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Mechanical characterization of adobe masonry
(Springer Nature, 2021-01-01)
The characterization of the mechanical properties and behaviour of adobe masonry is fundamental for the understanding of the structural behaviour of adobe constructions. Thus, in the last decades, experimental studies focused on this topic have been carried out by different authors. Many of the existing experimental works, however, were carried out aiming to support broader studies focused on the seismic behaviour of adobe constructions and are not very detailed. Moreover, authors tend to adopt different procedures in their experimental work, since there are few indications in existing standards for testing adobe masonry. The wide variety in materials used, both for the adobes and mortars, further complicates this work, making it difficult to compare results obtained in different studies. This chapter provides an overview of the indications given by standards and other technical recommendations for the mechanical testing of adobe masonry. It presents a review of existing research on the mechanical behaviour of adobe masonry, addressing studies that focus on: (i) compression behaviour, (ii) shear behaviour, (iii) joint shear behaviour. It provides a global analysis of the existing knowledge, suggesting improvements for normative documents and identifying future research needs.
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Mechanical characterization of adobe bricks
(Springer Nature, 2021-01-01)
The mechanical characterization of adobe bricks is an important first step in the study of the behaviour of adobe masonry. For this reason, in the last decades, different authors have conducted research on the mechanical behaviour of adobes from various regions of the world. Despite the importance of mechanical characterization, there are still only a few standards and normative documents with clear indications for the mechanical testing of earthen materials and, in general, these indications are not thorough and vary among different countries. Consequently, authors tend to adopt different types of test specimens and procedures in their experimental work, thus obtaining results that are not directly comparable. The fact that the materials and procedures traditionally used are also not standardized, varying greatly from region to region, also contributes to the difficulty of comparing results from different studies. This chapter presents a review of the indications provided by codes, standards and other technical recommendations for the mechanical testing of adobe bricks, as well as a detailed review of procedures adopted, and results obtained by different authors regarding the mechanical characterization of traditional adobe bricks. This chapter focuses, in particular, on the behaviour of adobe bricks when subjected to simple compression. It provides an overview of the existing knowledge and identifies needs for future research and development.
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Seismic strengthening techniques for adobe construction
(Springer Nature, 2021-01-01)
Heavy damage to adobe constructions observed after earthquakes, experimental programmes and numerical simulations have demonstrated high vulnerability levels that require appropriate strengthening measures. Given that a large fraction of adobe constructions are located in less developed countries, there is a need for effective strengthening techniques that are low-cost and easy to install at the same time. In this chapter, a comprehensive selection of research studies is critically reviewed to provide useful information to researchers and professionals involved in the conservation and retrofit of adobe constructions.
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Quasi-static in-plane testing of adobe masonry walls and structures
(Springer Nature, 2021-01-01)
The lateral seismic capacity and the in-plane failure pattern of adobe masonry may be understood by performing quasi-static experimental tests on full-scale adobe walls. Information regarding the maximum lateral capacity and the displacement ductility are normally obtained during these tests. Also, information about limit states could be obtained. Along the years, universities in Europe, Asia and Latin America have performed this type of tests and the results of some of these works are summarized in this chapter.
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Research developments and needs on seismic performance and strengthening of adobe masonry constructions
(Springer Nature, 2021-01-01)
The significant amount of studies on adobe masonry constructions, which have received growing interest from researchers and practitioners, allows preliminary conclusions on the state-of-the-art to be drawn. Besides, several research needs can be delineated to create the basis for knowledge development and implementation of seismic risk mitigation programmes. Past studies moved from material characterization to structural performance assessment through numerical simulation and experimental testing, as well as seismic strengthening. Future lines of research could focus on test standardisation, non-destructive and minor-destructive testing, full-scale testing to support structural modelling and strengthening, and numerical simulation through discrete element and equivalent frame methods.
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Adobe constructions in the world: a first overview
(Springer Nature, 2021-01-01)
Adobe constructions date back thousands of years and are a significant fraction of the world’s built heritage, including UNESCO sites. Even though adobe dwellings are still built in some regions, a number of experimental and theoretical studies have delineated the vulnerability levels of these constructions. A significant concentration of adobe constructions in regions with moderate-to-high levels of seismic hazard has been observed as well, resulting in huge human losses during earthquakes. Therefore, the knowledge of the structural performance and seismic reinforcement of adobe constructions provides the basis for their structural vulnerability reduction, allowing disaster risk mitigation and community preparedness. This is also a strategic task to meet sustainability and community resilience goals in multiple countries, where guidelines for both existing and new adobe constructions must be implemented. This chapter provides readers with preliminary information on history, worldwide distribution, construction features and observed performance of adobe constructions for different demand scenarios. These topics are recalled and discussed in more detail in subsequent chapters.
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Analytical fault tree and diagnostic aids for the preservation of historical steel truss bridges
(Elsevier, 2021-12-23)
Historical steel bridges represent an important construction typology integrating the constructive heritage of the past century that needs to be preserved. Exposure to fatigue phenomenon, aging, improper design or execution, extreme events, and other aggressive environmental agents can seriously compromise the conservation and performance of these structures as some recent catastrophic collapses have shown (Mississippi River bridge, Minneapolis, Minnesota 2007; Kinzua Bridge State Park, Pennsylvania 2003). In this context, the diagnostic of historical steel bridges becomes of basic importance to identify and implement maintenance, monitoring and conservation strategies. Fault Trees are useful tools for practitioners that provide a complete overview of possible failures. In the related literature, this instrument is mainly applied with approaches that are based on previous experience or failures detected in similar structures, and so the Fault Tree can only provide qualitative support. This paper proposes a new method to achieve an “Analytical” Bridge Fault Tree linking the technician's experience and the numerical simulations of different fault scenarios. The latter are achieved by a numerical model able to consider fatigue failure and different concurring causes in the analysis (e.g., and aggressive phenomena, corrosion, defects, lack of maintenance). The proposed approach was applied to a historical railway steel truss bridge located in the East of Spain (Valencia Region) in order to show its applicability and potential.
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Experimental in-plane behaviour and drift-based fragility assessment of typical Peruvian confined masonry walls
(Elsevier Ltd, 2022-07-25)
Around 56% of dwellings in Lima are constructed with confined masonry walls, and over 70% are built without engineering design and supervision. This building stock is exposed to the seismic activity of the Peruvian coastline. Then, in case of a severe earthquake, many of these buildings may suffer significant damage and eventually collapse, causing high economic losses and fatalities. Thus, it is essential to investigate the seismic behaviour of these constructions to understand their seismic vulnerability. This work studied the seismic performance of typically confined masonry walls built with hollow bricks based on cyclic in-plane tests. The imposed boundary conditions allowed the walls to behave as a cantilever. The influence of vertical pre-compression was also explored by performing separate tests with and without such load. Outcomes suggest that these walls may collapse after 0.5% drift. Also, mechanical features like stiffness degradation and damping values were calculated for different displacement limit states. Finally, fragility curves of confined masonry walls considering different unit types (i.e. solid, hollows, tubular), axial load ratio, and horizontal reinforcement are computed. The results demonstrate that tubular units should be forbidden as bearing walls, and horizontal reinforcement inside the walls improves their displacement ductility.

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