New Selection Process for Retaining Walls Based on Life Cycle Assessment and Economic Concerns

Abstract:

Earth-retaining walls (ERWs) are widely used structures in civil engineering, a field known for their substantial environmental impact. However, the current practice of selecting ERW types for a project often neglects environmental concerns. To address this issue, this study proposes a novel process to enhance the rationality of ERW selection. It involves assessing the performance of commonly used ERW types in terms of both environmental issues and economic considerations. The proposed process relies on calculating a total cost (TC), which incorporates the costs of two crucial environmental indicators: carbon dioxide (CO₂) emissions and cumulative energy demand (CED), evaluated using life cycle assessment (LCA), in addition to considering the traditional construction cost of the ERW. By determining the TC for various retaining wall options, engineers can identify the optimal ERW type for a specific project. To validate the effectiveness of this environmental-economic approach, a case study was conducted comparing two ERW types: the conventional concrete-reinforced retaining wall (CRRW) and the geosynthetic-reinforced retaining wall (GRRW). The study evaluated structures constructed at four different heights, ranging from 3 m to 6 m. The results demonstrate that the GRRW is the optimal option, offering a lower TC than the equivalent wall conventionally built with reinforced concrete across all evaluated heights. However, the difference in TC between the two ERWs is more pronounced for taller walls. At a height of 3 m, the total cost ratio between the CRRW and the GRRW is moderate at 1.2, while it substantially increases to 2.5 at a height of 6 m. In conclusion, the proposed process was effectively applied to the case study, providing valuable insights into the assessment of earth-retaining structures from both environmental and economic perspectives. It can assist engineers in prioritizing and selecting the most sustainable and cost-effective ERW type for a specific project.

• Periodical: International Journal of Engineering Research in Africa (Volume 66)
• Pages: 29-44
• DOI: https://doi.org/10.4028/p-OVz45X
• Online since: September 2023
• Authors: Hend Zbidi*, Saloua El Euch Khay
• Keywords: CO₂ Emissions, Cost, Cumulative Energy Demand, Earth-Retaining Walls, Life Cycle Assessment

References

[1] G. Heerten, Reduction of climate-damaging gases in geotechnical engineering practice using geosynthetics, Elsevier, Geotextiles and Geomembranes, 30 (2012) 43-49.

DOI: 10.1016/j.geotexmem.2011.01.006

[2] A. Petek Gursel, E. Masanet, A. Horvath, A. Stadel, Life-cycle inventory analysis of concrete production: A critical review, Cem. Concr. Compos. 51 (2014) 38–48.

DOI: 10.1016/j.cemconcomp.2014.03.005

[3] M.E. Boesch, S. Hellweg, Identifying Improvement Potentials in Cement Production with Life Cycle Assessment, Environ. Sci. Technol. 44 (2010) 9143–9149.

DOI: 10.1021/es100771k

[4] F. Collins, Inclusion of carbonation during the life cycle of built and recycled concrete: influence on their carbon footprint, Int. J. Life Cycle Assess. 15 (2010) 549–556.

DOI: 10.1007/s11367-010-0191-4

[5] E. Wang, Z. Shen, A hybrid Data Quality Indicator and statistical method for improving uncertainty analysis in LCA of complex system – application to the whole-building embodied energy analysis, J. Clean. Prod. 43 (2013) 166–173.

DOI: 10.1016/j.jclepro.2012.12.010

[6] N. Yusof, N.Z. Abidin, S.H.M. Zailani, K. Govindan, M. Iranmanesh, Linking the environmental practice of construction firms and the environmental behaviour of practitioners in construction projects, J. Clean. Prod. 121 (2016) 64–71.

DOI: 10.1016/j.jclepro.2016.01.090

[7] V. Yepes, J.V. Martí, T. García-Segura, Cost and CO2 emission optimization of precast–prestressed concrete U-beam road bridges by a hybrid glowworm swarm algorithm, Autom. Constr. 49 (2015) 123–134.

DOI: 10.1016/j.autcon.2014.10.013

[8] M. Jayakeerti, G. Nakkeeran, M. Durai Aravindh, L. Krishnaraj, Predicting an energy use intensity and cost of residential energy-efficient buildings using various parameters: ANN analysis, Asian Journal of Civil Engineering, 47 (2023).

DOI: 10.1007/s42107-023-00717-y

[9] G. Nakkeeran, L. Krishnaraj, Optimization and performance analysis of residential building for sustainable energy design through BIM, Journal of Engineering Research, 9 (2022).

[10] C.K Anand, B. Amor, Recent developments, future challenges and new research directions in LCA of buildings: a critical review, Renew. Sustain. Energy, 67 (2017) 408–416.

DOI: 10.1016/j.rser.2016.09.058

[11] K.F. Bizjak, S. Lenart, Life cycle assessment of a geosynthetic-reinforced soil bridge system – A case study, Elsevier, Geotextiles and Geomembranes, 46 (2018) 543–558.

DOI: 10.1016/j.geotexmem.2018.04.012

[12] W. Taktak, A. Loulizi, Selection of a pavement structure from technically established alternatives based on construction cost, energy consumption, and carbon footprint, International Journal of Engineering Research in Africa, 62 (2022) 85-106.

DOI: 10.4028/p-xx05a5

[13] I.P. Damians, R.J. Bathurst, E.G. Adroguer, A. Josa, A. Lloret, Sustainability assessment of earth-retaining wall structures, Environ. Geotech. jenge. 16.00004 (2016).

DOI: 10.1680/jenge.16.00004

[14] P. Zastrow, F. Molina-Moreno, T. García-Segura, J.V. Martí, V. Yepes, Life cycle assessment of cost-optimized buttress earth-retaining walls: A parametric study, J. Clean. Prod. 140 (2017) 1037–1048.

DOI: 10.1016/j.jclepro.2016.10.085

[15] J.J. Pons, V. Penadés-Plà, V. Yepes , J.V. Martí, Life cycle assessment of earth-retaining walls: an environmental comparison, J. Clean. Prod. 192 (2018) 411–420.

DOI: 10.1016/j.jclepro.2018.04.268

[16] F. Molina-Moreno, J.V. Martí, V. Yepes, Carbon embodied optimization for buttressed earth-retaining walls: Implications for low-carbon conceptual designs, J. Clean. Prod. 164 (2017) 872–884.

DOI: 10.1016/j.jclepro.2017.06.246

[17] R.K. Giri, K.R. Reddy, Sustainability assessment of two alternate earth-retaining structures, Geotech. Spec. Publ. GSP, 256 (2015) 2836–2845.

DOI: 10.1061/9780784479087.265

[18] R. Frischknecht, S. Büsser-Knöpfel, R. Itten, M. Stucki, H. Wallbaum, Comparative life cycle assessment of geosynthetics versus concrete retaining wall, 18th. Int. Conf. Soil Mech. Geotech. Eng. Challenges, Innov. Geotech., ICSMGE 2013, 3 (2013) 1979–1982.

[19] A. Colas, D. Garnier, G. Habert, Y. Tardivel, Advances on structural, environmental and economical analysis of dry-stone retaining walls, SAHC2014 - 9th International Conference on Structural Analysis of Historical Constructions, (2014) 14–17.

[20] A.T. Balasbaneh, D. Yeoh, M.I. Juki, M.H.W. Ibrahim, A.R. Zainal Abidin, Assessing the life cycle study of alternative earth-retaining walls from an environmental and economic viewpoint, Environmental Science and Pollution Research, 28 (2021) 37387–37399.

DOI: 10.1007/s11356-021-13190-4

[21] EN ISO 14040, Environmental Management, Life Cycle Assessment, Principles and Framework, 2006.

[22] EN ISO 14044, Environmental Management, Life Cycle Assessment, Requirements and Guidelines, 2006.

[23] J. Hong, G.Q. Shen, Y. Peng, Y. Feng, C. Mao, Uncertainty analysis for measuring greenhouse gas emissions in the building construction phase: a case study in China, J. Clean. Prod. 129 (2016) 183–195.

DOI: 10.1016/j.jclepro.2016.04.085

[24] S. Nocera, O. I. Galati, F. Cavallaro, On the uncertainty in the economic valuation of carbon emissions from transport, Journal of Transport Economics and Policy, 52 (2018).

[25] International Bank for Reconstruction and Development, the World Bank, Carbon Pricing Leadership Coalition, Carbon Pricing Leadership Report, Washington DC, 2020.

[26] M.N. Hassoun, A. Al-Manaseer, Structural concrete: theory and design, Hoboken, Wiley, 6 (2015).

[27] M. Zermani, K. Belaid, R. Harzaz, P. Gendrin, Aménagement et soutènements avec massif renforcé par géootextile avec retour au parement et parement Atalus, 10ème rencontres Géosynthétiques, La rochelle, France, Mars 2015.

[28] Fine, GEO5 – Geotechnical Engineering Software, Fine – Civil Engineering Software, France. See http://www.finesoftware.fr (accessed 16/01/2023).

[29] Béton armé aux états limites, BAEL 91, Règles techniques de conception et de calcul des ouvrages et constructions en béton armé suivant la méthode des états limites, 1991.

DOI: 10.51257/a-v1-c2317

[30] Ecoinvent Center, 2016, Ecoinvent v3.3, http://www.ecoinvent.org/database/older-versions/ecoinvent-33/ecoinvent-33.html (accessed 30/01/2023).

DOI: 10.4018/978-1-59140-342-5.ch003

[31] J.P. González, G.G. Gosálbez, J.M.M. Sanz, L.J. Jiménez, Statistical analysis of the ecoinvent database to uncover relationships between life cycle impact assessment metrics, J. Clean. Prod., 112 (2016) 359–368.

DOI: 10.1016/j.jclepro.2015.05.129