HUSAIN M. AL-MUSLIMNADHIR I. AL-NASRI

Outline Introduction Sabkha area Road crossing Bend design Anchor blocks Conclusion

JOR

DA

N

ABQAIQ

TANAJIB

JUBAIL

ABU-ALI

QATIF

BERRI

DHAHRAN

BAHRAIN

ARABIAN

GULF

TURAIF

QAISUMAH

QATAR

ABU-ALI

BAHRAIN

ARABIAN

GULF

TURAIF

QAISUMAH

Ras Tanoura

ABQAIQ

JOR

DA

N

ABU-HADRIYAH

TUFAIH

JUBAIL

ABU-ALI

SAFANIYAH

DHAHRAN

QAISUMAH

ABQAIQ

ABU-ALI

DHAHRAN

BAHRAIN

ARABIAN

GULFQAISUMAH

JJ

Southern AreasABQAIQ

JUBAIL CUSTOMERS

KHURSANIYAH

CRUDE NETWORKGAS Network

JUBAIL

RIYADH

Product Network

Saudi Aramco Pipeline Network

Type of Pipeline Installation Above ground unrestrained pipeline Above ground fully restrained pipeline Under ground restrained pipeline

Sabkha area Sabkha means area of high-level water table The water is very salty and highly corrosive The pipe must not come in contact with water Special pad design and sequence of

construction

Sabkha pad design

Sabkha sequence of construction Prepare the construction pad Excavate the trench Lower the pipe and backfill Construct the pipe berm

Sabkha area

Construction of ROW and pad

Sabkha areaROW Pad

ROW pad

Pipeline pad

Preparing the trench

Lowering the pipe and backfilling

Constructing the berm

Stabilizing the berm

Road crossing

Loads on Pipelines

Total Load on Pipeline = Live load + Earth load + Internal Loads

Earth Load

Live Load

Internal Load

Carrier pipeMinimum depthbelow surface

Drainage ditch

Minimum depthbelow ditch (0.9 m)

Figure 1: Road Crossing

Railroad (1.7 m )

Road (1.2 m)

Minimum Depth of Cover

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

1 2 3 4 5 6 7 8 9 10 11 12 13Depth of cover (ft)

Abs

olut

e m

axim

um st

ress

(psi

)

D/t = 50D/t = 60D/t = 70D/t = 80D/t = 90D/t = 100D/t = 110.1D/t = 120D/t = 129.9D/t = 139.9D/t = 150

Absolute maximum stress variation for 60 inch pipe diameter and high density sabkha as native soil

Stresses vs. depth of cover

Analysis of Pipeline Under Road & Railroads Methodologies

Crossi (two versions) Based on the API RP1102, 1968 edition

Cornell/GRI developed PC-PISCESL software Included in the 1993 edition of API RP1102, Steel Pipelines Crossing

Railroads and Highways” Limitations

○ 2 ≤ D ≤ 42○ 12.5 ≤ D/t ≤ 100○ 3 ft ≤ Backfill Height ≤ 10 ft

Pipeline toolbox Aramco Study (Analysis and Design for Buried Pipeline. ADBP)

Limitations50 ≤ D/t ≤ 150

Extended Study12 ≤ D/t ≤ 150

ADBP 2.0

Minimizing The Pipeline Stresses Under Crossings Installing concrete slab. Increasing the depth of cover. Increasing the pipeline wall thickness. Reinforcing the pipeline with sleeve.

Pipeline bends Elastic bend Cold bend Hot bend

Bend design The standard design is 210 m radius bend Smaller radii required calculation and/or

thrust anchors Design was optimized by numerical

analysis

Bend analysis model

D

t

Pipe Bend

RbRbθ

A

A

Section - AA

Hc D = Diameter of the pipe

t = Thickness of the pipeHc = Depth of coverRb = Radius of the bendθ = Angle of the bend

Thrust anchor Full thrust without considering soil friction Large size anchor blocks Block size was reduced significantly

Thrust anchors construction

Thrust anchor new software Analysis and Design of Thrust Anchor

Blocks (ADTAB) Size Optimization of Thrust Anchor

Blocks (SOPTAB)

Conclusion Saudi Aramco standards are dynamic to

capture Lessons learned from projects Industry best practices Company funded research projects

Typical Pipeline Construction Activities Route Surveying Mobilizing equipment and personnel Transporting and storing pipe and materials Topsoil stripping (as required) Grading Stringing (transport and laying of pipe on the ROW) Welding, ultrasonic, and NDE of welds Installing coating at the pipe joints Trenching Lowering pipe into the trench Installing crossings Backfilling Restoring the ROW

Clearing and Grading

ROW

Acquisition

Grading

Cut and fills

Survey

Trenching

Rock-Free Rock

Drilling

Trenching

Blasting

Padding

Stringing

Stringing

Welding / Coating

Welding NDT Coating Tie-insLowering-in

BackfillBerm

Lowering-in

Backfill Berming /stabilizing

Stabilizing

Road crossing concrete slab

Casing Requirements

Casing is required only for railroads. Casing minimum wall thickness per table -3 Casing diameter ≥ 2 size larger than carrier pipe Insulators/spacers shall be installed Casing ends shall be sealed Vents/drains are not mandatory

Road crossing analysis model

13 T 10 T10 T6 T

4 m

18 m

1.2 min 2.0 max

H

D

t i

Scope of SAES-L-460 This standard defines the minimum design and

installation requirements governing pipeline crossings under roads, parking lots, railroads, and airport runways.

This standard applies to pipelines in all services.

This standard supplements the latest edition of API RP 1102 “Steel Pipelines Crossing Railroads and Highways.”

Additional requirements imposed by the Saudi Arabian Government shall apply to crossings of Government roads and railroads.