"uuid","repository link","title","author","contributor","publication year","abstract","subject topic","language","publication type","publisher","isbn","issn","patent","patent status","bibliographic note","access restriction","embargo date","faculty","department","research group","programme","project","coordinates"
"uuid:3ed81b29-9a60-460b-b1a4-3560b46958cd","http://resolver.tudelft.nl/uuid:3ed81b29-9a60-460b-b1a4-3560b46958cd","Caracas, ciudad de secuelas: Prácticas de cuidado después de la emigración y el colapso","Gzyl, Stefan (TU Delft Theory, Territories & Transitions)","","2024","This article examines the caretaking practices of vacant domestic spaces amid a migratory crisis and generalized collapse. Caracas is conceptualized as a ‘city of aftermath’, where the material residues of modernity are reconfigured in response to the logic of crisis and the needs of migrants, re-signifying spaces and extending their life beyond the conditions of their production. The text is centered on the figure of the caretaker. Based on interviews, site visits, and photography, the article examines the daily routines of Carlos, who looks after more than twenty apartments in Caracas. His work is entwined with migrants’ trajectories and local needs, generating new economies and support networks around the maintenance and adaptation of vacant spaces. In this way, caretaking practices offer clues for a reading of the city that transcends progress/decline oppositions and their respective imaginaries: the new and the ruin.","crisis; maintenance; mantenimiento; middle class; repair clase media; reparación; ruin; ruina","es","journal article","","","","","","","","","","","Theory, Territories & Transitions","","",""
"uuid:a922afcf-1fea-42b3-9536-f2eebe30852d","http://resolver.tudelft.nl/uuid:a922afcf-1fea-42b3-9536-f2eebe30852d","Data-driven ballast layer degradation identification and maintenance decision based on track geometry irregularities","Zhao, Wenbo (China Academy of Railway Sciences); Qiang, Weile (China Academy of Railway Sciences); Yang, Fei (China Academy of Railway Sciences); Jing, Guoqing (Beijing Jiaotong University); Guo, Y. (TU Delft Railway Engineering)","","2023","Ballast layer defects are the primary cause for rapid track geometry degradation. Detecting these defects in real-time during track inspections is urgently needed to ensure safe train operations. To achieve this, an indicator, the track degradation rate (TDR) was proposed. This rate is calculated using track geometry inspection data to locate and predict railway-line sections with ballast layer defects. The TDR is determined by the monthly standard deviation of the rail longitudinal level, which is one aspect of track geometry. The Ballast Layer Health Classification (BLHC) is designed by assessing the two successive TDRs before and after track geometry maintenance actions. The BLHC is used to categorize the conditions of the ballast layer, including normal periodic deterioration, abrupt deterioration, effective maintenance, rising deterioration, and severe deterioration. Both the TDR and BLHC were validated through field assessments of ballast layer conditions, where the two indicators were found to be effective in revealing defects. The results indicate that the TDR is sensitive to ballast layer defects, while the BLHC can quickly identify the location of these defects. Consequently, the BLHC can provide real-time guidance for ballast layer maintenance.","ballast degradation; Ballast inspection; data science; maintenance; track geometry; track irregularity","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:877bed45-d775-40bb-bde2-d2322cb334f0","http://resolver.tudelft.nl/uuid:877bed45-d775-40bb-bde2-d2322cb334f0","Decisions on life-cycle reliability of flood defence systems","Klerk, W.J. (TU Delft Hydraulic Structures and Flood Risk)","Delft University of Technology (degree granting institution)","2022","Many countries rely on flood defence systems to prevent economic damage and loss-of-life due to catastrophic floods. Asset managers of flood defence systems need to cope with the consequences of structural degradation, and changing societal and environmental conditions, in order to satisfy performance requirements and optimize societal value of flood defence assets. This is a continuous effort of planning, executing and evaluating a variety of different system interventions. These can be aimed at both reducing the uncertainty on (e.g., inspection or monitoring), or improving the performance of a flood defence system (e.g., reinforcement). Performance is typically expressed as the reliability on a system level, which in this thesis is interpreted as the life-cycle reliability: the estimated reliability with all foreseen interventions in time. The key objective of this thesis is to improve decisions on life-cycle reliability of flood defence systems. This is elaborated for three key topics, with a focus on earthen flood defences (also known as levees or dikes)...","flood defences; levees; asset management; risk-based decision making; Bayesian decision theory; inspection; maintenance; uncertainty reduction; reinforcement; optimization; reliability","en","doctoral thesis","","978-94-6384-313-3","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:1c6cea78-cbb0-4f08-b165-c9f47ed728d3","http://resolver.tudelft.nl/uuid:1c6cea78-cbb0-4f08-b165-c9f47ed728d3","""No Fun, but Very Effective"": Consumers' Evaluation of Design Strategies for Product Care","Ackermann, L. (TU Delft Marketing and Consumer Research; University of Salzburg); Mugge, R. (TU Delft Marketing and Consumer Research; TU Delft Design, Organisation and Strategy); Schoormans, J.P.L. (TU Delft Marketing and Consumer Research)","Fitzpatrick, C. (editor)","2022","Product care describes consumers' activities to prolong the lifetime of a product, such as repair, maintenance or careful handling. By keeping the product in a functional state, replacement can be postponed. Previous research has identified eight design strategies that can foster product care among consumers. To use these design strategies to their full potential, a deeper understanding of their
effectiveness is needed. The current study aimed to evaluate the design strategies with consumers. We conducted interviews with 15 consumers and discussed the effectiveness of our strategies for product care in the consumers’ daily life. Results indicate that the effectiveness of our strategies varies over products and product categories. A combination of strategies seems to be the most promising approach for fostering product care among consumers. Our research contributes to the scientific knowledge by
providing deeper insights into the conditions under which design strategies for product care are most effective.","product longevity; maintenance; repair; behavioural change; consumer behaviour","en","conference paper","University of Limerick","","","","","","","","","Design, Organisation and Strategy","Marketing and Consumer Research","","",""
"uuid:9634fc62-d95f-47f3-b32b-5a6ee93041c1","http://resolver.tudelft.nl/uuid:9634fc62-d95f-47f3-b32b-5a6ee93041c1","A Systematic Literature Review of Predictive Maintenance for Defence Fixed-Wing Aircraft Sustainment and Operations","Scott, Michael J. (Royal Melbourne Institute of Technology University); Verhagen, W.J.C. (Royal Melbourne Institute of Technology University); Bieber, M.T. (TU Delft Air Transport & Operations); Marzocca, Pier (Royal Melbourne Institute of Technology University)","","2022","In recent decades, the increased use of sensor technologies, as well as the increase in digitalisation of aircraft sustainment and operations, have enabled capabilities to detect, diagnose, and predict the health of aircraft structures, systems, and components. Predictive maintenance and closely related concepts, such as prognostics and health management (PHM) have attracted increasing attention from a research perspective, encompassing a growing range of original research papers as well as review papers. When considering the latter, several limitations remain, including a lack of research methodology definition, and a lack of review papers on predictive maintenance which focus on military applications within a defence context. This review paper aims to address these gaps by providing a systematic two-stage review of predictive maintenance focused on a defence domain context, with particular focus on the operations and sustainment of fixed-wing defence aircraft. While defence aircraft share similarities with civil aviation platforms, defence aircraft exhibit significant variation in operations and environment and have different performance objectives and constraints. The review utilises a systematic methodology incorporating bibliometric analysis of the considered domain, as well as text processing and clustering of a set of aligned review papers to position the core topics for subsequent discussion. This discussion highlights state-of-the-art applications and associated success factors in predictive maintenance and decision support, followed by an identification of practical and research challenges. The scope is primarily confined to fixed-wing defence aircraft, including legacy and emerging aircraft platforms. It highlights that challenges in predictive maintenance and PHM for researchers and practitioners alike do not necessarily revolve solely on what can be monitored, but also covers how robust decisions can be made with the quality of data available.","aircraft; decision-making; defence; diagnostics; maintenance; predictive; prognostics; uncertainty","en","journal article","","","","","","","","","","","Air Transport & Operations","","",""
"uuid:8c7648ae-bea3-4555-9b88-a295d3a0b499","http://resolver.tudelft.nl/uuid:8c7648ae-bea3-4555-9b88-a295d3a0b499","A topological characterisation of looped drainage networks","Meijer, D.H. (TU Delft Sanitary Engineering; Deltares); Korving, Hans (Deltares); Clemens-Meyer, François (Deltares; Norwegian University of Science and Technology (NTNU))","","2022","Hydrodynamic models are used to analyse water networks (water distribution, drainage, surface water, district heating, etc.). The non-linear nature of water flows necessitates the use of iterative solution methods in hydraulic modelling. This requires a relatively large computational effort. To reduce this effort, networks, network forcing and/or the flow in networks are often simplified and analysed using the Graph Theory. The simplification options depend on the network characteristics. There are many topological features to describe Graph-based networks. In this paper, these characteristics are summarised, applied on 7 urban drainage networks and discussed. As the topological features do not describe the networks in a uniform manner, a new type of topological characterisation of looped drainage networks (Network Linearisation Parameter, NLP) is proposed based on linearized hydraulics and bottlenecks identified in paths to outfalls.","Asset management; Graph Theory; linearized hydraulics; maintenance; network analysis; network structure; network topology; urban drainage networks","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:9eead00d-cdff-4678-96e9-9a86446c8bba","http://resolver.tudelft.nl/uuid:9eead00d-cdff-4678-96e9-9a86446c8bba","Identifying critical elements in drinking water distribution networks using graph theory","Meijer, D.H. (TU Delft Sanitary Engineering; Deltares); Post, Johan (Partners4UrbanWater); van der Hoek, J.P. (TU Delft Sanitary Engineering; Waternet); Korving, Hans (Deltares); Langeveld, J.G. (TU Delft Sanitary Engineering; Partners4UrbanWater); Clemens, F.H.L.R. (TU Delft Sanitary Engineering; Deltares)","","2021","Drinking water distribution networks (WDNs) are a crucial infrastructure for life in cities. Deterioration of this ageing, and partly hidden from view, infrastructure can result in losses due to leakage and an increased contamination risk. To counteract this, maintenance strategies are required to maintain the service level. Information on the most critical elements of a WDN, with respect to the functioning of the system as a whole, is essential for prioritising maintenance or rehabilitation activities. In this study a Graph theory based method is developed and applied for efficiently identifying the most critical elements. The main advantage of this method is that it avoids the need to perform elaborate hydrodynamic model calculations. Instead, the structure of the network is the main starting point. The results show that the structure of the network is more decisive than the hydraulics with respect to the criticality of the system’s performance as a whole. Results depict that the suggested approach is applicable not only to the main (primary) network, but also to the capillaries which are normally beyond the scope of the traditional methods applied so-far because of the complexity of the networks and the required calculation time.","asset management; critical elements; deterioration; drinking water distribution networks; Graph theory; leakages; maintenance","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:bd095093-d9be-49c7-96b3-567b1ab35aeb","http://resolver.tudelft.nl/uuid:bd095093-d9be-49c7-96b3-567b1ab35aeb","Accuracy of visual inspection of flood defences","Klerk, W.J. (TU Delft Hydraulic Structures and Flood Risk; Deltares); Kanning, W. (TU Delft Hydraulic Structures and Flood Risk; Deltares); Kok, M. (TU Delft Hydraulic Structures and Flood Risk); Bronsveld, J. (Waterschap Rivierenland); Wolfert, A.R.M. (TU Delft Integral Design & Management)","","2021","Prioritisation of flood defence maintenance is typically based on visual inspection. However, literature shows that the Probability of Detection (PoD) of visual inspection can vary significantly. Here we investigate the PoD for visual inspections of flood defence structures, the consistency of damage classification, and the influence of different variables on the PoD, such as past experience. Four flood defence sections were inspected by 22 different inspectors for a variety of damage types, such as animal burrowing and damage to block revetments. It is found that the PoD varies significantly both per damage type and inspector. Additionally, the estimated severity of damages varies significantly in comparison to the reference situation: over half of the registered damages is assigned a different severity compared to the reference, which potentially leads to incorrect maintenance measures. A likely explanation for the variation in results is the complexity of inspection guidelines and task definitions. Therefore it is advised to simplify inspection guidelines and use more focussed inspections for the most important types of damage. This likely leads to both a reduction of the number of false negatives associated with an increase in flood risk, and better risk-based asset management and maintenance prioritisation in general.","flood defence; flood risk management; maintenance; Probability of Detection; Visual inspection","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:f15dbaed-d186-4b4f-8a75-4bcf67c13317","http://resolver.tudelft.nl/uuid:f15dbaed-d186-4b4f-8a75-4bcf67c13317","DeepTC-Enhancer: Improving the Readability of Automatically Generated Tests","Roy, Devjeet (Washington State University Pullman); Zhang, Ziyi (Washington State University Pullman); Ma, Maggie (Infra Supply Chain and Automation); Arnaoudova, Venera (Washington State University Pullman); Panichella, A. (TU Delft Software Engineering); Panichella, Sebastiano (Zurich University of Applied Science (ZHAW)); Gonzalez, Danielle (Rochester Institute of Technology); Mirakhorli, Mehdi (Rochester Institute of Technology)","","2020","Automated test case generation tools have been successfully proposed to reduce the amount of human and infrastructure resources required to write and run test cases. However, recent studies demonstrate that the readability of generated tests is very limited due to (i) uninformative identifiers and (ii) lack of proper documentation. Prior studies proposed techniques to improve test readability by either generating natural language summaries or meaningful methods names. While these approaches are shown to improve test readability, they are also affected by two limitations: (1) generated summaries are often perceived as too verbose and redundant by developers, and (2) readable tests require both proper method names but also meaningful identifiers (within-method readability). In this work, we combine template based methods and Deep Learning (DL) approaches to automatically generate test case scenarios (elicited from natural language patterns of test case statements) as well as to train DL models on path-based representations of source code to generate meaningful identifier names. Our approach, called DeepTC-Enhancer, recommends documentation and identifier names with the ultimate goal of enhancing readability of automatically generated test cases. An empirical evaluation with 36 external and internal developers shows that (1) DeepTC-Enhancer outperforms significantly the baseline approach for generating summaries and performs equally with the baseline approach for test case renaming, (2) the transformation proposed by DeepTC-Enhancer results in a significant increase in readability of automatically generated test cases, and (3) there is a significant difference in the feature preferences between external and internal developers.","deep learning; empirical study; evolution; maintenance; program comprehension; software testing; test case generation","en","conference paper","IEEE / ACM","","","","","Accepted author manuscript","","","","","Software Engineering","","",""
"uuid:47c4dad9-4f8f-4321-b7e7-85122e8250ec","http://resolver.tudelft.nl/uuid:47c4dad9-4f8f-4321-b7e7-85122e8250ec","Monitoring and statistical modelling of the solids accumulation rate in gully pots","Rietveld, M.W.J. (TU Delft Sanitary Engineering); Clemens, F.H.L.R. (Deltares); Langeveld, J.G. (TU Delft Sanitary Engineering; Partners4UrbanWater)","","2020","Gully pots are utilized for conveying runoff to drainage systems, as well as for reducing the system’s solids loading by retaining suspended solids. However, the accumulation of solids in gully pots reduces their removal efficiency, leading to an increase in solids transport towards the drainage system. This article aims to identify the main drivers of the solids accumulation in gully pots and, thus the relevant processes for wash-off models. The solids accumulation rates in 407 gully pots were monitored within a period of ~14 months and were analysed by means of a linear mixed model and a regression tree. The parameters vegetation factor, rainfall volume, and filling degree are the main drivers of the accumulation process. These parameters are linked to the solids build-up in a catchment, solids transport, and solids retention in gully pots, which means that none of these 3 processes is dominant.","catch basin; field data; Gully pot; maintenance; solids; urban drainage","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:75a45bcd-c318-4b16-bb31-04a72f4e9368","http://resolver.tudelft.nl/uuid:75a45bcd-c318-4b16-bb31-04a72f4e9368","System-Level Design for Reliability and Maintenance Scheduling in Modern Power Electronic-Based Power Systems","Peyghami, S. (Aalborg University); Palensky, P. (TU Delft Intelligent Electrical Power Grids); Fotuhi-Firuzabad, Mahmoud (Sharif University of Technology); Blaabjerg, Frede (Aalborg University)","","2020","Power electronic converters will serve as the fundamental components of modern power systems. However, they may suffer from poorer reliability if not properly designed, consequently affecting the overall performance of power systems. Accordingly, the converter reliability should be taken into account in design and planning of Power Electronic-based Power Systems (PEPSs). Optimal decision-making in planning of PEPSs requires precise reliability modeling in converters from component up to system-level. This paper proposes model-based system-level design and maintenance strategies in PEPSs based on the reliability model of converters. This will yield a reliable and economic planning of PEPSs by proper sizing of converters, cost-effective design of converter components, identifying and strengthening the converter weakest links, as well as optimal maintenance scheduling of converters. Numerical case studies demonstrate the effectiveness of the proposed design and planning strategies for modern power systems.","Design; maintenance; planning; power converter; power system; reliability; wear-out failure","en","journal article","","","","","","","","","","","Intelligent Electrical Power Grids","","",""
"uuid:98f6e8e7-d689-47d4-8acd-3e490b4e6db0","http://resolver.tudelft.nl/uuid:98f6e8e7-d689-47d4-8acd-3e490b4e6db0","Adjusting freight train paths to infrastructure possessions","Bešinović, Nikola (TU Delft Transport and Planning); Widarno, B. (Student TU Delft); Goverde, R.M.P. (TU Delft Transport and Planning)","","2020","This paper tackles railway timetabling with infrastructure work possessions. It introduces the integrated Passenger and Freight Train Timetable Adjustment Problem (PF-TTAP) which handles both passenger as well as freight trains. To deal with possessions, passenger trains are typically retimed, reordered or partially cancelled, while for freight trains it is important to reach their destination, possibly using an alternative path. Alternative paths for freight trains are generated using the k-shortest path algorithm. To solve the PFTTAP, a mixed integer linear programming (MILP) problem is developed to simultaneously retime, reroute and cancel trains in the network. The model aims at minimizing deviations from the original timetable and in particular selecting alternative freight paths with the least turning activities and noncommercial stops. The model was tested on the Dutch national railway network. The PF-TTAP model successfully created an alternative hour pattern satisfying all the railway stakeholders.","Railway; disruption; freight; maintenance; passenger; possessions; resilience; timetable adjustment","en","conference paper","IEEE","","","","","Accepted author manuscript","","","","","Transport and Planning","","",""
"uuid:3f6e11ce-da0f-4a17-922d-346b7404c757","http://resolver.tudelft.nl/uuid:3f6e11ce-da0f-4a17-922d-346b7404c757","Water Injection Dredging and Fluid Mud Trapping Pilot in the Port of Rotterdam","Kirichek, Alex (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Deltares); Rutgers, Ronald (Port of Rotterdam)","","2019","As conventional dredging and relocation of sediment deposits is highly expensive, port authorities seek for more efficient solutions for reducing the costs of maintenance dredging. One of the well-known solutions is water injection dredging (WID). In general, WID is proven to be cheaper than the hopper dredging by leaving the sediment in place, thus, eliminating substantial costs for relocation of the dredged sediment.
In autumn 2018, the utility of WID and fluid mud trapping was investigated in the Port of Rotterdam. As a first step, the sediment trap was made in the Calandkanaal. Next, the WID actions were carried out for fluidization of the top layer sediment around the deepening and horizontal transport of the fluidized mud into the sediment trap. The WID actions were monitored by means of multi-beam and single-beam echo-sounding surveying methods at low (15-38 kHz) and high frequencies (200-400 kHz). After WID has taken place, the sediment trap was regularly surveyed for 3 months. Apart of abovementioned echo-sounding surveying methods, different penetrometers were used for monitoring the settling and consolidation processes in the sediment trap. We used Graviprobe, Rheotune and DensX for measuring the shear strength, the yield stress and the density of sediment, respectively. These measurements were compared to the ones in laboratory, where the densities and the yield stresses of sediment samples were measured independently.
It was concluded that the water injection dredging method can be efficiently used for fluidizing and transporting weak fluid mud layers. In-situ measuring tools are available for characterizing the behavior of fluidized sediment. Based on our experimental investigation, it can be concluded that new cost-effective port maintenance strategy is feasible in the port.","Water injection dredging; sediment trap; shear strength; maintenance","en","conference paper","CEDA - Central Dredging Association","","","","","Accepted Author Manuscript","","2020-05-08","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:57eb0947-760b-43a9-9826-f96312bae7d0","http://resolver.tudelft.nl/uuid:57eb0947-760b-43a9-9826-f96312bae7d0","Finding the relevance of staff-based vehicle relocations in one-way carsharing systems through the use of a simulation-based optimization tool","Santos, Gonçalo Gonçalves Duarte (Lisbon Technical University; Universidade de Coimbra); Correia, Gonçalo (TU Delft Transport and Planning; Universidade de Coimbra)","","2019","This paper proposes a real-time decision support tool based on the rolling-horizon principle that manages staff activities (relocations and maintenance) of a one-way carsharing system and considers carpooling the staff in the relocated carsharing vehicles for extra cost reduction. The decision support tool is composed of three elements: a forecasting model, an assignment model and a filter. Two assignment models are proposed and tested: rule-based and optimization. The rule-based model uses simple rules to respond to system status changes, and the optimization model is a mixed integer programing (MIP) model prepared to work in real-time. A simulator was designed to test the decision support tool and an application is done to the city of Lisbon, Portugal, showing that the benefits of staff relocations can be rather low. It was verified that the number of relocations that can physically be performed by each staff member in the case study provide only a small improvement in the revenues, which is unlikely to overcome the costs associated with hiring and staff activity.","Carsharing; maintenance; optimization; relocations; simulation","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:51e225f2-31a7-4793-87ac-f0f6c1792591","http://resolver.tudelft.nl/uuid:51e225f2-31a7-4793-87ac-f0f6c1792591","Measuring the solids loading of urban drainage systems via run off","Rietveld, M.W.J. (TU Delft Sanitary Engineering); Clemens, F.H.L.R. (TU Delft Sanitary Engineering; Deltares); Langeveld, J.G. (TU Delft Sanitary Engineering; Partners4UrbanWater)","","2019","Sewer and urban drainage systems deal with the runoff of areas that lack infiltration capacity. During wet weather, solids that are present on the street are (re)mobilised and transported to the drainage system by the runoff. These solids and their associated pollutants can have detrimental effects on receiving water quality. This paper presents a new measurement device which has been developed to measure the inflow of solids in gully pots. This device has been applied to 100 gully pots over a period of a year, rendering a large dataset of solid inflows to the sewer. The results indicate that only 25% of solids is captured in gully pots without this device. This renders a huge potential for further optimisation of gully pot management, which is typically optimised towards prevention of blockage rather than removing a maximum amount of solids.","Catch basin; gully pots; maintenance; solids; urban drainage","en","conference paper","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:176ddb86-5cc9-4ddd-87d0-aebee47b5b1e","http://resolver.tudelft.nl/uuid:176ddb86-5cc9-4ddd-87d0-aebee47b5b1e","Committee III.2: Fatigue and Fracture","Garbatov, Y.; Ås, S.K.; Branner, Kim; Choi, B.K.; den Besten, J.H. (TU Delft Ship Hydromechanics and Structures); Dong, P.; Lillemäe, I.; Lindstrom, P.; Lourenço de Souz, M.; Parmentier, G.; Quéméner, Y.; Rizzo, C.M.; Rörup, J.; Vhanmane, Suhas; Villavicencio, R.; Wang, F.; Yuan, Yue","Kaminski, M.L. (editor); Rigo, P. (editor)","2018","Concern for crack initiation and growth under cyclic loading as well as unstable crack propagation and tearing in the ship and offshore structures. Due attention shall be paid to the suitability and uncertainty of physical models and testing. Consideration is to be given to practical application, statistical description and fracture control methods in design, fabrication and service.","Fatigue; fracture; steel; aluminium; polymer composites; damage accumulation; crack growth; fabrication; inspection; maintenance; reliability; design; verification; fitness for service; rules; standards","en","conference paper","IOS Press","","","","","","","","","","Ship Hydromechanics and Structures","","",""
"uuid:7b04bf33-16fe-4ab1-befa-dfb55f3bc9d5","http://resolver.tudelft.nl/uuid:7b04bf33-16fe-4ab1-befa-dfb55f3bc9d5","Optimal scheduling of track maintenance activities for railway networks⁎","Su, Z. (TU Delft Team Bart De Schutter); De Schutter, B.H.K. (TU Delft Team Bart De Schutter)","","2018","We consider optimal scheduling of track maintenance activities for a railway network divided into sections. The goal is to find an optimal time schedule for the maintenance activities and optimal routes for the maintenance crew (including all necessary equipment and technicians) that minimize the total setup costs and the travel costs over the whole planning horizon. The maintenance time budget, which can be the same, different, or flexible for each period, and the minimum time to maintain a section are also taken into account. We recast the track maintenance scheduling problem with three different settings as three variants of the Capacitated Arc Routing Problem with Fixed cost (CARPF), which are solved by transforming them into three node routing problems. The proposed approach is demonstrated using a case study of a part of the Dutch regional network.","arc routing problem; logistics; maintenance; railway infrastructure; scheduling","en","journal article","","","","","","","","","","","Team Bart De Schutter","","",""
"uuid:9026f664-a03a-4cd2-9e7a-a9589889d6dc","http://resolver.tudelft.nl/uuid:9026f664-a03a-4cd2-9e7a-a9589889d6dc","Evolution of Decision Support Systems for Railway Infrastructure Managers","Buhksh, Zaharah Allah (University of Twente); Stipanovič, Irina (University of Twente); Gavin, Kenneth (TU Delft Geo-engineering); Doree, Andre (University of Twente)","","2018","Infrastructure maintenance is a complex task due to operational needs of service quality, availability demands, traffic intensity, and budget constraints. Traditionally, maintenance decisions are based on infrastructure managers' experiences, judgments, and available choices. Though, the technology push and the availability of an abundance of data have made an urge to derive the decisions and insights from data. This data-driven approach resulted in computerized solutions, e.g. decision support system (DSS), which are rich in data but poor in insights. The DSS confronted with data management challenges of data acquisitions, data cleaning, and data reliability further complicate the already complex task of maintenance decision-making. To tackle these challenges of maintenance decision-making and data management, a decision-driven approach is suggested for the development of DSS. The decision-driven approach builds on the definition of decision context specified by infrastructure manager. The data requirements are provided by decision context, where the interrelationships between the data and the decision context are made explicit by developing an information model. We illustrate the decision-driven approach for DSS development using a case study of maintenance decisions for bridge selection. It is found that the decision-driven approach directs the focus towards the decision context definition and decision analysis while minimizing the overhead of data management.","decision-driven; decision support system; railway assets; maintenance","en","conference paper","","","","","","","","","","","Geo-engineering","","",""
"uuid:ae9d5983-dd22-46ee-883b-ee1999f4ac53","http://resolver.tudelft.nl/uuid:ae9d5983-dd22-46ee-883b-ee1999f4ac53","Life-Cycle Management Model for Tunnels","Škarič−palič, Sandra (Infra Plan Consulting Ltd.); Stipanović Oslaković, Irina (University of Twente); Kovačević, Meho Saša (University of Zagreb); Gavin, Kenneth (TU Delft Geo-engineering)","","2018","Tunnels are a vital link in transport networks which represent a significant investment in all life cycle phases from planning, investigation works, construction and operation. Decisions through the whole life cycle of a tunnel should be based on solid facts and reliable data especially in the context of considerable impacts on both the environment and society. The calculation of total life time costs for different design alternatives, maintenance options and societal impacts can be used to compare different technical solutions and select the optimal design and maintenance alternative.
Generally problems related to tunnel degradation can be divided into those caused by external pressure and those caused by the deterioration of materials. These problems are gradually increased through all life cycle stages of a concrete structure such as a tunnel, therefore decisions about the timing and the type of maintenance should be based on degradation prediction models and monitoring of the structure performance or degradation processes. Uncertainties in the decision making process can be decreased by using information from monitoring which are used to establish triggering thresholds for the structure passing certain performance levels. In this paper the use of monitored tunnel deformations in a life cycle management model for a tunnel is presented. The monitoring data gives information about tunnel long term deformations that are used in the decision making process, in order to prevent occurrence of tunnel damage and consequently large maintenance costs.","tunnels; maintenance; life cycle management model; decision making","en","conference paper","University of Zagreb","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-02-02","","","Geo-engineering","","",""
"uuid:7aa1ce87-eefd-41a2-b25d-2dc41dc76bb5","http://resolver.tudelft.nl/uuid:7aa1ce87-eefd-41a2-b25d-2dc41dc76bb5","Bilateral collaboration in built heritage material research and resource maintenance supportive to smart and sustainable cities","Quist, W.J. (TU Delft Heritage & Technology); Clarke, Nicholas (TU Delft Teachers of Practice; University of Pretoria); van Hees, R.P.J. (TU Delft Heritage & Technology; TNO)","Conradie, D.C.U. (editor); du Plessis, C. (editor); van den Dobbelsteen, A.A.J.F. (editor)","2017","Built heritage contains value on many scales. On the most basic level it represents the investment of building materials following a constructional logic. As the use of once-predominant materials goes out of fashion due to changing technological regimes and architectural styles, knowledge about them is lost. Yet retaining and maintaining their embodied energies in place is an important aspect of resource efficiency. Waste management, circularity and in situ retention of built fabric as useful resource is a sustainability ambition for built environment systems in general and for heritage conservation in particular.
The Netherlands and South Africa have a long historic association. Therefore commonality is to be found in the constructional logic of the shared built heritage of both countries. This historic association brought the transfer of construction components through material streams as well as the transfer of knowledge from the Netherlands to climatically different South Africa. It is expected that the historic transfer of knowledge and materials from the Netherlands to South Africa has led to climate adaptive and practical alterations of Dutch principles. These hold potential to shed valuable new light on retaining built fabric in the Netherlands average temperatures are increasing. Dutch knowledge on maintenance and repair can augment the rather scant South African body of knowledge on material maintenance and repair.
This paper will explore the possibilities for collaborative research on material maintenance and repair from the perspective of Smart and Sustainable Cities, identifying opportunities for collaboration in the commonalities that exists between the Netherlands and South Africa.","maintenance; material resources; repair; shared built heritage; the Netherlands-South Africa","en","conference paper","CSIR","","","","","","","","","","Heritage & Technology","","",""
"uuid:e813298e-93d8-4a76-a7ab-72b327bcde4b","http://resolver.tudelft.nl/uuid:e813298e-93d8-4a76-a7ab-72b327bcde4b","Prediction of belt conveyor idler performance","Liu, X. (TU Delft Transport Engineering and Logistics)","Lodewijks, G. (promotor); Pang, Y. (copromotor); Delft University of Technology (degree granting institution)","2016","","bulk material; condition monitoring; maintenance; belt conveyor; idler; reliability","en","doctoral thesis","TRAIL Research School","978-90-5584-207-0","","","","TRAIL Thesis Series T2016/14, The Netherlands TRAIL Research School","","","","","Transport Engineering and Logistics","","",""
"uuid:156459c6-1216-45b3-95ca-9aa93619e164","http://resolver.tudelft.nl/uuid:156459c6-1216-45b3-95ca-9aa93619e164","Risk Based Maintenance in Electricity Network Organisations","Mehairjan, R.P.Y.","Smit, J.J. (promotor); Djairam, D. (promotor)","2016","Presently, maintenance management of assets in infrastructure utilities such as electricity, gas and water are widely undergoing changes towards new working environments. These are mainly driven against the background of stringent regulatory regimes, an ageing asset base, increased customer demands and constrained financial resources. Therefore, it becomes imperative for infrastructure utilities to strive towards more effective and efficient operation and maintenance approaches. In this light, new asset management approaches such as risk management are gaining more interest worldwide. In this research the focus has been on the framework for introducing modern maintenance management in electricity network organisations. It covers the development and practical application of enabling factors for maintenance management such as organisation capabilities, maturity models, structured and comprehensive frameworks for assessing risk based maintenance policies and decision-making tools and technologies. Thus, an integral, multi-disciplinary, approach towards maintenance management needs to be established, which is a challenge that has been taken up in this thesis for electricity network organisations.","maintenance; management; risk; electricity network; asset management; reliability; condition monitoring; organisation; maturity models; ISO 55000; utility; performance; risk based maintenance; statistical life data analysis; strategy","en","doctoral thesis","","","","","","","","2016-05-08","Electrical Engineering, Mathematics and Computer Science","Electrical Power Engineering","","","",""
"uuid:a1a551d4-6ede-4049-b8c1-4d3f53d33ac8","http://resolver.tudelft.nl/uuid:a1a551d4-6ede-4049-b8c1-4d3f53d33ac8","Functional thresholds for designmaintenance of urban pavements: Functional criteria for sustainable design of urban pavements","Pradena, M.A. (TU Delft Pavement Engineering; University of Concepcion); Houben, L.J.M. (TU Delft Pavement Engineering)","","2016","Functional criteria have been mostly defined in urban pavements using subjective methods, rather than by means of objective and repeatable procedures. The Whole
Body Vibration, the Heart Rate Variability, and new technologies to determine the
IRI (International Roughness Index), are nowadays available. For that, an analysis of
available technologies is made under a PC-O (Pavements Clients-Oriented) integral
perspective, including simulations with the HDM-4 computer program. The IRI
criteria for speeds allowed on urban roadways, i.e. the so-called IRIcity criteria, are
proposed in the paper.","pavements; functionality; design; maintenance; IRI; HDM-4","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:19dfb43e-e9af-4b56-85c3-4c0f63f802eb","http://resolver.tudelft.nl/uuid:19dfb43e-e9af-4b56-85c3-4c0f63f802eb","Dutch municipalities and the quality of the owner-occupied housing stock","Meijer, F.M.; Visscher, H.J.","","2015","Owners are responsible to maintain their own dwellings in an adequate manner. In practice however all kinds of constraints occur. Lack of financial means and insufficient (technical or practical) knowledge are the most important barriers. Because the quality of owner-occupied housing exceeds the individual interest; there are also general concerns to consider. Qualitative seriously substandard owner occupied dwellings can have negative effects on streets and neighbourhood. That is why Dutch municipalities pay more and more attention to the quality of the private housing sector. They observe that the physical quality of parts of the older owner-occupied stock is far from satisfying and partly seriously substandard. Apart from the maintenance situation, energy saving is an important other reason for municipalities to show an interest in the private housing sector, because of its large energy saving potential. Municipalities are coping with the question if and (if yes) how they can kill these two birds (quality and energy improvement) with one stone. On the basis of studies in several municipalities the question will be answered how municipalities can effectively intervene to improve the (physical and energetic) quality of owner-occupied housing.","energy saving; housing quality; maintenance; policy instruments; private housing stock","en","conference paper","Royal Institution of Chartered Surveyors (RICS)","","","","","","","","Architecture and The Built Environment","OTB","","","",""
"uuid:5238d48c-722c-4928-9ab8-b05ff771228e","http://resolver.tudelft.nl/uuid:5238d48c-722c-4928-9ab8-b05ff771228e","Upcoming Role of Condition Monitoring in Risk-Based Asset Management for the Power Sector","Mehairjan, R.P.Y.; Zhuang, Q.; Djairam, D.; Smit, J.J.","","2014","The electrical power sector is stimulated to evolve under the pressures of the energy transition, the deregulation of electricity markets and the introduction of intelligent grids. In general, engineers believe that technologies such as monitoring, control and diagnostic devices, can realize this evolvement smoothly. Unfortunately, the contributions of these emerging technologies to business strategies remain difficult to quantify in straightforward metrics. Consequently, decisions to invest on these technologies are still taken in an ad hoc manner. This is far from the risk-based approach commonly recommended for asset management (AM). The paper introduces risk-based management as a guiding principle for maintenance management. Then, the triple-level AM model (strategic, tactical and operational) as the foundation to define risk-based AM is described. Afterwards, two categories of risks, one triggered by technical stimuli and the other by non-technical stimuli are introduced. It is shown that the main challenge of managing risks with technical stimuli is to have the ability to understand the technical cause of failures, which is located at the operational level within the triple-level AM model. One method to quantitatively understand the technical cause of failures is by means of condition diagnostic and monitoring technologies. Therefore, the aim of this paper is to clarify the potential contribution of condition diagnostic and monitoring technologies to risk-based decision making for the power sector. This paper shows that, in practice, the implementation of condition diagnostic and monitoring technologies is mainly driven by purely technical asset based considerations without evaluating the contribution to, for instance, risks. This paper provides a list of aspects in which condition diagnostic and monitoring may contribute to risk evaluation with technical stimuli. The listed aspects (which are: (1) asset specific condition data, (2) timely condition data and (3) predictive condition data) can be regarded as input for the probability of failure and as influencing input for the consequence of failure, hence benefiting quantitative risk studies and AM activities (such as condition assessment/maintenance or replacement). Finally, these benefits can be evaluated afterwards in a risk-based AM planning stage, so that asset managers can justify investments on necessary technical improvements of condition monitoring systems.","asset management; maintenance; risk management; condition monitoring; electricity networks","en","conference paper","Springer","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Electrical Sustainable Energy","","","",""
"uuid:9bb17c02-80c4-4e2a-917b-6b3eed182132","http://resolver.tudelft.nl/uuid:9bb17c02-80c4-4e2a-917b-6b3eed182132","How to achieve aircraft availability in the MRO&U triad","Kaelen, J.W.E.N.","Santema, S.C. (promotor)","2014","The financial crisis and the introduction of low-budget companies have brought major changes to the air freight community. Competition became stronger and cost control became more important. This led to new ways of organizing aircraft Maintenance, Repair, Overhauls and Upgrades (MRO&U), which became performance oriented. For the triad of participants in the maintenance process, the Original Equipment Manufacturer (OEM), the maintainers and the operator, this meant that they had to change their way of working, their processes and their culture. The focus shifted to delivering performance i.e. aircraft availability. The objective of the current research is to contribute to the development of a theory on how to achieve the performance objective aircraft availability as outcome of the MRO&U triad collaboration. This qualifies the current research as a theory building research. The outcome of the present research is a model on how to improve and optimize aircraft availability as outcome of collaboration in the aircraft MRO&U triad. This model on how to improve aircraft availability in the MRO&U process contributes to the increase of the turn-over per aircraft and hence the financial performance of airliners, as well as to the optimization of the MRO&U process. This research is therefore of interest for airline operators, aircraft maintainers and aircraft OEM’s.","aircraft; maintenance; optimization; MRO&U; collaboration; performance","en","doctoral thesis","","","","","","","","","Industrial Design Engineering","PIM","","","",""
"uuid:a60c3f4c-f5c9-499c-870d-76e8bc4ab299","http://resolver.tudelft.nl/uuid:a60c3f4c-f5c9-499c-870d-76e8bc4ab299","Automatic detection of squats in railway infrastructure","Molodova, M. (TU Delft Railway Engineering); Li, Z. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering)","","2014","This paper presents an automatic method for detecting railway surface defects called “squats” using axle box acceleration (ABA) measurements on trains. The method is based on a series of research results from our group in the field of railway engineering that includes numerical simulations, the design of the ABA prototype, real-life implementation, and extensive field tests.We enhance the ABA signal by identifying the characteristic squat frequencies, using improved instrumentation for making measurements, and using advanced signal processing. The automatic detection algorithm for squats is based on wavelet spectrum analysis and determines the squat locations. The method was validated on the Groningen–Assen track in The Netherlands and accurately detected moderate and severe squats with a hit rate of 100%, with no false alarms. The methodology is also sensitive to small rail surface defects and enables the detection of squats at their earliest stage. The hit rate for small rail surface defects was 78%.","Axle box acceleration (ABA); Rail transportation; maintenance; railway monitoring; surface defects on railway rails","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:2dbca9c3-f096-4bb5-806a-bd42e3f09d40","http://resolver.tudelft.nl/uuid:2dbca9c3-f096-4bb5-806a-bd42e3f09d40","Analysing outsourcing policies in an asset management context: A six-stage model","Schoenmaker, R.; Verlaan, J.G.","","2013","Asset managers of civil infrastructure are increasingly outsourcing their maintenance. Whereas maintenance is a cyclic process, decisions to outsource decisions are often project-based, and confusing the discussion on the degree of outsourcing. This paper presents a six-stage model that facilitates the top-down discussion for analysing the degree of outsourcing maintenance. The model is based on the cyclic nature of maintenance. The six-stage model can: (1) give clear statements about the present state of outsourcing in each step of the model; (2) facilitate discussion about the desired future state of outsourcing and (3) identify of room for improvement in aligning the steps of the model. We successfully tested the model at the Dutch Road Agency in various workshops. We validated the model in discussions with experts, using the description of the past and present degree of outsourcing by the English Highways Agency. The model proves to be a simple means of communication to explain the outsourcing policy. This paper also describes the recent developments in outsourcing by Main Roads Western Australia, using the model.","asset management; maintenance; infrastructure; roads; highways; outsourcing; policy; governance; performance management","en","conference paper","IPWEA","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","","",""
"uuid:e0ff9d05-ae08-41ab-9f63-4769c0da2f28","http://resolver.tudelft.nl/uuid:e0ff9d05-ae08-41ab-9f63-4769c0da2f28","Infrastructure Management: Dynamic control of assets","Verlaan, J.G.; Schoenmaker, R.","","2013","The infrastructure in the Netherlands is crucial for economic development on a national scale. Dramatic increases of transport and mobility accelerate ageing of infrastructure. The GNP of the Netherlands is strongly related to transport and to the two main ports (Port of Rotterdam and Amsterdam Airport Schiphol). The Netherlands is used to a high standard of infrastructure and expectations of the Dutch are that this will continue. But in the public mind new capital works are predominating and renewal of existing infrastructure is taken for granted. This paper focuses on the maintenance and renewal of existing infrastructure. The economic growth and finance conditions, that gave rise to its initial development, has changed and financing of renewal and acquisition of new projects needs to be accomplished in a new and more complex economic climate. In order to provide a reliable, well-manufactured infrastructure, which satisfies public expectations, planning of the necessary activities should be carried out on tactical as well as strategical levels. The research is based on systems theory, and conditions for effective control are developed. The conceptual model is validated in real life cases in the Netherlands. The result of the research could be used as a framework for controlled, tactical asset management processes. It involves the application of detailed asset management processes, procedures and standards. This allows development of sub-plans for the allocation of natural, physical and financial resources, which may serve to achieve strategic goals by meeting defined levels of service.","infrastructure; assets; control; process; maintenance; traffic load; valuation; accounting standards","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","","",""
"uuid:eba16d03-2aed-45da-b78b-cc74d42e1151","http://resolver.tudelft.nl/uuid:eba16d03-2aed-45da-b78b-cc74d42e1151","The dynamics of outsourcing maintenance of civil infrastructures in performance based contracts","Schoenmaker, R.; De Bruijn, J.A.; Herder, P.M.","","2013","","outsourcing; maintenance; roads; highways; contracting; strategic behavior; performance","en","conference paper","Springer","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","","",""
"uuid:288ed504-60e4-4e47-8e73-203ec5984a45","http://resolver.tudelft.nl/uuid:288ed504-60e4-4e47-8e73-203ec5984a45","Risk Based Maintenance of Petroleum Pipelines","Dawotola, A.W.","Vrijling, J.K. (promotor); Van Gelder, P.H.A.J.M. (promotor)","2012","","risk assessment; pipeline; maintenance","en","doctoral thesis","","","","","","","","2012-10-02","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:cc7bc6f9-c39c-4cf5-b62f-6bf8b99ea600","http://resolver.tudelft.nl/uuid:cc7bc6f9-c39c-4cf5-b62f-6bf8b99ea600","Owner-occupiers and the quality of their dwellings","Meijer, F.M.; Tambach, M.; Visscher, H.J.","","2012","Home-owners are in principal responsible for maintaining the physical quality of their dwellings. It is in their own interest to do this in an adequate manner, but all kinds of constraints can and do occur in practice. Lack of financial means and insufficient (technical or practical) knowledge are only two of the possible barriers. The quality of owner-occupied housing sector exceeds the individual interest, there are also general concerns to consider. Qualitative seriously substandard owner-occupied dwellings can have various negative effects on the neighbourhood. This paper is based on an on-going research project on the quality and maintenance situation of the owner-occupied sector in the Netherlands. Within this project almost 4.000 Dutch home–owners have recently been questioned about issues concerning the quality of their dwelling, the maintenance actions they undertake, the problems they encounter and the help or advise they would like to get. This paper presents the first results. The results especially will give insight in the way home-owners cope with maintaining the quality of their dwellings. Are they doing an adequate job or are interventions of the Dutch authorities (for parts of the sector) necessary?","home-owners; housing quality; housing stock; maintenance; policy instruments","en","conference paper","Arizona State University","","","","","","","","OTB Research Institute for the Built Environment","OTB Research","","","",""
"uuid:3b2e95c0-39a7-4073-825d-cb537f2311d4","http://resolver.tudelft.nl/uuid:3b2e95c0-39a7-4073-825d-cb537f2311d4","Environmental impacts during the operational phase of residential buildings","Blom, I.S.","","2010","To date, the focus in the field of sustainable building has been on new building design. However, existing residential buildings inflict great environmental burden through three causes: continuous energy consumption, regular building maintenance and replacements. This publication analyses and compares these three causes of environmental burden and shows that material resources needed for replacements generally have a limited potential to reduce environmental impact. Reducing energy consumption for climate control and electrical appliances is much more effective. According to the author, sustainable measures should be tested for shifts in the kind of environmental impact caused due to the use of alternative types of energy resources and altered material quantities. The sustainability of the electricity supply is essential to decrease the total environmental impact of the residential building stock.","life cycle assessment (LCA); residential buildings; energy consumption; maintenance; replacement; facade; climate system","en","book","IOS Press","","","","","","","","OTB Research Institute","Sustainable and Healthy Housing","","","",""
"uuid:b8d98368-2049-4c8c-8c00-fdd3b48ddae3","http://resolver.tudelft.nl/uuid:b8d98368-2049-4c8c-8c00-fdd3b48ddae3","Environmental impacts during the operational phase of residential buildings","Blom, I.S.","Priemus, H. (promotor); Hendriks, N.A. (promotor)","2010","To date, the focus in the field of sustainable building has been on new building design. However, existing residential buildings inflict great environmental burden through three causes: continuous energy consumption, regular building maintenance and replacements. This publication analyses and compares these three causes of environmental burden and shows that material resources needed for replacements generally have a limited potential to reduce environmental impact. Reducing energy consumption for climate control and electrical appliances is much more effective. According to the author, sustainable measures should be tested for shifts in the kind of environmental impact caused due to the use of alternative types of energy resources and altered material quantities. The sustainability of the electricity supply is essential to decrease the total environmental impact of the residential building stock.","life cycle assessment (LCA); residential buildings; energy consumption; maintenance; replacement; facade; climate system","en","doctoral thesis","IOS Press","","","","","","","","OTB Research Institute","Sustainable and Healthy Housing","","","",""
"uuid:a3280fd3-8a4d-4f22-b4d2-fed577cfb01f","http://resolver.tudelft.nl/uuid:a3280fd3-8a4d-4f22-b4d2-fed577cfb01f","Improving industrial maintenance contract relationships","De Jong, A.","Smit, K. (promotor)","2010","Unavailability of technical systems, such as aircraft, is expensive. Technical systems require maintenance to prevent and to remedy defects that cause unavailability. Users of technical systems usually bear the consequences of the risk of unavailability, in particular the loss of productivity. This is based on the presumption that users are best able to insure the risks, although maintenance organisations may be more capable to mitigate the risks. The risks are seldom allocated to maintenance organisations because users and maintenance organisations tend to have conflicting objectives. This raises the questions if a maintenance organisation can be motivated to pursue the objective of the user. This would be possible if the maintenance organisation is rewarded for the “commercial success of the user of the technical system”. If the maintenance organisation indeed pursues the objective of the user of the technical system, the maintenance organisation can make autonomous decisions about the maintenance activities. And if the maintenance organisation can make decisions, it can make investments in measures to mitigate risks, knowing that it can decide if these measures will be employed. This research shows that it is efficient and effective to transfer the risks of the unavailability of a technical system from the user to the maintenance organisation on the condition that the maintenance organisation (a) will be compensated for the risks of unavailability, (b) will be rewarded for the contribution of the technical system to the commercial success of the user, and (c) is assigned the required decision rights. This will in practice require new “collaborative” contracts that can be used for the supply of long-term maintenance services of technical systems where unavailability causes a significant economic risk, for example in aircraft maintenance.","collaboration; contracting; maintenance; management; risk","en","doctoral thesis","","","","","","","","2010-05-03","Aerospace Engineering","Aerospace Industrial Engineering and Management","","","",""
"uuid:bc001a92-cd84-4bfa-9ba3-a50001bdcf61","http://resolver.tudelft.nl/uuid:bc001a92-cd84-4bfa-9ba3-a50001bdcf61","Cost savings from performance-based maintenance contracting","Straub, A.","","2009","New procurement approaches combined with performance-based building approaches should reduce costs, but empirical qualitative and quantitative studies are lacking. Performance-based maintenance contracts give maintenance suppliers incentives to improve their way of working. Innovative, cost-effective solutions that meet the performance criteria can be achieved, especially if the principle of whole-life costing is being adopted. Indirect cost savings are expected as well. It enables maintenance contractors to assume responsibility for certain activities for which they are better equipped to perform than their clients. A calculation model was developed that calculates the net present value of the direct (product) and indirect (transaction) costs at project level for a competitive maintenance tendering approach and for performance-based maintenance contracts. The fi ndings show that performance-based maintenance contracts reduce both direct and indirect costs compared to a competitive tendering approach. Essential preconditions are an early supplier involvement and longer term contracts, giving opportunities for maintenance product and maintenance process improvements.","maintenance; performance-based contracts; transaction costs; whole-life costing","en","journal article","Vilnius Gediminas Technical University","","","","","","","","OTB Research Institute","Sustainable housing transformations","","","",""
"uuid:1cf834b5-6094-40d3-9822-c62745603a0f","http://resolver.tudelft.nl/uuid:1cf834b5-6094-40d3-9822-c62745603a0f","Blijvend vlakke wegen - CROW-werkgroep integraal wegontwerp - evaluatie van schadecases uit de praktijk","Egmond-Weijburg, C.; Galjaard, P.J.; Van Gurp, C.A.P.M.","","2008","This report presents an inquiry into cases of pavement design, construction and maintenance in which distress has been observed instigated by deeper subgrade or by inadequate attention for the interaction between subgrade and pavement structure. Almost all cases are situated in areas with subgrade of poor to marginal bearing capacity. The cases are classified according to traffic; cross-section and elevation; moisture, groundwater, weather and temperature; aggregates in the pavement structure and subgrade. Each case starts with a brief introduction description followed by a description of the main problems. The analysis reveals the main cause of distress and tries to explain for its origin. The next step describes feasible off-the-shelve solutions or indicates in which direction future improvements should be found. The report ends with reflections on future actions to develop an integral approach for pavement design. Recommendations are made for issues which should be elaborated in computations with complex numerical models (Finite Element Model).","pavement design; construction; maintenance; Finite Element Model; Blijvend Vlakke Wegen; Integraal Wegontwerp; Evaluatie van schadecases uit de praktijk; wegontwerp; wegbouwkundige constructie; Eindige Elementen Methode; Infrastructuur; CT02.10; CT02.11.11; integrale modellen; Delft Cluster","nl","report","Delft Cluster","","","","","","","","","","","","",""
"uuid:6e5130ac-7bba-4607-8690-22e849539334","http://resolver.tudelft.nl/uuid:6e5130ac-7bba-4607-8690-22e849539334","The purchasing of maintenance service delivery in the Dutch social housing sector: Optimising commodity strategies for delivering maintenance services to tenants","Van Mossel, J.H.","Priemus, H. (promotor); Telgen, J. (promotor)","2008","For housing associations, maintenance is an opportunity for high quality interaction with their tenants, and thus an opportunity for effectively influencing the quality of service delivery to tenants. Dutch housing associations have a market share of about one third of the entire Dutch housing stock. They spent around 2.8 billion euros a year on the maintenance of dwellings, of which external service suppliers account for approximately 90 percent. These suppliers can be seen as an extension of the housing associations in fulfilling their public tasks and private objectives. At the moment maintenance service delivery appears to be to the tenant of a suboptimal quality leading to a lower than potential tenant satisfaction. With this an essential part of the objectives of housing associations is not fulfilled optimally. This PhD-research reveals the essential determinants of maintenance service quality in order to promote tenant satisfaction. Commodity strategies for the purchasing of maintenance services are developed which make its optimization possible from the perspective of tenant satisfaction.","maintenance; housing associations; purchasing; service management; customer satisfaction; tenants; social housing","en","doctoral thesis","IOS Press","","","","","","","","OTB","","","","",""
"uuid:2eac935e-cdb1-4c0c-92d1-cbcc8dd2d867","http://resolver.tudelft.nl/uuid:2eac935e-cdb1-4c0c-92d1-cbcc8dd2d867","Markov processes for maintenance optimization of civil infrastructure in the Netherlands","Kallen, M.J.","Van Noortwijk, J.M. (promotor)","2007","The Netherlands, like many countries in this world, face a challenging task in managing civil infrastructures. The management of vital infrastructures, like road bridges, is necessary to ensure their safe and reliable functioning. The Directorate-General for Public Works and Water Management in the Netherlands manages the structures in the national road network. A large number of bridges and viaducts were constructed during the 1960's and 1970's. Due to many factors, it is difficult to determine the exact length of the remaining life of a structure. This is why the manager frequently performs inspections and registers the state of each structure in a database. A principal element of bridge management systems is the estimation of the uncertain rate of deterioration. This is usually done by using a suitable model and by using information gathered on-site during inspections. This thesis proposes a statistical and probabilistic framework, which enables the decision maker to estimate the rate of deterioration and to quantify his uncertainty about this estimate. The framework consists of a continuous-time Markov process with a finite number of states to model the uncertain rate at which the quality of structures reduces over time. The result of this research is a unified approach to modeling uncertain deterioration and decision making for optimal maintenance management. It has been succesfully applied to condition data of more than 3000 concrete structures in the Netherlands which were gathered from 1985 to 2004.","bridge; deterioration; uncertainty; Markov process; maintenance; reliability","en","doctoral thesis","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:239bdb2c-b59f-40d2-91b7-367139dbad13","http://resolver.tudelft.nl/uuid:239bdb2c-b59f-40d2-91b7-367139dbad13","Renovation techniques for fatigue cracked orthotropic steel bridge decks","de Jong, F.B.P.","Bijlaard, F.S.K. (promotor)","2007","This dissertation presents the research into renovation techniques for orthotropic steel bridge decks. These techniques are needed to solve fatigue problems in the decks of these bridges, as several fatigue cracks have been detected in the deck structure of these bridges the last decade. A well-known example of fatigue cracks are those observed in the deck plate of the Van Brienenoord bascule bridge in 1997, at that time a 7 year old bridge. The renovation techniques are part of a proposed maintenance philosophy for steel bridge decks. Lifetime calculations, inspections and renovation techniques are the three essential parts of this philosophy. A reliable lifetime calculation model for fatigue damage in the deck plate is described, including the influence of the asphalt surfacing. Accurate calculation results are obtained, both for movable and fixed bridges. Inspection programs can be based on the lifetime calculation results. Several innovative inspection techniques are presented briefly. For fixed bridges the replacement of the asphalt surfacing with a reinforced high performance concrete surfacing is an effective renovation method. For movable bridge decks three solutions that extend the lifetime of the orthotropic deck structure were researched in this thesis.","orthotropic; steel; bridge; fatigue; renovation; inspection; maintenance; high performance concrete","en","doctoral thesis","","","","","","","","","Civil Engineering and Geosciences","","","","",""
"uuid:f4da7581-6422-48da-9f26-1796fed2d96f","http://resolver.tudelft.nl/uuid:f4da7581-6422-48da-9f26-1796fed2d96f","Performance-based maintenance agreements by Dutch housing associations","Straub, A.","","2006","","maintenance; partnering; performance measurement; performance requirements; value","en","conference paper","University of Salford","","","","","","","","OTB Research Institute for the Built Environment","","","","",""
"uuid:89fc8eef-277e-4b94-a3bc-0cba11d35eb9","http://resolver.tudelft.nl/uuid:89fc8eef-277e-4b94-a3bc-0cba11d35eb9","Quality of social housing in the Netherlands and England","Meijer, F.M.; Vijverberg, G.A.M.","","2006","","building regulation; maintenance; social housing; quality; investment","en","conference paper","Hong Kong Polytechnic University; Dept. Building and Real Est","","","","","","","","OTB Research Institute for the Built Environment","","","","",""
"uuid:b30d21bb-c123-4d8c-b02f-cf6c1cb6dae8","http://resolver.tudelft.nl/uuid:b30d21bb-c123-4d8c-b02f-cf6c1cb6dae8","Railway design and maintenance from a life-cycle cost perspective: A decision-support approach","Zoeteman, A.","Van der Heijden, R.E.C.M. (promotor); Esveld, C. (promotor)","2004","","railway infrastructure; maintenance; life-cycle costing; decision support","en","doctoral thesis","TRAIL Research School","","","","","","","","Technology, Policy and Management","","","","",""
"uuid:944b12d1-e06a-42bc-bc9e-c15268d62181","http://resolver.tudelft.nl/uuid:944b12d1-e06a-42bc-bc9e-c15268d62181","Effect of Spatial Variability on Maintenance and Repair Decisions for Concrete Structures","Li, Y.","Vrouwenvelder, A.C.W.M. (promotor); Walraven, J.C. (promotor)","2004","Due to the increasingly number of elder and deteriorating structures, maintenance is becoming a serious and more complex problem in most of the countries. A lot of studies have been carried out in this area for years. However, the fact that a lot of parameters show spatial random variability, which is linked with dependencies on temperature, w/c ratio, cement type, humidity and workmanship, is not included explicitly in most of the previous studies. Therefore, the main objective of the project is to develop a maintenance cost prediction model that helps to determine the optimal maintenance strategy with special consideration of the spatial variability of concrete degradation. The scope of the research is limited to concrete structures and especially concrete bridges. The starting-point of this project is the functional requirements that a structure must meet during its service lifetime. In this thesis an improved and more realistic approach have been developed based on the commonly used probability-based reliability methods, but taking into account the spatial variability of concrete properties. It can provide not only the probability of failure of the structures over time like other reliability methods, but also can produce useful information as the proportion or percentage of the surface area that show concrete deterioration e.g., the area with initiation of rebar corrosion, cracking, spalling, etc. during the whole period of time. This information can facilitate the repair or maintenance strategies for concrete structures from practical point of view. In addition, a maintenance cost prediction model was developed. Decision making of the optimal maintenance or repair strategy is based on the maintenance cost-based optimisation method. The approach developed in the present research is a successful supplement to the current probability-based reliability analysis method and it is also a good way to apply theoretical models in practice, in which the calculation results can be comparable with the inspections directly. The approach is instantiated successfully in three practical cases. The great importance of finding the right spatial variation of the parameters is shown in this thesis so as to evaluate the structural condition correctly. It is strongly recommend that more tests should be implemented specially in the future for finding the real spatial fluctuation parameters of the structures, e.g., the value of fluctuation scale and the common source of correlation coefficient. The approach is worth of more research and development in the future.","spatial variability; maintenance; deterioration; concrete structures; repair; maintenance costs; decision making; life-cycle costs; probability-based; optimal maintenance strategy","en","doctoral thesis","Delft University Press","","","","","","","","Civil Engineering and Geosciences","","","","",""
"uuid:0a209a05-882b-4d29-8a60-5fd775eb7400","http://resolver.tudelft.nl/uuid:0a209a05-882b-4d29-8a60-5fd775eb7400","Performance-based maintenance procurement by Dutch housing associations","Straub, A.","","2004","OTB Research institute has established a long-term research program to performance-based maintenance procurement in the technical management of housing stock. Stakeholders: housing associations, contractors and the Dutch Building Research Foundation are directly involved in this research program. Literature reviews, case studies, expert meetings and modelling of processes are part of our research methods. Dutch housing associations contract out most of their maintenance work and improvements. The outsourcing and commissioning of maintenance is becoming less of a commitment to carry out specific works according to a work program, and more of a performance-based co-operation between the client and contractors. Housing associations have developed performance-based contracts for paintwork including work to the substrates, flat roofing, lifts and central heating systems. The performance has to do with the performance of the elements during time and sometimes also to the service level, e.g. the response time and active maintenance time for breakdown service. A breakthrough of performance-based maintenance contracts is obstructed by a lack of knowledge of clients and contractors, desired flexibility in maintenance policy by clients and their desired low market prices. In many cases the contract period is restricted to maintenance work cycles of elements. Maintenance contractors want to be kept involved in the maintenance of housing complexes during a long period, for the optimal use of their knowledge.","maintenance; outsourcing; performance-based; procurement; technical management","en","conference paper","Department of Building Services Engineering","","","","","","","","OTB","","","","",""
"uuid:fe7797a0-3862-41b8-b57f-5e81c798fe6f","http://resolver.tudelft.nl/uuid:fe7797a0-3862-41b8-b57f-5e81c798fe6f","Duurzame OnderhoudsSystematiek (DOS) voor voorzieningen op slappe bodem – onderdeel zettingsprognose","Maccabiani, J.; Spruit, R.; Van Deen, J.K.","","2003","De publieke ruimte met de binnenstedelijke infrastructuur van wegen, riolering, oever- en groenvoorzieningen vergt naast grote investeringen tevens een groot jaarlijks bedrag aan onderhoud. Met name in de gebieden met slechte bodemgesteldheid zijn deze jaarlijkse onderhoudskosten een grote last voor de betreffende gemeenten en lagere overheden. Grote uitgaven voor het beheer van de stedelijke infrastructuur op zettinggevoelige ondergrond leiden tot financiële problemen voor een aantal gemeenten in West-Nederland. Een geïntegreerd systeem voor beheer van ondergrondse èn bovengrondse infrastructuur ontbreekt momenteel. De instandhouding van openbare voorzieningen, zoals riolering, wegen, water en groen, op zeer slappe veenondergrond is een complexe zaak door het grote aantal technische aspecten dat daarbij een rol speelt in combinatie met de hoge kosten.","Decision Support System; settlement; maintenance; CT03.10; DOS; duurzaam; onderhouds strategie; slappe bodem; CT03.12.11; zettingsvoorspellingen; afwegingsmodellen; Delft Cluster; onderhoud; 04.01.02; zettingsvoorspellingen; zettingsprognose; afwegingsmodellen","nl","report","Delft Cluster","","","","","","","","","","","","",""
"uuid:f653eb1b-4989-4221-9c1f-f73d16767ec2","http://resolver.tudelft.nl/uuid:f653eb1b-4989-4221-9c1f-f73d16767ec2","Using a condition-dependent approach to maintenance to control costs and performances","Straub, A.","","2003","","condition assessment; defect; maintenance; performance; six-point condition scale","en","journal article","Emerald","","","","","","","","","","","","",""
"uuid:12108cb3-0624-4b72-b747-c80b06013f2b","http://resolver.tudelft.nl/uuid:12108cb3-0624-4b72-b747-c80b06013f2b","Economical optimization of the maintenance of a river bed protection construction","Kuijper, H.K.T.; Vrijling, J.K.","","1994","This example of optimizing the maintenance by minimizing the sum of the present values of the tisk and the costs of repair in a certain plan peliod is a part of a study done by the author by order of the Delft University of Technology. In this study also a classification of ageing models and a definition of the usefulness of inspection is given. By means of this definition the inspection peliod can be optimized.","river bed protection; economical optimization; ageing model; repair internal; maintenance; failure rate","en","journal article","Delft University of Technology","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""