APPLICATION OF WOOD-BASED SEISMIC RETROFITTING TECHNIQUES ON EXISTING TIMBER AND MASONRY STRUCTURES: DESIGN STRATEGIES, MODELLING APPROACHES AND PRACTICAL BENEFITS FOR TWO CASE-STUDY BUILDINGS

Reversible retrofitting techniques for protecting architectural heritage against seismic events have found increasing application in existing or historical buildings. In this framework, the use of wood-based strengthening solutions for both timber and masonry structures has shown promising results, as proved by several recent research studies. Starting from these outcomes, the present work aims at highlighting the potential of such timber-based retrofitting methods from both the academic and the professional perspective, considering two case-study buildings: a stone-masonry church from 18th century with a timber roof, and a Venetian sawmill composed of masonry and timber structural portions. In the first case-study building, the church of St. Andrew in Ceto (province of Brescia, Italy), the lack of joints among the roof timber members and the masonry walls, as well as the in-plane flexibility of the roof structure itself, made the church vulnerable to seismic actions and prone to local out-of-plane masonry collapses. The second case-study building, the sawmill of Vallaro (province of Brescia, Italy), was composed of two building units, one featuring mainly timber structural elements, the other consisting of masonry walls and a wooden roof. This second intervention was very complex, because of the different materials involved, their conservation state, and the need to transform part of the building in a museum, with increased design static and seismic loads. For both case studies, timber-based seismic retrofitting interventions were applied, consisting of the addition of new wooden members, and the use of plywood panels and cross-laminated timber elements. This work presents and discusses the adopted design and modelling strategies, as well as the practical benefits of the applied solutions. The present study can thus contribute to the promotion of timber-based techniques in the combined structural, seismic, and conservation upgrading of existing buildings belonging to the architectural heritage of seismic-prone countries.