The LCT Challenge: Defining New Design Objectives to Increase the Sustainability of Building Retrofit Interventions

Abstract

The decarbonization of the construction sector, which is one of the most impactful sectors worldwide, requires a significant paradigm shift from a linear economy to a circular, future-proofed and sustainable economy. In this transition, the role of designers and structural engineers becomes pivotal, and new design objectives and principles inspired by Life Cycle Thinking (LCT) should be defined and included from the early stages of the design process to allow for a truly sustainable renovation of the built environment. In this paper, an overview of LCT-based objectives and principles is provided, critically analyzing the current state of the art of sustainability and circularity in the construction sector. The effectiveness of applying such design principles from the early stages of the design of retrofit interventions is then demonstrated with reference to a case study building. Four seismic retrofit alternatives made of timber, steel and concrete, conceived according to either LCT principles or traditional, were designed and compared to a demolition and reconstruction scenario on the basis of five common environmental impact indicators. The indicators were calculated adopting simplified LCA analyses based on Environmental Product Declarations (EPDs), considering the product and End of Life stages of the building. The results of the comparative analyses confirm that LCT-based retrofit solutions are less impactful than both the traditional seismic retrofit interventions and the demolition and reconstruction scenario.

Methods and tools to address GHG emissions in the early design stage of building renovations: A state-of-the-art review

“…Passoni et al [12] applied Life Cycle Thinking (LCT) principles in the early design stages to assess the environmental impact of seismic retrofitting of four different alternatives. The authors gave special attention to phases B3, B4 and B5 and included a hazard risk in these phases of the use phase.…”

Removable, Reconfigurable, and Sustainable Steel Structures: A State-of-the-Art Review of Clamp-Based Steel Connections

“…As indicated in the previous section, within the areas where the circular economy [7][8][9][10] can be applied (prioritizing reuse over recycling) are structures, especially those made of steel, whose useful life is less than 50 years. When these structures are no longer functional, it is necessary to scrap them, generating a large amount of waste.…”

The Role of Life Cycle Structural Engineering in the Transition towards a Sustainable Building Renovation: Available Tools and Research Needs

“…Recently, simplified procedures have also been proposed to allow the estimation of those impacts even by unskilled professionals and designers. An example is represented by the adoption of environmental product declarations (EPDs) for the evaluation of the most commonly used environmental impact metrics of products (e.g., global warming potential, waste disposal, water consumption, amongst others) (Passoni et al [34]). EPDs also entail the adoption of specific data for the calculation of impacts, thus overcoming one of the main drawbacks of LCA analyses, which is the difficulty in selecting the most suitable data from available databases.…”

“…To make building renovation truly sustainable, concerted seismic risk mitigation and energy efficiency upgrading (i.e., aimed at reduced seismic expected losses and energy consumption) should be considered to enable an integrated reduction of running costs and environmental impacts throughout the building life cycle. Other performance objectives (as well as LCT and circular economy principles) are to be included while designing retrofitting strategies, examples of those being [7,34]:…”