RISK ASSESSMENT MATRIX FOR PORT INFRASTRUCTURE CHRIS EDWARDS AECOM Inc
Dec 24, 2015
RISK ASSESSMENT MATRIX FOR
PORT INFRASTRUCTURE
CHRIS EDWARDSAECOM 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
Penetration Depth
Chlorides (wt % conc)
Ultimate SurfaceChloride Level (Cc)
Critical Chloride Level (Cc)
Diffusion Profile
Difusion Layer (d)
Sorption Layer (s)
Cover (c)
Time Dependent Deterioration
Time Dependent Chloride Ingress & Corrosion
Repairs should be timelyThe ranking of assets allows:
• Remediation to be prioritised and scheduled
• Multi-year maintenance budgets to be estimated with confidence
1. Select the Likelihood Rating based on the data points
2. Select the weighting for each data point
3. Calculate the Likelihood Multi Criteria Assessment
4. Select the Consequence Ranking
5. Select the Consequence Weighting
6. Calculate the Consequence Multi Criteria Assessment
Calculate the Severity of Risk
The AECOM RAM is a multi-step process based on Likelihood and Consequences
Likelihood RankingRanking applies for each condition listed below
1 (very good)
2 (minor deterioration)
3 (signifcant deterioation)
4 (severe deterioration but
structurally sound)
5 (severe deteriorationn plus
reduced structural capacity)
Visual condition
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
Minor damage: Concrete show s first signs of deterioration. No signif icant rust staining. Long service life
Moderate damage: Failure to cover develops from localised to general nature. No signif icant reduction of structural integrity. Requires treatment w ithin 5 years to maintain durability
Severe Damage: Concrete has signif icantly deteriorated and structural integrity is being affected. Requires treatment w ithin 2 years. Requires removal or strapping of loose materials for safety
Extreme Damage: Major loss of section w ith signif icantly diminished structural condition and integrity. Requires treatment w ithin 1 year
Carbonation depth results
Very low: Observed carbonation depth < 10% of average concrete cover
Low: Observed carbonation depth 10% - 30% of of average concrete cover
Medium: Observed carbonation depth 40% - 60% of average concrete cover
High: Observed carbonation depth 60% to 80% of average concrete cover
Very High: Observed carbonation depth > 80% of average concrete 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
Medium: Observed chloride concentration (% by w t concrete) 0.04 to 0.06 at steel reinforcement location.
High: Observed chloride concentration (% by w t concrete) 0.06 to 0.08
Very High: Observed chloride concentration (% by w t concrete) > 0.08
Aggressive Soil & Groundwater
Benign: dry non-aggressive soilVery low : Non-aggressive soil and groundw ater. Sulfates (expressed as SO4) <5,000 ppm in soil or <1,00 ppm in groundw ater. pH>5.5
Low : Sulfates (expressed as SO4) 5,000-10,000 ppm in soil or 1,000-3,000 ppm in groundw ater. pH 4.5-5.5
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
Estimated loss of structural safety factor ranking
Very low : No loss of reinforcement section estimated
Low: Estimated loss of reinforcement section < 5% original cross section
Medium: Estimated loss of reinforcement section 5% to 10%
High: Estimated loss of reinforcement section 10% to 15% original cross section
Very High: Estimated loss of reinforcement section > 15% original cross section
Estimated remaining service lifetime ranking
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
1 Least important2 Low importance3 Medium Importance4 High importance5 Highest importance
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
Likelihood Multi Criteria Assessment
Pier Cap Deck Soffit Dolphin
Asset IDVisual
condition Weighting
Carbonation depth
results Weighting
Chloride ingress results
(corrosion threshold 0.06%
by weight of concrete)
Weighting
Estimated loss of structural safety factor
ranking
WeightingTotal Score
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
Consequence Ranking
Consequence Ranking
1 2 3 4 5 6
People Severity 0: No injury or health effect
Severity 1: Slight injury or health effect
Severity 2: Minor injury or health effect
Severity 3: Major injury or health effect
Severity 4: PTD or up to 3 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 IDTotal 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
People Assets Environment Reputation or Service
Total Score = Likelihood + ConsequenceAsset 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
Action
Consequence Table
Consequence Lower Value Upper Value
Severity 5 100 120Schedule 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
RISK ASSESSMENT MATRIX
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