Risk Assessment Matrix for Port Infrastructure

Report
RISK ASSESSMENT MATRIX
FOR
PORT INFRASTRUCTURE
CHRIS EDWARDS
AECOM Inc
Ports have a variety of infrastructure subject to deterioration.
The most severe deterioration occurs on the main working assets
such as wharves and jetties, principally from chloride attack on
steel.
Assets must be kept in good working
condition within tight budgets
Asset managers need to prioritise
their maintenance programs to be
able to plan for future budgets.
Often this is done on the basis of
condition alone and ignoring the
consequences of loss of service or
failure
The AECOM Risk Assessment
Deterioration Model (RAM) is
a tool that allows assets to be
ranked according to their
requirement for maintenance
based on condition and
consequence of loss of
service or failure
Time Dependent Deterioration
Time Dependent
Chloride Ingress
& Corrosion
Repairs should be timely
The ranking of assets
allows:
• Remediation to be
prioritised and
scheduled
• Multi-year maintenance budgets to
be estimated with confidence
The AECOM RAM is a multi-step process based on
Likelihood and Consequences
1. Select the Likelihood Rating based
on the data points
4. Select the Consequence Ranking
2. Select the weighting for each data
point
5. Select the Consequence Weighting
3. Calculate the Likelihood Multi
Criteria Assessment
6. Calculate the Consequence Multi
Criteria Assessment
Calculate the Severity of Risk
Likelihood Ranking
Ranking applies for each
condition listed below
Visual condition
1
(very good)
As built: No signs of
deterioration to concrete cover.
How ever, harline cracks may
exist. Concrete is intact and
sound. No loss of service life
2
(minor deterioration)
3
(signifcant deterioation)
Minor dam age: Concrete
show s first signs of deterioration.
No significant rust staining. Long
service life
Moderate dam age: Failure to
cover develops from localised to
general nature. No significant
reduction of structural integrity.
Requires treatment w ithin 5 years
to maintain durability
Carbonation depth
results
Very low : Observed carbonation Low : Observed carbonation
depth < 10% of average concrete depth 10% - 30% of of average
concrete cover
cover
Chloride ingress results
(corrosion threshold
0.06% by weight of
concrete)
Very low : Observed chloride
concentration (% by w t concrete)
< 0.02 at steel reinforcement
location
Low : Observed chloride
concentration (% by w t concrete)
0.02 to 0.04 at steel reinforcement
location
Estimated loss of
structural safety factor
ranking
Estimated remaining
service lifetime ranking
5
(severe deteriorationn plus
reduced structural capacity)
Severe Dam age: Concrete has
significantly deteriorated and
structural integrity is being
affected. Requires treatment
w ithin 2 years. Requires removal
or strapping of loose materials for
safety
Extrem e Dam age: Major loss of
section w ith significantly
diminished structural condition
and integrity. Requires treatment
w ithin 1 year
Medium : Observed carbonation High: Observed carbonation
depth 60% to 80% of average
depth 40% - 60% of average
concrete cover
concrete cover
Very High: Observed
carbonation depth > 80% of
average concrete cover
Very High: Observed chloride
High: Observed chloride
Medium : Observed chloride
concentration (% by w t concrete) concentration (% by w t concrete) concentration (% by w t concrete)
> 0.08
0.04 to 0.06 at steel reinforcement 0.06 to 0.08
location.
Low : Sulfates (expressed as
SO4) 5,000-10,000 ppm in soil or
and groundw ater. Sulfates
(expressed as SO4) <5,000 ppm 1,000-3,000 ppm in groundw ater.
pH 4.5-5.5
in soil or <1,00 ppm in
groundw ater. pH>5.5
Benign: dry non-aggressive soilV ery low : Non-aggressive soil
Aggressive Soil &
Groundwater
4
(severe deterioration but
structurally sound)
Medium : Sulfates (expressed as
SO4) 10,000-20,000 ppm in soil or
3,000-10,000 ppm in
groundw ater. pH 4-4.5
High: Sulfates (expressed as
SO4) >20,000 ppm in soil or
>10,000 ppm in groundw ater. pH
<4
Very low : No loss of
reinforcement section estimated
Low : Estimated loss of
reinforcement section < 5%
original cross section
High: Estimated loss of
Medium : Estimated loss of
reinforcement section 5% to 10% reinforcement section 10% to
15% original cross section
Very High: Estimated loss of
reinforcement section > 15%
original cross section
Very high: >90% of design life
remaining
High: 60% to 80% of design life
remaining
Medium : 40% to 60% of design
life remaining
Low : 20% to 40% design life
remaining
Very low : < 20% design life
remaining
Likelihood Weightings
Criteria
Weighting
Visual condition
3
Exposure environments
5
Carbonation depth results
1
Chloride ingress results
(corrosion threshold 0.06% by
weight of concrete)
4
Aggressive Soil and
Groundwater
3
Estimated loss of structural
safety factor ranking
4
Estimated remaining service
lifetime ranking
4
1
2
3
4
5
Least important
Low importance
Medium Importance
High importance
Highest importance
Likelihood Multi Criteria Assessment
Chloride ingress
results
Estimated loss
Carbonation
Visual
(corrosion
of structural
Total
Asset ID
Weighting
depth
Weighting
Weighting
Weighting
condition
threshold 0.06%
safety factor
Score
results
by weight of
ranking
concrete)
Pier Cap
2
3
1
1
4
4
2
4
31
Deck
3
3
1
1
4
4
4
4
42
Dolphin
3
3
1
1
3
4
4
4
38
Pier Cap
Deck Soffit
Dolphin
Consequence Ranking
Consequence
Ranking
1
2
3
4
5
6
People
Severity 0:
No injury or health
effect
Severity 1:
Severity 2:
Severity 3:
Severity 4:
Slight injury or health Minor injury or health Major injury or health PTD or up to 3
effect
effect
effect
fatalities
Severity 5:
More than 3 fatalities
Assets
Severity 0:
No damage
Severity 1:
Slight damage
Severity 2: Minor
damage
Severity 3:
Moderate damage
Severity 4: Major
damage
Severity 5:
Massive damage
Environment
Severity 0:
No effect
Severity 1:
Slight effect
Severity 2: Minor
effect
Severity 3:
Moderate effect
Severity 4: Major
effect
Severity 5:
Massive effect
Reputation
Severity 0: No
impact
Severity 1:
Slight impact
Severity 2: Minor
impact
Severity 3:
Moderate impact
Severity 4: Major
impact
Severity 5:
Massive impact
Consequence Weighting
Criteria
Weighting
People
3
Assets
5
Environment
2
Reputation
3
Consequence Multi Criteria Assessment
Asset ID
People
Assets
Environment
Reputation or Service
Total
Score
Ranking
Weighting
Ranking
Weighting
Ranking
Weighting
Ranking
Weighting
Pier Cap
2
2
3
5
1
1
2
3
26
Deck
3
3
4
5
1
1
3
3
39
Dolphin
2
2
2
5
1
1
5
3
30
User input from Consequence Ranking
Assigned from Consequence Multi Criteria Assessment
Total Score = Likelihood + Consequence
Likelihood Score
Consequence
Score
Total Score
Pier Cap
31
26
57
Schedule remediation in 5 -15 years
Deck
42
39
81
Schedule remediation within 2 years
Dolphin
38
30
68
Schedule remediation within 5 years
Asset
Consequence Table
Consequence
Lower Value
Upper Value
RISK ASSESSMENT MATRIX
Severity 5
100
120
Schedule remediation immediately or take the
asset out of service
Severity 4
80
99
Schedule remediation within 2 years
Severity 3
60
79
Schedule remediation within 5 years
Severity 2
40
59
Schedule remediation in 5 -15 years
Severity 1
20
39
On-going montoring on 3-5 yearly schedule
Action
THANK YOU

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