Characterization of dry-stack interlocking compressed earth blocks

Earth has been a traditional building material to construct houses in Africa. One of the most common techniques is the use of sun dried or kiln fired adobe bricks with mud mortar. Fired bricks are the main cause for deforestation in countries like Malawi. Although this technique is low-cost, the bricks vary largely in shape, strength and durability. This leads to weak houses which suffer considerable damage during floods and seismic events. One solution is the use of dry-stack masonry with stabilized interlocking compressed earth blocks (ICEB). This technology has the potential of substituting the current bricks by a more sustainable kind of block. This study was made in the context of the HiLoTec project, which focuses on houses in rural areas of developing countries. For this study, Malawi was chosen for a case study. This paper presents the experimental results of tests made with dry-stack ICEBs. Soil samples from Malawi were taken and studied. Since the experimental campaign could not be carried out in Malawi, a homogenization process of Portuguese soil was made to produce ICEBs at the University of Minho, Portugal. Then, the compression and tensile strength of the materials was determined via small cylinder samples. Subsequently, the compression and flexural strength of units were determined. Finally, tests to determine the compressive strength of both prisms and masonry wallets and to determine the initial shear strength of the dry interfaces were carried out. This work provides valuable data for low-cost eco-efficient housingThis work was carried out under the research project HiLoTec - Development of a Sustainable Self-Construction System for Developing Countries. The authors wish to thank Mota-Engil Constructing Group for supporting this project

Seismic Design and Preliminary Analyses of a Prefabricated Hybrid Steel-Concrete Wall

Steel frames with reinforced concrete infill walls (SRCWs) are an interesting structural solution for applications in seismic areas if designed to exploit the stiffness of reinforced concrete (RC) and the ductility and dissipative capacity of steel. Three horizontal resisting mechanisms can be identified in SRCW: 1) contribution of the steel frame; 2) direct interactions between the steel frame and the compression strut in the RC infill walls; 3) interactions between steel frame and the RC infill wall through friction and shear connectors. While Eurocode 8 considers SRCWs to behave essentially as RC walls, numerical analyses demonstrated that this assumption may be far from reality. Innovative solutions for SRCW and relevant design approaches were eventually proposed in order to achieve a structural system able to fully exploit the advantages of the steel and RC components. In this context, the present study investigates a type of innovative modular SRCW through numerical simulations allowing a better understanding of its structural behaviour

Experimental analysis and modelling of the mechanical behaviour of earthen bricks

In this paper the mechanical properties of earthen bricks produced by manual compaction have been investigated by a combined experimental and theoretical approach. Several compression tests have been executed on specimens of various composition and different dimensions, with the purpose of understanding the role of volume fractions of earth, sand and straw fibre, and the influence of the size effect. An important goal is the application of predictive models of the elastic properties to the considered material, and its assessment. An empiric linear correlation between the compressive strength and the experimental Young’s modulus is proposed