Lebenszyklusbetrachtungen als Grundlage für die Nachhaltigkeitsbewertung von Straßenbrücken

Lebenszyklusbetrachtungen spielen bei der Bewertung der Nachhaltigkeit von Bauwerken eine besondere Rolle. Sie fokussieren nicht nur auf die einmaligen Umweltwirkungen und die Investitionskosten bei der Herstellung von Bauwerken, sondern ermöglichen die ganzheitliche Beurteilung der fortlaufend anfallenden ökologischen und ökonomischen Wirkungen. Mit der Untersuchung von zwei Autobahnbrücken und zwei Überführungsbauwerken wird das Ziel verfolgt, einen einheitlichen Durchschnittswert für die ökologischen und die ökonomischen Wirkungen von Brückenbauwerken zu definieren. Der Beitrag befasst sich mit der Festlegung derartiger Referenzwerte und stellt erste Lösungsansätze zur Berücksichtigung des Recyclingpotentials von Materialien vor. Life cycle considerations as a base for assessment of the sustainability of road bridges. Life cycle considerations are important for the assessment of the sustainability of constructions. Taking the life cycle into account it is not only possible to determine single environmental impacts and investment costs arising during the construction of buildings, but also to assess the consecutive ecological and economical impacts. The aim of this study was to define a consistent average value for ecological as well as economical impacts of road bridges by evaluating two viaducts and two overcrossings. This article deals with the determination of those reference values and presents an approach how to deal with the recycling potential of materials within the life cycle assessment.     

Embodied energy and cost of building materials: correlation analysis

The US building sector consumes 48% of the nation’s annual energy as operating and embodied energy. Calculating embodied energy is difficult, complex and more resource-consuming than calculating operating energy due to a lack of complete, accurate and specific embodied energy data. One commonly used method to calculate embodied energy is input–output-based (IO) analysis, which utilizes economic data. The use of economic data indicates some relationship between embodied energy and cost. Some studies have investigated whether the embodied energy of a building can be predicted from its cost. These studies analyzed the relationship of the cost and embodied energy of a building and found a strong, positive correlation. However, when analyzed at the material level, the correlation weakened. This paper develops an improved input–output-based hybrid (IOH) model to calculate the complete, accurate and material-specific embodied energy of 21 commonly used building materials. After calculating and evaluating the embodied energy, the correlation of the embodied energy and cost of materials was analyzed. The results demonstrate a very strong and positive correlation between embodied energy and cost. In conclusion, more research may be required to predict embodied energy from cost data.     

空调冷热源生命周期成本评估

结合工程实例,选用离心式冷水机组 燃油热水锅炉(方案1)、燃油直燃溴化锂吸收式冷热水机组(方案2)、风冷热泵冷热水机组(方案3)作为冷热源备选方案.采用生命周期清单分析法得到各方案在生命周期内的大气污染物排放量,计算了包括生命周期环境成本在内的生命周期成本.方案2的生命周期环境成本最低,方案1的生命周期成本最低.     

Improved design of tubular wind tower foundations using steel micropiles

The constant increase in the wind power production leads to the need of higher wind towers, which brings up some questions regarding the effectiveness of tubular towers and respective foundations. This work focuses on the comparative structural design, life cycle behaviour and costs of onshore concrete shallow foundations for tubular wind towers (WT) when steel micropiles are used to improve resistance of the soil–structure interface (hybrid foundation). Typical wind loading for Turbine Class II and moderate seismicity (.25 g peak ground acceleration) is used to design and analyse 18 WT foundation case studies. This allows the comparison between shallow and hybrid foundations designed for three different hub heights and respective turbine rated power (80 m/2 MW, 100 m/3.6 MW and 150 m/5 MW) and for three different tubular tower solutions (steel, concrete and hybrid steel–concrete). The possible benefits of the solution using steel grouted micropiles are discussed in terms of potential environmental and economic impacts using life cycle analysis. The use of micropiles reveals to be an interesting solution to improve common shallow WT foundations since it allows the reduction of the dimensions of the foundation leading to significant environmental and cost benefits.     

Integrated assessment method for building life cycle environmental and economic performance

Life cycle assessment (LCA) is a powerful tool to identify a building’s environmental impact throughout its life cycle. However, LCA does have limits in practice because it does not consider the economic aspect of project implementation. In order to promote LCA application, a more comprehensive evaluation of building life cycle environmental and economic performance must be performed. To address these issues, we propose life cycle green cost assessment (LCGCA), a method that combines LCA with life cycle costing (LCC). In LCGCA the building’s environmental loads are converted to environmental costs based on the trading price of CO₂ certified emission reductions (CERs). These environmental costs are then included into the building life cycle cost. Subsequently an evaluation index of green net present value (GNPV) for LCGCA can be obtained. A governmental office building in Beijing was studied using LCGCA. Several design options were compared and the sensitivity of the CER price was analyzed. The research also shows that conclusions reached by LCGCA may be different from those of traditional LCC, which does not include environmental costs. The application of LCGCA needs the support of environmental policies. A sound environmental tax mechanism is expected to be established in China soon, which will enable LCGCA to be a useful tool to guide sustainable building design efficiently.     

空调热源的寿命周期评价

基于寿命周期评价方法建立了空调热源的寿命周期清单模型,用寿命周期影响评价法对热泵、电锅炉、燃油锅炉、天然气锅炉和燃煤锅炉作为空调热源的环境影响进行了评价。评价结果表明天然气锅炉的环境影响最小,寿命周期评价方法可用于可持续节能的研究。