Emergy-based hybrid evaluation for commercial construction engineering: A case study in BDA

In the context of the global energy crisis, building construction engineering occupies a dominant position in the urbanization. To better comprehend the role of commercial construction engineering in urban economy, a comprehensive emergy-based hybrid evaluation framework is presented in this paper for the first time. The structure engineering of the landmark buildings in E-town, Beijing (Beijing Economic-Technological Development Area, BDA) is analyzed through a series of eco-efficiency indicators to reflect its eco-efficiency. Over one hundred items are considered in this study based on the most exhaustive first-hand project data. The solar emergy and empower density of the case engineering are quantified to be 4.78E+19 sej and 2.73E+14 sej/yr/m², respectively. The material inputs prove to be the largest component (about 90% of the total), within which steel and concrete are the two largest contributors. This situation is originated from the fact that all the case buildings are reinforced-concrete structured. Labor input, as the second largest contributor, accounts for 8.42% of the total, followed by service inputs (0.43%). The Percent Renewable Index (%R) is calculated as 7.49%, representing that renewable natural resources share a negligible proportion in commercial structure engineering. However, parts of the economic products are originally derived from the renewable natural sources, and these parts account for about 85% of the total renewable natural resources. Thus, even though a low dependence on local renewable resources and a heavy environmental stress on the environment are observed in the case engineering, the renewability of the case engineering still can be improved through some specific measures such as manufacturing process improvement and raw material source adjustments.