W. Koops MSc

Wim Koops

(Deze pagina is alleen beschikbaar in het engels)

The service life of Infrastructure Assets How to improve predictability

Wim Koops, Rijkswaterstaat Dienst Verkeer en Scheepvaart

March 09, 2012

The research topic concerns research into the predictability of the Service Life of infrastructure assets and how to improve this. The concerned infrastructure assets, in this research, are part of the Water Infra System (bridges, river locks and barriers) of the Directorate General of Public Works and Water Management of the Netherlands or in Dutch Rijkswaterstaat and abbreviated as RWS. Many of these infrastructure assets which have been built in the 1920s and 1930s are near the end of their intended service life (design life). RWS should be prepared that 10% of these infrastructure assets will reach the end of their intended Service Life (design life) within the next 20 years. Four classes of deterioration, which lead to the end of Service Life, were distinguished. Out of the four classes of deterioration, obsolescence (analysis) was chosen as the main topic of this research. The research contributes to obsolescence analysis by exploring solutions to create coherent information on customer demands versus performance requirements.
The approach is, firstly, to study on obsolescence and methods to structure information on requirements, secondly, by surveying the respective RWS processes, and thirdly, by combining the findings of the study and survey in a ‘reference model’ that gives insight in obsolescence of infrastructure assets. The model can be used for predicting the end of Service Life. All four classes of deterioration were structured in an enhanced deterioration tree.

The ‘reference model’ was examined with the test case “Krammer Locks”. Especially for conducting the test case, a review group was formed. They helped to deliver information on the test case, as experts helped ranking / score information and were involved in testing the ‘reference model’. The members are professionally involved with the sustainment of the ‘Krammer Locks’. Within RWS the assigned funding of infrastructure assets during the Service Life, is two-fold and controlled by two separate processes:
1. The ‘Regulation of Long-term Program Infrastructure and Environment‘ (MIRT) process, mandatory for projects and major (re)constructions (Acquisition /design);
2. The ‘Service Level Agreement’ (SLA) process, mandatory for the sustainment of infrastructure assets by means of Maintenance, Traffic- and Water Management.

The two separate processes cause, beside a financial separation, also an information gap between the design and sustainment phases of infrastructure assets. Both symptoms, financial separation and the information gap, constrain Service Life prediction. For obsolescence analysis, comparing design requirements and customer demands, the information gap should be reduced, and as part of Service Life prediction, an integral investment decision based on Life Cycle Cost (LCC) is recommended.

The research question is then:

“How can information concerning performance requirements be structured to improve the predictability of the end of Service Life of infrastructure assets caused by obsolescence?”

The ‘Theoretical framework’ provides answers, on which obsolescence aspects are distinctive for deterioration of infrastructure assets, and which methods can be used to structure information on performance requirements. The findings are combined in a theoretical proposition, which serves as a basis for the ‘reference model’. For obsolescence analysis, a top-down/bottom-up system development process is explained as part of Systems Engineering. It was noticed that for obsolescence analysis, the sub processes ‘Requirement analysis’ (RA) is dominant. However, in case of existing infrastructure assets, without having all -as built- system development information, also the sub processes ‘Functional Analysis’(FA) and ‘System Analysis’ (SA) are necessary to define the system requirements bottom-up. The focus then is not on creating new information, but on structuring existing information to interconnect with other structuring
methods used within RWS (in the design and sustainment phase) and to define and rank performance requirements, supporting the monitoring of obsolescence, with respect to Service Life Prediction. To correlate, as closely as possible, with existing methodologies used within RWS and supporting the monitoring of obsolescence, the three following steps are recommended as a base for the reference model:
A. Start by defining system borders and apply synthesis of system parts, “System Analysis”, part of Systems engineering, using a ‘System Breakdown Structure’ (SBS);
B. Set up a functional hierarchy, “Function Analysis” part of Systems Engineering, using FFBD’s;
C. Make a matrix “House of Quality” (HoQ) to relate causes of obsolescence (external influences) per ‘type’ to functions and (applicable) performance requirements with QFD.

The ‘reference model’ was constructed and provided with instructions. The model, with iterative steps, was based on; firstly the theoretical proposition, secondly the deterioration tree and thirdly the standard (six layer)system-decomposition of RWS. The reference model is the integration of all three research subjects. To test the reference model, it was subject to a qualitative analysis. The analysis explains differences between the research variables (which are expected to change) and the outcome of the reference model, i.e. the test case results of “Krammer Locks”. The interview questions, part of the qualitative analysis, were formulated for a ‘non-standard semi structured group interview’ to conduct with the review group finalizing the test case. The interview method was chosen because of the qualitative data to review, and the possibility for in-depth analysis of the reference model. The group interview revealed that the ‘reference model’ was providing new information on existing performance requirements. However, the interpolation and score of the HoQ need further development. The HoQ provides the features necessary, but not all information was available.
The research led to three recommendations:
1. Conducting further research into “Modern QFD” and additional instruments, to define the interpolation of the ‘obsolescence margin’ of TPM’s, to the score of the HoQ;
2. The HoQ and the maintenance plans for infrastructure assets should be combined in integral sustainment plans for infrastructure assets;
3. New MIRT projects should set up a Life Cycle Management (LCM) process in the ‘Exploration phase’ to agree with the ‘MIRT 2’ gateway decision. The HoQ should be used, as part of LCM, to transfer performance requirements (TPM’s) through all life cycle phases of Service Life of infrastructure assets.

De Thesis kunt u hier bekijken (EN).

De Thesis presentatie kan hier bekeken worden (EN).

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