Earthen architecture has a significant share in the world’s fund of both residential architecture and cultural heritage. It provides a home to more than half of the world’s population and can be found in seismically active areas. Empirically acquired knowledge on building with rammed earth (RE) has usually been passed down from generation to generation by word of mouth, with no written scientific grant for the load-bearing capacity and resistance of structural elements. Today, many countries still do not have standards for the design of RE structures. In the development of new as well as existing design standards, the results of experimental research play a significant role. The focus of this study was on unstabilized RE, which is locally available material with low embodied energy. This paper elaborates experimental campaigns, within which meticulous techniques were employed to provide new knowledge on RE for use in earthquake-prone areas. Furthermore, this paper includes: (i) ranges of values of mechanical properties determined on RE specimens from all over the world; (ii) a comparative summary of experimental research conducted on walls and buildings to assess their seismic performance; (iii) an overview of standards and testing methods used in experiments; and (iv) recommendations for further research.

Earthen architecture largely supports the concept of sustainable building. In the seismically active area of eastern Croatia, there is a large number of rammed earth houses, many of which are over 100 years old. All these houses were built using empirical knowledge, i.e., without applying national design standards. In order to support the preservation of ethnic villages and traditional rammed earth houses, a field survey was conducted. Parts of the walls of traditional rammed earth houses were collected, and the material was thoroughly analyzed. Samples of rammed earth were reproduced, and tests were carried out with the aim of determining the shear strength to subsequently determine the seismic behavior of Croatian traditional earthen architecture. This paper presents the results of shear strength tests on samples with different particle size distributions, lime content, the straw of different cereals but also hemp fibers. An increase in shear strength was observed with the addition of natural fibers to the samples.

Rammed earth buildings constitute a large part of the housing stock in rural areas. Although these houses are recognized as a cultural heritage, detailed analyses of their architectural features, geometric parameters crucial for structural stability, and soil properties used for their construction have not yet been carried out in Croatia. The aim of this study is to collect basic data on the architectural features and material properties of rammed earth walls through field research in Croatia. These data are crucial for both numerical and experimental studies to improve the understanding of the structural behavior of rammed earth houses. Data were obtained through field research and a detailed survey of 22 houses. The houses were analyzed, samples of the rammed earth walls were collected, and their properties were tested in the laboratory. This study contributes to a better understanding of regional building practices and provides data that will enable us to identify the causes of damage in future studies and to select rehabilitation measures to preserve the authentic symbols of cultural heritage.

Physical properties of the soil in the walls of traditional eastern Croatia rammed earth houses In eastern Croatia rammed earth houses were traditionally built in the past. The choice of suitable soil for building rammed earth houses depends on several soil properties. Moreover, since there are no standards or recommendations for construction of rammed earth houses in Croatia, the construction and renovation of such houses is almost nonexistent nowadays. With the aim of forming detailed recommendations for eastern Croatia area in near future, soil samples were collected from existing houses to test the physical properties of the soil. Obtained results showed that Atterberg limits are within the limits of the recommended values and published results in the literature, while particle size distribution differs from most recommendations and published results.