Risk Management – Correlation and Dependencies for Planning, Design and Construction Philip Sander Alfred Moergeli John Reilly
Advanced Probabilistic Risk Modeling Risks Occurring Multiple Times Content Advanced Probabilistic Risk Modeling Risks Occurring Multiple Times Event Tree Analysis RAMS Analysis
Advanced Probabilistic Risk Modeling The advantages of very advanced, probabilistic risk modeling (RIAAT 2014), such as currently used for the Koralm and Brenner Base Tunnels in Austria, include: Better, more complete modeling of the project and the ability to correlate risk events A more detailed risk assessment and useful risk management information More transparency and reporting of outcomes, e.g., ranking of risks, tornado diagrams The ability to monitor and document changes to the project The ability to integrate change order management Although correlations (and dependencies) are a ubiquitous concept in modern risk management, they are also one of the most misunderstood concepts.
Correlations and Dependencies Correlations quantify how specific change on one project element or characteristic is linked to a change in related project elements. Example 1: A change in the price of steel will cause changes in the cost of several related project elements. Example 2: A probability of high labor costs can lead to a high impact of time-related cost in other project elements. Dependencies characterize risks that are related: One risk may trigger one or more other risks, or one risk may influence the consequence (value) of another risk (or multiple risks). Example: If a TBM is stuck in a fault zone, it might get buried and, as a further consequence, deadlocked, etc.
Lower Inn Valley Railway Corridor (Tyrol/Austria) Risks Occurring Multiple Times Lower Inn Valley Railway Corridor (Tyrol/Austria) The project includes the construction section 1 (Kundl‐Baumkirchen) of the Lower Inn Valley Railway Corridor. It is part of the Brenner Base Tunnel scheme. The railway track has an approximate length of 40 km. 32 km are underground.
Risks Occurring Multiple Times Scenario: Cyclic excavation in a rock zone comes with the danger of cave-ins. Probability of Occurrence: It is expected that 2 cave-ins will occur in this section. Of course, it is also possible that there will be no cave-ins at all, and in worst cases there could be more than two. Financial Impact: The financial impact is modeled as a triangular function with the parameters: Min: 50,000 ML: 65,000 Max: 90,000
Risks Occurring Multiple Times Scenario two cave-ins Scenario one cave-in Scenario three cave-ins Scenarios four and more cave-ins Probability that no cave-in will occur Deterministic Approach: 2 x 65,000 = 130,000
Koralm Base Tunnel (Southern Austria) Event Tree Analysis Koralm Base Tunnel (Southern Austria) With a total length of 32.8 km and a maximum cover of 1.250 m the base tunnel will traverse the Koralpe mountain range. The tunnel system is designed with two single-track tubes (approx. 82 m² per tube) and cross drifts at intervals of 500 m. Excavation for the Koralm tunnel is executed by two double shield TBM’s for long distances.
Event Tree Analysis
Event Tree Analysis
Event Tree Analysis 1 Fault Zone 20 Fault Zones
Functional System Safety (FSS)
Bow Tie Analysis – Combination of a Fault Tree with an Event Tree Analysis
RAMS – System in Context
RAMS – Reliability, Availability, Maintainability & Safety
RAMS – FTA RAM
RAM – Interpretation of Results
RAMS – FTA Safety Analysis Period = 1h