The trend in many countries is to outsource maintenance with competitive tendering. The design of the tender is then a crucial issue. A new type of tendering contract, called "Integrated Bridge Maintenance", was introduced in one experimental area in Sweden. In this case the preventive bridge maintenance is separated from the standard road maintenance contract. The ideas behind these changes are that the new approach can increase efficiency through a combination of in­creased specialization, economies of scale and through giving the private contractor a greater degree of freedom concerning exactly what to do and exactly when to do it. A pilot project has been running since 2004 for all bridges in Uppsala County with about 400 bridges and since 2007 for all bridges in Örebro County with about 700 bridges.   The experiences and lessons from this pilot project are presented in this thesis together with guidelines on how to procure Integrated Bridge Maintenance in the future. An important feature of the contract was that it contained a combination of specific measures that the contractor should carry out and properties of the bridges that the contractor was responsible to maintain. This created a balance between predictability and flexibility for the contractor. The contractor could make long term planning for the work. The client was satisfied because of increased com­petence and a low price. The latter can partly be explained by the possibility for the specialised bridge crew to receive additional work from other clients. As information about old bridges always is incomplete a partnering structure needs to be built into the contract. Experi­ence has also shown that a conscious policy to maintain long run competition is important. The general conclusion is that the project was seen as successful and as creating more "value for money".   To manage a bridge stock optimally from a life cycle perspective is a very complex task, since the condi­tions for the individual bridge can vary greatly from place to place which the answers from the research questions indicate. Besides following-up and evaluating the Integrated Bridge Maintenance projects a number of research questions have been studied.   Is Integrated Bridge Maintenance a successful method to increase the effectiveness and to increase the standard in bridge maintenance alternatively increasing the service life for the bridge stock at an optimal cost, i.e., will IBM lead to lower LCC? It is difficult to answer this question with exact numbers after so short time, but so far the opinion is that the effectiveness has increased. How can a bridge stock develop over a long time e.g. 15 years? Based on historical data one can calculate, for instance, new construction rate, demolition rate and average age for the bridge stock. This information could together with different future scenarios be a basis for different bridge management strategies for the actual bridge stock. What is the real service life for a bridge? Survival analysis for the different types of bridges in the actual bridge stock will give a good estimate of the different expected service life. Why and at which age are bridges de­molished? Two main reasons were found in this study: deterioration process of the bridge had gone too far and/or load bearing capacity was too low, and road were rerouted. What is the real service life for a bridge edge beam, one of the most often repaired element of Swedish bridges? Survival analysis of edge beams located on different types of roads will give a good estimate of the different expected service life.   How should a long-term contract for bridge maintenance and specially Integrated Bridge Maintenance be procured? The bridge manager should have a good understanding of the answers on the research ques­tions above when the tender documents are to be prepared for the actual bridge stock. Thereafter the area that the contract should cover could be chosen, a good balance between properties and measures, defining the working cycle for properties, a flexible partnering structure in the contract and a suitable length of the contract (x years) inclusive an option (+ y years) and finally good incentives in the contract.   To sum up, the main purpose with the doctoral project has been reached. A model for procurement of bridge maintenance has been developed; see the projects in Uppsala and Örebro. The contractor has deve­loped more effective methods for bridge maintenance. The doctoral project has been a step closer to the end goal of reducing the society’s costs for bridge maintenance in the future. The bridges should be func­tional to the lowest possible cost during its expected service life (LCC). The doctoral project has also con­tributed with new knowledge in the area of bridge maintenance, the actual development of a bridge stock over time, real service life for road bridges in Sweden and survival analysis. / QC 20100826

QC 20100930

The built environment usually constitutes a very important part of the real capital of a nation, and the construction sector represents more than 10% of the yearly Gross National Product of the industrialised world. Good planning of all construction is important, and consideration of the service life of the work is of great interest and is a significant aspect of sustainability considerations. The need for more knowledge about degradation of materials, for structured methodology, and for working tools for those involved in the planning process, has resulted in an extensive effort in pre-normative research and standardisation regarding this field. This thesis presents a discussion on service life planning and the role of the Factor Method in such work, and especially, discussion of modification and development of the methodology. In the design process, the need to evaluate the service life of products is a great challenge, as the results will depend on both material properties and the environment in which the material is placed or used. A practical solution has to be based on a good knowledge in the field, but also on a sound working strategy, to ensure that different design scenarios can be compared in a standardised or structured way. The Factor Method is a promising working tool for such an evaluation and comparison, but is as such, still more of a methodology, than a method. Examples of the use of the methodology are still very limited, and the method as such, is much discussed by researchers. However, its future will depend upon how practical it will be to apply in use. The method is useful to estimate the service life of products, based on a known reference service life and a number of modifying factors. These factors in turn depend on the conditional differences between the specific project and the reference, in-use conditions. This thesis discusses the required precision of such a methodology, especially in light of inherent distributions in material properties, and the fact that the consequences of failure are often very limited. In such cases, the standardised Factor Method is considered to be quite useful, and should give the parties involved a good means for working in a structured and systematic way. / QC 20101019

The focus in environmental management has during the last decades in many cases shifted to include all the phases in a product’s (or a service’s) life – the life-cycle perspective. The transport system has a large environmental pressure on the environment. Train traffic is habitually regarded as an environmentally preferable mean of transport, mainly depending on that trains often are driven by electricity. This view is also true when the operation phase alone is considered; at least if the electricity derives from renewable sources. In a life-cycle perspective the advantages of this mean of transport get less apparent. The extraction of the raw materials requires plenty of energy, energy which often is produced by fossil fuels. A dominating part of the material-related energy requirements in the railway infrastructure can be referred to a few materials. The main part of these materials can be found in a few products; rails, railway ties, ballast materials, cables and the contact wire system. It is here that the effort to reduce the environmental impact of the railway infrastructure should lie to become most efficient. The aim of the thesis is to investigate how the environmental pressure is affected by the service lives, i.e. the technical durability as well as the durability in practise, of the most energy-intense railway products, as well as reuse of them. The objective is to map estimated service lives and reuse in order to create scenarios representing the present state of how the products are used and reused in Sweden. The scenarios are used in order to analyse the importance of focusing on service lives and reuse when reducing environmental pressure. The objective is also to find out which possibilities and hindrances there are to increase the service lives and the reuse of the products. To investigate the environmental pressure of the railway infrastructure, embodied energy is used as indicator. Embodied energy represents the energy needed to produce a product, from extracting the materials to the production phase. The present state concerning service lives and reuse of the studied products are mapped through interviews with employees at Banverket and at VTI. The empirical material is analysed and scenarios are created in order to evaluate the environmental importance of service lives and reuse. Organizational issues concerning service lives and reuse are also investigated. The present state service lives varies between 25 and 100 years for the realistic scenarios for all the products. The estimated service lives varies between 25 and 100 years for the new technology scenarios. When it comes to the best-case scenarios the estimated service lives varies between 60 and 120 years, depending on railway product. The only products reused today are rails and railway ties. There are considerable improvements to be made by increasing service lives, and this pertains to all the studied products. The reductions in embodied energy per year go up to 75 % if the New-Technology Scenario is applied and to 33 % if the Realistic Scenarios are applied. If the Low Realistic Scenarios are applied the reductions goes up to 50 %. A great improvement potential exist for all the products if the New-Technology Scenarios are applied. The products where the main improvement potential when it comes to the Realistic and the Low Realistic Scenarios exist are the macadam-ballast, the cables, the rails and the railway ties. If the New-Technology Scenarios are applied for all the products the total improvement span is as much as 69 % altogether. If the Low Realistic Scenario instead is applied, the improvement span is calculated to 38-39 % (depending on the exchange level of macadam-ballast). If the Realistic Scenario is applied, the improvement span is calculated to 23 % and if the Best-Case Scenario is applied the span is calculated to 7 %, depending on that the most energy efficient strategy is to reuse the products possible to reuse. The main part of this improvement potential derives from the rails and the railway ties. In reducing the environmental pressure it is important to make use of the products as much as possible, i.e. to reuse them and use them as long as possible. If rails and railway ties are reused and made use of during their entire service life, all energy invested in the products is made use of. The most environmental sound alternative is to reuse the products which are reusable and to use these products as long as they last. This gives a need for embodied energy of 16 GJ/yr and km for the railway ties and 38 GJ/yr for the rails on the mainline track. The energy allocated to the tracks where the products are reused is calculated to 3 GJ/yr and km for the railway ties and to 7 GJ/yr and km for the rails. Actions of maintenance prolong the durability of the products, e.g. by increasing the stability in the embankment and hence reduce the wearing. The administration of the used material is the main problem in order to create a well-functioning reuse of railway articles. This includes transports, storage and documentation of products. Tradition and routines also stand in the way of creating a sustainable reuse of these products.

In this study, a detailed service life assessment procedure for solid propellant rockets under random environmental temperature and transportation loads is introduced. During storage and deployment of rocket motors, uncontrolled thermal environments and random vibratory loads due to transportation induce random stresses and strains in the propellant which provoke mechanical damage. In addition, structural capability degrades due to environmental conditions and induced stresses and strains as well as material capability parameters have inherent uncertainties. In this proposed probabilistic service life prediction, uncertainties along with degradation mechanisms are taken into consideration. Vibration loads are accounted by utilizing acceleration spectral density values which are induced during various deployment scenarios of ground, air and sea transportation. Furthermore, thermal loads are represented with a mathematical model being a harmonic function of time. Throughout the finite element analyses, a linear viscoelastic material model is to be used for the propellant. Change in the structural capability of the propellant with time is calculated using Laheru&#039 / s cumulative damage model. Moreover, to include aging effect of the propellant, Layton model is used. To determine the effects of induced stress and strains under variations and uncertainties in the random loads and material constants, mathematical surrogate models are constructed using response surface method. Limit state functions are utilized to predict failure modes of the solid rocket motor. First order reliability method is used to calculate reliability and probability of failure of the propellant grain. With the proposed methodology, instantaneous reliability of the propellant grain is determined within a confidence interval.

Controlled Low Strength Materials (CLSM) are cementitious self-compacting materials, comprised of low cement content, supplementary cementing materials, fine aggregates, and water. CLSM is typically used as an alternative to conventional compacted granular backfill in applications, such as pavement bases, erosion control, bridge abutments, retaining walls, bedding and backfilling of pipelines. This dissertation presents the findings of an extensive study carried out to determine the corrosivity of CLSM on ductile iron and galvanized steel pipelines. The study was performed in two phases and evaluated more than 40 different CLSM mixture proportions for their corrosivity. An extensive literature survey was performed on corrosion of metals in soils and corrosion of reinforcement in concrete environments to determine possible influential factors. These factors were used as explanatory variables with multiple levels to identify the statistically significant factors. Empirical models were developed for percent mass loss of metals embedded in CLSM and exposed to different environments. The first and only service life models for ductile iron and galvanized steel pipes embedded in CLSM mixtures were developed. Models indicated that properly designed CLSM mixtures can provide an equal or longer service life for completely embedded ductile iron pipes. However, the service life of galvanized pipes embedded in CLSM should not be expected to be more than the service life provided by corrosive soils.

­^¤åºK­n At the beginning of the 1990s, our government has invested aggressively into the field of Semiconductors and at the same time provided many opportunities and trainings for the professionals. This has enabled for the top professionals to excel in their respective field of work thus cultivating many outstanding manufacturers for the industry. Today, majority source of the automation equipments in the field of Semiconductors remains largely imported. These preferences lead to a higher cost ratio and cost effectiveness and has provided an uneven playing ground for our native corporations ready to take the overseas player head-on. Hereby, this report will focus on the nature of the product life cycle of the field to provide an insight to a suitable business and service model for our native corporations specializing in the mid and backend of Semiconductors to conform to the rigorous demand of the industry. The report also looks into individual corporations¡¦ competitiveness and their current roles in the supply chain for the industry. Their strategy and business model will be discussed and recommendations provided to improve their current practices to fulfill the evolving markets. The proposals and recommended business model can also be applied to other industries where the electro-optical industry and the next highly anticipated environmental friendly products industries could be adopt in the near future.

Material damage such as dislocations and microcracks are characteristic of early stages of fatigue. Accumulation of these nascent cracks leads to non-linear elastic response of the material. These non-linearities can be detected from harmonic generation for propagating elastic waves. The long term goal of this study is to investigate the non-linear elastic propagation in parts with complex geometry. Cellular Automata is introduced as a new simulation method, in order to develop new analysis on quadratic non-linearities. An existing linear code was progressively modified to take into account a different constitutive law. Also the boundary conditions need to be reviewed to ensure free stress with the non-linear behavior. The propagation of the longitudinal wave is investigated in detail. Numerical accuracy is validated from comparison with a closed, for both linear and non-linear code. The reflection of the non-linear P-wave gives confirmation for the correct treatment of the boundary condition. Finally the capabilities of the Cellular Automata code are underlined for reflection of Lamb waves for various boundary conditions.

No description available.

<p>Lifetime Engineering (or Life Cycle Engineering) is a technical approach for meeting the current objective of sustainable development. The approach is aimed to turn today’s reactive and short-term design, management and maintenance planning towards an optimised and long-term technical approach. The life cycle based management and maintenance planning approach includes condition assessment, predictive modelling of performance changes, maintenance, repair and refurbishment planning and decisions. The Life Cycle Management System (LMS) is a predictive and generic life cycle based management system aimed to support all types of decision making and planning of optimal maintenance, repair and refurbishment activities of any constructed works. The system takes into account a number of aspects in sustainable and conscious development such as human requirements, life cycle economy, life cycle ecology and cultural requirements. The LMS is a system by which the complete system or parts thereof, works in co-operation or as a complement to existing business support systems. The system is module based where each module represents a subprocess within the maintenance management process. The scope of this thesis is focused on development and adaptation of the predictive characteristic of LMS towards a presumptive user. The objective is to develop and adapt a Service Life Performance Analysis module applicable for condition based Facility Management System in general and for condition based Bridge Management System in particular. Emphasis is placed on development and adaptation of a conditional probability based Service Life Performance Analysis model in which degradation models and Markov chains play a decisive role. The thesis deals also with development and adaptation of environmental exposure data recording and processing, with special emphasis on quantitative environmental classification in order to provide a simplified method of Service Life Performance Analysis.</p>