An overview of the most advanced frameworks for bridge asset management

During this paper it will be discussed some important novelties related to the topic of bridge asset management. In a first step, it will be covered the problematic of bridge assessment through the use of Key Performance Indicators. An emphasis will be made to the outcomes from the COST Action TU 1406 (www.tu1406.eu). Then, it will be discussed how these indicators can be used in the management of existing bridge stock. It will be introduced the problematic of performance predictive models and how maintainability could be integrated for the Life Cycle Cost analysis. At the end it will be discussed the difference between the management of a single and a network of bridges, what type of optimization models and decision-support algorithms can be used. An example is shown through the main results from the research and development project SustIMS – Sustainable Infrastructure Management Systems. The main objective is to show operators how the standardization of this procedure, and how these frameworks would contribute for a more sustainable and efficient management of their bridge stock.This article is based upon the work from COST Action TU1406, Quality specifications for roadway bridges, standardization at a European level (BridgeSpec), supported by COST (European Cooperation in Science and Technology).info:eu-repo/semantics/publishedVersio

An Alternative Interpretation for the Moduli Fields of the Cosmology Associated to Type IIB Supergravity with Fluxes

We start with a particular cosmological model derived from type IIB supergravity theory with fluxes, where usually the dilaton is interpreted as a Quintessence field. Instead of that, in this letter we interpret the dilaton as the dark matter of the universe. With this alternative interpretation we find that in this supergravity model gives a similar evolution and structure formation of the universe compared with the $\Lambda$CDM model in the linear regime of fluctuations of the structure formation. Some free parameters of the theory are fixed using the present cosmological observations. In the non-linear regimen there are some differences between the type IIB supergravity theory with the traditional CDM paradigm. The supergravity theory predicts the formation of galaxies earlier than the CDM and there is no density cusp in the center of galaxies. These differences can distinguish both models and can give a distinctive feature to the phenomenology of the cosmology coming from superstring theory with fluxes.Comment: 7 pages, 5 figures, references added, minor modifications, typos corrected. Version accepted for publication in IJMP

Industry energy optimization: A case study in a biodiesel production site

This paper presents a case study of heat exchanger network (HEN) retrofit with the objective to reduce the utilities consumption in a biodiesel production process. Pinch analysis studies allow determining the minimum duty utilities as well the maximum of heat recovery. The existence of heat exchangers for heat recovery already running in the process causes a serious restriction for the implementation of grassroot HEN design based on pinch studies. Maintaining the existing HEN, a set of alternatives with additional heat exchangers was created and analysed using some industrial advice and selection criteria. The final proposed solution allows to increase the actual 18 % of recovery heat of the all heating needs of the process to 23 %, with an estimated annual saving in hot utility of 35 k(sic)/y

COST Action TU 1406 quality specifications for roadway bridges (BridgeSpec)

Roadway bridges, being one of the most critical road infrastructures components, require regular maintenance actions. Therefore, it becomes important to define strategies to maximize societal benefits, derived from the investment made in these assets. Consequently, this investment should be planned, effectively managed and technically supported by appropriate management systems, supported in quality control plans. For this purpose, authorities need to produce an asset management plan which should, not only define the goals to be achieved by exploiting the roadway bridge network, but also identify the investment needs and priorities based on a life cycle cost criteria. Additionally, a proper condition assessment of these assets must be conducted to support the decision-making process regarding their preservation. A COST Action recently started in Europe with the aim of standardizing the establishment of quality control plans for roadway bridges. This paper describes this Action and, particularly, its most recent developments. MaintenanceThis article is based upon work from COST Action TU-1406, Quality specifications for roadway bridges, standardization at a European level (BridgeSpec), supported by COST (European Cooperation in Science and Technology)

Análise experimental do comportamento até à rotura de vigas de betão armado

O presente artigo incide sobre a análise experimental do comportamento de um conjunto de vigas de betão armado, ensaiadas até rotura no Laboratório de Estruturas da Universidade do Minho (LEST-UM). Estas foram construídas e betonadas em simultâneo, apresentando diferentes distribuições de armadura longitudinal, recobrimento e espaçamento de armadura transversal. Procedeu-se ao ensaio de um total de 36 vigas simplesmente apoiadas, e 32 vigas apoiadas num dos extremos e encastradas no outro. O carregamento aplicado correspondeu a duas cargas concentradas, aplicadas a 1/3 e 2/3 do vão. Algumas das vigas apresentaram roturas típicas de flexão e, outras, de corte. Apresentam-se os principais resultados experimentais e os resultados obtidos com uma análise de sensibilidade, que permitiu aferir a relação existente entre armaduras utilizadas, valores de recobrimento e condições de apoio, com os diferentes modos de rotura.Fundação para a Ciência e a Tecnologia (FCT

Uncertainty evaluation of civil engineering structures behavior

All decisions that concern the development and management of existent infrastructure are of extremely importance for society. However, it is verified that these decisions are influenced by a huge source of uncertainties that must be taken into account. A methodology that consider this, and, which objective, is to support such decisions, is developed within this research. In order to support such methodology, a numerical model is developed. Such model is then calibrated using backanalysis procedures, so that, given results, could best fit obtained experimental data. The developed model is continuously updated with collected data, by using inference processes. Then, a full probabilistic analysis is performed in order to evaluate the respective structure behavior. This paper describes such methodology, and the respective application with a batch of reinforced concrete beams, tested at laboratory, till failure. The developed methodology is applied with success and obtained results revealed the respective importance in future decisions concerning the societal infrastructure. Further steps consider the application of such methodology with a real structure.Fundação para a Ciência e a Tecnologia (FCT

Uncertainty evaluation of reinforced concrete structures behavior

The evaluation of reinforced concrete structures behavior is doted of uncertainty as parameters, like used materials and geometry, are not deterministic. This article presents experimental tests and respective numerical study of a series of simply and mixed supported reinforced concrete beams, which were loaded till rupture. Those beams were executed at same time, presenting different longitudinal reinforcement, distance between transversal reinforcement and concrete covering. Such beams were first analyzed using a calibrated deterministic non-linear numerical model. In order to take into account the uncertainty, a probabilistic nonlinear analysis was then executed. The results from numerical analysis were defined by random distributions. Experimental data was grouped by beam typologies and characterized by a random distribution, also. An index, which relates the proximity of both random distributions, was then defined. Such index will characterize, in a more rigorous and consistent way, if the structural behavior is, or not, within the expected one.Fundação para a Ciência e a Tecnologia (FCT

Non linear probabilistic analysis of reinforced concrete structures

The behaviour of reinforced concrete bridges is doted of uncertainty as main parameters, like the ones related to material properties, are variable and not deterministic. In order to take this into consideration, a non linear probabilistic analysis should be developed. This paper presents an application of it on the evaluation of the structural behaviour of two batches of reinforced concrete beams, which were loaded, in laboratory, up to failure. However, when performing it, a previous attention must be paid to the intervenient parameters. In fact, on the one hand it is important to consider the highest number of parameters as possible but, on the other hand, this implies higher computational costs. In order to avoid this, it is essential to identify, by developing a sensitivity analysis, all critical parameters. A comparison of numerical results with obtained experimental data is executed, being, the advantages of such kind of analysis, pointed out.Fundação para a Ciência e a Tecnologia (FCT

An overview of COST Action TU1406, quality specifications for roadway bridges (BridgeSpec)

Publicado em "Life-cycle of engineering systems: emphasis on sustainable civil infrastructure: proceedings of the Fifth International Symposium on Life-Cycle Civil Engineering (IALCCE 2016), ISBN 978-1-138-02847-0"Life-cycle analyses are used in condition assessment of new and existing bridges as well as for evaluation of maintenance strategies. During the implementation of asset management strategies, maintenance actions are required to keep assets at desired performance levels. In case of roadway bridges, performance indicators, which can be obtained by inspections, non-destructive tests or monitoring systems, are established for components. These indicators, along with the definition of standardized performance goals, allow to assess the accomplishment of quality control plans. In Europe there is a large disparity regarding the way performance indicators are quantified and goals specified. Therefore, a discussion at a European networking level, seeking to achieve a standardized approach in this subject, will bring significant benefits. COST Action TU1406 aims to bring together research and practicing communities in order to establish a European guideline in this issue, based on the existing practices across the involved European countries.COST (European Cooperation in Science and Technology

Advanced evaluation of civil engineering structures behaviour

The development, maintenance and operation of infrastructures are central tasks on continued success of society. The decision processes involved in these tasks concern all aspects of managing. The main objective from a societal perspective is to improve the quality of life of individuals both for present and future generations. On the other hand, from the owner point of view, the main objective is to maximize the economic return of investments. If all aspects of decision problem would be known with certainty, the identification of optimal decisions would be straightforward by means of traditional cost-benefit analysis. However, our understanding of problems involved in decision analysis is often far less than perfect. In fact, the decision problem in engineering is subject to significant uncertainty. Infrastructures are constituted by civil engineering structures disposed in a series system. Accordingly, in any time instant, to decide about the optimal decision, the operator should evaluate each structural behavior. A structural analysis based in a probabilistic model is always preferable than in a deterministic one, as all possibilities of structural behavior are considered. Accordingly, within this research project, a methodology for advanced civil engineering structures evaluation, was developed.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/10705/2002