Search Results (8)

In geotechnical earthquake engineering, enhancing the seismic properties of foundation soil to modify the characteristics of earthquake waves transmitted to structures presents a viable solution. This study investigates the effect of placing an isolation layer, composed of a mixture of recycled tire rubber and sand, beneath structures to mitigate seismic forces acting on buildings situated on soil layers with high amplification potential. In other words, the role of a soil layer functioning as a seismic isolator is examined. To achieve this objective, the seismic behavior of building-type structures is analyzed through numerical simulations, supplemented by laboratory experiments available in the literature. The numerical analyses are performed in the frequency domain using the finite element method within a one-dimensional (1D) framework. To validate the feasibility of the proposed isolation layer based on parametric analysis results, comparisons are made with laboratory tests available. In the literature, seismic isolation applications with thicknesses ranging from 1 to 3 m resulted in reductions of 6.8% to 16.17% in response spectral accelerations measured at the surface, while improvements in Fourier amplitude ratios ranged between 12.03% and 13.98%. This approach aims to provide an economical and efficient solution for earthquake-resistant structures while simultaneously promoting sustainability by recycling waste tires, contributing both to environmental conservation and economic benefits. Full article

The present work explores the use of geophysical surveys as valuable tools for the study and sustainable management of landslides, with a particular focus on Ecuador. As an Andean country, Ecuador’s geomorphology and geology are dominated by volcano-sedimentary materials and processes, which confers a high susceptibility to landslides. In the last few years, a number of landslide events (such as those at La Josefina, Alausí, and Chunchi) have given rise to disasters with significant material damage and loss of life. Climatic events, affected by climate change, earthquakes, and human activity, are the main landslide triggers. Geophysical surveys, like seismic refraction, electrical resistivity tomography (ERT), and ground-penetrating radar (GPR), are easy and low-cost techniques that provide valuable and critical subsurface data. They can help define the failure surface, delimit the mobilized materials, describe the internal structure, and identify the hydrological and geotechnical parameters that complement any direct survey (like boreholes and laboratory tests). As a result, they can be used in assessing landslide susceptibility and integrated into early warning systems, mapping, and zoning. Some case examples of large landslide events in Ecuador (historical and recent) are analyzed, showing how geophysical surveys can be a valuable tool to monitor landslides, mitigate their effects, and/or develop solutions. Combined or isolated geophysical techniques foster sustainable management, improve hazard characterization, help protect the most vulnerable regions, promote community awareness for greater safety and resilience against landslides, and support governmental actions and policies. Full article

This paper discusses the concept of geotechnical seismic isolation (GSI) systems, characterized by new principles of action, to reduce seismic loads on buildings. The advantages and disadvantages of GSIs and their environmental and economic reliability are analyzed. The aim of the study is to develop a geotechnical seismic isolation system in the form of vertical barriers, using a rubber–soil mixture (RSM). The novelty of the work lies in the definition of effective structural and technical solutions of vertical seismic barriers made of RSM, characterized by reliability in providing seismic isolation. The ground and superstructure interactions are modeled in PLAXIS 2D software from 2021, using the finite element method, using the accelerogram of the Kobe and Northridge earthquakes. The results confirm the positive impact of using an RSM as an effective GSI geometrical. The results show that the GSI system using an RSM reduces horizontal accelerations by 60%. Significant acceleration reductions of 40–60% are also observed when the thickness and depth of GSI seismic barriers are increased. The results of the study contribute to the substantiation of methodology and scientific and technical efficiency of geotechnical seismic isolation as an economically favorable design alternative to the traditional seismic isolation system. Full article

Masonry buildings in high-intensity seismic and cold regions of China face the dual challenges of frost heaving and seismic hazards. To explore the potential of a sand cushion instead of the frozen soil layer to deal with these problems, a cost-effective sand cushion-based Geotechnical Seismic Isolation System (GSI-SC) was developed in this study, where a sand cushion is introduced between the structural foundation and natural soil, while the space around the foundation is backfilled with sand. Shaking table tests on a one-story masonry structure equipped and non-equipped with the GSI-SC system were undertaken to investigate its effectiveness in seismic isolation, where the input wave adopted the north–south component of the EL Centro wave recorded in 1940, and the peak input acceleration (PIA) was set as 0.1 g, 0.2 g, and 0.4 g. It is found that the GSI-SC system significantly reduced the seismic response of the structure, effectively achieving seismic isolation. For a PIA of 0.4 g, the GSI-SC system reduced the acceleration of the roof panel and the inter-story displacement of the structure by 33% and 39%, respectively. Numerical simulations were performed to evaluate the seismic response of buildings equipped and non-equipped with the GSI-SC system. The simulation results matched well with the experimental results, verifying the effectiveness of the newly developed seismic isolation system. The GSI-SC system can provide the potential to reduce frost heave and earthquake disasters for buildings in high-intensity seismic and cold regions. Full article

This paper presents the results of a study on the relevance of seismic isolation systems for protecting architectural monuments from seismic and vibration impacts. This work aims to develop a method for protecting architectural monuments from seismic and vibration effects by installing geotechnical seismic isolation systems made of various geomaterials, such as a silicate soil mixture (SSM), a cement–soil mixture (CSM), a bitumen–soil mixture (BSM), and a rubber–soil mixture (RSM). The novelty of the work lies in the results of studying the wave processes in different models of geomaterials to assess their effectiveness in a seismic isolation system in the form of damping barrier screens to ensure the seismic resistance of architectural monuments. By comparing the amplitude–frequency characteristics of various geomaterials, it was found that the rubber–soil mixture (RSM), the cement–soil mixture (CSM), and the bitumen–soil mixture (BSM) have the most effective damping properties. A proposed method for protecting architectural monuments with geotechnical seismic isolation in the form of vertical screen barriers and technology for their installation ensures the integrity and safety of architectural monuments at all stages of construction and operation. Full article

Low-income regions do not have the economic strength to use conventional isolators; therefore, low-cost alternatives are needed. The recent series of earthquakes in Turkey has once again demonstrated the destructive power of this natural disaster and highlighted the need for high-quality earthquake-resistant structures. In this context, a comprehensive experimental parametric study on the use of natural stone pebbles (ASL-1) and stone pebbles in combination with a geogrid layer (ASL-2) as suitable materials for a GSI system is conducted and the main results are presented. The seismic behavior of five different models was tested using four different acceleration diagrams with different peak ground accelerations (PGAs). Characteristic displacements, accelerations, and strains were measured. The results and conclusions presented are based on the integration and synthesis of several previously conducted studies. Full article

The anti-seismic problem of rural residential buildings is the weak link of seismic retrofitting in China. Recently, geotechnical seismic isolation (GSI) technology based on rubber–sand mixtures (GSI–RSM) using rubber–sand mixtures (RSM) between the structural foundation and the foundation soil has been proven to have the possibility of potential applications in rural residential buildings. Many theoretical studies exist on the effectiveness of seismic isolation of the GSI–RSM system, but few studies on either the seismic response test of model buildings placed on the RSM layer or the large-scale shaking table test exist. Therefore, this study considers a large shaking table test performed on a 1/4 single-story masonry structure model with and without a GSI–RSM system by selecting a standard input ground motion and varying input acceleration amplitudes. The test results show that the GSI–RSM system can reduce the seismic response of superstructures. The isolation effect of the GSI–RSM system is low in small earthquakes and increases with increasing earthquake magnitude. Overall, the RSM layer can filter part of the high-frequency components of the earthquake to transmit to the superstructure and consume more seismic energy by generating friction slip in the interaction with the structural foundation. Full article

Geotechnical seismic isolation (GSI) has emerged as a potential technique to mitigate the effects of earthquakes, with many applications to structural configurations, such as bridges and buildings. It consists of absorbing the seismic energy from the soil to the superstructure by interposing a superficial soil layer in order to reduce the accelerations that filter from the soil to the structure. This mitigation technique is particularly suitable in developing countries since GSIs are low-cost seismic isolation systems that through relatively simple manufacturing processes allow to safe costs and stimulate many applications. The presented study aimed to perform 3D numerical finite element models that overcome the previous contributions by performing several structural configurations. Several historical earthquakes are considered in this paper, and the results may be applied to drive general assessments of the technique in case of future seismic hazards. Full article