PROJECT : REPLACEMENT OF POTABLE WATER ASBESTOS
CEMENT MAINS, JUBAIL
Project N°
Contract N°
EPPM Document N°
Rev
AR15-12
PO 7200020600
R1512-CLC-CV-00-001
A
Date
31/10/2012
Sheet
1
6
from
THRUST BLOCK CALCULATION
THRUST BLOCK CALCULATION
REPLACEMENT OF EXISTING ASBESTOS
CEMENT (AC) POTABLE WATER MAINS AT
JUBAIL INDUSTRIAL CITY
A
15/01/2013
REV
DATE
001 / AR 15/12
Issued for review
Designation
HAMDI
KALLEL
NAME
Issued by
VISA
AMINE
BAROUNI
NAME
Verified by
VISA
FATHI
HASNAOUI
NAME
Approved by
10 /12
VISA
THRUST BLOCK CALCULATION
REF: R1512 -CLC-CV-00-001
Rev. A
PAGE: 2/6
CONTENTS
1.
INTRODUCTION................................................................................................................... 3
1.1.
PROJECT DESCRIPTION .............................................................................................................................................. 3
1.2.
DOCUMENT OBJECTIVE ............................................................................................................................................ 3
1.3.
REFERENCES OF DOCUMENTS ................................................................................................................................ 3
1.4.
CODES AND STANDARDS ........................................................................................................................................... 3
2. BASIC HYPOTHESIS ............................................................................................................. 3
2.1.
CONCRETE ............................................................................................................................................................... 3
2.2.
CHARACTERISTICS OF THE GROUND ......................................................................................................... 3
2.3.
CHARACTERISTICS OF THE PIPELIGNE ..................................................................................................... 3
3. APPLIED LOADS .................................................................................................................... 4
4. THRUST BLOCK VERIFICATION....................................................................................... 4
4.1.
HORIZONTAL BEND -TYPE1- ................................................................................................................................... 4
4.2.
UPWARD VERTICAL BEND-TYPE2- ......................................................................................................................... 5
4.3.
DOWNWARD VERTICAL BEND-TYPE3- .................................................................................................................. 6
4.4.
REDUCERS -TYPE4- ................................................................................................................................................ 6
002/AR15/12
10/12
REF: R1512 -CLC-CV-00-001
Rev. A
PAGE: 3/6
THRUST BLOCK CALCULATION
1.
INTRODUCTION
1.1. PROJECT DESCRIPTION
The project consists of the replacement of the existing asbestos cement (AC) potable water mains at Jubail
industrial city with new pipes of approved material along the same alignment and to the same level of existing water
mains.
The site of the project is located at the west bank of the Arabian Golf, 112km north of Dhahran, in eastern
province of KSA(27° 2’ 24” North, 49° 22’ 12” East).
1.2. DOCUMENT OBJECTIVE
The scope of this report is the calculation and the verification of the thrust block.
1.3. REFERENCES OF DOCUMENTS
Document Title
Document no.
PHASE 1 - THRUST BLOCK DETAILS
7200020600-JWDF-CE-025
1.4. CODES AND STANDARDS
AWWA M23 PVC Pipe-Design and Installation.
AWWA M45 Fiberglass Pipe Design Manual.
AWWA M55 PE Pipe-Design and Installation
2.
BASIC HYPOTHESIS
2.1. CONCRETE
Density of block material
γ c =2, 2 T/m3
2.2. CHARACTERISTICS OF THE GROUND
Soil bearing capacity
S b = 2 daN/cm²
Unit weight of soil
γ s = 1800 kg/m3
Soil internal friction angle
φ = 30 degree
Cohesion
Cs = 0 kN/m2
2.3. CHARACTERISTICS OF THE PIPELIGNE
Design pressure
002/AR15/12
P = 16 bar
10/12
THRUST BLOCK CALCULATION
3.
REF: R1512 -CLC-CV-00-001
Rev. A
PAGE: 4 / 6
APPLIED LOADS
Pipeline thrust shall be calculated using the following formulas.
-
Pipeline thrust at bends:
T = 2PA sin ∆/2
where:
T = resultant thrust force
P = internal pressure
A = internal area based on the diameter of the sealing element
∆ = angle of deflection
-
Pipeline thrust at reducers:
T = P(A-A’)
where:
T = resultant thrust force
P = internal pressure
A = area of pipe adjacent to the large end of the reducer
A’ = area of pipe adjacent to the small end of the reducer
4.
THRUST BLOCK VERIFICATION
4.1. HORIZONTAL BEND -TYPE1-
For horizontal bends, the required thrust block bearing area can be calculated by the following equation:
Area / (
Where:
) ≤ (SF)
Area = area of thrust block
SF = safety factor (suggest 1.5)
A passive resistance thrust block design is required if the height of the thrust block is greater than 0.5 times the depth
from finish grade to the bottom of the designed thrust block.
The required thrust block area using this method can be calculated as follows:
001/AR15/12
04 /10
REF: R1512 -CLC-CV-00-001
Rev. A
PAGE: 5 / 6
THRUST BLOCK CALCULATION
)
Area /(
Where:
≤ (SF)
Area = area of thrust block
SF = safety factor (suggest 1.5)
H t = total depth to bottom of block
N d = tan² (45°+ φ /2)
∆
(°)
11.25
22.5
45
90
Diam
(mm)
a
(mm)
b
(mm)
c
(mm)
h
(mm)
H min
(mm)
T
(T)
h/Ht
Bearing area
check
300
450
600
800
300
450
1200
300
450
600
300
600
800
2000
1000
800
800
1600
800
1200
1400
1200
800
800
4100
1500
800
1000
2800
2000
2500
2500
2200
800
1000
1800
1500
1000
1500
2500
1200
1600
2200
1200
1000
1500
1000
2000
1500
2000
3500
1500
2000
2800
1700
1000
1500
500
1500
1500
1700
2000
1000
1200
1500
1500
2.22
4.99
8.87
15.77
4.41
9.93
70.61
8.66
19.48
34.62
15.99
> 0.5
> 0.5
> 0.5
> 0.5
> 0.5
> 0.5
> 0.5
> 0.5
> 0.5
> 0.5
> 0.5
_
_
_
_
_
_
_
_
_
_
_
Passive
resistance
check
2.25
2.14
4.35
1.86
2.35
2.15
1.83
1.99
1.99
2.14
1.72
4.2. UPWARD VERTICAL BEND-TYPE2-
Gravity thrust blocks are designed so that the weight of the block offsets the unbalanced upward force in the vertical
direction.
V.(γ c /T) ≥ (SF) = 1, 5
∆
(°)
11.25
001/AR15/12
Diam
(mm)
300
350
450
600
1200
b
(mm)
1300
1600
1800
2200
3600
c
(mm)
1300
1600
1800
2200
4000
h
(mm)
1000
1000
1200
1300
2000
H min
(mm)
1000
475
700
1500
700
T
(T)
2.22
3.02
4.99
8.87
35.47
V.(γ c /T)
1.7
1.9
1.7
1.6
1.8
04 /10
REF: R1512 -CLC-CV-00-001
Rev. A
PAGE: 6 / 6
THRUST BLOCK CALCULATION
4.3. DOWNWARD VERTICAL BEND-TYPE3-
The thrust block should be an adequate size to ensure that the bearing strength of the soil is not exceeded.
The equation of the required thrust blocks bearing area:
Area / (
) ≤ (SF)
∆
(°)
11.25
Diam
(mm)
150
300
350
450
600
1200
b
(mm)
450
1000
800
1000
1000
2000
c
(mm)
600
600
1200
1200
1200
1500
h
(mm)
225
400
500
400
500
1200
H min
(mm)
3175
1500
1675
1400
1500
1800
T
(T)
0.55
2.22
3.02
4.99
8.87
35.47
Bearing area
check
9.7
5.4
6.4
4.8
2.7
1.7
4.4. REDUCERS -TYPE4-
D1/ D2
(mm)
350/300
800/450
1200/800
001/AR15/12
b
(mm)
2100
3000
3500
c
(mm)
800
2000
2200
h
(mm)
1000
2400
3000
H min
(mm)
600
3000
3000
T
(T)
4.08
54.98
100.53
h/Ht
>0.5
>0.5
>0.5
Bearing
area check
_
_
_
Passive resistance
check
2.78
2.61
2.03
04 /10