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Environmental impact shares of a reinforced concrete earth-retaining wall with buttresses

http://blog.360gradosenconcreto.com/tipos-muros-contencion-prefabricados-concreto/

Abstract: Structural engineers focus on the reduction of carbon emissions in reinforced concrete structures, while other impacts affecting ecosystems and human health become secondary or are left behind. The featured life cycle assessment shows the impacts corresponding to each construction stage of an earth-retaining wall with buttresses. In this study the contribution ratio of each input flow is analyzed. Accordingly, concrete, landfill, machinery, formwork, steel, and transport are considered. Results show that despite the concrete almost always accounts for the largest contribution to each impact, the impact shares of steel present noticeable sensitivity to the steel-manufacturing route. The parameter of study is the recycling rate, usually 75% reached in Spain. Noticeable variation is found when the recycling content increases. The relationship between the impacts of each material with the amount of material used discloses research interest.

 

Keywords: Life cycle assessment, Functional unit, Steel recycling rate, Concrete ratio, Photochemical oxidation, Ozone depletion, Global warming.

Reference:

MOLINA-MORENO, F.; MARTÍ, J.V.; YEPES, V.; CIROTH, A. (2017). Environmental impact shares of a reinforced concrete earth-retaining wall with buttresses. The Ninth International Structural Engineering and Construction Conference, Resilient Structures and Sustainable Construction ISEC-9, Valencia, Spain July 24-July 29.

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17 Julio, 2017
 
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Carbon embodied optimization for buttressed earth-retaining walls: implications for low-carbon conceptual designs

Nos acaban de publicar en la revista de Elsevier del primer decil, Journal of Cleaner Production, un artículo donde se estudia el diseño de los muros de contrafuertes optimizados para reducir sus emisiones de CO2. Este artículo forma parte de nuestra línea de investigación BRIDLIFE en la que se pretenden optimizar estructuras atendiendo no sólo a su coste, sino al impacto ambiental que generan a lo largo de su ciclo de vida. El artículo lo podéis descargar GRATUITAMENTE hasta el 27 de agosto de 2017 en el siguiente enlace:

https://authors.elsevier.com/a/1VLOP3QCo9NDzg

Abstract:

This paper shows the differences between the design of a reinforced concrete structure considering two objectives to minimize; economic cost and CO2 emissions. Both objectives depend on the amount of two high carbon intensive materials: cement in the concrete and steel; therefore, these objectives are related. As the balance between steel and cement per m3 of concrete depends on several factors such as the type of structure, this study focuses on buttressed earth-retaining walls. Another factor that determines the balance between steel and concrete is the height of the wall. Thus, the methodology considers a parametric study for optimal designs of buttressed earth-retaining walls, where one of the parameters is the wall height. One of the objectives is to show the variation in cost when CO2 is minimized, respectful of minimizing the economic cost. The findings show that wall elements under bending-compressive strains (i.e. the stem of the buttressed retaining wall) perform differently depending on the target function. On one hand, the study reveals an upward trend of steel per unit volume of concrete in emission-optimized earth-retaining buttressed walls, compared to the cost-optimized. On the other hand, it is checked that unlike the cost-optimized walls, emission-optimized walls opt for a higher concrete class than the minimum class available. These findings indicate that emission-optimized walls penalize not only concrete volume, but also the cement content, to the extent that a higher concrete class outperforms in reduced emissions. Additionally, the paper outlines how and to what extent the design of this typology varies for the two analyzed objectives in terms of geometry and amount of materials. Some relevant differences influencing the geometry of design strategies are found.

Keywords:

Cargon emission; CO2; earth-retaining wall; reinforced concrete; Harmony search; Threshold accepting

Reference:

MOLINA-MORENO, F.; MARTÍ, J.V.; YEPES, V. (2017). Carbon embodied optimization for buttressed earth-retaining walls: implications for low-carbon conceptual designs. Journal of Cleaner Production, 164:872-884.

13 Julio, 2017
 
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Lifetime reliability-based optimization of post-tensioned box-girder bridges

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23 Mayo, 2017
 
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Multi-objective design of post-tensioned concrete road bridges using artificial neural networks

Nos acaban de publicar en línea en la revista Structural and Multidisciplinary Optimization (revista indexada en JCR en el primer cuartil) un trabajo de investigación en el que utilizamos las redes neuronales artificiales junto para el diseño multiobjetivo de puentes postesados de carreteras. Os paso a continuación el resumen y el enlace al artículo por si os resulta de interés. El enlace del artículo es el siguiente: http://link.springer.com/article/10.1007%2Fs00158-017-1653-0

Referencia:

García-Segura, T.; Yepes, V.; Frangopol, D.M. (2017). Multi-objective design of post-tensioned concrete road bridges using artificial neural networks. Structural and Multidisciplinary Optimization, doi:10.1007/s00158-017-1653-0

Abstract:

In order to minimize the total expected cost, bridges have to be designed for safety and durability. This paper considers the cost, the safety, and the corrosion initiation time to design post-tensioned concrete box-girder road bridges. The deck is modeled by finite elements based on problem variables such as the cross-section geometry, the concrete grade, and the reinforcing and post-tensioning steel. An integrated multi-objective harmony search with artificial neural networks (ANNs) is proposed to reduce the high computing time required for the finite-element analysis and the increment in conflicting objectives. ANNs are trained through the results of previous bridge performance evaluations. Then, ANNs are used to evaluate the constraints and provide a direction towards the Pareto front. Finally, exact methods actualize and improve the Pareto set. The results show that the harmony search parameters should be progressively changed in a diversification-intensification strategy. This methodology provides trade-off solutions that are the cheapest ones for the safety and durability levels considered. Therefore, it is possible to choose an alternative that can be easily adjusted to each need.

Keywords:

Multi-objective harmony search; Artificial neural networks; Post-tensioned concrete bridges; Durability; Safety.

Method for estimating the social sustainability of infrastructure projects

Niigata soil liquefaction. Wikipedia

La evaluación de la sostenibilidad social de los proyectos no es un tema sencillo ni inmediato. Si bien los impactos medioambientales se han estudiado en el ámbito científico con cierta profundidad, los impactos sociales de las infraestructuras se han investigado mucho menos. Es más, en numerosas ocasiones dichos impactos se han minusvalorado. Pues bien, nos acaban de publicar un artículo en la revista Environmental Impact Assessment Review (revista indexada en el JCR, primer cuartil de impacto) en el cual proponemos una metodología que permite afrontar este reto.

Elsevier permite descargar de forma gratuita este artículo hasta el 14 de junio de 2017 accediendo al siguiente enlace: https://authors.elsevier.com/a/1UxW7iZ5spJDe

Referencia:

SIERRA, L.A.; PELLICER, E.; YEPES, V. (2017). Method for estimating the social sustainability of infrastructure projects. Environmental Impact Assessment Review, 65:41-53. https://doi.org/10.1016/j.eiar.2017.02.004

Highlights:

  • Method to select suitable infrastructure projects from the social sustainability point of view
  • Emphasizes social interactions of the infrastructure in the short and long term
  • Distinguishes the social sustainability of infrastructure projects in different locations
  • Efficiency of a social contribution in terms of early social benefits and a long-term distribution
  • Supports early decision-making of public agencies regarding infrastructure projects

 

Abstract:

Nowadays, sustainability assessments tend to focus on the biophysical and economic considerations of the built environment. Social facets are generally underestimated when investment in infrastructure projects is appraised. This paper proposes a method to estimate the contribution of infrastructure projects to social sustainability. This method takes into account the interactions of an infrastructure with its environment in terms of the potential for short and long-term social improvement. The method is structured in five stages: (1) social improvement criteria and goals to be taken into account are identified and weighed; (2) an exploratory study is conducted to determine transfer functions; (3) each criterion is homogenized through value functions; (4) the short and long-term social improvement indices are established; and finally, (5) social improvement indices are contrasted to identify the socially selected alternatives and to assign an order of priority. The method was implemented in six alternatives for road infrastructure improvement. The results of the analysis show that the method can distinguish the contribution to social sustainability of different infrastructure projects and location contexts, according to early benefits and potential long-term equitable improvement. This method can be applied prior to the implementation of a project and can complement environmental and economic sustainability assessments.

Keywords:

  • Social contribution;
  • Social improvement;
  • Infrastructure;
  • Method;
  • Social sustainability

 

 

Special Issue “Sustainable Construction”

High visibility: indexed by the Science Citation Index Expanded, the Social Sciences Citation Index (Web of Science) and other databases. Impact Factor: 1.343 (2015)

Special Issue “Sustainable Construction”

A special issue of Sustainability (ISSN 2071-1050). This special issue belongs to the section “Sustainable Engineering and Science“.

Deadline for manuscript submissions: 30 November 2017

Special Issue Editors

Guest Editor

Prof. Dr. Víctor Yepes
Concrete Science and Technology Institute (ICITECH), Department of Construction Engineering and Civil Engineering Projects, Universitat Politècnica de València Valencia, Spain
Interests: multi-objective optimization; life-cycle assessment; decision-making; sustainability; concrete structures; CO2 emissions; construction management

Guest Editor

Dr. Tatiana García-Segura
Concrete Science and Technology Institute (ICITECH), Department of Construction Engineering and Civil Engineering Projects, Universitat Politècnica de València Valencia, Spain
Interests: multi-objective optimization; durability; safety; sustainability; post-tensioned bridges; maintenance; blended cement; recycled concrete

Special Issue Information

Dear Colleagues,

This “Sustainable Construction” Special Issue comprises selected papers for Sustainability. Construction is one of the main sectors generating greenhouse gases. This industry consumes large amounts of raw materials, such as stone, timber, water, etc. Additionally, infrastructure should provide service over many years without safety problems. Therefore, their correct design, construction, maintenance and dismantling are essential to reduce economic, environmental and societal consequences. That is why promoting sustainable construction is becoming extremely important nowadays. This Special Issue is seeking papers that explore new ways of reducing the environmental impacts caused by the construction sector, as well promoting social progress and economic growth. These objectives include, but are not limited to:

  • The use of sustainable materials in construction
  • The development of technologies and processes intended to improve sustainability in construction
  • The optimization of designs based on sustainable indicators
  • The reduction of the economic, environmental and social impact caused by production processes
  • The promotion of durable materials that reduce the future maintenance
  • The life-cycle assessment
  • Decision-making processes that integrate economic, social, and environmental aspects

Papers selected for this Special Issue are subject to a rigorous peer-review procedure with the aim of rapid and wide dissemination of research results, developments and applications.

Submission

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Sustainability is an international peer-reviewed Open Access monthly journal published by MDPI.

Keywords

  • sustainable materials
  • life-cycle assessment
  • sustainable and efficient technologies and processes
  • design optimization
  • durable materials
  • maintenance minimization
  • decision-making
10 Marzo, 2017
 
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Special Issue on Advanced Optimization Techniques and Their Applications in Civil Engineering

Civil Engineers are involved with the creation, monitoring, and management of infrastructural resources, as well as the e›cient, economic utilization and management of renewable natural resources. Nowadays a rapid growth of computer performance enables and encourages new developments in civil engineering as well as related areas. For instance, the construction industry investigates new designs with minimum cost, minimum CO2 emissions, or embodied energy, among other objectives. Conventional optimization techniques are usually inadequate to nd best designs by taking into account all design variables, objectives, and constraints in the complex civil engineering problems. Applications of optimization techniques are most exciting, challenging, and of truly large scale when it comes to the problems of civil engineering in terms of both quality and quantity. In order to overcome the di›culties, researchers are interested in advanced optimization techniques. In the recent literature, researchers have applied the advanced optimization techniques to dišerent purposes.

The aim of this special issue is to collect the studies using optimization algorithms in civil engineering problems such as structural engineering, construction management, and environmental engineering. Potential topics include but are not limited to the following: Intelligent optimization Swarm and evolutionary optimization techniques Single and multiobjective optimization Predictive modeling and optimization Computational complexity and optimization Continuous or discrete optimization Structural optimization Size, shape, and topology optimization New design optimization applications in civil engineering New and novel approaches and techniques for solving optimization problems in civil engineering New research in any areas closely related to optimization and civil engineering designs Authors can submit their manuscripts through the Manuscript Tracking System at http://mts.hindawi.com/submit/journals/ace/otace/

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Design optimization of precast-prestressed concrete road bridges with steel fiber-reinforcement by a hybrid evolutionary algorithm

http://www.tierra-armada.com/

http://www.tierra-armada.com/

Recientemente hemos publicado un artículo donde hemos empleado un algoritmo evolutivo híbrido para optimizar tanto el coste como las emisiones de CO2 de puentes en viga artesa, con la particularidad de usar hormigones con fibras de acero. Se trata de un problema combinatorio complejo, con 41 variables de diseño, que se aplicó a un puente de 30 m de luz y una anchura de calzada de 12 m. Os dejo a continuación el artículo completo.

Abstract: 

In this paper, the influence of steel fiber-reinforcement when designing precast-prestressed concrete (PPC) road bridges with a double U-shape cross-section is studied through heuristic optimization. A hybrid evolutionary algorithm (EA) combining a genetic algorithm (GA) with variable-depth neighborhood search (VDNS) is formulated to minimize the economic cost and CO2 emissions, while imposing constraints on all the relevant limit states. The case study proposed is a 30-m span-length with a deck width of 12 m. The problem involved 41 discrete design variables. The algorithm requires the initial calibration. Moreover, the heuristic is run nine times so as to obtain statistical information about the minimum, average and deviation of the results. The evolution of the objective function during the optimization procedure is highlighted. Findings show that heuristic optimization is a forthcoming option for the design of real-life prestressed structures. This paper provides useful knowledge that could offer a better understanding of the steel fiber-reinforcement in U-beam road bridges.

Keywords: hybrid evolutionary algorithm, precast-prestressed concrete, steel fiber-reinforcement, U-shape cross-section.

Reference:

YEPES, V.; MARTÍ, J.V.; GARCÍA-SEGURA, T. (2017). Design optimization of precast-prestressed concrete road bridges with steel fiber-reinforcement by a hybrid evolutionary algorithm. International Journal of Computational Methods and Experimental Measurements, 5(2):179-189.

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3 Enero, 2017
 
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Optimization of buttressed earth-retaining walls using hybrid harmony search algorithms

Para empezar este año 2017, nada mejor que te comuniquen la publicación de un artículo de investigación el mismo día 1. Se trata en este caso de la utilización de algoritmos heurísticos híbridos para optimizar el coste de muros de contrafuertes. Se ha publicado en la revista Engineering Structures.

Como suele ser habitual en la editorial Elsevier, os podéis descargar GRATUITAMENTE el artículo hasta el 20 de febrero accediendo al siguiente enlace:

https://authors.elsevier.com/a/1UJQQW4G4Bl2d

Abstract:

This paper represents an economic optimization of buttressed earth-retaining walls. We explore the optimum solutions using a harmony search with an intensification stage through threshold accepting. The calibration of the resulting algorithm has been obtained as a result of several test runs for different parameters. A design parametric study was computed to walls in series from 4 to 16 m total height. The results showed different ratios of reinforcement per volume of concrete for three types of ground fill. Our main findings confirmed that the most sensitive variable for optimum walls is the wall-friction angle. The preference for wall-fill friction angles different to 0 in project design is confirmed. The type of fill is stated as the main key factor affecting the cost of optimum walls. The design parametric study shows that the soil foundation bearing capacity substantially affects costs, mainly in coarse granular fills (F1). In that sense, cost-optimum walls are less sensitive to the bearing capacity in mixed soils (F2) and fine soils of low plasticity (F3). Our results also showed that safety against sliding is a more influential factor for optimum buttressed walls than the overturning constraint. Finally, as for the results derived from the optimization procedure, a more suitable rule of thumb to dimension the footing thickness of the footing is proposed.

Keywords:

Structural design; Heuristics; Harmony search; Cost optimization; Concrete structures

Reference:

MOLINA-MORENO, F.; GARCÍA-SEGURA, T.; MARTÍ, J.V.; YEPES, V. (2017). Optimization of buttressed earth-retaining walls using hybrid harmony search algorithms. Engineering Structures, 134:205-216. http://dx.doi.org/10.1016/j.engstruct.2016.12.042

 

 

2 Enero, 2017
 
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Heuristic design of a precast-prestressed concrete U-beam and post-tensioned cast-in-place concrete slab road bridges

Viaducto St. Cloud, Francia – 2000. http://vslmex.com.mx/

En estos momentos es posible automatizar completamente el diseño óptimo de puentes usando algoritmos heurísticos. A continuación os dejo, en abierto, un capítulo de libro en el que se explica tanto la optimización de un puente de vigas artesas prefabricado como otro construido “in situ” como losa de hormigón postesado. Se trata de un trabajo incluido dentro del proyecto de investigación BRIDLIFE. Este tipo de técnicas acabarán imponiéndose en unos años en los paquetes informáticos de cálculo. Sin embargo, resulta muy importante resaltar que el proyectista es el que tiene la última palabra en el diseño.

Referencia:

Martí, J.V.; Alcalá, J.; García-Segura, T.; Yepes, V. (2016). Heuristic design of a precast-prestressed concrete U-beam and post-tensioned cast-in-place concrete slab road bridges. In: Hernández, S.; Brebbia, C.A.; de Wilde, W.P. (eds.), High Performance and Optimum Design of Structures and Materials II. WIT Transactions on The Built Environment, Vol. 166. WIT Press, pp. 17-28. ISBN: 978-1-78466-143-4.

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20 Diciembre, 2016
 
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