UPV



Resultados de la búsqueda By Etiquetas: heuristic-optimization


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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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.

Descargar (PDF, 337KB)

 

20 Diciembre, 2016
 
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Structural design of precast-prestressed concrete U-beam road bridges based on embodied energy

ph_vigas-artesa

Puente de vigas artesa prefabricadas. Fuente: Pacadar

¿Cómo se pueden diseñar puentes pretensados prefabricados en vigas artesa haciendo que el consumo energético para su fabricación y puesta en obra sea el mínimo posible?

Highlights

  • An automated procedure for optimizing the design of structures is presented.
  • There is a parabolic relation between the span length and the minimum energy.
  • The energy reduction has an average cost impact of 3.23€ per square meter of deck.
  • Since both criteria are dependent, 1€ reduction is equivalent to 4 kW h saving.

 

 

Abstract

S09596526An automated procedure for optimizing the design of precast-prestressed concrete U-beam road bridges is presented. The economic cost and the embodied energy are selected as the objective functions based on production materials, transport and placement. Heuristic optimization is used to search for the best geometry, the concrete type, the prestressing steel, and the reinforcement for the slab and the beam. The results for both objectives provide improved opportunities to learn about low-energy designs. The most influential variables for the energy efficiency goal are analyzed. The relationship between the span length and the embodied energy is described by a good parabolic fit for both optimization criteria. The findings indicate that the objectives do not exhibit conflicting behavior, and also that optimum energy designs are close to the optimum cost designs. The analysis also revealed that a reduction by 1 Euro can save up to 4 kWh. It is recommended to reduce the reinforcement in the slab as well as increase the volume of concrete in both slab and beams in order to achieve higher energy efficiency. It is also worth noting that web inclination angle should be increased when the depth increases for longer span lengths to maintain the optimum slab span lengths in the transverse direction.

Keywords

  • Heuristic optimization;
  • energy savings;
  • sustainable construction;
  • precast-prestressed concrete structures

Referencia:

MARTÍ, J.V.; GARCÍA-SEGURA, T.; YEPES, V. (2016). Structural design of precast-prestressed concrete U-beam road bridges based on embodied energy. Journal of Cleaner Production, 120:231-240. DOI: 10.1016/j.jclepro.2016.02.024(link)

22 Marzo, 2016
 
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Universidad Politécnica de Valencia