Life-cycle Cost (life-cycle + cost)

Distribution by Scientific Domains


Selected Abstracts


Effect of cumulative seismic damage and corrosion on the life-cycle cost of reinforced concrete bridges

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 7 2009
R. Kumar
Abstract Bridge design should take into account not only safety and functionality, but also the cost effectiveness of investments throughout a bridge life-cycle. This paper presents a probabilistic approach to compute the life-cycle cost (LCC) of corroding reinforced concrete (RC) bridges in earthquake-prone regions. The approach is developed by combining cumulative seismic damage and damage associated with corrosion due to environmental conditions. Cumulative seismic damage is obtained from a low-cycle fatigue analysis. Chloride-induced corrosion of steel reinforcement is computed based on Fick's second law of diffusion. The proposed methodology accounts for the uncertainties in the ground motion parameters, the distance from the source, the seismic demand on the bridge, and the corrosion initiation time. The statistics of the accumulated damage and the cost of repairs throughout the bridge life-cycle are obtained by Monte-Carlo simulation. As an illustration of the proposed approach, the effects of design parameters on the LCC of an example RC bridge are studied. The results are valuable in better estimating the condition of existing bridges and, therefore, can help to schedule inspection and maintenance programs. In addition, by taking into consideration the two deterioration processes over a bridge life-cycle, it is possible to estimate the optimal design parameters by minimizing, for example, the expected cost throughout the life of the structure. A comparison between the effects of the two deterioration processes shows that, in seismic regions, the cumulative seismic damage affects the reliability of bridges over time more than the corrosion even for corrosive environments. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Energy conservation conflicts in district heating systems

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2003
Björn Rolfsman
Abstract In Sweden, district heating of buildings is in common use. This paper deals with the district heating tariff. Many economists argue that the tariff should be based on short-range marginal costs, but in practice this never occurs. Traditionally instead, the prices are set so they are lower than the alternatives. A case study is presented dealing with a residential building in Navestad, Norrköping. For this building, the life-cycle cost with extra wall insulation and the introduction of a heat pump has been calculated. A comparison of two perspectives, the present tariff and a tariff-based short-range marginal cost, is done. It is shown that there is a conflict between the two perspectives. For the tariff based on short-range marginal cost, neither extra insulation nor an introduction of a heat pump is profitable. However, with the present tariff, a bivalent system with a heat pump and district heating is profitable. Copyright © 2002 John Wiley & Sons, Ltd. [source]


Optimal use of solar collectors for residential buildings

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 11 2001
Stig-Inge GustafssonArticle first published online: 5 JUN 200
Abstract Solar radiation is an abundant free resource which may be used in the form of solar heated water. This is achieved in solar collectors which, unfortunately, are expensive devices and, further, the warm water must be stored in accumulators,items which also cost money. This paper shows how we have optimized the situation for a block-of-flats in Sweden. In order to find this point we have used the minimum life-cycle cost (LCC) concept as a criterion. The best solution is therefore found when that cost finds its lowest value. It is also examined under which conditions solar collectors are part of the optimal solution and further it is calculated what happens if this optimal point is abandoned, i.e. how much will the LCC increase if other than optimal solutions are chosen. LCC optimization for multi-family buildings almost always results in a heating system with low operating costs such as district heating or dual-fuel systems where a heat pump takes care of the base load and an oil boiler the peak. The installation cost must, however, be kept to a reasonable level. Expensive solar panel systems are therefore normally avoided if the lowest LCC shall be reached, at least for Swedish conditions. This is so even if the solar system has a very low operating cost. For buildings where the only alternative energy source is electricity, solar collectors seem to be on the rim of profitability, i.e. for an energy price of about 0.6 SEK kWh,1. Copyright © 2001 John Wiley & Sons, Ltd. [source]


A review of the state of the art of personal rapid transit

JOURNAL OF ADVANCED TRANSPORTATION, Issue 1 2000
Article first published online: 19 JAN 2010, J. Edward Anderson
The paper begins with a review of the rational for development of personal rapid transit, the reasons it has taken so long to develop, and the process needed to develop it. Next I show how the PRT concept can be derived from a system-significant equation for life-cycle cost per passenger-mile as the system that minimizes this quantity. In the bulk of the paper I discuss the state-of-the-art of a series of technical issues that had to be resolved during the development of an optimum PRT design. These include capacity, switching, the issue of hanging vs. supported vehicles, guideways, vehicles, control, station operations, system operations, reliability, availability, dependability, safety, the calculation of curved guideways, operational simulation, power and energy. The paper concludes with a listing of the implications for a city that deploys an optimized PRT system. [source]


Next-Generation Architecture to Support Simulation-Based Acquisition

NAVAL ENGINEERS JOURNAL, Issue 4 2000
Dr. B. Chadha
ABSTRACT The ability to make good design decisions early is a significant driver for simulation-based acquisition to effectively lower life-cycle cost and cycle time. Building virtual prototypes, enabling one to analyze the impact of decisions, achieves effective simulation-based acquisition processes. Virtual prototypes need to support a comprehensive set of analyses that will be performed on the product; hence, all aspects of product data and behavior need to be represented. Building virtual prototypes of complex systems being designed by a multi-organizational team requires new architectural concepts and redesigned processes. Implementation of these new architectures is complex and leveraging commercial technologies is necessary to achieve feasible solutions. One must also carefully consider the state of the current commercial technologies and frameworks as well as the organizational and cultural aspects of organizations that use these systems. This paper describes key architectural principles that one must address for a cost-effective implementation. The paper then discusses key architectural concepts and trade-offs that are necessary to support virtual prototypes of complex systems. [source]


LOPA misapplied: Common errors can lead to incorrect conclusions,,

PROCESS SAFETY PROGRESS, Issue 4 2009
Karen A. Study
Abstract Layer of Protection Analysis is a powerful tool for quantitative risk assessments. If applied correctly, it can provide quick and efficient guidance on what additional safeguards are needed, if any, to protect against a given scenario. If misapplied, an overly conservative calculation of risk may result in over-instrumentation, additional life-cycle costs, and spurious trips. A nonconservative calculation of risk could result in an under-protected system and unacceptable risk of an undesired consequence occurring. This article describes several categories of common errors, some overly conservative and some nonconservative. Case studies of actual plant scenarios are used to illustrate. © 2009 American Institute of Chemical Engineers Process Saf Prog 2009 [source]


Stoffliche und konstruktionsbezogene Besonderheiten beim Einsatz von UHFB im Brückenbau am Beispiel von drei Pilotprojekten

BETON- UND STAHLBETONBAU, Issue 9 2009
Michael Reichel Dipl.-Ing.
Brückenbau; Entwurf und Konstruktion Abstract Seit 1997 wurden weltweit ca. 30 Brücken aus UHFB (Ultrahochfester Beton) gebaut. Wegen der hohen Leistungsfähigkeit von UHFB, vor allem in Bezug auf seine Festigkeits- und Dauerhaftigkeitseigenschaften, ist er geradezu prädestiniert für Ingenieurbauwerke und damit auch für Brücken. Übliche Konstruktionsprinzipien des Betonbaus lassen sich jedoch nicht einfach auf den neuen Werkstoff übertragen. Die konsequente Einbeziehung der Eigenschaften und Besonderheiten des neuen Werkstoffes sowie die Berücksichtigung der Forderungen der Nachhaltigkeit führen zu filigranen, modularen und flexiblen Bauweisen, die sich ihrem Konstruktionsprinzip nach zwischen Beton- und Stahlkonstruktionen einordnen lassen. Bei Betrachtung der gesamten Lebenszykluskosten sind mit solchen Bauweisen wirtschaftliche Bauwerke mit eminentem Nutzen für die Volkswirtschaft möglich. Nach einer allgemeinen Betrachtung werden anhand der Erfahrungen bei Konstruktion, Bemessung und Ausführung von drei verschiedenen Pilotprojekten in Österreich die Besonderheiten und neuen Erkenntnisse beispielhaft erläutert. Special Features of Material and Structure in the Application of UHPC for Bridge Construction exemplified by three Pilot Projects Since 1997 nearly 30 bridges have been built worldwide using UHPC (Ultra High Performance Concrete). Due to the high performance of UHPC, especially owing to its strength and durability properties, this material is predestined for engineering structures and as a result also for bridges. Common design philosophies in concrete construction can not easily be adapted to this new material. The consistent incorporation of the properties and special features of this new material as well as the demands for sustainability lead to filigree, flexible and modular buildings. Therefore the design philosophy can be classified between concrete and steel constructions. Considering the complete life-cycle costs, such constructions permit economical buildings with an eminent benefit for the national economy. After general consideration, the special properties and the new insights gained are exemplified based on experiences during construction, dimensioning and implementation of three different pilot projects in Austria. [source]