The criticality related to the consumption of operational energy and related greenhouse gas (GHG) emissions of existing buildings is clearly decreasing in new buildings due to the strategies tested and applied in recent years in the energy retrofit sector. Recently, studies have been focusing on strategies to reduce environmental impacts related to the entire life cycle of the building organism, with reference to the reduction of embodied energy (and related greenhouse gas emissions) in building materials. As part of EEA’s European EBC project, Annex 57, a wide range of case studies have been promoted with the aim of identifying design strategies that can reduce the embodied energy and related greenhouse gas emissions of buildings. The aim of this paper is to investigate the most common construction systems in the construction industry (concrete, steel, wood) through the analysis of three contemporary architectural works, with the aim of identifying the predisposition for environmental sustainability of each technological system, thus guiding the operators in the sector towards design choices more compatible with the environmental requirements recommended by European legislation.

With the increasing focus on the construction sector (e.g., following the European Green Deal initiative) with the aim to reduce emissions by 55% by 2030 (compared to 1990 levels), as well as achieve full decarbonisation by 2050, the built environment remains a strategic domain for the R&I (Research and Innovation) agenda. Indeed, the building and construction sector is the main contributor to greenhouse gas emissions (39% of global emissions as of 2018), highlighting the need to start a process of decarbonisation of this sector. The overall reduction in the environmental impact of building materials is achieved by establishing sustainable continuity between the end-of-life phase of the building and the production phase of individual building components. In particular, with reference to the end-of-life phase of the building (BS EN 15978: 2011), the Minimum Environmental Criteria foresee the preparation of a plan for the disassembly and selective demolition of the building, which allows the reuse or recycling of materials, building components and prefabricated elements used. According to the guidelines of a low-carbon construction design, which takes into account a circular economy, the following thesis deals with a methodological proposal to study “dry” construction systems (wood and steel). In particular, the study intends to reach the development of such an elaboration by carrying out an assessment of the environmental impact of a process of selective disassembly and demolition of steel building systems. The model is developed on the basis of a reading of the level of sustainability of emblematic case studies, appropriately identified, i.e., ‘quality’ architectures, built with ‘dry’ (steel) building systems.

The New Italian Procurement Code (Legislative Decree No. 50/2016), in compliance with the EU directives 26/02/2014, has introduced, among other things, the possibility of obtaining awards, during the awarding of the contract , in terms of reducing the estimated energy impact in the life cycle of the work. The objective of this study was to direct architectural design towards conscious choices that are compatible with environmental legislation. The study, therefore, aimed to analyze the characteristics of the most widespread (wet and dry) construction systems, in order to determine environmental sustainability thresholds referring to each of the four systems hypothesized for the development of the model. The simulated cases for the definition of the model refer to the following construction systems: M1 (structural system in load-bearing masonry); M2 (constructive system with frame structure and traditional brick cladding); M3 (constructive system with metallic bearing structure and dry stratified shell); M4 (constructive system with wooden supporting structure and dry stratified shell). The results indicated design scenarios aimed at using constructive systems that present advantages in terms of disassembly, recovery and reuse of the various components; in addition to the attitude of such systems, to be resilient, or to be able to be adapted and transformed during the life cycle of the building organism.

In the light of recent emergencies represented by climate change and global warming, with the consequent policies to reduce greenhouse gas emissions, this research aims at offering a response to the need for decarbonization of anthropization processes of territories, on a building and urban scale. This study elaborates a methodology, according to an integrated qualitative-quantitative approach, which combines the strategic need for sustainable mobility with the need to enhance the value of natural and environmental interesting places, typical of the Mediterranean area and in particular the ones which represented the heart of Magna Graecia. This strategy is implemented through a growing mobility offer in recent years: sustainable cycling tourism, which is included in the wider and more widespread strategic action of greenways. However, these strategies do not often meet the interests of the public administration, which is refractory to face great costs in exchange for a hypothetical return on investment, in the long term; the result is the abandonment and degradation of territories characterized by a remarkable naturalistic, landscape and environmental value. The aim of this study, therefore, is to provide operators in the sector (public administration, Cilento National Park Authority, economic operators, etc.) with a decision-maintenance tool, through the definition of priority criteria for interventions, according to an economic sustainability approach of the intervention and adopting an integrated qualitative-quantitative methodology. The intervention, as a whole, involves a cycle path of about 600 km, passing through 70 countries of the territory. Therefore, assuming the impossibility of being carried out at the same time, as a whole, it has been divided into 23 functional lots: the methodology intends, precisely, to define the priority and necessity criteria that determine the classification of importance of the 23 routes (sub-interventions), identified in this study.

The overall reduction in the environmental impacts of the construction industry is a complex process that requires methodological and applicative studies on the evaluation of the sustainability of the life cycle, related to both individual product and of the building system as a whole. In this context, with reference to the end-of-life phase of the building, the management of the disassembly and selective demolition plan of the building, allowing the reuse or recycling of the materials as well as of the building components and prefabricated elements used is fundamental. This research aimed to develop a methodology, applied to timber building systems, to mitigate CO2e emissions during the decommissioning and disposal of the building. The quantitative model developed considers the rates of the CO2e emissions involved in C (end-of-life) and D (benefits and loads beyond the system boundary) phases of building sustainability assessment. The model was applied to two wooden buildings: one with an XLAM structure and another one with a framed structure. In both cases, from the perspective of reusing the wood components for a subsequent life cycle, C and D phases of the process achieved an overall negative CO2e emission rate thanks to the offsetting from the carbon storage property of wood. This research has thus demonstrated the possibility of making the wood construction process circular through a zero-emission approach.