2nd Preboard Design Nov 2018 Edited

3rd PRE-BOARD EXAMINATION: NOVEMBER 2018 STRUCTURAL DESIGN AND CONSTRUCTION OCTOBER 28, 2018 8:00AM-1:00PM

SET A

SIT 1: A hollow beam with cross-section given in figure RCD01 is simply supported over a span of 4 m. The cracking moment of the beam is 78 kN·m. 1) Find the maximum uniform load in kN/m the beam can carry without cracking. A) 39 B) 44 C) 48 D) 59 2) Calculate the modulus of rupture in MPa of concrete used for the beam. A) 4.35 B) 3.25 C) 3.77 D) 3.54 3) If the hollow part of the beam is replaced with a square of side 200 mm, what is the new cracking moment in kN·m? A) 71.51 B) 76.37 C) 66.18 D) 81.11 SIT 2: The frame shown in the figure MECH02 supports a weight W. Neglect the weight of members and friction. 4) Determine the tension in cable FG if W = 150 lb. A) 250 lb B) 338 lb C) 351 lb D) 367 lb 5) Determine the pin reaction at B. A) 312 lb B) 338 lb C) 341 lb D) 352 lb 6) Determine the maximum weight that can be supported if the breaking strength of the cable FG that supports the frame is 400 lb. A) 178 lb B) 165 lb C) 192 lb D) 170 lb SIT 3: A monolithic floor framing plan is shown in the figure RCD02. The columns are 400 mm x 400 mm, girders are 300 mm wide and 600 mm deep and slabs are 100 mm thick. The floor supports a superimposed service dead load of 9.384 kPa and service live load of 6 kPa. ACI Moment Coefficients are given below. Use load combination 1.2D + 1.6L 7) Calculate the factored positive moment in kN·m for slab MIJN. A) 11.92 B) 8.21 C) 8.08 D) 15.17 8) Calculate the required shear at F for girder EF. A) 385 B) 393 C) 373 D) 368 9) Calculate the factored negative moment kN·m at F for girder EF. A) 182.24 B) 156.12 C) 141.87 D) 150.34 SIT 4: A W350x82 column (bf = 250 mm, d = 350 mm) carries a factored axial load of 1,632 kN. It bears on a steel base plate 500 mm x 600 mm on a square footing 2.4 m x 2.4 m x 450 mm. Concrete cover to bar centroid of steel reinforcement for bending = 100 mm. Critical section for shear is defined at distance “d” for one way shear and distance “d/2” for two way shear, from midway of column face and edge of base plate. 10) Calculate the ultimate beam shear stress in MPa at critical section.

A) 0.54 11)

C) 0.76

D) 0.65

Calculate the ultimate punching shear stress in MPa at critical section.

A) 1.35 12)

B) 0.82 B) 1.53

C) 1.41

D) 1.08

Calculate the maximum ultimate banding moment in kN·m on the footing slab if the critical section for bending is midway of column face and edge of base plate.

A) 242.67

B) 348.21

C) 366.14

D) 233.26

SIT 5: For the cable loaded as shown in the figure MECH02. 13) Which of the following gives the value of the stress of BC in KN?

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3rd PRE-BOARD EXAMINATION: NOVEMBER 2018 STRUCTURAL DESIGN AND CONSTRUCTION OCTOBER 28, 2018 8:00AM-1:00PM 14) 15)

SET A

A) 2.96 B) 4.81 C) 5.13 D) 6.95 Which of the following gives the value of 2? A) 32.2 B) 49.78 C) 25.61 D) 19.07 Which of the following gives the total length of the cable in meters? A) 8.25 B) 9.60 C) 10.34 D) 12.05

SIT 7: A cylindrical steel pressure vessel 400 mm in diameter with a wall thickness of 20 mm, is subjected to an internal pressure of 4.5 MN/m^2. 16) Calculate the tangential stresses in the steel. A) 45 MPa B) 50 MPa C) 55 MPa D) 60 MPa 17) Calculate the longitudinal stresses in the steel. A) 22.5 MPa B) 25 MPa C) 27.5 MPa D) 30 MPa 18) To what value may the internal pressure be increased if the stress in the steel is limited to 120 MN/m^2? A) 8 MPa B) 12 MPa C) 16 MPa D) 24 MPa SIT 8: A box girder of prestressed concrete bridge of span 40 m has overall dimensions of 1200 mm by 1800 mm as illustrated in figure RCD03. The uniform thickness of the walls is 200 mm. the live load analysis indicates a maximum live load moment of 2000 kN·m at the mid span. The beam is prestressed by parabolic cables with an effective force of 7000 kN. The cables which are concentric at supports have an eccentricity of 800 mm at the mid span section. 19)

Calculate the total stress in MPa at mid span section, top fiber of the box girder.

A) 2.23 20)

B) 3.6

C) 6.73

D) 9.86

Calculate the total stress in MPa at mid span section, bottom fiber of the box girder.

A) 2.23

B) 3.6

C) 6.73

D) 9.86

SIT 10: A flooring system consists of parallel W14x30 steel sections spaced 3 m on centers with simple span of 6 m laterally supported fully by the floor. The beams support a 200 mm thick slab. The flooring system is designed for a ceiling load of 750 N/m^2. The properties of the I-beam sections are: d = 350 mm, bf = 170 mm, tf=10 mm, tw=7 mm, Ix = 121,123x10^3 m^4, W = 440 N/m, Fy = 248 MPa, E = 200,000 GPa. Use Wt. of concrete = 24 kN/m^3. 21)

Calculate the allowable moment strength of the section if it is compact and laterally supported with allowable flexural stress of 0.66Fy.

A) 125.62 MPa 22)

C) 113.29 MPa

D) 226.60 MPa

Calculate the maximum floor live load (kPa) an individual beam can sustain with non-composite action.

A) 2.70 23)

B)107.45 MPa

B)2.40

C) 3.60

D) 8.40

Calculate the maximum web shear stress (MPa) if the live load is 2.4 kPa .

A) 29.74

B) 9.73

C) 8.81

D) 20.82

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3rd PRE-BOARD EXAMINATION: NOVEMBER 2018 STRUCTURAL DESIGN AND CONSTRUCTION OCTOBER 28, 2018 8:00AM-1:00PM

SET A

SIT 10: A flooring system consists of parallel W14x30 steel sections spaced 3 m on centers with simple span of 6 m laterally supported fully by the floor. The beams support a 200 mm thick slab. The flooring system is designed for a ceiling load of 750 N/m^2. The properties of the I-beam sections are: d = 350 mm, bf = 170 mm, tf=10 mm, tw=7 mm, Ix = 121,123x10^3 m^4, W = 440 N/m, Fy = 248 MPa, E = 200,000 GPa. Use Wt. of concrete = 24 kN/m^3. 24)

Calculate the nominal moment strength of the steel beam according to the provisions given at the back pages.

A) 142.6 MPa 25)

C) 190.61 MPa

D) 166.1 MPa

Calculate the maximum floor live load (kPa) an individual beam can sustain by LRFD method.

A) 2.76 26)

B) 157.4 MPa

B) 2.85

C) 3.67

D) 3.17

Calculate the maximum floor live load an individual beam can sustain by ASD method.

A) 2.76

B) 2.85

C) 3.67

D) 3.17

SIT 12: A plate is used as a bracket and is attached to a column flange as shown in figure STD02. Assume the base metal shear is adequate. 27)

Calculate the direct shear load in the welds in N/mm.

A) 206.15 28)

C) 191.43

D) 270.76

Calculate the maximum resultant load in the welds in N/mm.

A) 427.89 29)

B) 187.04 B) 581.05

C) 466.98

D) 634.04

Calculate the required size of the fillet weld if electrode E70xx is used with Fu = 482 MPa if the allowable shear stress on the fillet weld is 0.3Fu.

A) 4 mm

B) 5 mm

C) 6 mm

D) 7 mm

SIT 13: A stress-graded unseasoned Apitong with 80% stress grade is selected for use as a column. The section size is 100 mm x 250 mm. The member is 3.6 m long, with weak way lateral support at mid-height and lateral support both ways at each end. Assume all supports are pinned. Allowable working stresses are given below: Bending and tension parallel to grain 16.5 MPa Compression parallel to grain 9.56 MPa Compression perpendicular to grain 2.20 MPa Modulus of Elasticity in Bending 7.31 GPa 30) Determine the classification of the column.

A) Short B) Intermediate 31)

Which of the following gives the allowable compressive stress in MPa?

A) 6.73 32)

C) Long D) Not Allowed B) 8.40

C) 9.56

D) 11.62

Which of the following most nearly gives the maximum axial load?

A) 239 kN

B) 210 kN

C) 168 kN

D) 135 kN 3

3rd PRE-BOARD EXAMINATION: NOVEMBER 2018 STRUCTURAL DESIGN AND CONSTRUCTION OCTOBER 28, 2018 8:00AM-1:00PM

SET A

SIT 14: The cylindrical steel column has an outside diameter of 100 mm and inner diameter of 85 mm. See figure STRM07. The column is separated from the concrete foundation by a square 180 mm bearing plate. Working compressive stress is 180 MPa for the column and the working bearing stress is 10 MPa for concrete. 33) Find the maximum value of P that can be applied to the column if the compressive stress in not exceeded. A. 324 kN B. 392 kN C. 425 kN D. 481 kN 34) Find the maximum value of P that can be applied to the column if the bearing stress in not exceeded. A. 324 kN B. 392 kN C. 425 kN D. 481 kN SIT 15: The boom AC as shown in the figure STRM08 is a 120 mm square steel tube with a wall thickness of 7.5 mm. The boom is supported by the 15-mmdiameter pin at A, and the 11.25-mm-diameter cable BC. The working stresses are 150 MPa for the cable, 108 MPa for the boom, and 81.6 MPa for shear in the pin. 35) Determine the largest P that can be applied as shown if the working stress in the cable is not exceeded. A. 29.37 kN B. 30.24 kN C. 35.12 kN D. 39.54 kN 36) Determine the largest P that can be applied as shown if the working stress in the boom is not exceeded. A. 382 kN B. 347 kN C. 248 kN D. 275 kN 37) Determine the largest P that can be applied as shown if the shear stress in the pin is not exceeded. A. 29.37 kN B. 30.24 kN C. 35.12 kN D. 39.54 kN SIT 16: The circular bar 20 mm in diameter shown in STRM09 is bent into a semicircle with a mean radius of 600 mm. Given P = 2000 N and F = 1000 N. 38) Compute the horizontal reaction at A. A. 866 B. 1732 C. 1000 D. 1232 39) Compute the moment in kN·m developed in section a-a. A. 350 B. 420 C. 260 D. 510 40) Compute the shear force in kN developed in section a-a. A. 67 B. 82 C. 150 D. 184 SIT 17: A square plate 2 m on each side is supported by four steel tie rods 6mm-diameter from an overhead central point as shown in the figure STRM10. The plate supports a surface load of W in kPa. The point of attachment A is 1.25 m above the plane of the plate. 41) Determine the maximum load W (kPa) the tie rods can support if the allowable tensile stress on it is 450 MPa. A. 8.43 B. 12.83 C. 10.12 D. 5.64 42) Determine the elongation of each steel tie rod if W = 8.5 kPa. A. 4.28 mm B. 6.46 mm C. 2.84 mm D. 3.54 mm 43) Determine the vertical displacement of the plate. A. 4.28 mm B. 6.46 mm C. 2.84 mm D. 3.54 mm SIT 18: A cantilever hollow circular steel shaft has an outside diameter of 100 mm and thickness of 10 mm.

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3rd PRE-BOARD EXAMINATION: NOVEMBER 2018 STRUCTURAL DESIGN AND CONSTRUCTION OCTOBER 28, 2018 8:00AM-1:00PM 44)

Determine the maximum torque that can be applied without exceeding a shearing stress of 60 MPa.

A) 4.1 kN·m 45)

B) 8.6 kN·m

C) 5.8 kN·m

D) 6.9 kN·m

Determine the maximum torque that can be applied without exceeding a twist of 0.5 deg/m. Use G=83 GPa.

A) 4.2 kN·m 46)

SET A

B) 7.1 kN·m

C) 2.4 kN·m

D) 5.9 kN·m

Determine the maximum shear stress if the applied torque at the free end is 8 kN·m.

A) 41 MPa

B) 118 MPa

C) 69 MPa

D) 107 MPa

SIT 19: A highway load composed of a uniform load of magnitude 100 kN/m and a concentrated load of 150 kN passes through a simply supported beam 10 m long and an overhang of 3 m to the right. 47) Based on the influence line diagram for the maximum reaction at the left support, determine the reaction.

A) 150 kN 48)

C) 605 kN

D) 650 kN

Based on the influence line diagram for the maximum shear at the midspan, determine the maximum negative shear.

A) 150 kN 49)

B) 455 kN

B) 170 kN

C) 245 kN

D) 375 kN

Based on the influence line diagram for the maximum moment at the midspan, determine the maximum positive moment.

A) 1625 kN-m

B) 1400 kN-m

C) 1250 kN-m

D) 375 kN-m

SIT 20: Identify the following items described below. 50) Post-tensioning system where the ducts are never grouted and the tendon is held in tension solely by the end anchorage.

A) Bonded Post Tensioning B) Unbonded Post Tensioning 51)

A method of pre-stressing reinforced concrete in which tendons are tensioned before the concrete is placed.

A) Pre-tensioning B) Post Tensioning 52)

C) Relaxation D) Elastic Shortening

Time-dependent reduction of stress in prestressing tendon at constant strain.

A) Shrinkage B) Creep 54)

C) Pre-casting D) Post Casting

The continuous deformation of concrete over extended periods of time and sustained loads.

A) Shrinkage B) Creep 53)

C) Anchored Post Tensioning D) Unanchored Post Tensioning

C) Relaxation D) Elastic Shortening

It is the pre-compression of probable tension zone to eliminate tension and reduce amount of deflection.

A) Rebonding B) Reinforcing

C) Prestressing D) Precasting

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3rd PRE-BOARD EXAMINATION: NOVEMBER 2018 STRUCTURAL DESIGN AND CONSTRUCTION OCTOBER 28, 2018 8:00AM-1:00PM 55)

SET A

A method of pre-stressing reinforced concrete in which the concrete is cast and cured before tendons are tensioned.

A) Pre-tensioning B) Post Tensioning

C) Pre-casting D) Post Casting

SIT 21: A 4-span continuous beam supports a uniformly distributed load of 30 kN/m over the entire span. The distance between supports is 5 m. 56) Determine the negative bending moment at the first interior support from the left in kN·m. A) 62.50 B) 93.75 C) 80.36 D) 53.57 57) Determine the negative bending moment at the middle interior support in kN·m. A) 62.50 B) 93.75 C) 80.36 D) 53.57 58) Determine the maximum positive moment of the end span. A) 31.25 B) 41.67 C) 52.73 D) 57.88 SIT 22: A W 600 x 110 beam is supported by a bearing plate 300 mm x 200 mm x 25 mm on a wall with a thickness of 300 mm. Properties of W 600 x 110 beam d = 600 mm, bf = 225 mm, tf = 18 mm, tw = 12 mm, K = 36 mm, fc’ = 24 MPa, fy = 248 MPa The allowable bearing stress is 0.35 fc’, allowable bending stress is 0.75 Fy and allowable web yielding stress is 0.66 Fy. Determine the maximum reaction at the beam for the following conditions. 59) Considering the bearing of concrete wall.

A) 1440 kN

B) 504 kN

C) 1224 kN

D) 575 kN

60) Considering bending of plates at a distance K.

A) 333.6 kN 61)

B) 178.9 kN

C) 168.2 kN

D) 193.5 kN

Due to allowable web yielding stress at a distance (N + 2.5K).

A) 569.61 kN

B) 792.3 kN

C) 436.6 kN

D) 839.21 kN

SIT 23: A W600x110 beam is supported at the end by a bearing plate 300 mm x 200 mm x 25 mm on a concrete wall of thickness 300 mm. Properties of W600x110 beam are: d = 600 mm, bf = 225 mm, tf = 18 mm, tw = 12 mm, K = 36 mm, fc’ = 24 MPa, Fy = 248 Mpa 62) Calculate the ultimate end reaction based on web yielding.

A) 1440 Kn 63)

D) 863 Kn

B) 1125 Kn

C) 839 Kn

D) 1935 Kn

Calculate the ultimate end reaction based on bending of the bearing plate about the minor axis considering its nominal strength is the plastic moment if Fy = 345 Mpa.

A) 322 Kn 65)

C) 1224 Kn

Calculate the ultimate end reaction based on bearing on concrete support assuming the plate is centered on the wall.

A) 792 Kn 64)

B) 504 Kn

B) 723 Kn

C) 448 Kn

D) 392 Kn

This is an irregularity where the story strength is less than 80% of that in the story above. A) Weight irregularity B) Soft story C) Weak story D) Stiff story

6

3rd PRE-BOARD EXAMINATION: NOVEMBER 2018 STRUCTURAL DESIGN AND CONSTRUCTION OCTOBER 28, 2018 8:00AM-1:00PM 66)

67)

68)

69)

70)

SET A

This is an irregularity where the lateral stiffness is less than 70 percent of that in the story above or less than 80 percent of the average stiffness of the three stories above A) Weight irregularity B) Soft story C) Weak story D) Stiff story This is an irregularity where the effective mass of any story is more than 150% of the effective mass of an adjacent story. A roof that is lighter than the floor below need not be considered. A) Weight irregularity B) Soft story C) Weak story D) Stiff story This is an irregularity where the maximum story drift at one end of the structure transverse to an axis is more than 1.2 times the average of the story drifts of the of the two ends of the structure. A) Out of plane offset B) Torsional irregularity C) In-plane discontinuity D) Vertical geometry irregularity This is an irregularity where the horizontal dimension of the lateralforce-resisting system in any story is more than 130% of that in the adjacent story. A) Horizontal geometric irregularity B) Out of plane offset C) Vertical geometric irregularity D) In-plane discontinuity Re-entrant irregularity is where the plan configurations of a structure and its lateral force resisting system contain re-entrant corners, where both projections of the structure beyond a re-entrant corner are greater than how many percent of the plan dimension of the structure in the given direction? A) 5 B) 10 C) 20 D) 15

SIT. 24: A rectangular beam 250 mm wide, 500 mm deep is to be designed for a factored moment of 300 kN·m. Use concrete strength f’c = 21 MPa and steel yield strength fy = 420 MPa for 20-mm bars and 16-mm bars. Use concrete bar centroid for tension bars 70 mm and for compression bars 80 mm. 71) Determine the maximum steel ratio for a singly reinforced condition in positive bending with the given material strengths if the tensile strain is limited to 0.004 upon crushing of concrete. A. 0.01548 C. 0.01355 B. 0.02837 D. 0.01923 72) Determine the required amount of 20 mm tension bars in mm^2 for a failure with strain of 0.004 for. Use reduction factor according to NSCP 2015. A. 1456 C. 2220 B. 1664 D. 2492 73) Determine the required amount of 16 mm compression bars in mm^2. A. 1024 C. 528 B. 475 D. 764 SIT . 25: A simply supported beam 16 m long is simply supported at a distance “b” from both ends. It supports a uniform load of 120 kN/m over the entire length.

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3rd PRE-BOARD EXAMINATION: NOVEMBER 2018 STRUCTURAL DESIGN AND CONSTRUCTION OCTOBER 28, 2018 8:00AM-1:00PM

SET A

74)

Find the value of “b” that will give the smallest magnitude for the maximum bending moment in the beam. A. 3.31 m B. 4.0 m C. 4.67 m D. 2.33 m

75)

What is the value of this bending moment? A. 659 kN·m B. 662 kN·m C. 1,319 kN·m

F I G U R E S

A N D

N S C P

D.

960 kN·m

P R O V I S I O N S :

RCD01 300 mm

150 mm

600 mm

8

3rd PRE-BOARD EXAMINATION: NOVEMBER 2018 STRUCTURAL DESIGN AND CONSTRUCTION OCTOBER 28, 2018 8:00AM-1:00PM

SET A

MECH02 2m

2m

1.5m

A 1 2m B

D 2

2m

C

3 kN 8 kN

RCD03

RCD02

5.5 m A

B

6m

C

5.5 m

D 2.5 m

E

F

G

I

J

H K

H 2.5 m L 2.5 m

M

N

O

P

ACI MOMENT COEFFICIENTS POSITIVE MOMENT = Cwuln2 End spans Discontinuous end unrestrained……… Discontinuous end integral with support Interior spans……………………………… NEGATIVE MOMENT = Cwuln2 At exterior face of first interior support Two spans…………………………………………… More than two spans………………………….. At other faces of interior supports…………… At face of all supports for slabs with spans not exceeding 3 meters; and beams where ratio of sum of column stiffness to beam stiffness exceeds eight at each end of the span…………………………… At interior face of exterior support for members built integrally with supports: Where support is a spandrel beam…………………

C 1/11 1/14 1/16

1/9 1/10 1/11

1/12

1/24

9

3rd PRE-BOARD EXAMINATION: NOVEMBER 2018 STRUCTURAL DESIGN AND CONSTRUCTION OCTOBER 28, 2018 8:00AM-1:00PM Where support is a column………………………… SHEAR At face of first interior support …………………… 1.15 wuln/2 At face of all other supports …………………………. wuln/2 Where C = coefficient wu = factored load ln = CLEAR span for +M and V; = AVERAGE adjacent CLEAR span for –M

RCD05

STRM06

STD02

STRM07

SET A

1/16

P

10

3rd PRE-BOARD EXAMINATION: NOVEMBER 2018 STRUCTURAL DESIGN AND CONSTRUCTION OCTOBER 28, 2018 8:00AM-1:00PM

SET A

y h = 600 mm

RCD08

8-25 mm dia b=400 mm

x 12 mm dia

STRM08

STRM09

STRM10

F

a P

a

A

30o

1.25 m 60o

B

2m

2m

11

3rd PRE-BOARD EXAMINATION: NOVEMBER 2018 STRUCTURAL DESIGN AND CONSTRUCTION OCTOBER 28, 2018 8:00AM-1:00PM

SET A

12