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Seismic isolation using granulated tire-soil mixtures for less-developed regions: Experimental validation
Abstract
In this study, shaking‐table experiments were conducted with a novel seismic isolation system (Geotechnical Seismic Isolation, GSI) to validate its dynamic performance during earthquakes. This isolation technique uses shredded rubber–soil mixtures to reduce the structural response to earthquakes, and thus may not only provide economical structural safety for buildings in less‐developed regions, but could also consume a large amount of waste tires worldwide. The present experimental results show that the GSI system has potential to significantly mitigate seismic hazards. Copyright © 2013 John Wiley & Sons, Ltd.
... A few investigations explored the performance of RSm as Geotechnical Seismic Isolation (GSI) system at laboratory scale (Kaneko et al., 2013;Xiong and Li, 2013;Bandyopadhyay et al., 2015;Tsang et al., 2020;Bernal-Sanchez et al., 2020). The findings from these investigations have shown a reduction of both horizontal and vertical accelerations at the structural and surface level attributed to the increase in material damping. ...
... One common element of the previous studies is the material disposition. At a larger scale, a unique design configuration has been adopted whereby a horizontal RSm layer is added below a full-scale structure (Kaneko et al., 2013;Xiong and Li, 2013;Bandyopadhyay et al., 2015;Vratsikidis and Pitilakis, 2022). The results of these experiments showed an appreciable reduction in horizontal acceleration at rubber contents greater than 20% by mass. ...
... This reduction suggests the potential for effectively dampening and isolating the acceleration response, thereby improving the overall seismic performance of the modelled soil-structure. This outcome aligns with previous research (Kaneko et al., 2013;Xiong and Li, 2013;Bandyopadhyay et al., 2015;Vratsikidis and Pitilakis, 2022), which has shown that the inclusion of RSm, in the form of a horizontal layer beneath the structures under study, may result in the attenuation of incoming energy. Notably, these previous studies also utilised rubber content exceeding 20%, consistent with the findings of the current study. ...
This study presents a Geotechnical Seismic Isolation (GSI) system proposed for utilising Rubber-Soil mixtures (RSm) to enhance the dynamic performance of a modified soil and foundation structure. The inclusion of RSm enables the system to exhibit lower stiffness and increased energy dissipation capacity, thereby facilitating the benefits of dynamic soil-foundation structure interaction. However, most of prior research on RSm has been predominantly limited to the elemental scale, restricting its application in practical scenarios. In this study, the dynamic response of a modified soil foundation was studied by incorporating soft zones in the form of trench fills comprising RSm. The design configuration was examined by altering the material composition added to the trenches with various rubber percentages: 0, 20%, 40%, 60% and 100% by mass. Experimental tests were conducted via a 1-g shaking table, subjecting a modelled soil-structure system to a series of sinusoidal excitations in a set frequency range (i.e., 2-9Hz). Adding low (20%) or high (>60%) rubber contents led to an amplification of the input acceleration with respect to the initial scenario. However, findings from this study demonstrate that adding 40% rubber can reduce up to 35% the resultant amplification at frequencies near the resonance of the host soil's natural frequency (i.e., 7.5 Hz-8.5Hz). Consequently, this study highlights the potential of integrating RSm trench fills as an alternative design consideration to mitigate incoming disturbances and safeguard both new and existing constructions near the soil foundation.
... In the literature, laboratory or experimental works have played a crucial role in the research of GSI-RSM systems, particularly through the utilization of shaking table tests [8,12,[17][18][19][20]. Shaking table tests and other experimental setups have enabled researchers to observe and measure the real behavior of structures and their interaction with GSI-RSM systems with a high level of accuracy and control. ...
... By subjecting scaled models or physical structures to simulated earthquake ground motions, shaking table tests allow for the evaluation of the system's response under realistic loading conditions. Xiong and Li [18] conducted experimental tests using a shake table on a mixture of soil and rubber. They examined the performance of using this mixture and demonstrated its effectiveness in reducing the structural response to earthquakes, particularly for low-rise buildings. ...
... Notably, this attenuation effect is more pronounced in cases where higher rubber contents and thicker RSM layers are utilized. These findings align with previous research studies encompassing various experimental techniques such as shaking table tests [2,18,20,21], centrifuge tests [3,39], large-scale field testing [19], and numerical investigations [9,13]. The consistency of these findings across different research approaches supports the robustness and reliability of the observed trends in the reduction of acceleration response due to the incorporation of the RSM layer. ...
This paper presents a comprehensive investigation into the seismic performance of structures utilizing Rubber-Sand Mixture (RSM) as a Geotechnical Seismic Isolation (GSI) system. Shaking table tests were conducted to evaluate the effectiveness of the RSM layer in modifying the acceleration response and settlement of structures under dynamic loading. The effectiveness of the RSM layer was found to be influenced by various factors, including the rubber content, depth ratio (the RSM layer to the footing width), and ground compaction. The study considers a wide range of RSM depth ratios (0.1-0.8), providing valuable insights into the optimal design of buildings equipped with RSM. The experimental results demonstrate a significant reduction in acceleration response for low-rise and medium-rise buildings, as well as potential benefits for tall buildings with a large depth ratio. However, increasing the RSM thickness is accompanied by larger settlement, highlighting the need for a balance between reducing acceleration and controlling settlement. There is a limit to the effectiveness of the depth ratio beyond which, the de-amplification and final seismic settlement become less sensitive to changes in RSM layer thickness. The study reveals that the RSM layer exhibits a more pronounced reduction in acceleration response in loose ground conditions compared to denser ground conditions. However, even in denser ground, the inclusion of RSM layers contributes to improved seismic performance to a lesser extent. The findings align with prior studies, emphasizing the potential of RSM layers in mitigating the seismic response of structures. By appropriately incorporating RSM layers and considering site-specific factors, engineers can enhance the resilience of structures, leading to safer and more earthquake-resistant built environments.
... Rubber is a non-biodegradable material, and its accumulation causes serious environmental imbalances. It is known as a 'black pollutant' [1]. Hence, the utilization of scrap rubber tires is of paramount importance. ...
... Numerical studies carried out by Tsang et al. [21] and Pitilakis et al. [22] as well as shake table studies by Xiong and Li [1] also points out the potential use of sand-rubber tire shred mixtures in effective earthquake protection. Apart from earthquake energy dissipation by GSI layers due to the vibration damping nature of rubber present in it, the high durability and non-biodegradable nature of rubber makes the GSI system an eco-friendly and sustainable solution for costly base isolation techniques. ...
... The potential use of the sand-rubber mixture (SRM) as geotechnical seismic isolation layer beneath building foundations was proposed by Tsang [48]. Use of shredded scrap tiresand mixtures placed below the foundation as earthquake protection layer was found to partially dissipate earthquake energy before it propagates to the foundation [1,21,22]. Apart from reducing the level of shaking in the horizontal direction, the distinctive advantage of the method is that it also significantly reduces the shaking level in the vertical direction [48]. Similar studies on the use of sandbags and synthetic liners as energy-absorbing layers for seismic protection underneath foundation were carried out by Yegian et al. [49]. ...
In the present study, a geotechnical seismic isolation (GSI) bed, composed of geosynthetic-reinforced sand–rubber tire shred mixture layer between the base of the building foundation and the supporting soil medium, is considered to mitigate ground vibrations. The index and engineering properties including dynamic properties of sand–rubber tire shred mixtures are carried out to assess their suitability for seismic base isolation of buildings. In addition to that, the liquefaction resistance of sand rubber mixtures is also evaluated. Further, laboratory-based model experiments and Finite Element (FE) modeling was carried out for footing resting on geogrid-reinforced GSI layer under static loading. Further, 2D seismic response of a typical building on GSI was also carried out using finite element code ABAQUS. Finally, results of a series of field experiments conducted to study the response of model footing resting on the geogrid-reinforced GSI bed subjected to horizontal ground vibration are presented. Further, a 3D finite element (FE) model of the field study was developed in the time-domain to simulate and investigate the response of geogrid-reinforced GSI bed on a multi-layered soil system for different surface wave characteristics. In general, it was found that GSI with geogrid reinforcement is found to be effective in the mitigation of ground vibrations due to earthquakes and other source of vibration.
... In 2007, Tsang proposed using a sand-rubber mixture (SRM) as a geotechnical seismic isolation layer beneath building foundations. Studies by Tsang et al. (2012Tsang et al. ( ,2021, Xiong andLi (2013), andPitilakis et al. (2015) have demonstrated that this method can reduce both horizontal and vertical shaking levels. Similar studies have examined the use of sandbags and synthetic liners as energy-absorbing layers for seismic protection, with Yegian et al. (2004), Jain et al. (2004), and Ansari et al. (2011 reporting lower accelerations compared to fixed-base structures. ...
... In 2007, Tsang proposed using a sand-rubber mixture (SRM) as a geotechnical seismic isolation layer beneath building foundations. Studies by Tsang et al. (2012Tsang et al. ( ,2021, Xiong andLi (2013), andPitilakis et al. (2015) have demonstrated that this method can reduce both horizontal and vertical shaking levels. Similar studies have examined the use of sandbags and synthetic liners as energy-absorbing layers for seismic protection, with Yegian et al. (2004), Jain et al. (2004), and Ansari et al. (2011 reporting lower accelerations compared to fixed-base structures. ...
... Pitilakis et al. (2015) noted that SRM layers are particularly effective for mid-rise buildings, reducing design shear force and displacement. Shaking-table experiments conducted by Xiong and Li (2013) and Bandyopadhyay et al. (2015) with shredded rubber-soil mixtures as isolation material placed below concrete blocks confirm the suitability of SRM for seismic isolation. Previous studies have also reported that the damping ratio of SRM increases with an increment in rubber content (Hazarika et al. 2010;Anastasiadis et al. 2012;Senetakis et al. 2012;Ehsani et al. 2015) and that it has low liquefaction potential (Hazarika et al. 2007;Kaneko et al. 2013;Mashiri et al. 2016). ...
... The new artificial soil, rubber sand mixture (RSM), consists of recycled granulated rubber and natural sand in appropriate proportions, accompanied by large elasticity modulus, light mass, and high damping [11][12][13][14][15]. It has been shown that RSM can be widely used in civil engineering, such as light fillers behind abutments or retaining walls [16,17], pipeline backfilling [18,19], roads and slopes [20,21], and natural base isolator for earthquake protection [22,23]. A complete list of summaries can be found in the work of Wu et al. [24]. ...
... In comparison to the pure RSM isolation layer [23] and other base isolation systems [37][38][39] (e.g., sliding isolators and plastic plate-reinforced isolators), the RSMCB layer presents multiple benefits. First, it can be placed on the foundation without additional excavation. ...
... One of the most studied materials for GSI applications is rubber, which use represents a sustainable solution for the environment through scrap tyre recycling [19][20][21]. Many researchers proposed a rubber-based GSI technique consisting of continuous layers of rubber-soil mixtures (RSM) to be realised underneath the foundation [22][23][24][25][26][27][28][29][30][31][32][33][34][35]. Brunet et al. [26] showed that 2 or 3 m are sufficient enough to obtain encouraging results in terms of reduced surficial accelerations. ...
... This is opposite to what is typically seen in granular materials without inclusions and means that the RSM is less effective at shallow depths. Excessive percentage of rubber in the RSM was also discussed to cause rocking or in general stability problems [18,24]. Recently, Akhtar and Tsang [37] analysed the dynamic properties of polyurethane-coated RSM. ...
This study shows the modelling of the dynamic properties of sand-polyurethane composite materials through the Artificial Neural Network method (ANN). Such properties are relevant to assess the effectiveness of polyurethane injected into the foundation soil as Geotechnical Seismic Isolation (GSI) system. Three FeedForward Neural Network (FFN) models are developed for the prediction of the shear modulus decay, the normalised shear modulus decay and the damping ratio curve. Four inputs are considered, namely the dynamic properties of pure sand and pure polyurethane, the volumetric percentage of polyurethane and the isotropic confining stress. Each model is trained and tested on a database including previous experimental results of Resonant Column (RC) tests performed on layered sand-polyurethane specimens, with polyurethane volumetric percentages varying from 10% to 30%. In all cases, the network architecture is found to be optimal with a single hidden layer and the number of hidden neurons from 4 to 6 according to the complexity of the data to be fitted. By comparing the predicted properties with the experimental results, a good prediction quality of the models is shown both in terms of the coefficient of correlation R 2 and the Mean Squared Error MSE. A relative importance analysis finally reveals that polyurethane mainly affects the properties of the composite materials with its volumetric percentage, rather than its dynamic properties especially in terms of shear modulus.
... The 1 g shake table scaled model tests were widely adopted to simulate complex soilstructure systems subjected to seismic loads (Dolce et al. 2007;Martinelli and Filippou 2009;Hokmabadi et al. 2015). In the past, the nonlinear response of the GSI-foundation system was investigated using shaking table experiments wherein rigid blocks with surcharge load were employed to simulate the actual vertical pressure from buildings (Xiong and Li 2013;Bandyopadhyay et al. 2015). These studies optimized the GSI system composed of SRM with 35% to 55% rubber content ideal for seismic protection, in which increased GSI layer thickness enabled a high reduction in seismic demand. ...
... It is evident from the literature on GSI that studies considering the actual seismic response of scaled model building/framed structures resting on GSI systems are limited. In the existing 1 g shake table studies, vibration isolation mechanisms of GSI system were typically considered only for the footing without considering the building response (Xiong and Li 2013;Bandyopadhyay et al. 2015). Moreover, these studies used SRM as the only geomaterial in the GSI system, which can lead to significant settlement problems. ...
Seismic protection of buildings using the Geotechnical Seismic Isolation (GSI) system placed between the natural soil and the building foundation has recently emerged as an innovative and economical alternative to the traditional base isolation system. The present study aims to experimentally investigate the effectiveness of the GSI system composed of horizontal layers of Sand Rubber Mixture (SRM), a high damping energy-absorbing material reinforced with geogrids for seismic protection of mid-rise buildings. A series of 1-g laboratory shaking table tests were carried out on a five-story model framed structure placed on the GSI system in a laminar shear box filled with sand subjected to input excitation of 0.1 Hz to 10 Hz frequency range. The shake table tests were carried out under different base conditions of model structure: (1) pure sand, (2) SRM-GSI system and, (3) geogrid reinforced SRM-GSI system. The seismic performance of the model structure was compared for test beds with and without the GSI system by evaluating and analysing the recorded acceleration-time histories. The results indicate that while both SRM-GSI and geogrid reinforced SRM-GSI system effectively reduces the acceleration response of the buildings; however, the geogrid reinforcement was highly effective in reducing vertical ground settlement and contributing to improved lateral stiffness compared to the SRM-GSI case. The introduction of the geogrid reinforced SRM-GSI system tends to reduce the lateral displacements on the superstructure by 35%, besides minimizing the foundation rotation. In addition, the geogrid reinforced SRM-GSI system significantly reduces the interstorey drift of the model framed structure. Overall, the effectiveness of the geogrid reinforced SRM-GSI system in reducing seismic damages and permanent displacements of typical mid-rise buildings was experimentally demonstrated in the present study.
... This is an outcome from numerical and analytical results (Tsang et al. 2008(Tsang et al. , 2009(Tsang et al. , 2019(Tsang et al. , 2022Xu et al. 2009;Pitilakis et al. 2015;Brunet et al. 2016). The results from numerical studies are backed up by physical testing, including shaking table tests (Xiong et al. 2011;Xiong and Li 2013;Kaneko et al. 2013;Nikitas et al. 2014Nikitas et al. , 2016Bandyopadhyay et al. 2015;Tsiavos et al. 2019;Yin et al. 2022) and centrifuge tests (Tsang et al. 2021). ...
... Simplistically, the closest the tire base is to the surface, and the thicker it is, the more significant is the effect towards the change in the dynamic characteristics of the structural response. The efficiency of a tirebased foundation, as a seismic isolation, when the thickness increases, has been seen in Kaneko et al. (2013) and Xiong and Li (2013), however both studies are not accounting the liquefaction phenomenon, which is the focus of this research. An interesting observation in Fig. 9 is that the acceleration content in the case where the tire base is not in place (Test 1), is lower than the cases where the tire base was in place (Test 2 and 3). ...
Soil liquefaction is a phenomenon associated with strong earthquakes and it can affect large areas. High-rise and low-rise buildings, residential structures typically of 1-2 storeys, may be equally prone to the destructive consequences of liquefaction. For the case of high-rise buildings, expensive solutions like well-designed piles with ground improvement can be used. However, in the case of smaller residential structures, this is not economically viable. To this purpose, the current research explores the effectiveness of a novel proposed low-cost liquefaction protection technique, where the soil underneath the foundation is replaced by a sand-tire chip mixture base reaching down to a certain depth. Series of triaxial and shaking table tests were performed for a range of parametric scenarios to, mainly mecha-nistically, assess the effectiveness of such a mitigation technique, since similar previous studies are extremely limited. The tests have shown that the closest the considered base is to the surface, the thicker it is and with higher tire ratio, the more effective it can become on controlling the pore pressure rise that leads to liquefaction.
... However, studies have also shown that a rubber particle-soil mixture is still an isotropic material; it has a small shear modulus in the horizontal direction, and the vertical compression modulus is also small, which leads to large compression deformation under static load. Therefore, its elastic modulus is low, which easily causes instability in the foundations of the structure and increases the frequency of the left and right swaying of the structure under seismic load [35]. In order to solve the above problems, this paper proposes to add cement as a cementing and curing agent to the RS soil to improve the shear strength. ...
... However, studies have also shown that a rubber particl soil mixture is still an isotropic material; it has a small shear modulus in the horizon direction, and the vertical compression modulus is also small, which leads to lar compression deformation under static load. Therefore, its elastic modulus is low, whi easily causes instability in the foundations of the structure and increases the frequency the left and right swaying of the structure under seismic load [35]. In order to solve t above problems, this paper proposes to add cement as a cementing and curing agent the RS soil to improve the shear strength. ...
To investigate the static and dynamic characteristics of rubber–sand composite soil (RS soil) reinforced with cement, a series of triaxial compression tests and resonant column tests was performed by considering the influence of rubber content (10%, 20%, 30%, 40%, and 50%), cement content (0, 1.5, 2.5, 3.5 and 4.0 g/100 mL), and effective consolidation confining pressure (50, 100, and 150 kPa). Compared with the RS soil, the addition of cement significantly improved the shear strength of a cement–rubber–sand composite soil (RCS soil), based on an undrained shear test. The increase in cement content not only makes the elastic modulus and cohesion of the RCS soil increase but also reduces the internal friction angle of the RCS soil. With the increase in rubber content, the failure of the RCS soil samples changes from strain-softening to hardening, and the prediction equation of the initial elastic modulus of the RCS soil is given herein when the recommended cement content is 3.5 g/100 mL. The effects of rubber content, cement content, and effective confining pressure on the dynamic shear modulus and damping ratio of the RCS soil were studied via the resonant column test. The test results show that the increase in rubber content slows down the modulus attenuation of the RCS soil, but increases its damping ratio. The test results also show that the increase in cement content makes the bonding force between particles greater so that the modulus attenuation of the RCS soil becomes slower and the damping ratio is reduced. At the same time, according to the change rule of the maximum dynamic shear modulus of the RCS soil with the rubber content, when the recommended cement content is 3.5 g/100 mL, an empirical formula and recommended value of the shear modulus Gmax of the RCS soil are proposed.
... The previous research [32,33] along with the past studies from the authors have shown that the sand and rubber tire shreds mixed in a controlled proportion can also be the potential materials for the seismic base isolation system of buildings. Additionally, limited physical model studies were reported to evaluate the seismic performance of sand-rubber tire shred mixtures using shake table tests [34][35][36][37][38]. However, most of these studies modeled the foundation as a small concrete block. ...
The sand-rubber tire shred mixtures have gained research importance for their potential as geotechnical seismic base isolation materials as found from the laboratory element testing on them. This paper deals with studying the possible isolation effect of the optimum sand-rubber tire shred mixture block used as a foundation material for the scaled physical models. A series of impact hammer tests were conducted on a single bay, scaled steel framed structure representing typical low-rise buildings. The dynamic response of the structure is studied by enumerating the fundamental frequency and the damping effects as a consequence of the usage of this novel geomaterial in the foundations. The influence and the potential of the sand-rubber tire shred mixture are highlighted by investigating the response of the structures with different foundation base conditions with various floors and loading conditions. Different base conditions comprise the structures placed on control materials like pure sand and pure rubber tire shred blocks beneath the footing. It is found that using a sand-rubber tire shred mixture in the foundation significantly reduces the fundamental frequency of the structure (up to 30%) and increases the damping ratio. The present study supports the findings of past laboratory studies that the sand-rubber tire shred mixture with the 10% gravimetric rubber content can be used as an effective seismic isolation material.
... The accumulation of rubber causes serious environmental imbalances. It is known as 'black pollutant' (Xiong and Li, 2013). In the past, few studies have been conducted on scrap rubber tire-sand mixtures (Madhusudhan et al., 2017(Madhusudhan et al., , 2020(Madhusudhan et al., , 2021. ...
... Banović [21] conducted a shake table study on the effectiveness of several geotechnical isolation methods, the results show that the composite seismic-resistant layers significantly reduce the seismic forces of the rigid building. The seismic isolation mechanisms for GSI mainly include four types: (1) By changing the material properties of the soil [22], the natural frequency of the SSI system can be decreased, thereby improving the seismic performance of the structure. This seismic isolation mechanism is similar to conventional structural base isolation, with the main differences being the form and location of the seismic isolation. ...
... In terms of experimental research, Hazarika et al. [22] found that the use of tire debris and/or sand-mixed tire debris as a compressible cushion could not only reduce the dynamic load of the structure but also significantly reduce the dynamic-induced permanent displacement of the structure. Xiong and Li [23] and Bandyopadhyay et al. [24] carried out small-scale shaking table tests on the GSI-RSM system, where rubber-sand mixtures were positioned below the concrete or rigid block as the isolation material. Anastasios et al. [25] performed direct shear tests to sort out the failure mechanism of the rubber sand layer, further confirming its applicability in seismic isolation. ...
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.
... Post-consumer recyclates (PCR) such as waste tire rubber, known for its energy-absorbing properties, show potential for promoting such eco-friendly goals in the seismic isolation of buildings. This layer effectively reduces seismic vibrations, ensuring protection for infrastructure (Tsang, 2009(Tsang, , 2023 Comprehensive research on GSI methods utilizing rubber-soil mixtures (RSM) has explored their promising dynamic response in mitigating earthquake-induced stresses (Tsang, 2008(Tsang, , 2012Kaneko et al., 2013;Xiong and Li, 2013;Pitilakis, Karapetrou and Tsagdi, 2015;Abdullah and Hazarika, 2016;Xue et al., 2021;Brunet, De la Llera and Kausel, 2016;Forcellini and Alzabeebee, 2022;Aloisio et al., 2023;Bernal-Sanchez, Leak, and Barreto, 2023;Vratsikidis and Pitilakis, 2022;Mizher et al., 2024). ...
Traditional construction practices consume significant energy, emit carbon, and generate waste—prompting a shift towards sustainable earthquake-resistant systems. Nonetheless, a comprehensive life cycle assessment (LCA) of such systems remains scarce. This research bridges the gap by evaluating the environmental impact of repurposing waste tire rubber and polyurethane-coated rubber (PUcR) for cost-efficient seismic isolation. To this aim, a comparative LCA of conventional concrete slabs, natural soil foundations, rubberized concrete (RuC) slabs, rubber-soil layers, and PUcR-soil layers revealed key insights. Firstly, RuC is proven to be more sustainable than conventional concrete. Secondly, integrating 30 % recycled tire rubber in the foundation soil cut energy use by 153.50 MJ/m3 and carbon emissions by 30.75 kg CO2 eq/m3. Thirdly, incorporating 30 % waste PUcR in the foundation soil preserved 227.12 MJ/m3 energy and slashed emissions by 134.76 kg CO2 eq/m3. This underscores the significance of sustainable earthquake-resistant construction approaches and LCA-driven decision-making to bolster conservation and recycling endeavors.
... Consequently, wall barriers emerge as the optimal option for vibration isolation in deep tunnels. There are currently various analysis methods employed to investigate the vibration isolation effectiveness of barriers, including numerical analysis methods 35,36 , finite element methods 30,[37][38][39][40][41][42][43] , model tests, and field experiments [44][45][46][47][48][49] . Theoretical analyses, models, and field experimental studies are typically limited to simpler cases. ...
To investigate the vibration isolation effect of composite vibration isolation walls on surface vibrations in suburban railway deep tunnels under various influencing factors, an integrated numerical model of the train was initially developed. This model solved the wheel-rail interaction force and was applied to a three-dimensional volume coupling model of the track soil. Subsequently, the model's reliability was validated through comparison with measured data. Afterward, the vibration isolation effects of various types of EPS material vibration isolation walls were examined, with a focus on exploring the impact of thickness, material proportion, and relative positioning of the materials within the vibration isolation wall composed of EPS material and concrete. Research indicates that with an increase in the burial depth of a single material vibration isolation wall, its effective vibration isolation frequency range gradually widens. When the burial depth of the vibration isolation wall exceeds the tunnel burial depth, the vibration isolation effect is optimal. Composite vibration isolation walls, with thicknesses smaller than single-material vibration isolation walls, exhibit superior vibration isolation effects compared to their single-material counterparts. The effective vibration isolation frequency band of composite vibration isolation walls differs from that of single-material vibration isolation walls. Using the optimal-size vibration isolation wall of a single material as a composite vibration isolation wall enhances the vibration isolation effect of peak acceleration in the frequency domain by 16.58% and peak velocity by 16.95%. Moreover, frequency domain peak displacement experiences a 30.73% improvement in the vibration isolation effect.
... Seismic isolation in the GSI system is achieved by using engineered soils with high damping properties and low shear modulus surrounding the building foundation at a limited depth [4][5][6][7][8]. The main advantage of this method is that partial energy dissipation occurs within the soil itself before the seismic wave reaches the foundation and superstructure [9,10]. Recently, research on GSI methods has been gradually extended to seismic protection of bridge structure and pile-supported bridge piers [11,12]. ...
This work discusses seismic isolation technologies and analyses the concept of geotechnical seismic isolation (GSI) system, which is characterized by new principles of operation, using geomaterial with modified properties to reduce inertial seismic loads on buildings and structures. The aim of the study is to develop a geotechnical seismic isolation system in the form of vertical barriers, with different geometrical characteristics, using rubber-soil mixture (RSM). The novelty of the work consists in determination of effective constructive and technical solutions of vertical seismic barriers from RSM, which are characterized by reliability in providing seismic isolation of construction objects. Soil and superstructure interactions are modeled in Plaxis software, using the Northridge earthquake accelerogram. The results confirm the positive impact of using RSM as an effective material for GSI vertical barriers. The present numerical and experimental results show that the GSI system using RSM can significantly reduce the seismic hazard. The results of computational-experimental modeling will become a research, analytical and design basis for the development of new ways to ensure earthquake resistance of construction objects.
... For applications in infrastructure, recycled rubber improves seismic performance in mechanically stabilized earth (MSE) walls by lowering lateral earth pressure, increasing energy dissipation, and boosting deformation capacity [32]. In earthquake engineering, rubber-soil mixtures function as low-modulus materials for vibration damping and geotechnical seismic isolation around foundations [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47]. ...
Assessing the material ramifications of waste tire rubber stands as a pivotal endeavor for its practical utility. Dynamic leaching analysis emerges as indispensable in delineating its potentialities within sustainable engineering domains. Waste materials stemming from tire recycling industries, notably polyurethane-coated rubber (PUcR), may exhibit promising viability owing to attenuated leaching, thus fostering the circular economy paradigm. Towards this end, upflow column percolation leaching tests were conducted on recycled rubber-soil mixture (RSM) alongside PU-coated rubber-soil mixture (PUcRSM). Analysis through Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) unveiled the leaching dynamics of assorted metals in RSM and PUcRSM, notably showcasing markedly diminished cumulative zinc content (by 99.4%) in PUcRSM, coupled with mitigated electrical conductivity, redox potential, and eluate pH. Leveraging HYDRUS-1D for analytical modeling predicated on the advection-dispersion equation further underscored these insights. These findings suggest that waste PUcR presents itself as a viable option, distinguished by its diminished leachability, suitable for a wide array of applications. These applications include vibration damping in infrastructure, tunnel linings, asphalt roads, rubberized concrete, and lightweight backfill materials for bridges and retaining walls, among others. This initiative will contribute to recycling a substantial quantity of over 1 billion used tires produced annually, ultimately supporting the circular economy ethos through assured and adaptable repurposing of waste from tire rubber recycling industries.
... The seismic isolation effect is caused by a combination of lateral and inelastic rocking flexibility of the deformable substrate under the three-dimensional components of the ground shaking (Mergos et al., 2005). Several numerical and experimental studies have been conducted in recent years to prove the effectiveness of GSI systems, but they generally refer to heavy building archetypes (Xiong et al., 2013;Pitilakis et al., 2015;Panjamani et al. 2015) or bridge structures (Forcellini, 2017). This study focuses on light wood frame residential construction, to verify the applicability of GSI to systems characterized by low weight and relatively high vibration periods, which are significantly different from those previously investigated. ...
This study investigates the effectiveness of using Rubber-Soil Mixtures (RSM) to create a Geotechnical Seismic Isolation (GSI) system for wood frame residential buildings. This GSI system relies on the non-linear properties of RSM to achieve seismic isolation through dynamic soil-foundation-structure interaction. It requires minimum modification to the traditional foundation systems, making it suitable for low-to-medium-rise construction. The RSM, obtained from repurposed rubber compounds, offers an economical and sustainable alternative to isolation devices, extending the use of seismic isolation beyond critical structures and infrastructure. To achieve this, upcycled tire chips are mixed into the soil to create RSM layers. These layers modify the stiffness property of the subgrade, and increase seismic energy dissipation, while also reducing excess pore-water pressure accumulation, and mitigating liquefaction potential. To understand the isolation mechanism of such a GSI system, an archetype single-family residential wood frame building is analyzed through direct soil structure interaction, incorporating the RSM layers. Various strong motion records are used as input motions, and the impact of the subsurface material nonlinearity on key model parameters is discussed. The effects of the RSM layers are analyzed in terms of acceleration and displacement control, deformation of the foundation system, and reduction in strain energy demand for the superstructure. The results demonstrate the efficacy of the GSI system in reducing the seismic demand, as well as its ability to reduce rocking effects, and reversible foundation deformations. These factors enhance the system's capacity to redistribute seismic forces and minimize damage to the superstructure.
... Geotechnical seismic isolation techniques make use of locally available materials like limestone sand, sand bitumen mixture (Banovic et al., 2018), and rubber soil mixtures to enhance the seismic resilience of structures (Tsang et al., 2021). In developing countries, these locally available materials are commonly employed for simple constructions and cost-effective seismic mitigation of structures (Tsang, 2008;Tsiavos et al., 2021;Xiong & Li, 2013). ...
Numerical analysis is implemented for Tuned Inerter Damper (TID) incorporated into an isolated sliding structure subjected to harmonic excitation. The strong nonlinearity of the sliding isolator affects the control of the superstructure’s displacement, as indicated by previous studies. In this work, the working mechanics of TID added to sliding isolated structure is investigated. Analytical solutions are derived for both sliding and stick motion state of structure with TID under harmonic ground excitation and different motion states. The main novelty of this work lies in the evaluation of TID performance in sliding isolated structures using explicit expressions for various motion modes. Further, benchmark sliding isolated structure with TID under real seismic excitation is investigated. Under harmonic excitations, the differential equations governing the stick and sliding motions of the TID in sliding isolated structures are derived. The accurate results are obtained and dynamic equations are formulated for sliding isolated structure. The three fundamental modes of the TID in sliding isolated structures, namely stick-stick, stick–slip, and slip-slip, were presented. Natural frequency, damping ratio and ground motion excitation for TID with sliding isolated structure are observed to be less as compared to friction isolation. The incorporation of TID into sliding isolated structures exhibited improved performance owing to the isolation of the structure from sliding. Slip will occur more easily for sliding isolated structure in slip-slip mode, therefore increasing inerter is more beneficial for reducing displacement at frequency range of 1 to 1.5Hz.
... Against the backdrop of escalating waste tire disposal worldwide, research on the dynamic mechanism of RSM composed of waste rubber and natural sand has become a frontier topic in geotechnical seismic isolation (Tsang et al. 2021). A promising technique is using a rubber sand mixture (RSM) layer as a natural base isolator (Xiong and Li 2013). The isolation strategy involves forming an artificial weak interlayer by filling the RSM cushion around the foundation of the building. ...
This study proposes the use of soil bags filled with a rubber sand mixture (SFRSM) to address the issue of weak stability associated with rubber-sand layers for seismic isolation. To evaluate the dynamic characteristics of the SFRSM, large-scale cyclic simple shear tests were conducted to investigate the effects of rubber content, vertical pressure, shear displacement amplitude, fill percentage, and laying scheme. Furthermore, shaking table tests were carried out to evaluate the impact of vibration intensity and frequency on the seismic isolation of SFRSM layers. The results indicate that (1) Compared to the rubber-sand layer, the SFRSM exhibits a lower shear modulus and higher damping, indicating its potential for greater seismic isolation and energy dissipation. (2) The dynamic characteristics of the SFRSM were significantly influenced by the fill percentage and laying scheme, suggesting that an effective isolator capable of withstanding various external conditions could be developed. (3) The isolating effect of the SFRSM layer is attributed to its ability to dampen high-frequency vibration components effectively. Additionally, the threshold frequency required to trigger attenuation decreases with an increasing number of SFRSM layers. In summary, these experimental results provide evidence that the proposed innovative strategy enhances the strength and vertical stiffness of the original rubber-sand layer, making it well-suited for seismic design applications in low-rise buildings in less-developed regions.
Highlights 1. A novel seismic isolation strategy using the soil bags filled with rubber-sand mixture (SFRSM) was proposed. 2. Large-scale cyclic simple shear tests were conducted to evaluate the dynamic properties of SFRSM. 3. The influence of key parameters on the dynamic shear modulus and damping ratio of SFRSM was analysed. 4. The proposed strategy is well suited for the seismic design of low-rise buildings in less-developed regions.
... Innovative techniques have emerged to control seismic responses by altering earthquake input motion characteristics. These include using isolating synthetic liners in the soil mass to reduce earthquake acceleration at the soil surface and incorporating rubber soil mixtures under foundations for energy dissipation [4][5][6]. The concept of rocking isolation in foundation design is also gaining traction as an effective method to reduce seismic forces on structures. ...
Sources such as wind or severe seismic activity often exert extreme lateral loading onto the shallow foundations supporting high-rise structures such as bridge piers, buildings, shear walls, and wind turbine towers. Such loading conditions may cause the foundation to exhibit nonlinear responses such as uplift and bearing capacity mobilization of the supporting soil (i.e., rocking behavior). Previous numerical and experimental studies suggest that while such inelastic behaviors may engender residual deformations in the soil–foundation system, they offer potential benefits to the overall integrity of structures through dissipating energy and reducing inertia forces transmitted to the superstructure, thereby limiting seismic demand on structural elements. This study investigates the effect of footing shape on the rocking performance of shallow foundations in different subgrade densities and initial vertical factor of safety (FSv). To this end, a series of reduced-scale slow cyclic tests under 1 g condition were conducted using a single degree of freedom (SDOF) structure model. The performance of different footing shapes was studied in terms of moment capacity, recentering ratio, rocking stiffness, damping ratio, and settlement. For three foundations with different length-to-width ratios, the results indicate that increasing the safety factor and length-to-width ratio leads to thinner, S-shaped moment–rotation curves, mainly owing to the enhanced recentering capability and the P-δ effect. Moreover, across all foundation types, the repetition of a limited loading cycles with consistent rotation amplitude does not cause stiffness degradation or moment capacity reduction.
... This method reduces both the horizontal and vertical shaking of buildings from earthquake. The effectiveness of geotechnical seismic isolation (GSI) systems using SR mixtures with different rubber contents has been investigated experimentally and numerically in several studies and it has been reported that the acceleration and interstory drift in superstructures is significantly reduced (Tsang et al. 2012;Xiong and Li 2013;Pitilakis et al. 2015;Brunet et al. 2016;Tsiavos et al. 2019). Tsang and Pitilakis (2019) determined that, when SR mixtures are used as GSI systems under foundations, the horizontal and rocking rigidities decrease compared with the natural foundation soils, and thus rocking isolation can be provided through the reversible deformations that occur in the SR layer below the foundations. ...
Waste tires, which are a serious environmental threat due to the ever-increasing number of on-road vehicles, must inevitably be effectively recycled. Many researchers have posited that granular soil and crumbed waste tire mixtures can be used to reduce seismic forces in so-called geotechnical seismic isolation (GSI) systems because of the high-energy absorption capacity of sand and rubber (SR) mixtures. However, there are concerns about the stability of superstructures due to the high compressibility of SR mixtures. Asphalt mixtures have also gained new application areas outside of transportation engineering, such as in hydraulic structures and seismic isolation, due to their ductile, cohesive and viscoelastoplastic properties in recent years. In this study, sand–rubber–bitumen (SRB) mixtures were produced by adding bitumen as a binder to SR mixtures containing crumbed rubber (CR) at different ratios (1%, 2%, 3%, and 4% of the sand weight). The dynamic properties of the SRB mixtures were determined by cyclic simple shear tests, depending on vertical and cyclic stresses. We found that the SRB mixture containing 3% CR had the maximum damping ratio (D) and that an increase in the rubber content of SRB mixtures causes a decrease in the secant shear modulus (Gsec). In addition, it was observed that the Gsec increased with the vertical stress and decreased with the cyclic stress ratio. In comparing the D and Gsec values of the SRB mixtures with those of SR mixtures under similar loading conditions, it was found that the SRB mixtures had both higher D and stiffness. As a result, SRB mixtures are more suitable than SR mixtures in terms of damping, and SRB mixtures can be an alternative material for use in GSI systems.
... Rubber-sand particles have many advantages such as light weight, durability, economy, good shock absorption and isolation effects, and convenient construction. There are already some engineering application examples abroad [1][2][3][4][5][6][7]. Scholars at home and abroad have conducted a series of studies on the rocksoil isolation system with rubber-sand mixture as backfill material: Liu Fangcheng et al. ...
In order to verify the effectiveness of the Geotechnical Seismic Isolation (GSI), a series of finite element parameter studies were carried out. The finite element calculation model of the GSI system and superstructure is established. The finite element analysis conditions consist of two kinds of confining pressures, three kinds of RSM ratios and three kinds of seismic wave inputs, a total of 32 kinds of conditions. Comparing the analysis results of the parameters, it can be seen that the dynamic shear modulus of the RSM sample increases with the increase of the confining pressure, but the degree is affected by the input of seismic waves. The greater the peak value of the input acceleration, the more obvious the isolation effect; As the RSM ratio increases, it decreases, but it is not greatly affected by the input of seismic waves, and the isolation effect remains basically the same. The numerical simulation results verify the isolation effect of GSI, which can be used as a reference for practical engineering applications in the future.
... Post-consumer recyclates (PCR) such as waste tire rubber, known for its energy-absorbing properties, show potential for promoting such eco-friendly goals in the seismic isolation of buildings. This layer effectively reduces seismic vibrations, ensuring protection for infrastructure (Tsang, 2009(Tsang, , 2023 Comprehensive research on GSI methods utilizing rubber-soil mixtures (RSM) has explored their promising dynamic response in mitigating earthquake-induced stresses (Tsang, 2008(Tsang, , 2012Kaneko et al., 2013;Xiong and Li, 2013;Pitilakis, Karapetrou and Tsagdi, 2015;Abdullah and Hazarika, 2016;Xue et al., 2021;Brunet, De la Llera and Kausel, 2016;Forcellini and Alzabeebee, 2022;Aloisio et al., 2023;Bernal-Sanchez, Leak, and Barreto, 2023;Vratsikidis and Pitilakis, 2022;Mizher et al., 2024). ...
... To further explore the application of RSM, extensive research has been conducted to investigate the pile-soil interaction through experiments and simulations when RSM is employed. Xiong and Li (Xiong and Li, 2013) conducted shaking table experiments and observed that a rubber content of 35 % in the RSM layer provides effective seismic protection while meeting the superstructure bearing capacity requirements. Pitilakis et al. (Pitilakis et al., 2015) developed a finite element model of a soil-structure system to validate the beneficial effects of using RSM as a foundation layer on the structural response under dynamic loading. ...
... Rubber-sand particles have many advantages such as light weight, durability, economy, good shock absorption and isolation effects, and convenient construction. They have attracted the attention of many scholars at home and abroad and conducted a series of research [1][2][3][4][5]. Liu Fangcheng et al [6][7][8] conducted a series of experimental studies on the composite blocks formed by filling the cavity of the concrete hollow block with rubber sand, and the results showed that the composite blocks with rubber sand core have good shock isolation effect. ...
In order to understand the effect of moisture content on the dynamic characteristics of rubber-sand particles (Rubber-Soil Mixture, RSM), a dynamic triaxial test was carried out. Before the test, the rubber particles and sand were mixed according to the rubber volume ratio of 0%, 25%, 30%, 40%, 50%, 75%, and 100%, and the water content was 0%, 5%, and 10%. The confining pressure control of the triaxial test is 50, 100, 200, a total of 63 groups of tests. In the test, the effects of dynamic triaxial confining pressure, rubber particle content and moisture content on RSM were investigated respectively. The test results show that: (1) under the same rubber particle content, the dynamic shear modulus of the RSM sample increases with the increase of the confining pressure; (2) with the increase of the rubber particle content, the dynamic shear modulus of the RSM sample increases. The shear modulus decreased significantly; (3) The change of water content did not cause significant changes in the dynamic shear modulus of RSM samples. The test results can be used as a reference for the engineering application of RSM seismic isolation technology in the future.
... The use of rubber-soil mixtures (RSM) as a GSI foundation material, originally proposed by Tsang (2008), is the most researched (Abdullah and Hazarika 2016;Akhtar and Tsang 2023;Aloisio et al. 2023;Bernal-Sanchez, Leak, and Barreto 2023;Brunet, De la Llera, and Kausel 2016;Chiaro et al. 2023;Forcellini and Alzabeebee 2023;Kaneko et al. 2013;Pitilakis et al. 2021;Pitilakis, Karapetrou, and Tsagdi 2015;Tsang et al. 2009Tsang et al. , 2012Tsang et al. , 2021Vratsikidis and Pitilakis 2023;Xiong and Li 2013;Xue et al. 2021). The GSI-RSM system exploits the beneficial effects of seismic soil-foundation-structure interaction. ...
Base isolation is a low-damage seismic design strategy that can be used for constructing resilient structures. Geotechnical seismic isolation (GSI) is a new category of emerging base isolation techniques that has attracted global interest in the past decade. Research on GSI based on rubber-soil mixtures (RSM) has focused on structural performance under earthquake actions, whilst there are concerns over the serviceability limit states (SLS) requirements in relation to (i) human comfort under strong winds and (ii) ground settlement under gravity, which may induce cracking and durability issues in structures. This article presents the first study on the serviceability performance of buildings constructed with the GSI-RSM system. The finite element model of a coupled soil-foundation-structure system has been validated by data recorded from geotechnical centrifuge testing. The numerical estimates of ground settlement have also been compared with analytical predictions. It is concluded that the GSI-RSM system can satisfactorily fulfill the SLS requirements. © 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
... GRMs suitability and advantages as GSI in the form of a layer underlying the foundation of structures have been investigated numerically over recent years (Tsang 2009;Tsang et al. 2012;Pitilakis et al. 2015;Pistolas et al. 2010;Forcellini and Alzabeebee 2022;Tsang and Pitilakis 2019;Dhanya et al. 2020;Chiaro et al. 2020). On the other hand, only a few experimental studies are available in the literature, mainly limited to laboratory and small-scale testing (Kaneko et al. 2013;Xiong and Li 2013;Chiaro et al. 2021;Tsang et al. 2020;Bandyopadhyay et al. 2015;Tsiavos et al. 2019;Tasalloti et al. 2021a). Just one experimental campaign on a full-scale prototype structure was recently performed in Thessaloniki (Greece) in the framework of the Research Program SOFIA-SERA (Pitilakis et al. 2021;Abate et al. 2022). ...
Geotechnical Seismic Isolation (GSI) is an innovative technique for protecting structures in earthquake-prone areas. The main idea is to improve the foundation soil so that seismic energy is partially dissipated within GSI before being transmitted to the structure. Among other materials proposed for foundation soil improvement, gravel-rubber mixtures (GRMs), with rubber grains manufactured from end-of-life tires, have attracted significant research interest thanks to their good mechanical properties. GRMs also represent a modern recycling system to reduce the stockpile of scrap tires worldwide. The present study investigated numerically the effect of a GRM layer located underneath the shallow foundations of a real structure. The structure is a typical reinforced concrete building in southern Italy. A Finite Element Modelling (FEM) was carried out to evaluate the overall static and dynamic behaviour of the soil-GRMs-structure system. Three FEM models were performed with and without the GRM layer, varying the GRM layer thickness and the seismic inputs. The comparisons among the models allow us to assess the performance of the GRM underneath the foundations as a new eco-sustainable solution for the seismic isolation of structures.
... The proposed system was considered an aid towards the development of sustainable construction as it incorporates scrap rubber tire aggregates. The concept of using scrap tires as a medium of energy dissipation was experimentally tested by (Xiong and Li 2013). A different percentage of rubber was added to the soil and installed as an isolation medium; however, this change in the percentage of rubber did not show any significant effect on the seismic performance of the isolation system. ...
Masonry structures are frequently constructed in developing countries because of their affordability and ease of construction, even though they are vulnerable and perform poorly during earthquakes. Experimental and numerical studies were carried out to determine the optimum thickness of the isolation layer for a recently developed, low-cost seismic isolation system known as the Reinforced-Cut-Wall (RCW). The parameters of the isolation layer were optimized during the experimental and numerical investigations using hollow concrete blocks. Quasi-static cyclic tests were performed on a 1:3 reduced-scale brick masonry wall incorporating the RCW isolation scheme, validating the better performance of the proposed isolation technique.
... The high durability in addition to the strength of the vulcanised rubber has made the recovery of the material difficult, hence used tyres typically end up in landfills or stockpiles (ETRMA 2015). Tyres have however a number of opportunities for repurpose in Civil Engineering infrastructure, including the production of cement mixtures, road construction and geotextiles (Xiong and Li 2013). One of the more interesting applications is the combination of rubber-sand mixtures (RSm) and its ability to be used as a Geotechnical Seismic Isolation (GSI) technology to offset the destructive effects of seismic events ). ...
Rubber-soil mixtures are known to have mechanical properties that enable their use in backfills, road construction or geotechnical seismic isolation systems. The complexity of these mixtures comes from adding soft (i.e. rubber) particles that increases the number of particle properties to consider when studying the macroscopic behaviour. The distinction between sand-like and rubber-like behaviour is normally presented in relation to the rubber content and size ratio between particles. It is however unknown how the change on the mixture gradation affects the mechanical behaviour of RSm. Entropy coordinates condense the entire particle size distribution (PSD) to a single point on a Cartesian plane, accounting for all the information in the gradation. Grading entropy coordinates have been used to study typical geotechnical behaviours of mostly incompressible (i.e. sand) soils. In this study, entropy coordinates are used to analyse the correlation between the small-strain stiffness and liquefaction susceptibility of RSm and their PSDs. The results suggest that entropy coordinates can be used effectively on RSm as an alternative means of assessment of typical soil behaviours, being also able to distinguish between sand-like and rubber-like behaviours. Based on the 30 PSDs analysed, it is also evidenced that internal stability criterion proposed by Lőrincz (1986) can be used to predict the liquefaction susceptibility of RSm. The normalised base entropy (A) has also been shown to increase with the rubber content, which is linked to a lower liquefaction susceptibility, due to the supporting effect of rubber particles on strong-force chains formed of sand particles.
... GRMs suitability and advantages as GSI in the form of a layer underlying the foundation of structures have been investigated numerically over recent years (Tsang 2009;Tsang et al. 2012;Pitilakis et al. 2015;Pistolas et al. 2010;Forcellini and Alzabeebee 2022;Tsang et al. 2019;Dhanya et al. 2020;Chiaro et al. 2020). On the other hand, only a few experimental studies are available in the literature, mainly limited to laboratory and small-scale testing (Kaneko et al. 2013;Xiong and Li 2013;Chiaro et al. 2021;Tsang et al. 2020;Bandyopadhyay et al. 2015;Tsiavos et al. 2019;Tasalloti et al. 2021a). Just one experimental campaign on a full-scale prototype structure was recently performed in Thessaloniki (Greece) in the framework of the Research Program SOFIA-SERA (Pitilakis et al. 2021;Abate et al. 2022). ...
Geotechnical Seismic Isolation (GSI) is an innovative technique for protecting structures in earthquake-prone areas. The main idea is to improve the foundation soil so that seismic energy is partially dissipated within GSI before being transmitted to the structure. Among other materials proposed for foundation soil improvement, gravel-rubber mixtures (GRMs), with rubber grains manufactured from end-of-life tires (ELTs), have attracted significant research interest thanks to their good mechanical properties. GRMs also represent a modern recycling system to reduce the stockpile of scrap tires worldwide.
The present study investigated numerically the effect of a GRM layer located underneath the shallow foundations of a real structure. The structure is a typical reinforced concrete building in southern Italy. A Finite Element Modelling (FEM) was carried out to evaluate the overall static and dynamic behaviour of the soil-GRMs-structure system. Three FEM models were performed with and without the GRM layer, varying the GRM layer thickness and the seismic inputs. The comparisons among the models allow us to assess the performance of the GRM underneath the foundations as a new eco-sustainable solution for the seismic isolation of structures.
... Kaneko et al. [20] conducted a pseudodynamic response test, and the test results showed that the GSI system is effective in seismic isolation and liquefaction prevention. Xiong and Li [21] and Bandyopadhyay [22] placed RSM as isolation material under concrete or rigid block for a small shaking table test, which verified the isolation effectiveness of the GSI-RSM system. Anastasios et al. [23] studied the mechanical properties of the potential failure mechanism inside the RSM layer through the direct shear test, which further confirmed its applicability to seismic isolation. ...
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.
... Another type of vulnerable construction is one-to-two-storey houses that are typical in rural areas. Various GSI research groups have targeted this vulnerable type of housing in different parts of the world (Xiong and Li 2013;Nikitas et al. 2014;Tsiavos et al. 2019). The second case study building configuration can be built around this type. ...
Geotechnical Seismic Isolation (GSI) is an emerging category of earthquake protection systems that involve dynamic interaction between the structure and geomaterials. This new field of study has diversified and gained momentum through a decade of research. This paper attempts to consolidate the collective research efforts at a high level and put forward a vision plan for global collaboration amongst GSI researchers and for multi-sectoral engagement with end-users including governments, non-governmental organisations, builders, engineering professionals and local communities. Finally, resilience, sustainability and universality, as the three overarching goals of GSI, are highlighted.
... In addition, as a siding isolation system, geotechnical seismic isolation techniques using locally available materials such as limestone sand [13], sand-bitumen mixtures [14] and rubber-soil mixtures [15] were developed for structural seismic response mitigation. These techniques are characterized by low cost and simple construction and are of particular significance in developing countries [16][17][18]. ...
Previous studies have proven that adding an inerter to a sliding isolation structure can reduce the isolation displacement without compromising the control effect of the superstructure. However, due to the strong nonlinearity of the sliding isolator, approximate methods or numerical analyses are adopted to investigate inerter-added sliding isolation structures, which hinders the understanding of the inherent working mechanisms of such structures. This study derives exact analytical solutions during both sliding and stick motion states of inerter-added sliding isolation structures under harmonic ground motions and investigates the influence of an additional inerter on the motion states and responses of such structures. The main novelties of this paper are the employment of the inerter technique in a sliding system for performance improvement and explicit expressions of the dynamic responses and motion modes for inerter-added sliding isolation structures that assist in understanding the role of the additional inerter. Differential equations are established for both the stick and sliding motions of inerter-added sliding isolation structures subjected to harmonic ground excitations. The dynamic characteristics of the structure are analyzed, and accurate analytical solutions are derived for structural responses. The explicit forms for the occurrence conditions of three fundamental modes (i.e., the stick-stick, stick-slip and slip-slip modes) for the motion of the inerter-added sliding isolation structures are presented. Based on the derived analytical solutions, extensive parametric analyses are conducted to investigate the influences of the added inerter on the motion modes and responses of sliding isolation structures. By adding an inerter, a decreased natural frequency, a decreased damping ratio and a reduction in ground motion excitation are observed for the vibration of the superstructure in the inerter-added sliding isolation structure compared to that in the sliding isolation structure without an inerter. Furthermore, the inerter causes the slip-slip mode to occur more easily, which is preferred for sliding isolation structures when sliding occurs. An increasing inertance of the inerter is beneficial for reducing isolation displacement in general but contrary to reducing maximum acceleration in some frequency ranges and excitations with large amplitudes. The trade-off between the reduction of isolation displacement and acceleration is recommended for determining the inertance of the inerter in sliding isolation structures.
... Whilst the concept of GSI is not limited to a particular choice of materials, RSM were chosen because: (i) rubber has been widely used in vibration damping and isolation, and both the static and dynamic properties of RSM were available in the literature, and (ii) waste tyres are available in abundance with an urgent need of recycling, which also provides a green and economical source for RSM (Tsang 2012, Xiong & Li 2013, Tsiavos et al. 2019, Chiaro et al. 2019. Granulated RSM are characterised by nonlinearity and high damping in the mediumto-high strain range, with properties that can be adjusted via rubber content . ...
... Regarding the content and applicability of the method; it was also underlined that factors such as nonlinear soil behavior, resonance effects of the soil, liquefaction, ground settlement, and environmental effects should be evaluated. In subsequent studies, comprehensive numerical and experimental studies were carried out on the seismic isolation capacity of RSM layers formed with varying rubber contents [1,[5][6][7][8][9][10]. [1] Another example of the GSI method is developing an isolation layer using geosynthetic material with or without an RSM layer. ...
Seismic isolation is a method of protecting buildings from earthquake-induced deformations by using isolators and devices under the superstructure. The purpose of the seismic isolation method is to reduce the earthquake forces transferred from the ground to the structure by placing energy-absorbing elements between the foundation and superstructure. Especially in developing countries, the "Geotechnical Seismic Isolation (GSI)" system has been proposed as an isolation method to reduce earthquake-induced damages on buildings. This study, it is aimed to reduce the effects of earthquakes in a multi-story building with an isolation layer formed by a rubber-sand mixture (RSM). For this purpose, a 10-story reinforced concrete building was numerically modeled. Beneath the foundation of the building model, a seismic energy absorbent RSM layer was placed and its contact with the natural soil was interrupted by using geosynthetic liners. The model was subjected to the 1992 Erzincan (EW) Earthquake motion and its performance has been evaluated in terms of lateral displacements and accelerations. The numerical studies indicated a substantial improvement due to the use of the RSM layer. The accelerations measured by the superstructure decreased up to 48% by employing the isolation layer. The numerical analysis was carried out using the dynamic module of the PLAXIS 2D finite element analysis program.
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.
Growing concerns about seismic events enforced structural engineers and architects to embrace the hazardous effect of ground motion in design. To address this, researchers have developed various base isolation (BI) techniques. This study comprehensively reviews BI system types, techniques, and implementation. Exploring the dynamic response of three-dimensional BI devices and the mutual effects of isolation devices and soil-structure interaction during strong ground motion, the paper covers topics such as seismic isolation of nuclear power plants, cost analysis, and various optimization techniques. Furthermore, the paper investigates the behavior of isolation devices in beyond-design events, including blast and aircraft impact loading. In general, the seismic isolation and control device response is demonstrated through shaking table tests and computational analysis. The study sheds light on the functions of seismic isolation system by comparing them with fixed base structures. Additionally, the paper presents codal recommendations, recent advancements, and current practices, aligning them with historical developments and past reviews of different BI techniques, along with their
advantages and disadvantages. In conclusion, the closing remarks emphasize the future research prospects in this field.
p>As a new type of environmentally friendly lightweight composite material, rubber sand mixture has a wide application prospect in the field of engineering vibration isolation. In order to reveal the variation law of dynamic characteristics of different rubber sand mixtures, based on the dynamic triaxial test, the effects of rubber content and confining pressure on the backbone curve, dynamic shear modulus and damping ratio of mixtures were studied. The results showed that with an increase in the rubber content, the backbone curve of rubber sand mixture had a trend of ' ductile failure ' and the dynamic shear modulus of mixture decreased. The nonlinear coordinated variation could be found between the damping ratio and rubber content with a characteristic threshold of 40
%. The mechanical properties of rubber particles may be influenced by changing the type of ' skeleton structure ' inside the sample.</p
A sliding-based isolation system is an efficient strategy to enhance the seismic performance of low-rise brick masonry buildings, a common type of construction across the globe. The previously developed isolation systems lack a proper re-centering mechanism. Therefore, in this study, a low-cost isolation system, termed reinforced cut wall (RCW) with an appropriate re-centering mechanism, is designed and tested experimentally using a shake table, which hasn’t been tested previously. Two unconfined reduced scale (1:3) brick masonry buildings were subjected to frequency-based seismic excitation, and the model's corresponding acceleration and displacement response were captured. Compared to the fixed base model, considerable reductions were observed in the acceleration and displacement response in the case of the isolated model. Similarly, the inter-story drift and floor relative displacement response was also reduced in the isolated model. Furthermore, the rebars used for the re-centering mechanism remained within the linear viscoelastic range. Based on the experimental validation, the proposed low-cost RCW isolator was found to be an efficient isolation strategy for low-rise masonry buildings in high seismic regions.
Seismic isolation techniques are hardly implementable on existing historic structures, if their integrity is a matter of concern (Viggiani in 19th International conference on soil mechanics and geotechnical engineering, Seoul Korea, 2017; Flora in Third international symposium on geotechnical engineering for the preservation of monuments and historic sites, Naples, Italy, 2022). Recent results have shown that if a continuous barrier having a low dynamic impedance is created in the soil beneath the structure, both the absolute acceleration and relative displacement demands are significantly reduced without any direct intervention on the structure itself. Super Absorbent Polymers (SAP), mixed with the in-situ soil, are excellent candidates to the creation of these soft barriers. The first part of the paper reports a complete dynamic laboratory characterization of SAP-sand mixtures with different percentages of polymer in the soil. The results clearly show that small percentages of SAP have a minor effect on the reduction of the shear stiffness value, while when the percentage is higher than 40% a sharp drop is observed. It is also shown that SAP largely increases the damping ratio of the treated layer, being this an extremely beneficial effect for its seismically isolating application. In the second part of the paper, one and two-dimensional seismic response analyses were carried out to explore the beneficial effects of SAP-soil filtering barriers as parts of a Geotechnical Seismic Isolation (GSI) system. The paper also proposes a simplified analytical approach to design geotechnical seismic isolation using Super Absorbent Polymers.
Adoption of the rocking isolation concept in foundation design is considered as an effective method in reducing seismic loads of structures. Despite much research conducted on the rocking behavior of foundations, concerns regarding the practical application of the rocking foundation design concept still prevail. The concerns primary stem from the lack of accurate understanding and knowledge associated with the soil-foundation deformation mechanisms during rocking motions. Determination of deformation mechanisms and soil mass failure modes during foundation rocking helps to gain insight into the rocking behavior, recognize influential factors on foundation settlement or uplift, and propose appropriate improvement strategies to control foundation deformations. The primary objective of this study is to investigate the deformation behavior and failure modes of the soil mass beneath a rocking foundation with various initial static vertical factors of safety (F.S.v) and embedment depths. To this end, a series of reduced-scale slow-cyclic tests under 1g condition have been conducted using a single degree of freedom (SDOF) model. To determine soil deformation mechanisms, soil displacement fields have been measured using Particle Image Velocimetry (PIV) technique. Soil deformation mechanisms during loading and unloading paths, as well as causes leading to the foundation settlement or uplift have been evaluated and discussed. Additionally, changes in the effective soil-foundation contact area in different loading cycles have been examined based on the PIV results. Based on the results, soil deformation mechanisms in the loading portions include soil densification, wedge deformation and scoop deformation. As the footing embedment depth increases, wedge deformation mechanism becomes limited, while scoop deformation mechanism becomes stronger. Additionally, as the foundation F.S.v increases, the depth of influenced zone of the rocking foundation decreases and the soil displacement occurs to a more limited depth.
The pile foundation can be easily damaged in the earthquake event and there is a need to reinforce the foundation to protect the superstructure. The aim of this study is to propose a material for pile foundation by using wasted tire chips mixed with sand (i.e. sand-tire mixture) and study its effectiveness in an earthquake incident. This idea is learned from many sand-tire mixtures investigations. Laboratory monotonic triaxial tests were conducted based on the pure Nevada sand and sand-tire mixture (i.e. volume of sand to volume of tire was 6:4 in this study) as the input parameters for the subsequent numerical simulation. The numerical simulation was based on a centrifuge experimental results, which was also validated in this study. The simulation results show that the proposed method has a good effectiveness for a pile foundation, since the reduction in terms of the bending moment acting on the pile foundation is significant. In addition, even in the earthquake incident, the pile foundation still has the lateral support contributed from the adjacent sand-tire mixture, which is able to protect the pile foundation from buckling and fractured. This pile foundation behavior is different from that supported by the pure sand (i.e. without sand-tire mixture), which has zero lateral support to the pile foundation in the earthquake incident. However, there is an optimal reinforced length for the sand-tire mixture, where the effectiveness becomes insignificant.
Due to the attributes of low shear modulus and high initial damping, rubber sand mixtures (RSM) can be used as a soil alternative to reduce ground motions when seismic loads are of great concern. However, when RSM is used as a vibration isolation material for geotechnical seismic isolation systems, it suffers from a lack of load-bearing capacity. To overcome this, a three-dimensional interconnected geocell (one type of geosynthetics) is placed within RSM to increase the vertical confinement of the system. In this technical note, to investigate the shear modulus and damping ratio of geocell-reinforced RSM, large-scale cyclic triaxial tests were conducted on specimens prepared with four granulated rubber contents (by weight) and sheared under different cyclic shear strain amplitudes. The results show that Geocell reinforcement can restrict the development of local shear bands in the specimen, weaken the anti-S-shaped characteristics of hysteresis loops and enhance the damping ratio of RSM at large strain amplitudes. The tuck net effect causes an increase in the normal stress of both contact particles, and then leads to the degradation rate of the maximum shear modulus of RSM varying with the rubber content and vertical pressure. The normalized shear modulus degradation curves show the influence range of geocell reinforcement, and demonstrate that a rubber content of 20% for reinforced specimen may be an optimal value from the perspective of the stability of dynamic properties. Additionally, the quantitative analysis of the effect of geocell reinforcement on the mechanical behavior of RSM can provide a reference for subsequent theoretical research and engineering applications.
Open trenches are one of the most popular vibration isolation techniques used to reduce the transmission of ground vibrations. Despite several advantages of this systems for isolating ground vibrations, the major drawback is the geotechnical instability of the trenches. To solve this issue, the author have created a novel approach that involves filling the open trenches with hollow pipes in specific pattern. This is a novel method for mitigating ground vibrations by burying hollow pipes horizontally. Through the use of three-dimensional (3D) finite-element modeling, the effectiveness of such hollow pipes in decreasing ground vibrations generated by harmonic stress excitation on the ground surface was investigated. Compared to open trench barriers and in-filled trench, these pipe assemblages have been demonstrated to be highly successful in reducing ground vibration transmission while addressing issues of instability and enhancing vibration isolation efficiency. In PLAXIS3D, a dynamic numerical model is developed, and the results are validated against available solutions. Then, an optimized design technique for wave barriers is developed, and explore the effect of layered soil on vibration isolation effectiveness of hollow pipes.
Rubber–soil mixtures (RSM), formed by mixing two types of granules with vastly different mechanical properties, has the potential for serving as a cost-effective substitute for geotechnical fillings. Its micromechanical behavior at a microscopic scale, however, is not yet well understood. In this study, a numerical model of granulated RSM under biaxial compression conditions is established based on the discrete element theory and two-dimensional particle flow code. Microparameters of a particular RSM are studied and calibrated by comparison with triaxial consolidated drained shear tests. The volumetric fraction of sand is assigned as the index of the mixture, and the deviatoric stress–axial strain curves of RSM with different sand fractions are analyzed. Particle rotation, average coordination number, force chain structure, and energy dissipation with axial strains are further investigated to better understand the microscopic mechanisms of RSM. The main findings of the study include: (1) Rubber particles are highly deformable and fill the voids more easily than stiffer sand particles. This contributes to the high friction of sand–rubber interfaces, which delays or even inhibits the relative motion and tumbling of sand particles; (2) The force chains of sand particles are either braced from buckling until large axial strains by rubber particles occupying the intergranular voids or distributed by increased rubber–rubber contacts depending on the rubber content; and (3) RSM with a rubber volumetric content of 30–40% are optimal in that the force chain increases monotonically with axial strain with a stable load-deformation relationship. In addition, the sensitivity analysis of the effect of microparameters on the macroscopic behavior of RSM is presented, which can provide theoretical support for exploring the mechanical properties of similar mixed granular materials subjected to external loading.
Following the 1994 Northridge earthquake, the areas with a high density of reported breaks in water pipes in typical residential areas in San Fernando Valley and in Los Angeles often did not coincide with the areas having a high density of severely damaged (red-tagged) buildings. As the former is an indicator of large strains and nonlinear soil response, this observation suggests that the damage to buildings in some areas may have been smaller than expected because the soil dissipated part of the energy of the ground motion by nonlinear response. This paper presents an attempt to quantify this relationship between the density of red-tagged buildings, N (per km 2 ), and the severity of shaking (via peak horizontal ground velocity, v max, or modified Mercalli intensity, IMM), including the density of breaks in water pipes, n (per km 2 ), as a variable specifying the level of strain in the soil. Approximate empirical relationships for N = f(vmax, n) and N = f(IMM, n) are presented. The trends in the data indicate that, for vmax in the range from ;35 to ;125 cm/s, the rate of growth of N versus vmax tends to decrease at sites with large strain in the soil (i.e., large n). For vmax beyond ;150 cm/s, the beneficial effects of nonlinear soil response seem to fade out, as large differential motions associated with soil failure begin to contribute to the damage of structures. Assuming fairly uniform density and quality of building stock and of water pipes in the areas studied, the derived relationships are then used to map vmax and IMM in San Fernando Valley and in Los Angeles. The resulting maps are more detailed than what could be obtained from the density of strong motion stations and of sites with reports on felt intensity.
Processed waste tires mixed with soils are applicable in lightweight fills for slopes, retaining walls, and embankments that may be subjected to seismic loads. Rubber's high damping capacity permits consideration of granulated rubber/soil mixtures as part of a damping system to reduce vibration. The dynamic properties of granulated rubber/soil mixtures are essential for the design of such systems. This research investigates the shear modulus and damping ratio of granulated rubber/sand mixtures using a torsional resonant column. Specimens were constructed using different percentages of granulated tire rubber and Ottawa sand at several different percentages. The maximum shear modulus and minimum damping ratio are presented with the percentage of granulated rubber. It is shown that reference strain can be used to normalize the shear modulus into a less scattered band for granulated rubber/sand mixtures. The normalized shear modulus reduction for 50% granulated rubber (by volume) is close to a typical saturated cohesive soil. Empirical estimation of maximum shear modulus of soil/rubber mixtures can be achieved by treating the volume of rubber as voids.
Current design guidelines for shallow foundations supporting building and bridge structures discourage footing rocking or sliding during seismic loading. Recent research indicates that footing rocking has the potential to reduce ductility demands on structures by dissipating earthquake energy at the footing-soil interface. Concerns over cyclic and permanent displacements of the foundation during rocking and sliding along with the dependence of foundation capacity on uncertain soil properties hinder the use of footing rocking in practice. This paper presents the findings of a series of centrifuge experiments conducted on shear wall-footing structures supported by dry dense to medium dense sand foundations that are subjected to lateral cyclic loading. Two key parameters, static vertical factor of safety (FSV), and the applied normalized moment-to-shear ratio (M/(H·L)) at the footing-soil interface, along with other parameters, were varied systematically and the effects of these parameters on footing-soil system behavior are presented. As expected, the ratio of moment to the horizontal load affects the relative magnitude of rotational and sliding displacement of the footing. Results also show that, for a particular FSV, footings with a large moment to shear ratio dissipate considerably more energy through rocking and suffer less permanent settlement than footings with a low moment to shear ratio. The ratio of actual footing area (A) to the area required to support the vertical and shear loads (Ac), called the critical contact area ratio (A/Ac ), is used to correlate results from tests with different moment to shear ratio. It is found that footings with similar A/Ac display similar relationships between cyclic moment-rotation and cumulative settlement, irrespective of the moment-to-shear ratio. It is suggested that shallow foundations with a sufficiently large A/Ac suffer small permanent settlements and have a well defined moment capacity; hence they may be used as effective energy dissipation devices that limit loads transmitted to the superstructure.
The effectiveness of structural fuse mechanisms used to improve the performance of buildings during seismic loading depends on their capacity, ductility, energy dissipation, isolation, and self-centering characteristics. Although rocking shallow footings could also be designed to possess many of these desirable characteristics, current civil engineering practice often avoids nonlinear behavior of soil in design, due to the lack of confidence and knowledge about cyclic rocking. Several centrifuge experiments were conducted to study the rocking behavior of shallow footings, supported by sand and clay soil stratums, during slow lateral cyclic loading and dynamic shaking. The ratio of the footing area to the footing contact area required to support the applied vertical loads (A/A(c)), related to the factor of safety with respect to vertical loading, is correlated with moment capacity, energy dissipation, and permanent settlement measured in centrifuge and 1 g model tests. Results show that a footing with large A/A(c) ratio (about 10) possesses a moment capacity that is insensitive to soil properties, does not suffer large permanent settlements, has a self-centering characteristic associated with uplift and gap closure, and dissipates seismic energy that corresponds to about 20% damping ratio. Thus, there is promise to use rocking footings in place of, or in combination with, structural base isolation and energy dissipation devices to improve the performance of the structure during seismic loading.
In this, the second of a two-part paper, the analysis of the apparent frequency of a seven-story reinforced-concrete hotel building in Van Nuys, Calif., is extended to consider its time-dependent changes, both short and long term. The instantaneous apparent frequency is measured by two methods: windowed Fourier analysis and zero-crossings analysis. The results show that it changes from earthquake to earthquake and during a particular earthquake. The results also suggest "self healing" believed to result from settlement of the soil with time and dynamic compaction from aftershock shaking. Implications of such high variability of the system frequency on structural health monitoring, control of response, as well as on the design codes are discussed. Nonlinear response of the foundation soil acts as a sink of the incident seismic wave energy. It is suggested that it could be exploited in future designs to serve as a powerful and inexpensive energy-dissipation mechanism.
This paper presents the preliminary research works on a potential seismic isolation method that makes use of scrap rubber tires for the protection of low‐to‐medium‐rise buildings. The method involves mixing shredded rubber tire particles with soil materials and placing the mixtures around building foundations, which provides a function similar to that of a cushion. Meanwhile, the stockpiling of scrap tires is a significant threat to our environment, and the engineering community has been looking for long‐term viable solutions to the recycling and reuse of rubber. A finite element program has been developed for modeling the time‐domain dynamic responses of soil–foundation–structure system, by which the effectiveness and robustness of the proposed method have been evaluated. In general, the structural responses, in terms of acceleration and inter‐story drift, can be reduced by 40–60%. Copyright © 2012 John Wiley & Sons, Ltd.
This paper describes an experimental and theoretical study of the feasibility of using fiber reinforcement to produce lightweight low-cost elastomeric isolators for application to housing, schools and other public buildings in highly seismic areas of the developing world. The theoretical analysis covers the mechanical characteristics of multi-layer elastomeric isolation bearings where the reinforcing elements, normally steel plates, are replaced by a fiber reinforcement. The fiber in the fiber-reinforced isolator, in contrast to the steel in the conventional isolator (which is assumed to be rigid both in extension and flexure), is assumed to be flexible in extension, but completely without flexure rigidity. This leads to an extension of the theoretical analysis on which the design of steel-reinforced isolators is which accommodates the stretching of the fiber-reinforcement. Several examples of isolators in the form of long strips were tested at the Earthquake Engineering Research Center Laboratory. The tested isolators had significantly large shape factors, large enough that for conventional isolators the effects of material compressibility would need to be included. The theoretical analysis is extended to include compressibility and the competing influences of reinforcement flexibility and compressibility are studied. The theoretical analysis suggests and the test results confirm that it is possible to produce a fiber-reinforced strip isolator that matches the behavior of a steel-reinforced isolator. The fiber-reinforced isolator is significantly lighter and can be made by a much less labor-intensive manufacturing process. The advantage of the strip isolator is that it can be easily used in buildings with masonry walls. The intention of this research is to provide a low-cost lightweight isolation system for housing and public buildings in developing countries.
Designing earthquake-resistant low-to medium-rise structures is problematic in that their fundamental frequency of vibration is in the range of frequencies where earthquake energy is the strongest, so the building acts as an amplifier of the ground vibrations, with the floor accelerations increasing over the height of the building. Ultimately, the seismic design should reduce the accelerations in buildings to below the level of the ground accelerations. To do this the building must be flexible. Incorporating flexibility in a structural frame can cause problems, however: windows may fall out due to wind loads, partition walls may crack and floors may vibrate under foot. For a low-or medium-rise building, the necessary flexibility can only be achieved by using base isolation at the foundation level. A number of buildings have been built in the US using this innovative technology; this review will highlight a few of them.
This paper proposes a promising seismic isolation method particularly suitable for developing countries, which makes use of rubber–soil mixtures. Apart from reducing the level of shaking in the horizontal direction, the distinctive advantage of the proposed method is that it can also significantly reduce the shaking level of vertical ground motion, to which an increasing attention has been paid in the earthquake engineering community. On the other hand, the use of scrap tires as the rubber material can provide an alternative way to consume the huge stockpile of scrap tires all over the world. Moreover, the low cost of this proposed seismic protection scheme can greatly benefit those developing countries where resources and technology are not adequate for earthquake mitigation with well-developed, yet expensive, techniques. The proposed method has been demonstrated through a series of numerical simulations and a parametric study has also been carried out. Lastly, five important issues regarding the concept and feasibility have been discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Over 300 Million Waste Tires Each Year
- Crawford Renewable Energy
Crawford Renewable Energy. Over 300 Million Waste Tires Each Year. Available from: http://www.
crawfordrenewableenergy.com/about-us/the-problem-of-waste-tires/ [11 November 2012].