Despite the current awareness of the high seismic risk of earthen structures, little has been done so far to develop proper strengthening solutions for the rammed earth heritage. Based on the effectiveness of TRM for masonry buildings, the strengthening of rammed earth walls with externally bonded fibers using earth-based mortar is being proposed as a compatible solution. In this context, the investigation of bond behavior was conducted by means of direct tensile tests, pull-out tests and single lap-shear tests. The specimens were prepared using earth-based mortars and two different types of meshes (glass and nylon) while considering different-bonded lengths. The direct tensile tests on TRM coupons showed the high capacity of the nylon mesh in transferring stresses after cracking of the mortar. The pull-out tests highlighted that in the case of glass fiber mesh, the bond was granted by friction, while the mechanical anchorage promoted by the transversal yarns granted the bond of the nylon mesh. Finally, the single lap-shear tests showed that the adopted earth-based mortar seems to limit the performance of the strengthening.

This paper illustrates an innovative manufacturing procedure for producing handcrafted interlocking stabilized compressed earth blocks (ISCEBs). A comparison of the mechanical properties of ISCEBs is conducted to assess the influence of varying components. The ISCEBs are manufactured by employing different block densities with three distinct mixtures (earth, earth and lime, earth and straw) and by using a human-powered machine named Float RAM 1.0 Press. The manual press was conceived for regions with limited access to technology and allows the production of interlocking blocks via two modes of compaction: mono-directional and bi-directional. A production average of approximately 30 blocks/hour corresponding to the work of three people is achieved. Three-point bending tests and uniaxial compression tests are carried out to investigate the ISCEB mechanical behaviour. The improvements obtained by incorporating additives into the subset of ISCEBs made from a pure earth mixture are tested. The aim of this work is to identify, for this specific technology, the relationship between production parameters and the consequent behaviour of different stabilization methods. A correlation is found between the compaction force and the compression strength of ISCEBs. The addition of lime increases strength and causes the blocks to exhibit a brittle behaviour. Moreover, the incorporation of straw fibres improves the tensile strength and ductility without significantly affecting the compression strength of the blocks. Energy-based parameters are obtained for all the tests, allowing the assessment of the ISCEB mechanical and dissipation properties.

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City centres of Europe are often composed of unreinforced masonry structural aggregates, whose seismic response is challenging to predict. To advance the state of the art on the seismic response of these aggregates, the Adjacent Interacting Masonry Structures (AIMS) subproject from Horizon 2020 project Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe (SERA) provides shake-table test data of a two-unit, double-leaf stone masonry aggregate subjected to two horizontal components of dynamic excitation. A blind prediction was organized with participants from academia and industry to test modelling approaches and assumptions and to learn about the extent of uncertainty in modelling for such masonry aggregates. The participants were provided with the full set of material and geometrical data, construction details and original seismic input and asked to predict prior to the test the expected seismic response in terms of damage mechanisms, base-shear forces, and roof displacements. The modelling approaches used differ significantly in the level of detail and the modelling assumptions. This paper provides an overview of the adopted modelling approaches and their subsequent predictions. It further discusses the range of assumptions made when modelling masonry walls, floors and connections, and aims at discovering how the common solutions regarding modelling masonry in general, and masonry aggregates in particular, affect the results. The results are evaluated both in terms of damage mechanisms, base shear forces, displacements and interface openings in both directions, and then compared with the experimental results. The modelling approaches featuring Discrete Element Method (DEM) led to the best predictions in terms of displacements, while a submission using rigid block limit analysis led to the best prediction in terms of damage mechanisms. Large coefficients of variation of predicted displacements and general underestimation of displacements in comparison with experimental results, except for DEM models, highlight the need for further consensus building on suitable modelling assumptions for such masonry aggregates.