Strategies for Structural and Energy Improvement in Mid-Rise Unreinforced Masonry Apartment Buildings. A Case Study in Mestre (Northeast Italy)

Two-thirds of the Italian building stock was already built by the 1970s, largely according to gravity load design and using economical materials and poor workmanship. Currently, the structures, fixtures, and fittings of these buildings have reached the end of their service life, and they require both an assessment and an update to meet new standards and new needs. As an example of a common type, this article deals with the assessment of the present state and the proposal of an integrated structural and architectural intervention on an existing brick masonry mid-rise apartment building in the suburbs of Venice, Northern Italy. The structural analysis highlights a moderate vulnerability, despite the low seismic hazard, and the energy analysis indicates that the highest management costs are due to heating and sanitary uses. Low-impact strategies are preferred for each aspect of the required interventions. Their costs are counterbalanced by (a) the reduction to a fifth of the present management costs; (b) a 20% average increase in the economic value of the flats; and (c) a favorable tax regime at the national level. Transformed into parametric values, also useful for large scale analyses, these costs resulted in a sustainable monthly instalment from the owners, who may also benefit from the increased quality of the place where they live.