Peter TuftAS 2885.1 Launch, February 2007 1
AS 2885.1-2007
PENETRATION RESISTANCE
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 2
Why Penetration Resistance?
Incident Causes
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5
10
15
20
25
30
1970 1975 1980 1985 1990 1995 2000 2005
Half decade (year ending)
Nu
mb
er
of
Inci
den
ts
Lightning
External Forces
Earth Movement
Corrosion
Construction
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 3
It really happens
Acknowledgements:Rob Moore & Caltex
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 4
General Requirements
• Penetration resistance is one form of physical protection
• Mandatory in developed areas (T1, T2, S & I); see separate Clause 4.7
• May be used in R1 & R2 areas if required by SMS• Especially near isolated buildings (ie. within
radiation contours)
• From Clauses 4.11.1 & 4.11.2
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 5
Methods
• Calculate using Appendix M• Expected to be usual approach
• Physical testing• Beneficial for some projects in high
consequence areas
• Comparison with previous physical tests• Must be sufficiently similar
• From Clause 4.11.3
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 6
Calculation Objectives
• Determine minimum size of excavator to puncture pipe• For both general purpose and pointed teeth
• Determine likely puncture hole size, and hence failure mode• Rupture if hole ≥ critical defect• Leak if hole < critical defect• No penetration
• Should do calcs even if penetration resistance is not adopted as physical control• Useful reference data for SMS
• From Clause 4.11.3
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 7
Define the Threat
• Equipment type• Usually an excavator
• Equipment size (tonnes)• Penetrator (tooth) type• General purpose (chisel shaped)• Penetration (single sharper point)• “Tiger tooth” (twin sharp points)
• Penetrator dimensions
• From Clause 4.11.3
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 8
Calculation Principles
• No penetration if resistance > force
• RP > B F• RP = force required to penetrate pipe (for
given pipe parameter and tooth dimensions)• F = nominal force applied by machine• B = multi-purpose correction factor
• From Appendix M2
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 9
Pipe Resistance, RP
• Based on extensive APIA-sponsored research
• Excellent correlation between tests, FEA and equation:
RP 0.0007tW (U 410)(L 22.4)W
W 3.14
• Equation M3
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 10
Excavator Force, F
• Also based on APIA-sponsored research• Reasonable correlation between
excavator mass and bucket force:
FBucket 7.5WOP 0.045(WOP )2
• Equation M4
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 11
Factor B
• Multipurpose• Bucket force multiplier, empirical
experience, safety factor• Largely based on Australian field trials
• Range from 0.75 to 1.3• Original research suggested 1.8 to 2.0• Theoretically sound, but not achieved in
practice due to limited reaction force
• May change as further research progresses
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B Values
Circumstances B
Where WT not governed by penetration resistance
<0.75
Adequate resistance to typical excavator, but puncture possible if aggressive
0.75
Reasonable compliance with “No Puncture”
1.0
Where penetration must never occur, in some high consequence areas
≥1.3
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 13
Field Trials
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 14
… in Action
Acknowledgements:Phil Colvin & Alinta
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… and the Results
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Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 17
The Design Scenario
• Roma - Brisbane duplication
• DN 400, 450 km
• Land use ranging from rural to suburban
• 15.3 MPa, 10.2 MPa from city gate station
• Assume X80 pipe • SMYS = 552 MPa, UTS ≥ 621 MPa
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 18
The Design Problem
• Check penetration resistance for:
Location WTExcavato
rTeeth
Rural roadside
4.8 mm 20 tGen purpose(76 x 13 mm)
Suburban 8.4 mm 30 tTiger
(20 x 12 mm)
• Tooth dimensions from Table M3
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Rural Location
• 4.8 mm WT, 20 t excavator, GP teeth
• RP (pipe resistance) 275 kN
• Fbucket 131 kN
• B (adequate resistance) 0.75• B F 98 kN
• RP >> B F• Resistance >> machine force• No penetration• 4.8 mm WT OK for the identified threat
Peter Tuft - Penetration Resistance AS 2885.1 Launch, February 2007 20
Suburban Location
• 8.4 mm WT, 30 t excavator, tiger teeth
• RP (pipe resistance) 181 kN
• Fbucket 184 kN
• B (reasonable ‘No Puncture’) 1.0• B F 184 kN
• RP ≈ B F• Resistance ≈ machine force• No penetration, just• 8.4 mm WT minimum acceptable for the
identified threat
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Worth 1000 Words …
Penetration Resistance
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Excavator mass, t
Forc
e,
kN
Excavator force - lowExcavator force - nominalExcavator force - maxDozer forceResistance - GP teethResistance - Pen teeth
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Questions?
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