چكيده لاتين
As one of the most accessible building materials, soil has always played a fundamental role in the traditional and vernacular architecture of various regions around the world. The Superadobe technique, which is based on compressing soil into bags and connecting them with barbed wire, is one of the modern methods of using soil in construction. Among these techniques, the dome form is recognised as the most optimal and common structural form in Superadobe architecture. The present study aims to investigate the structural behaviour of Superadobe domes under gravity and earthquake loads, conducted through experimental and numerical approaches.
In the first section, numerous tests were performed to determine the mechanical properties of Superadobe materials. These tests included compression, bending, and shear of the connection surface, examining the effects of the presence or absence of bags, loading direction, sample dimensions, and the role of barbed wire in the performance of connections. The results demonstrated that combining soil with bags and barbed wire significantly increases the material’s strength, ductility, and stability. On average, the compressive strength of the samples increased up to 6.5 times the compressive strength of compacted soil, and the shear resistance of connections with barbed wire increased up to 5.6 times.
Subsequently, numerical analyses were performed using the finite element method in ABAQUS software in macro and semi-micro scales (with modelling of layers and connections). These analyses were based on the validation of several numerical models with the results of the aforementioned experiments. The effects of factors such as the presence of barbed wire, dome dimensions (span diameter of 4 m, 7 m and 10 m), geometry of the opening (semi-circular, shallow Ogival arch, and rectangular) and its quantity, the ratio of thickness to dome diameter (5%, 7.5%, 10% and 15%), and varying thickness from base to apex with apex-to-base thickness ratios of 1, 0.7 and 0.4, were evaluated using nonlinear time history analysis.
The analysis results showed that removing the barbed wire leads to a significant increase in structural deformations and damages. Damages mainly occur as tensile cracks at the base connection and around openings. Although changing the form of openings did not significantly affect seismic behavior, increasing their number led to intensified failure. It was found that a thickness to diameter ratio of around 7.5% provides suitable seismic performance and increasing it further does not significantly improve the behavior. Additionally, gradually decreasing the thickness from base to apex in large domes, especially with a span of 10 m, has a significant effect on reducing structural damage, particularly compressive damage.
Overall, domes with a span of less than 7 m exhibit suitable seismic performance, with less than 2% of their mass undergoing effective damage. Larger domes, if designed following principles such as decreasing the thickness from base to apex, will also demonstrate adequate structural performance.
