Resilient and sustainable infill masonry walls to face the environmental impact due to extreme wind actions and associated out-of-plane and in-plane loads acting on the envelope of reinforced concrete buildings

Abstract

The external envelope of reinforced concrete buildings (RC buildings) is subjected to external environmental actions, particularly those related to wind action, which could expose their unreinforced masonry (URM) infill walls, in case of high winds, to intense out-of-plane loads (OOP loads) and in-plane loads (INP loads, which could cause their cracking. Considering the projected effects of climate change, the growing claim for building sustainability generates novel chal¬lenges for the use of innovative and green construction materials with enhanced thermal properties and suitable mechanical resistance, added with a minimized carbon footprint. Lightweight concrete (LC) masonry units had an enlarged use in the construction of the facades of reinforced concrete buildings (RC buildings), through their applications in sustainable solutions of URM infill walls. In this paper, firstly, the expected increase in wind actions due to the expected effects of climate change is analysed. Subsequently, essential elements about wind action in facades and cross walls of the building´s vertical envelope, and about the effects of the in-plane loads (INP loads) and out-of-plane loads (OOP loads) due to wind on the behavior of URM infill walls, are presented here. Basic properties of relevant types of lightweight concrete masonry units with influence on the mechanical resistance of respective infill walls against cracking, particularly associated with tensile stress due to in-plane and out-of-plane loads, are analysed. Relevant characteristic behaviour of URM infills and of their confining RC elements in the case of OOP loads is analysed, in particular related to the onset of cracking of URM infill walls due to OOP associated with extreme wind loads. Finally, an analysis and discussion are made of the impact of cracking on the OOP strength against wind loads and the minimization of the adverse effects of OOP and INP loads due to wind and retrofitting with innovative materials. That improvement is explored, mainly, through the analysis of relevant innovative retrofitting techniques, such as sustainable solutions, preferably with tending use of natural carbon–neutral building materials.