Thermo-mechanical characterization and hysteretic behavior identification of innovative plastic joint for masonry infills in reinforced concrete buildings

Modern approaches in buildings design strive to fulfill multiple performance requirements simultaneously. Accordingly, as far as buildings in earthquake-prone areas are concerned, damage limitation under seismic loads must be ensured while paying attention on the issues related to the environmental sustainability of the construction, ranging from its ecological footprint to the thermal efficiency. Masonry infills in framed reinforced concrete buildings are especially important in this context. In fact, they are vulnerable to earthquakes and greatly impact on the environmental sustainability of the building because they employ a significant amount of construction materials and influence its energy consumption throughout the lifetime. In light of this, the main novelty of the present work is concerned with a new deformable joint for masonry infills in framed reinforced concrete buildings. A detailed description of such innovative system for masonry infills is provided, together with numerical and experimental investigations about its mechanical and thermal behavior. The proposed joint is made of recycled plastic material, namely Regenerated Polypropylene Homopolymer. Geometry and manufacturing process of the proposed joint are initially described. Then, stress–strain relationships for the plastic material are obtained from uniaxial tensile tests at different temperatures. An assembly of fired hollow clay bricks and plastic joints is also tested under in-plane cyclic load, and a phenomenological model is thus proposed to simulate the experimental hysteretic behavior. Finally, experimental tests and finite element-based numerical simulations are performed to investigate the thermal performance of masonry infills with plastic joints.