Sprayed cementitious mortars to strengthen urban buildings: Case study in Barcelona, Spain

Abstract

Cities the world over require more resilient architecture that satisfies stricter structural safety standards than in the past. However, there are too many urban building structures about to reach the end of their designed life. This is especially serious in the case of loadbearing brick architecture built during the Spanish post-war period, when mid-height edifices were built by means of slender brick wall-based structures due to the tight economic situation and an endemic need for dwellings. At present, it is necessary to invest in strengthening them by means of resilient and sustainable repairs in order to recover their functionality and safety. One of the alternatives used with this purpose is the spraying of cementitious materials, which has great potential but limited efficient applications. Thus, further studies about materials, procedures and structural design are needed to improve the available knowledge. In this context, this paper is part of a research project that aims to achieve a substantial scientific and technological advance to strengthen buildings with sprayed cementitious materials, increasing their global sustainability regarding the resilience of the urban settlements. Therefore, this project addresses four themes: 1) search for more sustainable materials that have low permeability and low shrinkage; 2) development of models that take into account the specificities of sprayed materials; 3) improvement of quality control procedures and 4) a proposal for durability models that allow an integrated design for the resulting composite structure. The main objective of this research project is to define a new strengthening methodology through spraying that will be more compatible with the boundary conditions and the requirements of each application. This article presents the programmed tests for this project’s second theme and its first results. From these results, some advantages and disadvantages in the case of Barcelona buildings are discussed and first conclusions about the application of this technique in this specific case study are presented.