Group06
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School
Concordia University *
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Course
BLDG 6831
Subject
Industrial Engineering
Date
Feb 20, 2024
Type
docx
Pages
26
Uploaded by MagistrateMusicSeaUrchin32
The Group Assignment of the Course:
CONSTRUCTION PROCESSES (BLDG492-6831 – UU)
G
ROUP
F
IRST
N
AME
F
AMILY
N
AME
S
TUDENT
ID
MARIO CESAR
CASTRO LA BARRERA
40270431
TASHWINI
MANJUNATH
40264245
SEYED ILIA
MOUSAVI
40204305
JENIL RANA
40263428
SHIVA
DARIHAKI
40221999
MD FAZLE
RABBI
40239821
H
ADI
HATAMI RASTGOO BAJGIRAN
40277000
MARIA
SHENODA
40270571
SAI KARTHIK
VAKKANTHULA
40260589
Instructor:
SHAHIN KARIMIDORABATI
Concordia University
Department of Building, Civil, & Environmental Engineering Fall 2023
Comments and Feedback
(FOR TUTORS/MARKERS ONLY)
Mark:
1)
EARTHMOVING MATERIALS AND OPERATIONS
A. C
ALCULATIVE
Q
UESTION
An earthwork excavation includes filling of a basement of dimensions 25m x 50m x 3m. The
material to be excavated is common earth. On a sample of 120 grams taken from the borrow
pit laboratory tests were conducted and it has been determined that the weight of the sample
when oven dried is 100 grams. Independently, a modified proctor test has also been
conducted and it has been determined that the required density is obtained at a moisture
content of 22%. Given this, which of the following is correct? A.
6250 LCY and 260 kg/ m
3 of water to be added.
B.
6945 BCY and 260 kg/ m
3 of water to be added.
C.
6250 LCY and 260,254 kg of water to be added.
D.
6945 BCY and 260,254 kg of water to be added.
Sol. The Correct answer is D.
Volume of fill = 25m x 50m x 5m = 6250 m
3 = 6250 CCY
To convert bank volume to compacted volume, we use shrinkage factor.
From Table 2 –5, shrinkage factor is 0.90
Volume of earthwork required = 6250 CCY / 0.75 = 6944.44 BCY say 6945 BCY
The % moisture content = sample weight – dry weight / dry weight = 120 –100/ 100 = 20%
As the moisture content in bank measure is less than that optimum moisture i.e., 20% < 22%,
additional water is required to be added to excavated material.
Weight of water in bank measure per cubic metre of soil = 1839 kg/ m
3
x 0.2 = 367.80 kg Weight of water in 8334 = 367.80 kg x 6945 m
3 = 2,554,371 kg
Weight of water in compacted measure per cubic metre = 2047 kg/ m
3
x 0.22 = 450.34 kg
Weight of water in 6250 = 450.34 kg x 6250 m
3 = 2,814,625 kg
Difference = 2,814,625 – 2,554,371 = 260,254 kg (or) 260 m
3
B. N
ON
-C
ALCULATIVE
Q
UESTION
2
Which of the following is the correct earthmoving process?
A.
Excavating, loading, hauling, placing, compacting, grading and finishing.
B.
Hauling, Loading, excavating, placing, compacting, grading and finishing.
C.
Excavating, Loading, placing, hauling, compacting, grading and finishing.
D.
Excavating, Placing, hauling, loading, compacting, grading and finishing.
Sol. The correct answer is A.
In the earthmoving process, first the required quantity is excavated then loaded into haul
units which haul the material to the required location. At the location the material is placed
in required shape and depth, and then compacted using appropriate machinery. At last, the
compacted material is brought to required grading and finishing.
2)
EXCAVATION EQUIPMENT
C. C
ALCULATIVE
Q
UESTION
An excavator is tasked with digging a trench which is 2000 meters long, 2 meters width and
2.5 meters depth. Consider the job conditions are poor, but the management has enough skills
and experience to perfectly coordinate the project. The project manager (P.M.) is
contemplating whether to use a medium-sized excavator priced at $210 per hour or a small-
sized excavator priced at $120 per hour. The materials are mostly including common earth.
For a small sized excavator, the maximum depth of cut is 6 meters and for the medium sized
is 8.3 meters. Which one of the excavators do you suggest for this job for the best-case
scenario.
A. More information needed to compare the two scenarios.
B. The medium sized excavator with the total amount of $8279.
C. The medium sized excavator with the total amount of $8715.
D. The small sized excavator with the total amount of $9224.
Sol. The correct answer is C.
3
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Total volume of the trench= 2000 (m)* 2 (m)* 2.5 (m)= 10000 m
3
Productivity for a small sized excavator:
V= 0.76 m
3
for best case scenario (according to table)
C= 200 c/h (according to table)
Depth of cut (% of maximum) = (2.5 m / 6 m) *100 = 41.67 %
Angle of swing = 45 degree, for best case scenario
Interpolation: S= 1.33 + ((1.28-1.33)/ (50-30)) *(41.67-30) = 1.30 (according to table)
B= 1.10 for best case scenario (according to table)
E= 0.63 (according to table)
Adjustment factor for trench= 0.95 for best case scenario (according to table)
Productivity = V*C*S*B*E*adjustment factor for trench = 0.76 (m
3
) * 200 (c/h) * 1.3* 1.1*
0.63* 0.95
Productivity= 130.09 (m
3
/h) for small sized excavator
Total amount of time needed to excavate the trench= 10000 (m
3
)/ 130.09 (m3/h) = 76.87 h
Total to be paid for the small excavator= 76.87 (h)* 120 ($) = 9,224.4 $
Productivity for a medium sized excavator:
V= 1.72 m
3
for best case scenario (according to table)
C= 160 c/h (according to table)
Depth of cut (% of maximum) = (2.5 m / 8.3 m) *100 = 30.12 %
Angle of swing = 45 degree, for best case scenario
S≈ 1.33 (according to table) (according to table)
B= 1.10 for best case scenario (according to table)
E= 0.63 (according to table)
Adjustment factor for trench= 0.95 for best case scenario
Productivity = V*C*S*B*E*adjustment factor for trench = 1.72 (m
3
) * 160 (c/h) * 1.33*
1.1* 0.63* 0.95
Productivity= 240.97 (m
3
/h) for medium sized excavator
4
Total amount of time needed to excavate the trench= 10000 (m
3
)/ 240.97 (m
3
/h) = 41.50 h
Total to be paid for the small excavator= 41.50 (h)* 210 ($) = 8,715 $
$ 8,715 < $ 9,224.4, So the medium sized excavator is better for these circumstances.
D. N
ON
-C
ALCULATIVE
Q
UESTION
Which of the following statements is NOT
correct regarding earthwork excavating
equipment?
A.
The three criteria to select the proper shovel: Maximum depth needed, working radius,
and dumping height.
B.
Heaped volume is the maximum volume that can be placed in the bucket without spillage
based on the material’s angle of repose.
C.
Maximum productivity of a dragline is obtained with a minimum swing angle.
D.
Shovels are good for above track level conditions and cannot operate and dig below track
level. Solution: The correct answer is A.
The three selection criteria indicated in the option A are applicable to a hydraulic
excavator but not to a shovel.
3)
LIFTING EQUIPMENT
E. C
ALCULATIVE
Q
UESTION
The maximum lifting capacity of a tower crane rigged with two-part line is 27,600 lb and the
maximum hoist speed is 100 fpm, within the structural capacity constraints of the tower and
jib configuration. For the same tower crane and jib configuration, what is the maximum
lifting capacity and speed for a four-part line.
A.
55,200 lb and 50 fpm
B.
55,200 lb and 100 fpm
C.
27,600 lb and 100 fpm.
D.
Unknown, more information required.
5
Sol. The correct answer is A.
The maximum lifting capacity of the crane is increased by 100% with four-part-line
configuration and the increased lifting capacity is accompanied by loss of 50% in vertical
hoist speed. [Peurifoy, R.L. “Chapter-17: Cranes, p. 565” in Construction Planning,
Equipment, and Methods, 7th Edition, McGraw-Hill Publications, Montreal, 2018.]
As such,
27,600 lb x 2 = 55,200 lb
100 / 2 = 50 fpm.
The maximum lifting capacity of tower crane with four-part line is 55,200 lb and the
maximum hoist speed is 50 fpm.
F. N
ON
-C
ALCULATIVE
Q
UESTION
Which of the following is true about two-part-line and four-part-line configurations of a
tower crane?
A.
When operating radius is less than 90 feet, the crane has a greater lifting capacity with a
two-part-line than the four-part-line arrangement.
B.
When operating radius is greater than 90 feet, the capacity of hoisting system controls the
load-lifting capacity
C.
When operating radius is less than 90 feet, the structural capacity of crane controls the
load-lifting capacity.
D.
When operating radius is greater than 90 feet, the crane has a greater lifting capacity with
a two-part-line than the four-part-line arrangement.
6
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Solution: The correct answer is D.
When the operating radius of a tower crane is less than 90 feet, a four-part line has more
lifting capacity than a two-part line. When the operating radius is greater than 90 feet, the
converse is true.
When the operating radius is greater than 90 feet, the structural capacity of the tower
crane controls the load-lifting ability, and when operating radius is less than 90 feet the
hoisting system controls the load-lifting ability.
4)
LOADING AND HAULING – PART 1
G. C
ALCULATIVE
Q
UESTION
Calculate the Max. Usable Pull for a vehicle with a weight of 12 tons, moving on a road with
a grade of 5%, a penetration of 3 cm, and at an altitude of 1000 meters. Assume a coefficient
of traction of 0.85. A.
11.5 tons
B.
10.2 tons
C.
6.5 tons
D.
17.9 tons
Solution: The correct answer is B.
1.
Calculate Rolling Resistance Factor: Rolling resistance factor (Kg/t)=20+(6×penetration)
Rolling resistance factor (Kg/t)=20+(6×3)=38 Kg/t
2.
Calculate Grade Resistance Factor: Grade Resistance factor (kg/t)=10×grade (%)
Grade Resistance factor (kg/t)=10×5=50 kg/t
3.
Calculate Grade Resistance: Grade resistance (Kg)=Vehicle weight (t)×Grade Resistance factor (Kg/t)
Grade resistance (Kg)=12×50=600 Kg
4.
Calculate Effective Grade: Effective Grade(%)=Grade (%)+Rolling Resistance factor (Kg/t)10
Effective Grade (%)=5+3810=8.8%
5.
Calculate Derating Factor:
7
Derating Factor (%)=Altitude (m) - 915×10−2
Derating Factor (%)=(1000−915)×10−2=8.5%
6.
Calculate Max. Usable Pull: Max. Usable Pull=Coefficient of traction×Weight on driving
wheels
Max. Usable Pull=0.85×12=10.2 tons
Therefore, the Max. Usable Pull for the given conditions is 10.2 tons.
H. N
ON
-C
ALCULATIVE
Q
UESTION
What is the significance of the "Coefficient of Traction" in determining a vehicle's maximum
usable pull?
A.
It represents the vehicle's total weight
B.
It indicates the force exerted at the rim of each driving wheel
C.
It influences the vehicle's pulling capability on different surfaces
D.
It measures the vehicle's horsepower
Sol. The correct answer is C.
The coefficient of traction is crucial because it influences how well a vehicle can grip
different surfaces. A higher coefficient means better traction, allowing the vehicle to exert
more force and pull heavier loads, especially on surfaces with lower friction. This directly
impacts the vehicle's pulling capability on various terrains.
8
5)
LOADING AND HAULING – PART 2
I.
C
ALCULATIVE
Q
UESTION
Determine how many dozers are needed to spread a stockpile of 15.50 m3 into a ditch with a
distance of 75 m. The crawler Dozer has a 5.40 LCM rated blade capacity and the highest
reverse speed of 6 kilometres per hour. Consider the management condition and the job
condition on the construction site are good and fair respectively. The bucket fill factor is 1.
A. 4
B. 8
C. 11 D. 9
Sol. The correct answer is B.
With regards to a stockpile, we concluded that it is in loose condition and consider it as loose
material. With regard to the highest reverse speed, we consider the crawler loader as a
direct drive transmission. Then the fixed time is 0.10. (Typical Dozer Cycle Times Table) The total C is the sum of C variable and the C fix. The C variable is the sum of doze and return.
Formula for this is DISTANCE over SPEED.
C variable doze is equal to 75 / 4*16.67 = 1.124
C variable return is equal to 75/ 6*16.67 = 0.749
C total is equal to 0.10 + 1.124 + 0.749 = 1.973
This is for one cycle, so 60 / 1.973 = 30.41 cycle/hr
The productivity formula is equal to:
P = V * C * E 5.40 * 30.41* 0.69 = 113.30 lcm/min
113.30 / 60 =1.88 LCM/ hr.
The number of Dozer = total volume / productivity
Total volume = bucket fill factor * 15.50 = 1 * 15.50 = 15.50
The number of Dozer = 15.50 / 1.88 = 8.24 = 8 Dozer
9
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J. N
ON
-C
ALCULATIVE
Q
UESTION
A construction operation involves spreading of clean granular gravel for creation of
subgrade of 6 metres width for a road. The subgrade has a camber of 1-in-50 (camber is the
cross-slope of the road for effective drainage of rainwater). The following dozer
configurations are available for selection and as a project manager what will be your
recommendation?
A. A dozer with a cushion blade with tilting adjustment
B. A dozer with a universal blade with pitching adjustment
C. A dozer with an angular blade with angling adjustment
D. A dozer with a straight blade with tilting adjustment
Sol. The correct answer is D
A dozer can be used to both excavate and spread soils. Tilting is the adjustment operation
for a dozer blade to achieve cross-slope when spreading or cutting soils. Of all the blades
that are available for a dozer, cushion blade cannot be tilted. Hence, the only choice for the
operation is a dozer with a straight blade with tilting adjustment.
6)
LOADING AND HAULING – PART 3
K. C
ALCULATIVE
Q
UESTION
Estimate the total turnaround distance for a single-engine two-axle tractor based on the following information:
Haul Route (single Pusher)
Down a 5% grade, 500 m
Up a 5% grade, 500 m
Rolling resistance factor= 50 Kg/t
Cycle time per hour= 4.41 min
A. 250 m B. 300 m C. 350 m D.400 m 10
Sol: The correct answer is B
1. Calculate the fixed time from the table for single pusher:
Spot time= 0.3 min
Loading time= 0.6 min
Maneuvering & Dump time= 0.7 min
Fixed total time= 1.6 min
2. Total cycle time= variable time + fixed time
4.41 min= variable time + 1.6
Therefore, variable time= 2.81 min
3. Calculate the effective grade.
Haul: -5 + 50/10 = 0%
Return: 5+ 50/10= 10%
Turnover: 0+ 50/10= 5%
4. Calculate the variable travel time for haul and return.
Haul: 0.8 min (from the loaded graph)
Return: 1.40 min (from the empty graph)
Since 4.41= 0.8 + 1.40 + turnaround time + 1.6
Therefore, turnaround time = 4.41- (0.8+1.4+1.6) = 0.61 min 5. From the empty graph find the turnaround distance using 0.61 min and 5% effective grade.
Therefore, turnaround distance = 300 m
11
L. N
ON
-C
ALCULATIVE
Q
UESTION
What type of scrapers are capable of achieving the highest efficiency in loading without the
assistance of a pusher tractor or another scraper?
A.
Elevating scarpers B.
Single powered axle scrapers C.
Crawler tractor scrapers D.
None of the previous answers
Solution: The correct answer is A
Of all the different types of scrappers available, “only the elevating scraper and the pull-
scraper are capable of achieving high efficiency in loading without the assistance of a pusher
12
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tractor or another scraper”. [ S.W. Nunnally, “Loading & Hauling: Scrappers Operation and
Employment” in Construction Methods & Management, Prentice-Hall Pearson, 8
th
Edition,
2011, P. 64] 7)
COMPACTING, GRADING, FINISHING, RIPPING
M.C
ALCULATIVE
Q
UESTION
A contractor is faced with the decision of selecting between 2 compaction machinery (wheel
tractor towed with tamping foot and a heavy pneumatic). It is known that the sandy soil
weighs 1931.8 kg/BCM. The compacted lift has a thickness of 5 in. One machine has an
effective roller width of 8m, while the other is equipped with a foot roller drum width of
4.5m. The cost per unit for the equipment with foot roller is $490/h, while the other is
$460/h. What is the least cost-effective equipment (unit cost in $/CCM) considering optimal
production?
A.
Wheel tractor towed with tamping foot, $0.48/CCM
B.
Wheel tractor towed with tamping foot, $0.70/CCM C.
Heavy pneumatic with tamping foot, $0.37/CCM D.
Heavy pneumatic with tamping foot, $1.30/CCM Solution: The correct answer is B
The answer is the Wheel tractor towed with tamping foot will be the most economic to choose as the price would be $ 0.70 per m3 compacted.
Step 1: Calculate the density.
= 1.7 gr/cm3
13
Step 2: Number of passes required for the compactor.
Number of passes = 11
Step 3: Estimate the Compactor Production
Wheel tractor towed with tamping foot:
= 698.27 CCM /h
Heavy pneumatic:
= 620.68 CCM /h
14
-
16 km/h and 8 km/h obtained from Table: Typical operating speed of compaction equipment.
-
16 km/h and 8 km/h are chosen because in the statement it mentions optimal production.
Step 4: Calculate Cost per Unit
Wheel tractor towed with tamping foot:
= $ 0.70 / CCM
15
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Heavy pneumatic:
= $ 0.74 / CCM
N. N
ON
-C
ALCULATIVE
Q
UESTION
Which compaction equipment is recommended for a wide range of materials, except for sand, clean, or silty materials?
E. Pneumatic F.
Steel wheel G.
Tamping Foot H. Vibratory
Solution: The correct answer is C
Tamping Foot is the only machine that can be used in varied materials such as rock, gravel, clean or silty, gravel, clayey, sand, clayey silt, clay, sandy or silty and clay heavy; however, this equipment is least effective on sand, clean or silty materials.
[ S.W. Nunnally, “Compaction and Finishing” in Construction Methods & Management, Prentice-Hall Pearson, 8th Edition, 2014, P.85, Figure 10] 16
8)
AGGREGATE PRODUCTION
O. C
ALCULATIVE
Q
UESTION
Concrete is to be produced at 200 cum per hour with a mix design of 1:2:4 (cement: fine
aggregate: coarse aggregate) by weight with a minimum cement content of 400 kg per cum.
The gradation of coarse aggregate is 25mm to 19mm - 70%, 19 to 13mm – 15%, 13 to 10mm
– 15%. Considering open circuit, which of the following crusher closed side setting requires
lowest total feed and yields the above gradation, so that the concrete production is
continuous.
A. 38mm B. 25mm C. 32mm D. 19mm
Sol. The correct answer is B.
Step – 1: Calculate the aggregate required to produce 200 cum of concrete per hour.
Mix design is 1:2:4 by weight and minimum cement quantity is 400 kg per cum
Total quantity of cement = 200 cum x 400 kg per cum => 80000 kg => 80 tonnes per hour
Quantity of coarse aggregate = 4 x Total quantity of cement
=> 4 x 80 tonnes
=> 320 tonnes per hour
320 tonnes per hour of coarse aggregate is required to produce 200 cum of concrete per hour.
Step – 2: Calculate the quantity of different aggregate sizes required.
25 – 19mm = 70% x 320 tonnes per hour => 224 tonnes per hour
19 – 13mm = 15% x 320 tonnes per hour => 48 tonnes per hour
13 – 10mm = 15% x 320 tonnes per hour => 48 tonnes per hour
Step – 3: Select screen sizes required based on aggregate sizes required.
The screen sizes required to yield the gradation in step-2 in the order of their placement in
screen deck are 25mm, 19mm, 13mm, and 10mm.
Step – 4: Select the crusher closed side setting with maximum retainage.
17
The total feed required is lowest when the percentage retained is highest for 25mm to
19mm. Based on the above table, the crusher closed side setting of 25mm yields highest
percent retained as follows:
Screen Size
% passing
25mm
79%
19mm
61%
13mm
41%
10mm
29%
Screen Size
Gradation
% retained
25mm
> 25mm
100 – 79 = 21%
19mm
25mm to 19mm
79 - 61% = 18%
13mm
19mm to 13mm
61 - 41% = 20%
10mm
13mm to 10mm
41% - 29% = 12%
Step – 5: check whether the total feed based on the percentage retained on each screen
is yielding the required output.
25 mm – 19mm:
The percentage of aggregate passing 25mm screen and retained on 19mm screen gives this
grading; the percentage retained on 19mm screen from step – 5 is 18%
Output = Total feed x percentage retained.
224 tonnes per hour = total feed x 18%
Total feed = 224 tonnes per hour / 18% => 1244.45 tonnes per hour
19mm - 13mm:
The percentage of aggregate passing 19mm screen and retained on 13mm screen gives this
grading; the percentage retained on 13mm screen from step – 5 is 20%
Output = Total feed x percentage retained.
48 tonnes per hour = total feed x 20%
Total feed = 48 tonnes per hour / 20% => 240 tonnes per hour
18
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13mm -10mm:
The percentage of aggregate passing 13mm screen and retained on 10mm screen gives this
grading; the percentage retained on 10mm screen from step – 5 is 12%
Output = Total feed x percentage retained.
48 tonnes per hour = total feed x 12%
Total feed = 48 tonnes per hour / 12% => 400 tonnes per hour
Every other crusher closed side setting requires total feed more than 1244.45 tonnes per
hour, as the
percentage of 25mm to 19mm retained is lower than 18%.
P. N
ON
-C
ALCULATIVE
Q
UESTION
Which of the following is the correct sequence of producing aggregate?
A.
Excavation, loading, hauling, crushing, screening, washing, storage.
B.
Excavation, crushing, screening, loading, hauling, washing, storage.
C.
Excavation, crushing, screening, washing, loading, hauling, storage.
D.
Excavation, screening, crushing, washing, loading, storage.
Sol. The correct answer is A.
To produce aggregate, rock or gravel is excavated, loaded into haul trucks, and transported to
the aggregate processing plant. Then the rock or gravel is crushed using rock crushers,
screened, washed using log washers, scrubber drums, etc. and then stored.
9)
CONCRETE FORM DESIGN
Q. C
ALCULATIVE
Q
UESTION
You are the project engineer of a multiple story building project. while preparing the casting
of the first typical floor slab designed for 200 lb/sq. ft, you have decided to lay out the joists
at minimum 30 inches spacing due to the limited formwork material available at site. You
have the choice between actual 1-inch plyform class 1 or actual 1-inch Eastern spruce for the
decking material spanning a single span, which will be satisfactory for the 30-inch joist
spacing? (Assume grains across the supports for the plyform calculations and l/360 for
deflection limit).
19
A.
Plyform class 1 B. Eastern Spruce C. Both of them D. None of them
Sol: The correct answer is B
Step-1: Calculate the design load for joist spacing
We design joist for 1ft X 1ft sheathing.
So, W (lb/ft)= 200 (lb/sq. ft)x 1ft = 200 lb/ft
Step-2: Calculate joist spacing for plyform class 1
Considering the plyform 1” , from table 13-6: d=1”
EI
=
0.641
×
10
6
F
b
KS
=
1.422
×
10
3
F
s
lb
Q
=
0.675
×
10
3
From table 13-5: choosing the plywood equations for 1 span condition:
Bending: l
=
9.8
(
F
b
KS
W
)
1
2
=
9.8
(
1.422
×
10
3
200
)
1
2
=
26.13
in
Shear: l
=
24
(
F
s
lb
Q
W
)
+
2
d
=
24
(
0.675
×
10
3
200
)
+
2
×
1
=
83
in
Deflection (l/360): l
=
1.37
(
EI
W
)
1
3
=
1.37
(
0.641
×
10
6
200
)
1
3
=
20.19
in
From these three values we can choose minimum value 20.19 in but it less than our minimum
requirement 30 in.
So, we cannot use plyform class 1 for above conditions.
Step-3: Calculate joist spacing for Eastern spruce
Considering the Eastern spruce 1 in
From table 13-8: d=1 in, b=12 in (As we assume 1ft x 1ft strip)
E
=
1.2
×
10
6
×
0.97
×
1
=
1.164
×
10
6
F
b
=
1050
×
0.86
×
1.25
=
1128.75
F
v
=
140
×
0.97
×
1.25
=
169.75
and from cross section, A
=
12
×
1
=
12
i n
2
20
I
=
bd
3
12
=
12
×
1
3
12
=
1
in
3
From table 13-5: choosing the wood equations for 1 span condition:
Bending: l
=
4
d
(
F
b
b
W
)
1
2
=
4
×
1
×
(
1128.75
×
12
200
)
1
2
=
32.92
in Shear: l
=
16
F
v
A
W
+
2
d
=
16
×
169.75
×
12
200
+
2
×
1
=
164.96
in
Deflection (l/360) : l
=
1.37
(
EI
W
)
1
3
=
1.37
×
(
1.164
×
10
6
×
1
200
)
1
3
=
53.09
in
From these three spacing we can choose minimum value 32.92 in that is greater than our
minimum requirement 30 in.
So, we use Eastern spruce for above conditions.
R. N
ON
-C
ALCULATIVE
Q
UESTION
Based on the following statements select the correct option.
I.
Initial cost is high for conventional formwork and low for industrialized formwork.
II.
Only wood used for conventional formwork and steel used for industrialized formwork.
III. Conventional and Industrialized formwork both can be handle by manually or
mechanically.
IV.
Conventional and Industrialized formwork both can be reuse.
A. I & III
B. II & IV
C. II
D. None of them Sol: The correct answer is D
I. False because Initial cost is high for industrialized formwork and low for conventional
formwork.
II. False because traditionally wood is used for conventional formwork, also steel may be
used for that. Similarly, mainly steel is used for industrialized formwork, also plywood
and wood may be used.
III. False because conventional formwork can be handled by manually and Industrialized
formwork handle by mechanically.
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IV. False because conventional formwork is non repetitive concrete elements and
industrialized formwork is repetitive concrete formwork.
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10)
CONCRETE PRODUCTION S. C
ALCULATIVE
Q
UESTION
Concreting of an element in a location exposed to freezing & thawing in a moist condition is
to be done based on the mix design 1:2:4 by weight (Cement: Fine Aggregate: Coarse
Aggregate). Which of the options is the correct quantity of water required (in kgs) for
producing 1 cum of concrete based on the following information:
Specific gravity of water – 1
Minimum quantity of cement – 350 kg per cum of concrete
Specific gravity of cement – 3.15
Specific gravity of fine aggregate in saturated surface dry condition – 2.65
Specific gravity of coarse aggregate in saturated surface dry condition – 2.65
Moisture content of fine aggregate – 5% Excess
Weight of representative sample of coarse aggregate in oven dry condition - 40 Kg
Weight of representative sample of coarse aggregate in saturated surface dry condition – 48 Kg
Weight of representative sample of coarse aggregate in field – 45 Kg.
A.
157.50 kg B. 227.50 kg C. 297.50 kg D.17.50 kg
Sol.
The correct answer is B The questions require us to calculate the quantities of concrete component required to
produce 1 cubic metre of concrete.
Step – 1: calculate the quantity of cement.
The quantity of cement required = 350 kg
Step – 2: Calculate the quantity of fine aggregate required
.
As the mix design specifies 1:2:4 ratio by weight,
Quantity of fine aggregate required = 2 x weight of cement quantity
=> 2 x 350 kg
=> 700 kg
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Step – 3: Calculate the quantity of coarse aggregate required
.
As the mix design specifies 1:2:4 ratio by weight,
Quantity of coarse aggregate required = 4 x weight of cement quantity
=> 4 x 350 kg => 1400 kg
Step – 4: Calculate the quantity of water required
.
As the concrete element is exposed to freezing & thawing in a moist condition, the water-
cement ratio from Table 7-4 is 0.45, Quantity of water required = 0.45 X cement quantity => 0.45 x 350 kg
=> 157.50 kg
Step – 5: Calculate excess water based on fine aggregate moisture content
.
Excess moisture content of fine aggregate is 5%.
Excess water in sand = 700 kg x 0.05 => 35 kg
Step – 6: Calculate excess/ less water based on coarse aggregate moisture content
.
Weight of coarse aggregate sample in oven dry condition = 40 kg
Weight of coarse aggregate sample in saturated surface dry condition – 48 kg
Weight of coarse aggregate sample in field condition – 45 kg
Moisture content (%) for SSD = weight
∈
SSD condition
−
weight
∈
ovendry condition
weight
∈
ovendry condition
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=> 48
−
40
40
=> 20%
Moisture content (%) in field = weight
∈
field condition
−
weight
∈
ovendry condition
weight
∈
ovendry condition
=> 45
−
40
40
=> 12.50 %
Water absorption of coarse aggregate to achieve SSD conditions = 20% - 12.50% =>
7.50%
In other terms, the pores of coarse aggregate in field condition are not in surface dry
condition, and water equal to 7.50% by weight of coarse aggregate will not be available for
hydration.
Water required to achieve SSD conditions for coarse aggregate = 7.50% x 1400 kg
=> 105 kg
Step – 7: calculate field mix quantities of water.
Adjusted water quantity = Original water quantity – excess water from fine aggregate + water required to achieve SSD condition of coarse aggregate => 157.50 kg – 35 kg + 105 kg
=> 227.50 kg
T. N
ON
-C
ALCULATIVE
Q
UESTION
Which of the following types of cement is recommended for using in production of concrete
that is planned to be used in cold-weather conditions?
A.
Type – I B. Type – III C. Type – IV D. Type - II
Sol. The correct answer is B Of the 5 types of cement, type-III cement also known as high early strength cement is
recommended for usage in cold-weather conditions or when early formwork removal is
required, as this cement develops 190% of type – I strength after 1 day of curing.
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