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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.