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Aapni Yojna Water Supply Project Thrust Blocks

Consultant Saraswati Technical Services (P) Ltd. Contractor NCC Ltd.

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PUBLIC HEALTH ENGINEERING DEPARTMENT, RAJASTHAN

AAPNI YOJANA II : RATANGARH SUJANGARH SECTION

DESIGN DOCUMENT SUBMISSIONS

SUBMISSION DETAILS

Project Aapni Yojana Phase II Ratangarh Sujangarh Section

Submission No AYPhII/TB/01

Document Design Report for Thrust Blocks for Aapni Yojna-II Ratangarh Sujangarh Section

Submission Date 12-03-2014 Revision No R0

SUBMITTED TO

SUPERINTENDING ENGINEER, PHED, PMC CIRCLE, CHURU, RAJASTHAN

SUBMITTED BY

NCC LIMTED,

W&E DIVISION, MADHOPUR HYDERABAD - 500081

CONSULTANTS

SARASWATI TECHNICAL SERVICES,

C-133, BAPU NAGAR, JAIPUR PIN-302015 TEL : 0141-2708469, FAX : 0141-4038133

E-MAIL : [email protected]


Consultant Saraswati Technical Services (P) Ltd. Contractor NCC Ltd.

SUBMISSION NO

Project Aapni Yojana Phase II Ratangarh Sujangarh Section

Submission No AYPhII/TB/01

Document Design Report for Thrust Blocks for Aapni Yojna-II Ratangarh Sujangarh Section

Submission Date 12-03-2014 Revision No R0

DOCUMENTS ATTACHED

Document No Document Details

AYRS/TB/01/DD-01 Design Report

AYRS/ TB /01/DN-02 Thrust Block Design Sheet for following cases

Pipe Classification Working Pressure

Angle of Bend

700 mm MS 6.0 Kg/sqcm

10, 16, 22, 30, 45,60, 75, 90 Degrees


10, 16, 22, 30, 45,60, 75, 90 Degrees


10, 16, 22, 30, 45,60, 75, 90 Degrees

400 mm DI 8.0 Kg/sqcm

11.25, 22.5, 45, 90 Degrees


11.25, 22.5, 45, 90 Degrees


11.25, 22.5, 45, 90 Degrees

AYRS/ TB /01/DN-03 Detailed Drawing and Dimensions of Thrust Blocks for MS Pipe

AYRS/ TB /01/DN-04 Detailed Drawing and Dimensions of Thrust Blocks for DI Pipe

REVISION HISTORY

Rev No Submission Date

Details

R0 12-03-2014


Page 1 of 12

Name of Project: PMC Phase-II, Ratangarh-Sujangarh Section Client: Additional Chief Engineer, Public Health Engineering

Department, Region Churu

Document Name: Design of Thrust Blocks

1. Theory

The Horizontal thrust at the bend is given by T = 2 P x A x Sin /2

Where T - Horizontal Thrust at the Bend P - Internal Pressure A - Internal area of Pipe - Deviation Angle

Thrust blocks for DI pipes, having rubber gasket be flexible shall be designed for free joints, thrust calculated, as above, with safety factor of 1.5 MS pipes having welded joints shall be designed for half the thrust as per following provisions of CPHEEO manual. CPHEEO Manual of Water Supply have provisions in Clause 6.16.18 at Page No 61 for MS pipe anchorage and is reproduced below;

Where steel pipes with welded joints are used, full anchorage is not generally necessary, since the longitudinal continuity of the pipe is capable of distributing the forces into the ground. If the pressures are high enough to merit it and sleeve joints are being used, the joints on the bends and on two pipes either side of them should be fully welded inside & outside and the trench is refilled with concrete to 150 mm above these pipes and bends. About half of thrust will be taken by the weight of the concrete and the remainder by the longitudinal stresses in the pipe.


Page 2 of 12

Accordingly, for design of Thrust Blocks for MS pipes, the concrete block sizing is done adopting half of the unbalanced horizontal thrust. For DI pipes, having flexible joints, TB would be designed for 100% value of thrust block.

The passive soil reaction against the concrete is Pp = 0.5 (H12- H22) l2 Tan2 (45 + /2)

Where

= Specific weight of soil N/m3 Pp = Passive soil reaction, N H1 = Distance from GL to Concrete block base, m H2 = Distance from GL to Concrete block top, m l2 = Width of concrete block in contact with soil, m

Friction resistance Fr = (WTB + Wp+ We) x

Where Wtb - Weight of Thrust Block Wp - Weight of Pipe & Water We - Weight of Soil above Thrust Block - Coefficient of friction between soil & Concrete This passive soil reaction and friction resistance of thrust block combined resist the horizontal thrust.

Total Resistance = Pp + Fr The Factor of Safety which is ratio of Total resistance to unbalanced horizontal Thrust shall be more than 1.5 Moreover, the width of block shall be such to satisfy the criteria of Safe Bearing Capacity.

2. Provisions regarding Thrust Blocks in Tender Document

i. Clause 4.4 (XXII), Page No XXXVI Providing thrust blocks at vertical and horizontal bends, for the combination of loads as per site conditions of each thrust block for deflections exceeding 4 degrees in vertical/ horizontal alignment. ii. Clause 4.21, Page No CXLIII It is proposed to provide anchorage in the form of thrust block at each deflection in horizontal as well as in vertical alignment of the pipeline as per requirement of designs, which shall resist the unbalanced pressure at bends. Gravity type of thrust blocks shall be provided at horizontal and vertical deflection in pipeline and shall be designed according to the test pressure and the soil conditions at the site of the thrust block. The thrust shall be according to the field test


Page 3 of 12

pressure of the pipe, acting on the outer diameter including the compressed rubber gasket. Before designing the thrust block the Contractor, in coordination with the Engineer-in-Charge shall assess the stability of the soil considering erosion due to wind and water. The thrust blocks shall be of concrete M15 or grade as specified in IS 456, cast on site with surface reinforcement of about 5 kg/m2. The calculations for the dimensioning and the shape of the thrust blocks have to be approved by the Engineer-in-Charge. Design of thrust block shall be done in accordance to the provisions laid down in IS 5330-1984.

iii. Clause 4.11.2, Page No CLXVV Thrust blocks shall be provided at each bend, tee, taper, end piece to prevent undue movements of the pipeline under pressure. They shall be constructed as per actual design and approval of Engineer in Charge according to the highest pressure during operation or testing of the pipes, the safe bearing pressure of the surrounding soil and the friction coefficient of the soil. Nominal steel shall be provided as per the provisions of CPHEEO manual and the construction of block shall be done in M15 grade of concrete.

iv. Clause 4.51, Page No CLXXX For construction of Valve Chambers, Anchor blocks and pedestal support, M20 grade of concrete shall be used. The thrust blocks shall be constructed using M-15 grade of concrete. The leveling course, wherever provided shall be of M10 grade. v. Clause 4.52, Page No CLXXXII It is proposed to provide anchorage in the form of thrust block at each deflection in horizontal as well as in vertical alignment of the pipeline as per requirement of designs, which shall resist the unbalanced pressure at bends. Gravity type of thrust blocks shall be provided at horizontal and vertical deflection in pipeline and shall be designed according to the test pressure and the soil conditions at the site of the thrust block. The thrust shall be according to the field test pressure of the pipe, acting on the outer diameter including the compressed rubber gasket. Before designing the thrust block the Contractor, in coordination with the Engineer-in-Charge shall assess the stability of the soil considering erosion due to wind and water. The thrust blocks shall be of concrete M15 or grade as specified in IS 456, cast on site with surface reinforcement of about 5 kg/m2. The calculations for the dimensioning and the shape of the thrust blocks have to be approved by the Engineer-in-Charge. Design of thrust block shall be done in accordance to the provisions laid down in IS 5330-1984. The thrust blocks shall be of reinforced cement concrete on site as per design and drawings to be approved by Engineer. There is no need to provide reinforcement for thrust blocks on pipeline of dia. 150 mm and below. Typical drawings of thrust blocks are enclosed in the volume III of the tender document. However, these drawings are for indicative purposes only. The contractor shall submit his own designs and drawings based on the actual site conditions for the approval of the Engineer-in-charge. The thrust blocks shall be cast directly against the undisturbed soil. If this is not possible, the backfilled soil at the contact surface shall be compacted well to full satisfaction of Engineer so that anchor block is not displaced during operation and testing.

3. Pipelines As per TD clause No 4.1 (Page No xxi-xxii), following pipelines are in scope of work under this contract


Page 4 of 12

S.No. Material Diameter Class etc

1 MS 1100 mm 9.0 mm

2 MS 1100 mm 7.1 mm

3 MS 800 mm 7.1 mm

4 MS 700 mm 7.1 mm

5 DI 600 mm K-7

6 DI 500 mm K-7

7 DI 400 mm K-7

4. Design Pressure for Thrust Blocks

Design pressure for the thrust block shall be 1.5 times the maximum working pressure in particular stretch of the pipeline corresponding to the design flow. The following table shows the maximum and minimum working pressure in the pipeline and ranges of working pressure for which thrust blocks have been designed.

Pipe Classification Working Pressure (Kg/sqcm) Design Pressure Range for Thrust Blocks (Kg/sqcm)

Maximum Minimum

MS 1100 mm 15 2 3, 6, 9, 12, 15, 18, 22.5

MS 800 mm 15 5 7.5, 12, 15, 18.75

MS 700 mm 6 2 3, 6, 9

Maximum and minimum design pressure for different diameters DI-K7 pipes are as below:

Pipe Classification Working Pressure (Kg/sqcm) Design Pressure Range for Thrust Blocks (Kg/sqcm)

Maximum Minimum

DI K-7 600 mm 8 2 3,6,9,12

DI 500 mm 8 2 3,6,9,12

DI 400 mm 8 2 3,6,9,12


Page 5 of 12

5. Angle of Bend for Design

MS bends shall be fabricated as per site requirements. In design we have provided angles of 10, 16, 22, 30, 45, 60, 75, 90 degrees. Thrust blocks are designed for these deviation angles. For angles more than 4 degrees and up to 10 degrees, TB designed for 100 deflections. Similarly, for bends falling in between two type designs, TB designed for higher degree bend shall be used and intermediate deviations, deflection shall be adjusted in flexible joints of pipes. DI bends are available in standard degrees of 11.25, 22.5, 45 and 90. Thrust blocks are designed for these deviation angles and different pressure ratings.. For smaller angles and intermediate deviations, deflection shall be adjusted in flexible joints of pipes.

6. Selection of thrust block Type design of thrust block shall be selected for maximum working pressure in a stretch and corresponding field test pressure

7. Design Sheets Sample design calculation sheets, for each size of pipe and degree of bend for maximum pressure is annexed with the report.

8. Design Summary The detailed design sheet for one typical thrust block is attached. The dimensional details of thrust blocks for various MS pipes for different pressure ranges and deviation angles are as follows;

No

min

al

Pip

e

Dia

me

ter

Pip

e

Th

ick

ne

ss

(mm

)

An

gle

of

Be

nd

Wo

rkin

g

Pre

ssu

re

Fie

ld T

est

Pre

ssu

re

He

igh

t o

f th

e

blo

ck

Len

gth

of

blo

ck a

t

cen

tre

on

Pip

e

Sid

e

Len

gth

of

blo

ck o

n t

he

soil

sid

e

Wid

th o

f

blo

ck b

eh

ind

Pip

e

mm mm Degrees Kg/sqcm Kg/sqcm mm mm mm mm

700 7.1 10 2 3 750 200 400 300

700 7.1 16 2 3 750 200 400 300

700 7.1 22 2 3 750 300 600 300

700 7.1 30 2 3 750 400 800 300

700 7.1 45 2 3 800 500 1000 300

700 7.1 60 2 3 800 600 1200 300

700 7.1 75 2 3 900 700 1400 300

700 7.1 90 2 3 900 800 1600 300


Page 6 of 12

No

min

al

Pip

e

Dia

me

ter

Pip

e

Th

ick

ne

ss

(mm

)

An

gle

of

Be

nd

Wo

rkin

g

Pre

ssu

re

Fie

ld T

est

Pre

ssu

re

He

igh

t o

f th

e

blo

ck

Len

gth

of

blo

ck a

t

cen

tre

on

Pip

e

Sid

e

Len

gth

of

blo

ck o

n t

he

soil

sid

e

Wid

th o

f

blo

ck b

eh

ind

Pip

e


700 7.1 10 4 6 750 300 600 300

700 7.1 16 4 6 800 400 800 300

700 7.1 22 4 6 800 500 1000 300

700 7.1 30 4 6 900 600 1200 300

700 7.1 45 4 6 1100 700 1400 300

700 7.1 60 4 6 1300 800 1600 300

700 7.1 75 4 6 1400 900 1800 300

700 7.1 90 4 6 1500 900 1800 300

700 7.1 10 6 9 750 400 800 300

700 7.1 16 6 9 850 500 1000 300

700 7.1 22 6 9 1000 600 1200 300

700 7.1 30 6 9 1100 700 1400 300

700 7.1 45 6 9 1200 1000 2000 300

700 7.1 60 6 9 1700 900 1800 300

700 7.1 75 6 9 1800 1000 2000 300

700 7.1 90 6 9 2000 1100 2200 300

800 7.1 10 5 7.5 900 300 600 300

800 7.1 16 5 7.5 1000 500 1000 300

800 7.1 22 5 7.5 1100 600 1200 300

800 7.1 30 5 7.5 1200 700 1400 300

800 7.1 45 5 7.5 1300 900 1800 300

800 7.1 60 5 7.5 1600 1000 2000 300

800 7.1 75 5 7.5 1700 1100 2200 300


Page 7 of 12

No

min

al

Pip

e

Dia

me

ter

Pip

e

Th

ick

ne

ss

(mm

)

An

gle

of

Be

nd

Wo

rkin

g

Pre

ssu

re

Fie

ld T

est

Pre

ssu

re

He

igh

t o

f th

e

blo

ck

Len

gth

of

blo

ck a

t

cen

tre

on

Pip

e

Sid

e

Len

gth

of

blo

ck o

n t

he

soil

sid

e

Wid

th o

f

blo

ck b

eh

ind

Pip

e


800 7.1 90 5 7.5 1800 1200 2400 300

800 7.1 10 8 12 900 500 1000 300

800 7.1 16 8 12 1000 700 1400 300

800 7.1 22 8 12 1200 800 1600 300

800 7.1 30 8 12 1300 1000 2000 300

800 7.1 45 8 12 1800 1100 2200 300

800 7.1 60 8 12 2200 1200 2400 300

800 7.1 75 8 12 2200 1400 2800 300

800 7.1 90 8 12 2200 1500 3000 300

800 7.1 10 10 15 900 600 1200 300

800 7.1 16 10 15 1300 700 1400 300

800 7.1 22 10 15 1400 900 1800 300

800 7.1 30 10 15 1500 1100 2200 300

800 7.1 45 10 15 1900 1300 2600 300

800 7.1 60 10 15 2200 1400 2800 300

800 7.1 75 10 15 2400 1500 3000 300

800 7.1 90 10 15 2600 1600 3200 300

800 7.1 10 12.5 18.75 1200 600 1200 300

800 7.1 16 12.5 18.75 1400 800 1600 300

800 7.1 22 12.5 18.75 1500 1000 2000 300

800 7.1 30 12.5 18.75 1900 1100 2200 300

800 7.1 45 12.5 18.75 2000 1500 3000 300

800 7.1 60 12.5 18.75 2400 1600 3200 300


Page 8 of 12

No

min

al

Pip

e

Dia

me

ter

Pip

e

Th

ick

ne

ss

(mm

)

An

gle

of

Be

nd

Wo

rkin

g

Pre

ssu

re

Fie

ld T

est

Pre

ssu

re

He

igh

t o

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e

blo

ck

Len

gth

of

blo

ck a

t

cen

tre

on

Pip

e

Sid

e

Len

gth

of

blo

ck o

n t

he

soil

sid

e

Wid

th o

f

blo

ck b

eh

ind

Pip

e


800 7.1 75 12.5 18.75 2500 1800 3600 300

800 7.1 90 12.5 18.75 2600 1900 3800 300

1100 7.1 10 2 3 1200 300 600 300

1100 7.1 16 2 3 1200 400 800 300

1100 7.1 22 2 3 1200 400 800 300

1100 7.1 30 2 3 1200 500 1000 300

1100 7.1 45 2 3 1200 700 1400 300

1100 7.1 60 2 3 1300 800 1600 300

1100 7.1 75 2 3 1400 900 1800 300

1100 7.1 90 2 3 1500 1000 2000 300

1100 7.1 10 4 6 1200 400 800 300

1100 7.1 16 4 6 1200 500 1000 300

1100 7.1 22 4 6 1200 700 1400 300

1100 7.1 30 4 6 1200 900 1800 300

1100 7.1 45 4 6 1400 1200 2400 300

1100 7.1 60 4 6 1600 1300 2600 300

1100 7.1 75 4 6 1800 1400 2800 300

1100 7.1 90 4 6 2000 1500 3000 300

1100 7.1 10 6 9 1200 500 1000 300

1100 7.1 16 6 9 1200 750 1500 300

1100 7.1 22 6 9 1800 700 1400 300

1100 7.1 30 6 9 2000 900 1800 300

1100 7.1 45 6 9 2400 1100 2200 300


Page 9 of 12

No

min

al

Pip

e

Dia

me

ter

Pip

e

Th

ick

ne

ss

(mm

)

An

gle

of

Be

nd

Wo

rkin

g

Pre

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re

Fie

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est

Pre

ssu

re

He

igh

t o

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blo

ck

Len

gth

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ck a

t

cen

tre

on

Pip

e

Sid

e

Len

gth

of

blo

ck o

n t

he

soil

sid

e

Wid

th o

f

blo

ck b

eh

ind

Pip

e


1100 7.1 60 6 9 2500 1300 2600 300

1100 7.1 75 6 9 2600 1500 3000 300

1100 7.1 90 6 9 2800 1500 3000 300

1100 7.1 10 8 12 1200 700 1400 300

1100 7.1 16 8 12 1300 900 1800 300

1100 7.1 22 8 12 1600 1000 2000 300

1100 7.1 30 8 12 2000 1100 2200 300

1100 7.1 45 8 12 2400 1400 2800 300

1100 7.1 60 8 12 2600 1600 3200 300

1100 7.1 75 8 12 2800 1800 3600 300

1100 7.1 90 8 12 2800 2000 4000 300

1100 7.1 10 10 15 1200 800 1600 300

1100 7.1 16 10 15 1500 1000 2000 300

1100 7.1 22 10 15 1800 1200 2400 300

1100 7.1 30 10 15 2000 1400 2800 300

1100 7.1 45 10 15 2400 1700 3400 300

1100 7.1 60 10 15 2600 2000 4000 300

1100 7.1 75 10 15 2800 2100 4200 300

1100 7.1 90 10 15 2900 2300 4600 300

1100 9 10 12 18 1400 800 1600 300

1100 9 16 12 18 1600 1100 2200 300

1100 9 22 12 18 1800 1400 2800 300

1100 9 30 12 18 2000 1700 3400 300


Page 10 of 12

No

min

al

Pip

e

Dia

me

ter

Pip

e

Th

ick

ne

ss

(mm

)

An

gle

of

Be

nd

Wo

rkin

g

Pre

ssu

re

Fie

ld T

est

Pre

ssu

re

He

igh

t o

f th

e

blo

ck

Len

gth

of

blo

ck a

t

cen

tre

on

Pip

e

Sid

e

Len

gth

of

blo

ck o

n t

he

soil

sid

e

Wid

th o

f

blo

ck b

eh

ind

Pip

e


1100 9 45 12 18 2400 2000 4000 300

1100 9 60 12 18 2600 2300 4600 300

1100 9 75 12 18 2800 2500 5000 300

1100 9 90 12 18 2800 2700 5400 300

1100 9 10 15 22.5 1400 1000 2000 300

1100 9 16 15 22.5 1800 1300 2600 300

1100 9 22 15 22.5 2200 1400 2800 300

1100 9 30 15 22.5 2400 1700 3400 300

1100 9 45 15 22.5 2800 2100 4200 300

1100 9 60 15 22.5 2800 2600 5200 300

1100 9 75 15 22.5 3000 2900 5800 300

1100 9 90 15 22.5 3000 3100 6200 300

Similarly, the summary of dimensions of Thrust Blocks for DI K-7 pipes is as given below;

No

min

al

Pip

e

Dia

me

ter

An

gle

of

Be

nd

Wo

rkin

g

Pre

ssu

re

Fie

ld T

est

Pre

ssu

re

He

igh

t o

f th

e

blo

ck

Len

gth

of

blo

ck a

t

cen

tre

of

pip

e a

xis

Len

gth

of

blo

ck o

n t

he

soil

sid

e

Wid

th o

f

blo

ck b

eh

ind

Pip

e

mm Degrees Kg/sqcm Kg/sqcm mm mm mm mm

400 11.25 2 3 500 200 400 300

400 22.5 2 3 600 300 600 300

400 45 2 3 800 400 800 300

400 90 2 3 1000 600 1200 300

400 11.25 4 6 600 300 600 300

400 22.5 4 6 700 500 1000 300


Page 11 of 12

No

min

al

Pip

e

Dia

me

ter

An

gle

of

Be

nd

Wo

rkin

g

Pre

ssu

re

Fie

ld T

est

Pre

ssu

re

He

igh

t o

f th

e

blo

ck

Len

gth

of

blo

ck a

t

cen

tre

of

pip

e a

xis

Len

gth

of

blo

ck o

n t

he

soil

sid

e

Wid

th o

f

blo

ck b

eh

ind

Pip

e


400 45 4 6 900 700 1400 300

400 90 4 6 1300 900 1800 300

400 11.25 6 9 600 400 800 300

400 22.5 6 9 800 600 1200 300

400 45 6 9 1200 800 1600 300

400 90 6 9 1700 1000 2000 300

400 11.25 8 12 600 600 1200 300

400 22.5 8 12 700 900 1800 300

400 45 8 12 1100 1200 2400 300

400 90 8 12 1700 1300 2600 300

500 11.25 2 3 600 250 500 300

500 22.5 2 3 700 350 700 300

500 45 2 3 1000 500 1000 300

500 90 2 3 1200 700 1400 300

500 11.25 4 6 700 400 800 300

500 22.5 4 6 800 600 1200 300

500 45 4 6 1200 800 1600 300

500 90 4 6 1600 1000 2000 300

500 11.25 6 9 700 500 1000 300

500 22.5 6 9 900 800 1600 300

500 45 6 9 1300 1100 2200 300

500 90 6 9 2000 1200 2400 300

500 11.25 8 12 800 600 1200 300


Page 12 of 12

No

min

al

Pip

e

Dia

me

ter

An

gle

of

Be

nd

Wo

rkin

g

Pre

ssu

re

Fie

ld T

est

Pre

ssu

re

He

igh

t o

f th

e

blo

ck

Len

gth

of

blo

ck a

t

cen

tre

of

pip

e a

xis

Len

gth

of

blo

ck o

n t

he

soil

sid

e

Wid

th o

f

blo

ck b

eh

ind

Pip

e


500 22.5 8 12 1100 900 1800 300

500 45 8 12 1600 1200 2400 300

500 90 8 12 2200 1500 3000 300

600 11.25 2 3 700 300 600 300

600 22.5 2 3 800 400 800 300

600 45 2 3 1000 700 1400 300

600 90 2 3 1400 800 1600 300

600 11.25 4 6 800 400 800 300

600 22.5 4 6 1000 700 1400 300

600 45 4 6 1400 900 1800 300

600 90 4 6 2000 1100 2200 300

600 11.25 6 9 1000 500 1000 300

600 22.5 6 9 1200 800 1600 300

600 45 6 9 1800 1100 2200 300

600 90 6 9 2200 1500 3000 300

600 11.25 8 12 1000 700 1400 300

600 22.5 8 12 1400 1000 2000 300

600 45 8 12 2000 1300 2600 300

600 90 8 12 2500 1700 3400 300

1 tb

Documents

design of thrust blocks

dimensions of thrust

half of thrust

deviation angle thrust

t horizontal thrust

thrust block design

ms pipes

di pipes