This paper introduces the key concepts of sustainability in the construction industry, together with a call for an urgent action to change the culture of all implied agents. The work presents an objective framework to evaluate sustainability through the analysis of the stages of the Integrated Life Cycle Assessment (ILCA). Such approach is applied to the global warming emissions indicator, and different aspects are investigated to support designers toward more sustainable designs. First, the principles for ILCA are introduced and sound values for the emissions of different structural materials are critically discussed and filtered taking into account the recently increased sensitivity to environmental aspects. On that basis, objective comparisons are presented for practical examples related to buildings and bridges. Specific design alternatives, based on the use of different materials and structural typologies, are also illustrated and compared to the original solution. The conclusions help the designer to identify which are the critical decisions leading to projects respectful of sustainability considerations. Specifically, material selection, structural efficiency, and a sound conceptual design are identified as the key aspects of sustainability.

The management of existing structures is raising a number of pertinent questions to the owners and engineers. Many structures built more than 50 years ago (even those built hundreds of years ago) usually no longer comply with safety requirements of current codes, which are typically addressed in new structures. This is not necessarily only caused by a poor original design or degradation with time, but it may be, for example, the consequence of increase in actions, reducing the level of reliability of a structure. This paper focuses on strategies to be adopted for existing structures which do not comply with code requirements for new constructions (e.g., to repair, to demolish, to rebuild, etc.) on the basis of a more holistic approach that includes economic, social, and environmental considerations. To that aim, first, a brief review of the background concepts on the reliability of structures is presented, highlighting the differences for new and existing structures. Following this analysis, suitable values for the reliability index (including sustainability considerations) are proposed, as well as tailored maintenance strategies. Finally, the paper presents a case study based on a real project to emphasize the benefits of adopting such a holistic perspective.