Case Study: Dealing with Reliability and Availability on Refurbishments

The case study aims to investigate how to approach R&A-related uncertainties in refurbished structures. In this specific project, the refurbishment comprised two parts. In the first part (western and central locks), the failure data of the existing structure elements were excluded due to lack of failure and inspection data. In the second part (eastern locks), failure data were included by following these steps:

• (Quick) Failure Mode, Effects, and Criticality Analysis (FMECA) to establish critical parts of the structure;

• Set up inspection programme for critical parts and translate inspection results to failure data;

• Use failure data in the Fault Tree Analysis to determine how they affect the design;

• Adapt the design until RA demands are met.

Despite realistic availability figures for the new structure elements, these figures in the first part do not represent the availability of the complete structure due to incomplete data. The second part, however, provides useful availability figures for the entire structure (existing and new). This approach allows the contractor to guarantee the reliability and availability of the whole refurbished structure.

Although this is common practice in the automotive and aerospace industry, this approach is relatively new for civil structures. The designers thus require a different mindset during the design process.