thrust2e

7/27/2019 thrust2e

http://slidepdf.com/reader/full/thrust2e 1/6

THRUST BLOCK DESIGN-WSD THRUST BLOCK TYPE 2

Uncategorised software

All users are responsible for

checking their own calculations.

Version Date

This spreadsheet carries out a design for WSD Type 2 Thrust Blocks.

The details of the calculations here should be read in conjunction with

Technical Note Nr I.1 (Appendix I) of the WSD Technical Manual TM/03

on Pipes and Pipelines.

Data is entered into the blue boxed cells (unprotected) in the worksheet THRUST2

General Design Parameters, such as soils data etc, are entered in cells E16:E25

Case parameters such as Pipe diameter, test pressure, bend angle, pipe cover are

entered into the design table K37:N61

Notes

1 The formula for pipe OD applies to ductile iron pipes. This will be good enough

for pipes with OD up to 5% greater than the nominal diameter.

For other pipes, eg AC Class 18,24 etc and PCP pipes, the formula in cell P38

should be amended. For AC pipes copy the formula from the cells below P38.

2 Dimension A is now defined as the chord length across the outside of the bend.

Previously it was the chord length on the bend centre line plus a bit.

This in fact makes little difference to the block design overal.

Dimension A may be changed by adjusting the formulae in cells E52: E53

3 Derivation added for formula used for solution , See Columns M-T of this sheet

4 In the EXCEL version, the formulae in column G are merely labels and have been typed in longhand.

In the LOTUS version, the formulae are the ones actually used to calculate the values.

REVISION RECORD

180419042.xls.ms_office Thrust2*.xls 10/15/2013

7/27/2019 thrust2e


Derivation of Formulae

VOLUME of BLOCK

Centre middle - rectangular =A.(B-A)/2.Z

Centre- top & bottom +A.(B-A)/2/2.(H-Z).

Ends - middle +(B-A).Z/2.(B-A)/2

Ends -top & bottom +(B-A).(H-Z)/3.(B-A)/2

Face +B.H.Lf2

Bit around Pipe +Vol3

Total Volume VolT= A.B.Z/2-A 2̂.Z/2+A.B.H/4-A 2̂.H/4-A.B.Z/4+A 2̂.Z/4+B 2̂.Z/4-A.B.Z/2+A 2̂.Z/4

+B^2.H/6-B^2.Z/6-A.B.H/3+A.B.Z/3+A^2.H/6-A^2.Z/6+B.H.Lf2+Vol3

= B^2.[Z/4+H/6-Z/6]

+B.[A.Z/2+A.H/4-A.Z/4-A.Z/2-A.H/3+A.Z/3+H.Lf2]

+[-A^2.Z/2-A^2.H/4+A^2.Z/4+A^2.Z/4+A^2.H/6-A^2.Z/6+Vol3]

= B^2.[H+Z/2]/6

+B.[(Z-H).A/12+H.Lf2]

+[-(Z+H/2).A^2/6+Vol3]

RESOLVING THRUSTS HORIZONTALL Fs.T=Ys/2.(Kp-Ka).[(CovB+H) 2̂-CovB^2].B+Yc.µ.VolT

Substituting VolT and grouping in terms of coefficients of B^n gives

0= B^2.[ (H+Z/2).µ.Yc/6] =YYB2

+B.[ (Kp-Ka).Ys/2.((CovB+H)^2-CovB^2) =YYB1.2.YYB2

-µ.Yc.(H-Z).A/12

+µ.Yc.H.Lf2]

+[ Yc.µ.Vol3 =YYB0.YYB2

-Yc.µ.(Z+H/2).A^2/6

-Fs.T]

B= -YYB1+SQRT(YYB1^2-YYB0)

+ve root applies

In Block Volume Calculation, (B-A)/2 is always >=0 as clearance between pipe and trench wall

is assumed to be never greater than Lf2.

Pipe cover

ODd

d

2H/3

H/3

Blockcover

SECTION X-X

Ground Level

Z

Lf2=200 min

X

X

B

Face cast against excavation

45

A

PLAN

180419042.xls.ms_office Thrust2*.xls 10/15/2013

7/27/2019 thrust2e


THRUST BLOCK DESIGN - STANDARD WSD THRUST BLOCK TYPE 2

Version & Date All Users are responsible for

checking their own calculation

Project Name: Standard Thrust Block

Description : Anchor Block Type 2 for BendsDesigned by:

Checked by:

Date:

SOIL & GENERAL DATA Suggested Values

for Standard design

Angle of soil friction DegS 30 deg 30

Factor of Safety (Sliding) FS 1.5 1.5

Submerged conditions Sf 0 dry 0=dry 1=submerged

Soil density(non submerged) Ysd 17.5 kN/m3 17.5

Soil sensity (submerged) Yss 9 kN/m3 9

Concrete density Ycd 23 kN/m3 23

Type 2 block parameters

Block Cover CovB 0.3 mDim d at block d2 0.2 m Ht of block above/below pipe

Depth of face before taper Lf2 0.2 m 0.2

Row ref in table ref 0

CASE PARAMETERS

Diameter DNmm 100 mm =INDEX(DATA,REF+1,1)

DN 0.1 m =DNMM/1000

Bend angle DegB 22.5 deg =INDEX(DATA,REF+1,2)

AngB 0.3927 rad =DEGB*PI()/180

Test pressure Pt 9 bar =INDEX(DATA,REF+1,3)

Cover to pipe Cover 1 m =INDEX(DATA,REF+1,4)/1000

CALCULATIONS

Angle of soil friction AngS 0.5236 rad =DEGS*PI()/180

Active Ka 0.333 =TAN(PI()/4-ANGS/2)^2

Passive Kp 3.000 =TAN(PI()/4+ANGS/2)^2

Net Kn 2.667 =KP-KA

Base friction Kb 0.577 =TAN(ANGS)

Pipe outside diameter OD 0.11879 m =$DN*1.0329+0.0155

Copy relevant formula up into OD box 0.11879 DI/GRP =$DN*1.0329+0.0155

0.1131 AC-12 =$DN*1.084+0.0047

0.1155 AC-18 =$DN*1.131+0.0024

0.12 AC-24 =$DN*1.2

Cross sectional area XAP 0.01108 =PI()*OD^2/4

Design thrust Td 3.89187 kN =XAP*PT*100*2*SIN(ANGB/2)

Dimension A Term 1 $E$52 0.07804 m =2*2*DN*SIN(ANGB/2)

(Empirical) Term 2 $E$53 0.14712 m =0.15*COS(ANGB/2)

Sum As 0.22515 m =E52+E53

Round off to nearest 50 A 0.250 m =ROUND(E54*2,1)/2

Effective Soil Density Ys 17.50 kN/m3 =IF(SF=0,YSD,YSS)

Effective concrete Density Yc 23.00 kN/m3 =IF(SF=0,YCD,YCD-9.8)

Depth to pipe centre Ds 1.059 m =COVER+OD/2

Block height at face Y1H 1.13909 m =(DS-COVB)*1.5

Block height at block Y2H 0.51879 m =OD+2*D2_

Block face base depth Z1H 1.43909 m =COVB+Y1H

Soil pressure only

Face Length $E$65 0.1263 m =TD*FS/(KN*YS*(Z1H^2-COVB^2)/2)

180419042.xls.ms_office THRUST2 10/15/2013

7/27/2019 thrust2e


rounded up to nearest 50 Y1B 0.250 m =MAX(ROUND(2*E65+0.049,1)/2,A)

Design with base friction

Area of conc at block YA1 0.01389 m2 =(A-OD/2*SIN(ANGB))*OD/2*COS(ANGB/2)

Volume of concrete at pipe $E$70 0.00588 m3 =YA1*Y2H-PI()*OD^2/8*(A-OD/2*SIN(ANGB/2))

$E$71 0.01226 m2 =D2_*OD/2+(OD/2)^2*(1-PI()/4)/2

$E$72 0.00264 m3 =E71*(A-3/2*OD*SIN(ANGB/2))

Vol2A 0.00852 m3 =E70+E72Weight of water at pipe WW 0.01748 kN =DN^2*PI()/4*(A-OD*SIN(ANGB/2))*9.81

Passive soil force YYB11 46.223 kN/m =YS*KN*(Z1H^2-COVB^2)/2

Block wt face YYB12 3.02521 kN/m =KB*YC*LF2*Y1H

bit at pipe YYB01 0.11317 kN =KB*YC*VOL2A

water at pipe YYB02 0.0101 kN =IF(SF=0,KB*WW,0)

taper YYB21 2.40868 kN/m2 =KB*YC*(Y2H+Y1H/2)/6

YYB13 -0.3432 kN/m =-KB*YC*A*(Y1H-Y2H)/12

YYB03 -0.1934 kN =-KB*YC*A^2*(Y2H+Y1H/2)/6

Thrust term YYB04 -5.8378 kN =-TD*FS

Soil cover at block face C1 0.300 m =COVB

Soil cover at pipe C2 0.800 m =COVER-D2_

Quadratic coefficients YYB2 2.40868 kN/m2 =YYB21

YYB1 10.1518 kN/m =(YYB11+YYB12+YYB13)/2/YYB2

YYB0 -2.4528 kN =(YYB01+YYB02+YYB03+YYB04)/YYB2

Final Block Details

Dimension B $E$91 0.250 m =MAX(-E88+SQRT(E88^2-E89),A)

Round up B 0.250 m =ROUND(2*E91+0.049,1)/2

Taper length TL 0 m =(B-A)/2

top slope 1 in 0 =TL/(COVER-COVB-D2_)

Volume $E$96 0.05695 m3 =B*Y1H*LF2

$E$97 0 m3 =TL/3*(B*Y2H+A*Y1H+(B*Y1H+A*Y2H)/2)

Vol22 0.06548 m2 =E97+E96+VOL2A


7/27/2019 thrust2e


Project Name: Standard Thrust Block

Description : Anchor Block Type 2 for Bends

Applicability and principal design parameters

Pipes with OD not greater than DN + 5%, eg DI, GRP OD = OD adopted for calculations

Granular soils, Hb = Height of thrust block overall

(Passive-Active) pressure integrated over height of block A = width of thrust block at pipe

B = width of thrust block at face

Angle of soil friction 30 degrees If top slope > 1in3 then consider Type 1 Block

Factor of safety 1.5 If Dim B > 5 m then consider increase in pipe cover

Cover to block 300 mm or a special design

Submerged conditions dry

Soil density(non submerged) 17.5 kN/m3

Soil sensity (submerged) 9 kN/m3

Concrete density 23 kN/m3

DESIGN TABLE RESULTS

Nom Bend Test Pipe Row Block Dimensions

Dia Angle Press Cover Ref OD Thrust H A B Volume top slope

mm deg bar mm mm kN mm mm mm m3 1 in

100 22.5 9 1000 0 119 3.9 1139 250 250 0.065 0.0

100 45 9 1000 1 119 7.6 1139 300 300 0.078 0.0

100 90 9 1000 2 119 14.1 1139 400 450 0.120 0.1

150 22.5 9 1000 3 170 8.0 1178 250 250 0.071 0.0

150 45 9 1000 4 170 15.7 1178 350 500 0.160 0.2

150 90 9 1000 5 170 29.0 1178 550 850 0.308 0.3

200 22.5 9 1000 6 222 13.6 1217 300 400 0.132 0.1

200 45 9 1000 7 222 26.7 1217 450 750 0.289 0.3

200 90 9 1000 8 222 49.3 1217 650 1350 0.665 0.7

250 11.25 9 1000 9 274 10.4 1255 250 300 0.103 0.1

250 22.5 9 1000 10 274 20.7 1255 350 550 0.208 0.2

250 45 9 1000 11 274 40.5 1255 500 1050 0.497 0.6

250 90 9 1000 12 274 74.9 1255 800 1850 1.149 1.1

300 11.25 9 1000 13 325 14.7 1294 250 400 0.153 0.2

300 22.5 9 1000 14 325 29.2 1294 400 750 0.331 0.4

300 45 9 1000 15 325 57.3 1294 600 1350 0.756 0.8

300 90 9 1000 16 325 105.8 1294 950 2450 1.924 1.5400 11.25 9 1000 17 429 25.5 1371 300 600 0.277 0.3

400 22.5 9 1000 18 429 50.7 1371 450 1100 0.626 0.7

400 45 9 1000 19 429 99.4 1371 750 2100 1.678 1.4

400 90 9 1000 20 429 183.7 1371 1250 3650 4.202 2.4

450 11.25 9 1000 21 480 32.0 1410 350 700 0.354 0.4

450 22.5 9 1000 22 480 63.6 1410 500 1300 0.837 0.8

450 45 9 1000 23 480 124.8 1410 850 2450 2.257 1.6

450 90 9 1000 24 480 230.6 1410 1400 4250 5.751 2.9

Lf2=200 min

X

X

B

Face cast against excavation

45 A

J

PLAN

Pipe cover

OD

d

d

2H/3

H/3

Blockcover

SECTION X-X

Ground Level


7/27/2019 thrust2e



thrust2e

Documents

Transcript of thrust2e