DESIGN OF WATER PIPELINE CROSSING ETIHAD RAIL

Project Location:

Date: 22-11-2014

Client: Etihad Rail

Contractor: Al Salmeen General Contracting LLC

Scope:

This design report comprises the design of water pipeline crossing the proposed Railway Track at west Samha. The pipeline is designed as per the guideline provided by the Client. (Appendix C). The crossing arrangement must be so designed to withstand the load imposed by the rolling stock.

Design Criteria:

The Design Calculations have been based on AWWA (American Water Works Association) Standards.

General:

The basis of design is to encase the ϕ600 carrier pipe in 1000ϕ GRC casing pipe, to be enclosed in Reinforced concrete to withstand the dead and live loads imposed by the train operation. The space between carrier pipe and casing pipe will be pressure grouted later on in order to provide it stability. The minimum depth of the

pressure grouted later on in order to provide it stability. The minimum depth of the RCC protection system is kept 2.3 m from the reduced ground level, as our crossing is lying in the area where the existing ground level is above the proposed cut level of the railroad.

2. Loading

2.1 Material densities

The following material densities are used to calculate the dead load of the members.

Reinforced Concrete = 2400 kg/m3

Rail = 70 kg/lm

Concrete Sleepers ( 2 m long) = 335 kg

Ballast = 1200 kg/m3

Backfill material = 19 kN/m3

2.2 Live Load

The crossing is designed to withstand the axle load of Cooper E80 loading. The details or this loading are shown in Figure 1.

Figure 1

Design consideration in GRP Casing Pipe

Allowable defelection from ring beding

Mean Pipe Diameter ≔D 1000 mm

Shape Factor ≔Df 4.5 ≔E 17 GPa

structural wall thikness ≔t 14.2 mm

thickness of liner ≔tL 1 mm

total thickness =≔tt +t tL 15.2 mm

Long term Ring bending strain, mm/mm ≔Sb %1.3

Fig 1

Design Factor ≔FS 1.5

Maximum ring bending strain due to deflection =≔εb ――Sb

FS0.009 ⋅――

1

mmmm

Maximum allowable vertical pipe deflection =≔∆ya ⋅⋅―εb

Df

D ―D

tt126.706 mm

Calculation of prediced vertical pipe declection , ∆y

Deflection Log Factor ≔DL 1.5

Soil Unit Weight ≔γ 19 ――kN

m3

Overburden Depth ≔H 3.05 m

Dead Load =≔WC ⋅γ H 57.95 kPa

Wheel Load Cooper E 80 ≔P 39 kPa Table 5-2

Impact factor =≔If +1 ⋅0.33⎛⎜⎝―――――(( −2.44 m H))

2.44 m

⎞⎟⎠

0.918

≔If 1

Multiple presence Factor ≔Mp 4

Live Load =≔WL ⋅⋅P If Mp 156 kPa

Bedding Coefficient ≔Kx 0.083

Pipe Stiffness ≔PS 5 kPa

Constrained soil modulus of the native soil at pipe elevation

≔Msn 10.3 MPa

≔Bd 1.25 m

Constrained soil modulus of the pipe zone embedment

≔Msb 29 MPa

'

=――Msn

Msb

0.355

≔Sc 0.45

=≔Ms ⋅Sc Msb 13.05 MPa

Predicted vertical pipe deflection

=≔∆y ⋅⋅⋅⎛⎝ +⋅DL WC WL⎞⎠ Kx ―――――――

D

⎛⎝ +⋅149 PS ⋅61000 Ms⎞⎠

103 0.025 mm

=――∆y

D⋅2.533 10−5 =――

∆ya

D0.127

∆y ∆y

=<――∆y

D――∆ya

D1 Ok

Combined Loading

The check for pipe pressure and deflection combined is as follows

Working pressure ≔Pw 1600 kPa

Hydraulic Design Basis =≔HDB ――Pw

FS1066.667 kPa

Working Strain =≔εpr ⋅Pw ―――D

(( ⋅⋅2 t E))0.003 ――

mm

mm

Rerounding coefficient =≔rc −1 ――――Pw

3000 kPa0.467

=⋅εb ―rc

Sb0.311 =――――――

⎛⎜⎝−1⎛⎜⎝――――

⋅εpr 1 kPa

HDB

⎞⎟⎠

⎞⎟⎠

FS0.667

=<⋅εb ―rc

Sb――――――

⎛⎜⎝−1⎛⎜⎝――――

⋅εpr 1 kPa

HDB

⎞⎟⎠

⎞⎟⎠

FS1 OK

Buckling check

Design factor ≔FSb 2.5

Scalar calibration factor to account for some nonlinear effects

≔Cn 0.55

Factor to account for variability in stiffness of compacted soil

≔ϕs 0.9

Poisson’s ratio for soil ≔v 0.3

Modulus correction factor for Poisson’s ratio, v, of the soil

=≔kv ⋅(( +1 v)) ―――(( −1 ⋅2 v))(( −1 v))

0.743

Correction factor for depth of fill

=≔Rh ―――――11.4

⎛⎜⎝

+11 ―――D

1000 H

⎞⎟⎠

1.036

Allowable buckling pressure

=≔qa ⋅⎛⎜⎝――1

FSb

⎞⎟⎠

⎛⎝ ⋅1.2 Cn

(( ⋅0.149 PS)).33⎞⎠ ⎛⎝ ⋅⋅⋅ϕs 106 Ms kv

⎞⎠.67

――Rh

10001135.593 kPa

Specific weight of water ≔γw 9800 ――N

m3

height of water table ≔hw 1.5 m

Water buoyancy factor =≔Rw −1 0.33⎛⎜⎝―hw

H

⎞⎟⎠

0.838

=⎛⎝ ++⋅γw hw ⋅Rw WC WL⎞⎠ 219.245 kPa

=<⎛⎝ ++⋅γw hw ⋅Rw WC WL⎞⎠ qa 1 Safe against buckling