ∑Pc are the summations for all columns in a story. For frames not braced against sideways, both δb and δs shall be computed. For frames braced against sideway, δs shall be taken as 1.0.
In equation (5.10.7) for members braced against sideway and without transverse loads between supports Cm maybe taken as:
But not less than 0.40. For all other cases,
Cm shall be taken as 1.0
A rectangular tied concrete column has dimensions of 300mm x 380mm. The column length is 4.5m. is to be constructed in a frame braced against sideway (the effective length factor K can be taken as 1 and EI = 34MN-m2.. The column is loaded in single curvature by the ultimate factored moment of 110kN.m at its top end and 120kN.m at its bottom end. The column carries factored axial loads due to dead load of 150kN, 350kN due to live load.
Which of the following gives the magnified factored moment (Mc) that will be used it design the steel reinforcement in accordance with the NSCP 1992.
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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.
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A ball is shot at a ground level at an angle of 80ball is shot at a ground level at an angle of 80 degrees with the horizontal with an initial velocity of 10m/sec. Which of the following most nearly gives the maximum height (h) attained by the ball?
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Section 5.10.3.2 and 5.10.3.3 of the 1992 National Code of the Phil. States as follows: Balanced strain conditions exists at a cross section when tension reinforcement reaches the strain corresponding to its specified yield strength fy just as concrete in compression reaches its ultimate strain of 0.003. For flexural members subject to combined flexure and compressive axial load, when the design axial load strength θPn is less than the smaller of 0.10 fc’ Ag or θPb. the ratio of reinforcement ρ provided shall not exceed 0.75 of the ratio ρb that would produced balanced strain conditions for the section under the flexure without axial load. For members with compression reinforcement, the portion of ρb equalized by compression reinforcement need not be reduced concrete beam has a width of 300mm and an effective of 400mm. Concrete strength is 24MPa and steel yield strength is 340MPa. Which of the following most nearly gives the maximum allowable steel area (As) in accordance with the 1992 NSCP strength design method.
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A non-prismatic simply supported beam has a total span of 8m. The 4m. long middle section of the beam has a moment of inertia twice the moment of inertia of the section beside the supports. The beam is acted upon by downward concentrated load acting at mid span equal to 10kN. Which of the following most nearly gives the slope (theta) at a point 2m. to the right of the left support (at the change in cross section.)
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A rod with cross-sectional area of 100sq.mm is stretched between two fixed points such that the initial tensile load is 10kN. The rod has an initial modulus of elasticity (E) equal to 180GPa. And a coefficient of linear expansion (alpha) equal to 0.00001 mm/degree centigrade. The initial tension is designed such that the rod will have a zero stress when there is a certain change in temperature of the rod. Which of the following most nearly gives the value of this temperature change T:
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The H2O table in a deposit of silt is lowered from a depth of 3m to a depth of 6m. all the silt is saturated even after the H2O table is lowered and the water content is 22%.
Which of the most nearly gives the change in effective pressure at a depth of 12m. on account of lowering of water table Sp.gr. of soil is 2.60
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The soil is said to be non-plastic if the liquid limit is less than:
a) 90
b) 50
c) 20
d) 60
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According to implementing Rules and Regulation PD 159, which of the following is not authorized to be a member of the PBAC.
a) Representative of Phil. Constructors Association
b) Representative of PICE
c) Representative of CPA
d) Representative of Road Engineers Association of the Phil.
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A concrete beam of rectangular cross section, 120mm x 300mm is to be reinforced by six, high tensile pre-stressing tendons each having a cross sectional area of 300mm2. If the level of pre-stress in the tendon is 150N/mm2 and if the reinforced beam is subjected to an axial tensile load of 150kN, determine the final stress in the concrete assuming that the ration of the elastic modulus of steel to that of concrete is 15:
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A simply supported beam 400mm by 800mm and span of 10.0m, is pre-stressed by a straight tendon with a force of 1200kN at an eccentricity of 200mm from the centroid. The beam supports a total weight. Calculate the stresses at the top fiber.
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Based on the AISC Specifications, the effective net area Ae at the root of the thread of a threaded tension member is Ae = 0.7854 (D – 0.9743/n)2 Where D is the nominal outside diam. Of the threads and n is the number of threads per 25.4mm. if the load is 250kN and the number of threads per inch of the threaded tension member is 4, Fy = 250MPa the diameter sufficient to carry the load is:
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A tied column is subjected to axial load and end moments. The conditions of the column are as follows:
Unsupported length, Lu 5.00m
Effective length factor, K 0.90
Flexural rigidity, EI 7500 x 109 N-mm2
Magnification factor, delta 1.20
Moment magnifying coef., Cm 0.533
Determine the ultimate load Pu in kN that this colum can carry. Use phi = 0.70.
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The rotation or twist in degrees of a shaft, 800mm long, subjected to a torque of 80N-m, 20mm in diameter, and shear modulus G of 80,000MPa is:
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A cubic meter of soil in its natural state weighs 1.75kN; after being dried, it weighs 15.08kN. The specific gravity of the soil is 2.70. Determine the void ratio of the original soil sample:
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The allowable capacity of a 10mm thick fillet weld, E60 electrode (Fu = 415MPa) is:
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A reinforced concrete beam has the following properties;
Beam with, b …………………………… 320mm
Effective depth, d ……………………… 640mm
Concrete strength, fc …………………… 25MPa
Reinforcing steel strength, fy …………. 400MPa
Compute the shear capacity of stirrups
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A W 410 x 74.4 supports a slab with a thickness of 150mm. The effective width of the slab was computed to be 2000mm. The structural steel section of the composite system has the following properties:
Beam depth, d 413mm
Flange width, bf 180mm
Cross sectional area, As 9480mm2
Moment of inertia 274.3 x 106mm4
Where is the new location of the neutral axis from the top of the slab in mm. Use n = 10m transform the area of concrete to steel.
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A steel beam 7.2m long carries a uniformly distributed load of 36kN/m throughout the span. It is simply supported at its end and at its center (a two 3.6m span continuous beam). If the shear (reaction) at the end support is 48.6kN, the maximum positive moment is developed at this distance from the end support.
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A footing is 2.40m by 1.50m. The total load P of 1,000kN on the footing has an eccentricity of 0.40m in the direction of the longer dimension. Determine the maximum soil pressure at the base.
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