The phenomenon of liquefaction poses significant challenges to the engineering design of buildings, especially in earthquake-prone areas. The impacts resulting from increased pore water pressure within the soil can lead to the deterioration of the foundation’s load-bearing capacity, resulting in dangerous landslides in buildings. Multiple historical events, such as the Niigata earthquake in 1964 and the Luzon earthquake in 1990, have clearly demonstrated this. This research reviews the relationship between nearby structures and the methods for leveling shallow foundations in liquefiable soils by utilizing a numerical model based on the theory of porous fluids for houses. The effects of distances between different foundations and patterns of earthquake acceleration on the dynamic behavior of the soil will be analyzed, providing important insights for designing more resilient and safer foundations in high-risk urban areas.
The Impact of Ground Shaking on Foundation Settlement in Liquefiable Soils
Liquefaction is a phenomenon that occurs during earthquakes, where the soil loses its load-bearing capacity and begins to move, leading to foundation settlement. One of the primary concerns in this context is the effect of adjacent buildings on the settlement of shallow foundations. Changes in internal water pressure due to ground shaking can lead to the deterioration of soil bearing capacity, exacerbating settlement. For example, the earthquake that occurred in Niigata in 1964 serves as a real-world model, where the shaking caused excessive settlement of buildings, resulting in significant damage to many of them.
Studies indicate that the proximity of buildings to one another has an impact on the dynamic response of foundations, attributable to the common pressures affecting the ground. Surrounding foundations act like piles, influencing pressure distribution in the soil. In cases where distances between foundations increase, it appears that settlement and lateral movement decrease, highlighting the importance of foundation design in urban areas with seismic risks.
For instance, simulation models have shown that as internal pressure acceleration increases during earthquakes, the settlement ratio may increase by as much as 110%. This information is valuable for construction engineers when designing light and heavy foundations, as they must consider nearby impacts and work to improve foundation designs to mitigate negative effects.
The Numerical Model Based on Biot’s Theory and Hydraulic Mechanics
Biot’s theory for modeling liquefied soil is one of the most advanced in studying foundation settlement. This theory is used to conduct complex numerical analyses that help predict the effects resulting from earthquakes. The stability and settlement problems arising from shaking allow the application of finite element modeling. In this study, the iterative system was used to satisfy the pressure wave associated with excess water and the resulting settlement.
The interaction between the fluid and the soil is represented by a system of equations, where some secondary pressure effects in static cases are disregarded. The simulation models include three different scenarios concerning increased acceleration and the spacing between light and heavy foundations, providing an opportunity for detailed analyses. The derived results illustrate how the soil responds under changing pressures and how foundations respond to those pressures.
Numerical estimates indicate that the inability of the soil to withstand pressure resulting from shaking leads to increased internal pressure and deterioration of foundation performance. By improving the behavior model, it becomes possible to provide practical recommendations that assist engineers in making better decisions when designing foundations, especially in areas that may be subject to earthquakes.
The Importance of Understanding Foundation Interaction Effects When Designing Buildings
Foundation interactions between adjacent buildings are critical factors in structural design, as they directly affect building performance during earthquakes. In urban areas, the presence of densely built structures is common, increasing the complexity in understanding the interactions between foundations. Studies suggest that proximity of foundations can improve the seismic performance of constructions in some cases, but it may also lead to excessive settlement and sway in other situations.
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These interactions must consider several factors, such as structural design, foundation dimensions, and soil type. For example, some studies have shown that corner buildings tend to tilt more than other buildings due to the uneven pressure distribution on the soil. Therefore, conducting thorough research on these aspects is crucial to avoid significant damage.
Additionally, modern tools such as finite element modeling provide opportunities for engineers to deeply understand dynamic factors and analyze the interactions between foundations more accurately. Through this understanding, design can be improved, and the risk of settlement can be reduced, ensuring the stability of buildings in earthquake-prone areas.
Design Recommendations to Enhance Shallow Foundation Resistance
This study aims to provide design recommendations that help improve the performance of shallow foundations in earthquake-prone areas. This requires considering multiple factors, including the spacing between foundations, soil type, and expected earthquake intensity. It is essential for engineers and research institutes to collaborate to develop innovative design strategies that ensure building safety.
Recommendations should include the use of advanced simulation models that account for close interactions between foundations. Practical experiments are also advised to support numerical theories, as this will help in understanding how foundations respond under specific conditions. Furthermore, the materials used in foundation construction can be enhanced with approved techniques to improve load-bearing capacity and liquefaction resistance.
Moreover, supporting engineering guidelines with predictive technologies and safety standards can enhance the ability to cope with earthquakes. Implementing these recommendations can lead to designing foundations that are more resistant to settlement and effectively bear loads, thereby enhancing overall safety and reducing potential damage. It is important for these recommendations to be part of the fundamental design methodology for architects and civil engineers when working on urban construction projects.
General Plasticity Model and Practical Applications
The process of analyzing the structural effectiveness of soil during rotational loading is critical in geotechnical engineering. Here, a general plasticity model derived from several factors such as excess pore pressure and the soil’s dynamic response is utilized. The PZ-III model for general plasticity is a fundamental tool for understanding soil behavior under loading conditions. This model is based on a set of physical variables such as stress and strain variables, which serve as criteria for estimating the soil’s load-bearing capacity during seismic events.
In the context of this model, a carefully selected set of parameters based on known values in the literature is used. The elastic compressibility modulus (E) is determined to be in the range of 10 to 50 megapascals, reflecting the state of soil compression and density. The Poisson’s ratio (ν) is found to be in the range of 0.3 to 0.35, indicating its typical behavior. The parameter related to severe strain behavior (Mg) is set between 1.0 and 1.2, where these values indicate the plastic behavior of soil under shock loading.
This model also aims to understand the impact of changes in environmental and structural factors on soil behavior. Using this model, we can predict how the soil will behave during earthquakes and under heavy loading conditions, assisting engineers in making appropriate decisions regarding architectural designs.
Model Parameters and Their Importance in Analyzing Soil Behavior
Geotechnical models require precise knowledge of various parameters related to soil behavior. For instance, the parameter related to the critical state and the slope of the critical state line and plastic capacity reflects the performance characteristics of soil under different pressures. The relative density of soil is measured to determine its compressibility, where it is categorized according to a value of 0.4 for density deficiency, significantly affecting its strength and behavior.
Research also shows the effects of lateral loading on soil behavior, investigating how such loading can lead to increased shear forces, potentially causing degradation and altering structural behavior. Mathematical models are used to perform complex calculations to determine the extent of such variable influences, assisting in predicting changes in torsion and compression states that may lead to structural failures.
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That, plastic loading transactions and the interaction of materials with different pressures have a significant impact on soil behavior. The relationships between stresses and strains are studied and used to estimate the potential weakness during plastic behavior, reflecting the depth of knowledge necessary to predict soil behavior under non-ideal conditions.
Model Accuracy Verification: Comparing Modeling with Centrifuge Tests
Verifying model accuracy is an important step for validating the results obtained from modeling. This is done by comparing the results of excess pore water pressure and the decrease occurring in the soil with the actual results obtained from centrifuge tests. The research indicates that the calculated values are based on events rooted in real testing patterns and experienced under similar conditions.
A model with specific dimensions of sandy Nevada soil with a median diameter that corresponds with the characteristics of unsaturated soil was tested. The results indicate a significant match between the observed decrease in experiments and the calculated results in the model. This agreement demonstrates the effectiveness of the model and its ability to reliably represent real cases.
With the rapid acceleration in technological advancements, it has become possible to build advanced models that reflect soil behavior in new and precise ways. Such models, including the application of precise engineering technology, offer improved performance that allows for more accurate predictions of potential soil behavior under excess loading conditions, supporting engineers’ ability to develop innovative solutions to geotechnical problems.
Numerical Examples: Studying the Effect of Foundation Spacing
Within the framework of several studies related to conducting numerical experiments, the effect of distances between foundations on soil behavior in collapse scenarios based on excess loading was investigated. These experiments require a precise understanding of soil behavior under various loads, including both light and heavy foundations, whether in limited or complete collapse patterns. The distributed configuration of soil opens new avenues for research in geotechnical designs.
When conducting these studies, the effect of distances between foundations clearly appears in the results. For instance, the structural comfort of different bases can lead to variations in seismic loss, changes, and conditions of excess fluid pressure, which are key factors in assessing structural stability.
Understanding soil behavior during loading conditions is essential for foundation design, making it crucial to study the variables comprehensively. This knowledge, supported by numerical experiments and analytical studies, provides a clear insight into how different structures handle to avoid collapses and develop innovative engineering solutions.
Vibration Sources and Their Impact on Buildings
In construction and civil engineering, vibration sources are significant factors that must be considered to achieve the stability of structures. Buildings typically emit vibrations from various sources, such as traffic, industrial activities, or even earthquakes. These vibrations aim to transfer energy to the soil, which can lead to negative effects on the foundations of the structures. To protect these buildings from vibrations, elements such as dampers or springs and absorbers are designed to reduce the longitudinal and horizontal effects of vibrations on foundations. When designing foundations, the properties of the underground soil are taken into account, such as soil permeability and behavior during vibration.
Response Analysis in Heavy and Light Foundations
In dynamic analysis, the different responses between heavy and light foundations when exposed to vibrations are studied. A heavy foundation, such as that used in tall buildings, is more susceptible to vertical and horizontal pressure and settlement compared to light foundations. For instance, varying values for horizontal and vertical displacements of heavy and light foundations have been recorded, where heavy foundations experienced greater impacts due to their weight. This difference in impact is primarily due to the design of the foundations and the properties of the surrounding soil. The greater the weight, the greater the effects during vibration, leading to different responses in the amount of settlement.
Impacts
Interference of Vibrations During Compression and Cohesion
The interference effects of vibrations during periods of compression and cohesion are central topics in this field. When vibrations occur, excess pressures build up in the pores of the soil layers, which can lead to loss of stability and disintegration, especially under conditions such as liquefaction. The study of these effects includes observations on the behavior of pore water and the loss of effective pressure in the soil. For example, research shows that typical soils exhibit liquefaction experiences when certain values of excess pressure are reached, causing failure in infrastructure.
Industrial Applications and Laboratory Experiments
Examining the behavior of different materials and aeration treatment requires laboratory experiments within precise control systems. Experiments conducted on heavy and light foundations demonstrate the methods used to understand the interaction of cement with surrounding systems. The outcomes of these experiments represent a critical component in foundation design, reflecting the focus on good practices to avoid future problems. Hydrostatic pressure measuring devices and liquefaction are used in these studies to analyze the interaction between various elements, as well as tensile and pulling tests to study the elastic effects on foundations.
Numerical Analysis and Risk Assessment
Numerical analysis can assist in focusing engineering efforts on predicting the future behavior of foundations under multiple influences. Advanced numerical models are employed to simulate various conditions that may affect foundations in cases of compression and cohesion. Through techniques such as kinematics and hydrology, engineers can assess the risks associated with foundation performance under different conditions, such as earthquakes or pressures caused by traffic. This detailed and precise analysis reflects how performance can be influenced by environmental conditions.
Conclusions on Hydraulic Behavior under Earthquake Impacts
During earthquakes, retention conditions change radically, necessitating careful monitoring of the techniques used. Studies show that during earthquakes, water may leak from certain areas under the foundations, leading to increased hydrostatic pressure. This pressure is attributed to earthquakes’ effects on the fluid balance in the soil, causing significant disruption to structural stability. Managing these pressures is critical in engineering design to ensure the safety of structures. Assessing the impacts of earthquakes and their hydraulic effects is fundamental in achieving safety and structural stability for buildings.
Seismic Effects on Foundations
Foundations represent one of the most crucial components of any building, as they bear loads and help distribute stresses on the underlying soil. Earthquakes significantly affect the stability of foundations, especially in liquefiable soils. Light and heavy foundations behave differently during ground shaking, and studies indicate that there is a varied response based on the foundation type, depth, and earthquake intensity. For instance, studies have shown that heavy foundations exhibit liquefaction at shallower depths compared to light foundations, which may only show liquefaction at greater depths. These differences are critical in designing foundations in earthquake-prone areas.
Dynamic Response of Foundations in Earthquake Conditions
The dynamic response of foundations relates to the changes resulting from an earthquake and depends on several factors including the spacing between foundations and their type. In cases of closer spacing between foundations, they tend to behave as though they are one foundation, increasing their horizontal and actual movements. This suggests that the design of foundations in closely spaced buildings must consider the effects resulting from this proximity. Research has shown that increasing the gap between foundations reduces horizontal movement and seismic stability. In the case of heavy foundations, horizontal movement tends to be less compared to light foundations, reflecting the critical role of weight in foundation stability during earthquakes.
Effect
Excess Pore Water Pressure in Soils
Excess pore water pressure in soils is considered one of the fundamental factors affecting the response of foundations during earthquakes. This pressure can lead to the liquefaction of soil, thereby deteriorating the soil’s bearing capacity. Studies have shown that heavy foundations can create significantly higher excess pore water pressure compared to light foundations, especially at depth. Excess pore water pressure plays a major role in increasing the stability rates for both light and heavy foundations, as heavy foundations exhibit higher levels of excess pore water pressure in lab experiments and field tests. This interaction makes it essential to study the effects of pore water pressure during earthquakes, particularly in weak or unreinforced soils.
Modern Techniques for Studying Foundation Response
Modern techniques for studying foundation response involve the use of digital models and earthquake simulations, where these techniques can provide accurate insights into the response of foundations under seismic conditions. The use of models such as the UBCSAND model has shown significant effectiveness in determining the dynamic response of foundations, helping to predict stability rates and potential settlement during an earthquake. Techniques such as finite element analysis bring a high level of accuracy when studying the effects of earthquakes on foundations, allowing engineers to better plan the designs of foundations in earthquake-prone areas. This type of analysis provides practical data for engineers, facilitating the development of effective engineering strategies for future foundation designs.
Strategies for Mitigating Earthquake Effects on Foundations
Modern engineering design strategies are essential for reducing the impacts of earthquakes on foundations. This includes using construction materials capable of enhancing a foundation’s ability to withstand seismic pressure. Effective engineering designs, such as deep foundations, are also considered conditional solutions. Additionally, establishing proper spacing between light and heavy foundations helps improve their response to seismic loads. Monitoring changes in pore water pressure as well as soil liquefaction during foundation design is considered a critical part of engineering design guidelines in earthquake-prone areas. Developing modern installation techniques and rehabilitating existing foundations contribute to enhancing building resilience during earthquakes.
Effects of Interaction Between Adjacent Foundations
The interactions between adjacent foundations are vital aspects of structural design and analysis. When designing foundations, the rigidity of foundations is sometimes assumed, and it is believed they operate independently. However, research indicates that closely spaced foundations do not behave independently; instead, they can act as a single foundation. This means that the forces and effects acting on one foundation can also influence nearby foundations, leading to more violent vibrations compared to isolated foundations.
When foundations are in close proximity to each other, the soil beneath them begins to vibrate as if it were a solid system, resulting in phase and amplitude synchronization. In urban environments, buildings are often very close together, which can increase seismic loads on the foundations. This highlights the importance of considering the mutual effects between adjacent foundations during the design phase, as their responses vary depending on how close they are to each other. Therefore, it is advisable to implement dynamic analysis models that take mutual effects into account to improve analysis results and accuracy in foundation design.
The Importance of Understanding the Impact of the Superstructure on Foundations
When studying engineering designs, the impact of the superstructure is often overlooked in current research. The superstructure, which includes the upper parts of the building such as walls and roofs, has a significant effect on the behavior of the foundations during seismic loading. Understanding these effects requires a deeper level of comprehension and modeling, as they can influence the structure’s response.
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For example, the weight of the superstructure can increase pressure on the foundations, which may lead to a different type of wear or even structural failure. In earthquake scenarios, this weight causes greater vibrations, which may enhance the effects of soil liquefaction. Therefore, ignoring these effects in the analysis can lead to an incorrect assessment of the risk levels associated with structures.
To understand the relationship between the superstructure and the foundations, advanced modeling should be employed that takes into account various factors such as liquefaction potential and a variety of loading types to mitigate the risk of failure. This ensures safer designs and better responses in the event of earthquakes or complex ground conditions.
Necessary Considerations for Seismic Risk Analysis
Assessing seismic risks requires a number of technical and scientific considerations. Liquefaction during earthquakes is a complex issue that requires a precise understanding. Studies show that soil can lose its bearing strength during ground shaking, directly affecting the stability of the foundations. Measuring excess pore fluid pressure is a key indicator of the level of liquefaction.
In this context, it is crucial to utilize finite element analysis in modeling so that it includes different scenarios to evaluate the response of soil subjected to earthquakes. Data derived from real-world field experiments and laboratory tests can be used to develop accurate models. By integrating these techniques, engineers can create more precise models that can help identify vulnerabilities in structure and improve safety.
The effect of spacing between foundations must also be considered, as certain distances can increase or decrease seismic risks. These considerations require engineers to study these dynamics in detail to ensure designs align with the highest safety standards and sound engineering practices.
Future Guidelines for Mitigating Liquefaction-Related Risks
Continuous research and innovation of new methods for analyzing soil-foundation interactions are urgent necessities. Developing new techniques that help assess potential risks and effects during earthquakes will significantly influence how buildings are designed in seismic zones. These techniques should include integrated assessment methods that consider the dynamic characteristics of the soil and the weight of the superstructure.
There is also a need to highlight the importance of collaboration between engineers and researchers to exchange knowledge and expertise. Successful practices require an overlap between academic analysis and practical application to improve the construction system. For example, studies of previous case models that were subjected to seismic stress may provide valuable insights on how to address similar challenges in the future.
Engineers must also keep up with the latest sensing technologies and artificial intelligence applications for analyzing data related to the health of buildings and foundations. By integrating modern technologies and science into design and analysis processes, the infrastructure’s response can be enhanced and potential risks from earthquakes can be reduced. Communities must also be prepared to adopt advanced policies that enhance the safety of earthquake-prone areas.
Seismic Effects on Shallow Foundations
The phenomenon of soil liquefaction due to earthquakes is considered one of the main causes affecting the structural stability of buildings. This occurs as a result of increased pore water pressure, which happens during seismic activity, leading to a decrease in shear strength and bearing capacity of the soil. These changes can be catastrophic in urban areas where buildings are close together, increasing safety concerns related to structures. Historically, we have seen multiple examples of this, such as the Niigata earthquake in 1964, where liquefaction caused the degradation of many reinforced concrete buildings. In the 1990 Luzon earthquake in the Philippines, soil liquefaction in Dagupan City led to significant settlements in several buildings.
research that suggests the impact of buildings close to each other can enhance inertia movements, where corner buildings and those at the ends of streets show a greater tendency. A study conducted by Tokimatsu et al. distinguished that the instability exposed to corners compared to the midsection of buildings may result from the pressure exerted by neighboring structures. This dynamic illustrates how a structure’s stability depends on its dimensions, internal pressure, and shear stress resulting from the interactions among buildings. In the 1999 Adapazari earthquake in Turkey, it was identified that thin saturated sandy layers were responsible for the damage due to the liquefaction phenomenon.
To achieve a deeper understanding of the interactions between soil and buildings, numerous experiments were conducted on practical models, where Li and Joubri performed tests in an artificial dryer to determine the factors leading to soil deposition and increased water pressure. The results confirmed that the effects resulting from the upper structure’s movement and volume change after liquefaction are the main factors related to deposition.
Interactions Between Soil and Foundations
The interactions between soil and foundations are a critical factor in understanding how foundations behave under seismic influences. These interactions are based on the presence of saturated sandy layers, where soil behavior depends on stiffness and stress conditions. Mathematical models such as the Biot model have been developed to represent these interactions, viewed as a system with two phases: the fluid phase and the soil phase.
Moreover, loads and settlements interact during earthquakes, where the Biot model provides the necessary balance mechanisms between pressure and load. Results from these studies indicate significant effects from both dynamic and static aspects. We can see how these forces resulting from earthquakes play an essential role in shaping soil pressure and weight distribution on foundations, leading to settlements that may be severe during strong earthquakes.
The advancement in understanding the behaviors of foundations under repeated loads increases the importance of field studies and computed models. Analytical models that addressed soil impact and techniques such as the Finite Element Method (FEM) have become widely used to investigate the complexities of this interaction. Aspects related to fluid movements, lateral pressures, and sliding are key focal points in managing rapid responses in earthquake situations.
Numerical Methods and Simulations
Numerical simulation models form an advanced method to understand foundation behavior under seismic influences. Thanks to the development of significant software and analytical techniques, models based on momentum balance and mass balance have been constructed that aid in solving the complex equations of soil-building interactions. The use of Finite Element Method is considered one of the strongest approaches employed in studying the adverse effects caused by earthquakes.
These simulations require foundational load calculations and examining their effects on various materials under dynamic conditions. Results show variability in the behavior of deep and shallow foundations corresponding to future challenges. The relationship between soil and foundations holds considerable importance, as modern urban planning relies on avoiding underground body interference. With the heightened risks from earthquakes, developing more precise models to understand changes resulting from water pressure is one of the primary objectives of modern societies.
Highly specialized techniques such as automatic factor analysis and extending the scope of seismic analysis bring significant added value to building more resilient cities. Recent studies also include the interaction between isolated and inverted foundations, emphasizing the critical importance of the long timeline required for storage and flow during earthquakes.
Challenges of Structural Design in Seismic Areas
Seismic conditions require radical changes in how buildings are designed. The close proximity of architectural bodies necessitates a tailored evaluation of foundation interaction and pressure. Protection against adverse effects on the urban environment is one of the major challenges for project owners and engineers. Engineering plans must account for the dynamic effects that earthquakes might impose on nearby foundations.
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There is a clear need to integrate considerations of the impacts arising from the urban environment, as these challenges require precise designs based on numerical and field studies. Through continuous analyses and the use of advanced methods in psychometric measurement and dynamic testing, ways can be identified to protect citizens and significantly improve safety levels.
The importance of the standards and guidelines used in designing buildings and urban planning is increasing in light of the ongoing effects of earthquakes. A deep understanding of architectural responsibilities and challenges should be matched by a commitment to developing advanced standards that may improve earthquake resistance and push sustainability forward.
Quantitative Analysis of Geological Behavior Under Cyclic Loading
Understanding the geological behavior of the foundations affecting the establishment of facilities requires several key factors, including phase transition and changes occurring in soil behavior under cyclic loading. In this context, a number of parametric parameters are employed that directly affect the soil behavior. Specific parameters, such as the phase transition coefficient, which controls soil capacity behavior, have been identified, while the plastic expansion coefficient influences the rate of plastic deformation accumulation. These parameters have been selected within certain ranges to achieve maximum accuracy in the digital modeling of geological behavior. For example, the plastic expansion coefficient has been set between 500 and 1000, while the pressure-expansion coefficient has been set within the range of 0.8 to 1.1 according to the relative density of the soil.
Current research is directed towards improving the numerical model to accurately reflect the actual soil behavior during cyclic loading, through various criteria such as general plastic behavior and unconsolidated models. This aids in understanding the effects resulting from permanent loading, changes in pore pressure, and calm cycles during interaction with earthquakes. By adding more detailed models, such as surface connection models and general plastic models, it becomes possible to accurately calculate changes in stress and deformation.
Behavioral Performance of Soil Under Excess Pore Pressure Conditions
Changes in excess pore pressure within the soil largely depend on the nature of the soil and the rate of its loading. The excess pressure parameter in FEM models is adjusted to monitor changes in excess pressure. In this context, previous experiments were relied upon to compare numerical results with experimental data from models measuring behavior under earthquake conditions. This is considered a pivotal part of geological discoveries, where the peak excess pressure in laboratory experiments is approximately 60.789 kilopascals, which approximately corresponds to the simulated numerical models.
One of the methods used to simulate how soil reacts to seismic loading is the use of centrifuge laboratories, where excess pore pressure is employed to study soil behavior. By measuring the overall stability and changes in excess pressure, deeper insights were obtained regarding how the soil responds to seismic loads. This deep understanding contributes to reducing the risks of land collapse under seismic effects and empowers the planning and construction of safer buildings.
Numerical Modeling and Dynamic Response of Foundations
In the field of numerical modeling, the main objective is to study the effects of distances between foundations under varying loading conditions, and the effects of lighter structures compared to heavier ones. Mixed and unlimited elements are used to monitor responses under different conditions. This includes modeling the impacts of collapse resulting from gaps between foundations and how they can affect the stability of the built infrastructure, by dividing the area of influence into nearby and distant zones using artificial transfer boundaries. This distribution is done in dimensions such as 48 meters × 12 meters, as it helps reduce the load of complex calculations.
By using a behavioral model that includes the soil’s ability to respond under different pressures, engineers and designers can obtain vital information about the impact of dynamic pressures. For instance, different loads from heavy structures can cause the soil beneath to adapt, necessitating that the models be accurate enough to predict those changes. The simultaneous study of pressures-related effects is one of the most important methods for improving the design of foundations and structures.
Analysis
Response of Foundations Under Dynamic Loads
The response of foundations was analyzed using models that simulate initial and final conditions under the influence of a periodic load. A static analysis was conducted before and after the application of dynamic loading. The analysis relied on basic equations reflecting the balance of forces and the influence of excess pressure. The study focused on the response of two types of foundations: heavy foundations and light foundations, under varying conditions related to the spacing between foundations. This analysis provides a deep understanding of how foundations respond in seismic environments and analyzes the impact of diverse factors such as weight and shape.
The analysis included different cases to allow for comparison of responses under the influence of earthquakes. It was evident that the forces resulting from the earthquake led to the creation of lateral displacement and a reduction in the leveling of foundations. It was observed that heavy foundations tended to move more than light foundations, indicating the importance of weight in enhancing structural stability under dynamic pressures.
Dynamic Response of Foundations Without Spacing
The first scenario features no spacing between the foundations, reflecting a real scenario where foundations are placed close to one another. Ground motion effects with specific frequencies and parameters were used to introduce dynamic loads. The results showed that heavy foundations experienced greater movement compared to light foundations, and this movement was then indicative of the excessive effect of the pore pressure that the foundations were subjected to. Additionally, internal effects such as excess pore pressure played a crucial role concerning the overall behavior of the foundations during the earthquake.
The analysis demonstrated that the earthquake causes simultaneous settlement of the foundations, with heavy foundations exhibiting a settlement rate of 6.65 cm, while light foundations experienced about 5% less settlement. These results enhance understanding of the inequality in how materials behave under different loads, leading engineers to improve the design process, especially in seismic areas.
Response of Foundations with 8 Meters of Spacing
In this case, the response of foundations was analyzed when there is an 8-meter spacing. The study illustrates how the spacing between foundations can affect dynamic response. Light foundations, due to their lower weight, were more prone to horizontal movement, with lateral displacement increasing by 71%. On the other hand, the settlement of heavy foundations was significantly less compared to that of light foundations, reflecting the impact of weight on foundation stability.
As a result, there is no negative effect under light foundations due to the absence of surrounding pressure, while under heavy foundations, soil densification occurs due to the excess load. The results indicate that repeated earthquake movements led to the generation of pore pressure again, necessitating examination of load distribution details and ensuring the stability of foundations against earthquakes.
Response of Foundations with 16 Meters of Spacing
In the final case, foundations were examined with a spacing of 16 meters. As the spacing increased, it became clear that the dynamic response varied significantly. This spacing increased the likelihood of uneven settlements between foundations. Settlements occurred in the foundations due to mutual pressure, with heavy foundations exhibiting much greater settlement compared to light foundations, which had significantly less settlement. This indicates that the spacing between foundations plays a major role in the dynamic response and provides the required level of safety.
The results show that the movement of light foundations in this case was significantly greater, symbolizing the importance of precise analysis in the engineering design for earthquake engineers. If these spacings are properly achieved, they can help achieve greater balance between dynamic response and structural stability.
Future Challenges and Ongoing Research
Through these analyses, the research emphasizes the need for a profound understanding of specific conditions and the structural response of foundations in seismic environments. The challenges faced include the ability to accurately predict how weight and spacing affect settlements and displacements. The responses recorded during analytical tests serve as a reference for future research that can contribute to improving foundation design and providing sustainable engineering solutions.
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new testing techniques and achieving improvements in equations and mathematical models will have a significant impact on the civil engineering industry, leading to enhanced safety and efficiency in buildings and public structures. The reuse of tests and experimentation in the field of soil and dynamic response will be crucial in making designs more suitable and innovative.
Analysis of the Impact of Light and Heavy Foundations on Soil Behavior Under Seismic Pressure
This study addresses the various effects caused by light and heavy foundations under a certain seismic pressure, focusing on the phenomenon of liquefaction. The foundation of the study is based on performance comparisons of foundations at different sizes and depths. A mathematical model was used to understand the behavior of foundations under different conditions of seismic acceleration and varying liquidity index (ru) values.
Among the key findings, the heavy structure tends to have a greater impact on soil pressure at depth, leading to the occurrence of liquefaction phenomenon in most cases. Amir Mazari, through previous studies, confirmed that heavy foundations generate excess pore pressure at most soil depths, raising the liquidity index value above 1, which indicates a higher risk of liquefaction concerning them. In contrast, light foundations show a less pronounced effect on that value, reflecting a different response in deep foundation cases.
The Impact of Foundation Spacing on Seismic Behavior
The spacing between foundations is a key factor affecting soil response under seismic pressure. As the distance between foundations increases, there is a noted decrease in lateral movement and settlement values. This decrease can be explained by the close structural masses being considered as a single mass, making the vibrations caused by the earthquake more impactful on the soil, while with an increased distance, each base is affected independently.
Experiments showed that the distance between foundations creates a difference in pressure and settlement behavior. When there is no spacing, foundations behave as a single unit exerting more force on the soil foundations, with changes in pressure under the foundations being proportional to the applied load. Conversely, as the spacing between foundations increases, the pressure pattern changes, distributing seismic pressure more efficiently under both foundations.
Analysis of High Intensity and its Impact on the Vertical Behavior of Foundations
Analysis results show that an increase in acceleration intensity leads to significant effects on the foundations’ dynamics. An increase in acceleration intensity from 0.1 g to 0.2 g results in a significant increase in settlement, reaching 90% for heavy foundations. This increase necessitates reconsideration of how foundations are designed and the importance of verifying their balance under these changing conditions.
Settlement values remain high under heavy foundations compared to light foundations due to the effects of weight and the area they cover. The research demonstrates how increased foundation depth affects its behavior and pressure distribution at depth, with studies showing that maximum settlement occurs beneath the foundation, decreasing as depth increases.
The Impact of Tension in the Permanent Joint on Submersion** Research has conducted a test that gathers all necessary information to determine the impact of density intensity in materials under multiple texts
Kelvin elements, which absorb emitted seismic energy, were used as part of the analysis. These elements were designed to ensure that pressure does not increase with increasing acceleration, thus mitigating the effects of vibrations on the foundations. The use of these elements plays a critical role in improving foundation behavior and preventing collapse in the event of strong earthquakes. Additionally, the analyses emphasize the importance of studying the impact of variables such as spacing between foundations and the intensity of seismic effects, and how they can play a pivotal role in designing foundations in seismic areas.
The Importance of Foundation Planning in Urban Environments and Potential Earthquakes
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in the end, the results indicate that good foundation design in earthquake-prone areas is something that must be taken seriously. Neglecting the interactions between adjacent foundations can lead to severe consequences, especially when they are close to one another, causing the foundations to act as a single block under load. The study suggests that seismic analysis should include an accurate estimation of how foundations interact with each other during an earthquake.
Thus, it is noted that the seismic response of foundations is significantly affected by their location, the weight of their structures, and the presence of distances between them. Foundation designs are a crucial element in constructing safe and effective structures, especially in areas susceptible to such natural events. Understanding patterns of movement and soil compaction can help engineers design robust foundational systems capable of withstanding the challenges that arise in these environments.
The Importance of Foundation Stability in Facing Earthquakes
The structural stability of buildings is one of the essential elements that ensure the safety of structures during natural disasters, especially earthquakes. The success of any construction project depends on its ability to withstand the forces resulting from ground movement. One of the most influential factors on the stability of buildings is the type of soil on which they are constructed. Liquefied soil, for example, can lead to significant settlements during an earthquake, which may result in building collapse. Therefore, civil engineers must devise effective strategies to mitigate the effects of liquefied soil.
Design strategies include using construction materials that contribute to enhancing the load-bearing capacity of buildings, in addition to assessing the geological characteristics of the soil before the construction process. Techniques such as laboratory testing and digital assessment are employed to predict how structures will respond under the influence of earthquakes.
Historically, there have been numerous incidents that illustrate the importance of these standards. For example, the earthquake that struck Luzon in the Philippines in 1990 showcased various soil effects on building stability. Analyzing the experiences of what happened during this earthquake can provide valuable lessons on how to improve building designs in areas susceptible to such risks.
Modern Technologies in Estimating Seismic Risks
Modern technology in measuring seismic risks is an important factor in civil engineering fields. Advanced digital models have been developed, enabling engineers to simulate soil behavior and its response under earthquake influences. These systems involve using real data derived from site tests in conjunction with continuous monitoring models during earthquakes. This research allows engineers the opportunity to accurately predict the performance of structures and plan for more efficient foundations.
Current projects highlight the application of machine learning and artificial intelligence techniques, contributing to improvements in estimation and prediction methods. These applications can analyze vast amounts of data and interpret patterns that may otherwise not be apparent. They also enable the use of exciting precision testing techniques, such as dynamic pressure tests, which provide accurate measurements of soil conditions.
New research in this field indicates the importance of collecting data before and during an earthquake to better understand how structures are affected and help them withstand seismic forces. These techniques have been utilized in multiple construction projects worldwide, leading to noticeable improvements in building stability and reduced damages resulting from earthquakes.
Foundation Strengthening Strategies to Mitigate Settlement Effects
Building structures require proactive designs against the negative effects resulting from settlement during earthquakes. One of these strategies is strengthening foundations using various techniques such as deep foundations or using reinforced materials. These techniques contribute to evenly distributing loads and reducing direct risks to the structures.
For example, some projects have utilized the piling method, where piles are installed in deeper soil layers to achieve stability. Consequently, pressure on the surface is reduced, and the piling structures will act as primary supports during seismic shocks.
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There is a need to develop environmentally friendly systems to enhance structural performance. By introducing sustainable materials and innovative techniques, the environmental impact of construction can be reduced while at the same time increasing safety. For example, the use of specialized concrete allows for the development of new dimensions in the load-bearing capabilities of buildings, thereby reducing the chances of injuries and damages.
Lessons Learned from Historical Earthquakes to Guide Building Practices
Presenting lessons learned from historical earthquakes is vital for improving future building practices. Several historical earthquakes have demonstrated vulnerabilities in structures, prompting a reconsideration of design methods. Many environmental disasters, such as the Niigata earthquake in Japan in 1964 or the San Francisco earthquake in 1906, provided rich information for analysis, illustrating how structures can fail and how necessary prevention protocols can be implemented.
Research and studies launched after each earthquake have provided an important database for understanding the behavior of buildings under stress. Moreover, the lessons learned have been integrated into determining new building standards, contributing to the reduction of risks in new constructions. The use of big data analytics in assessing the seismic performance of historical buildings is a field where investments have increased to improve seismic protection efficiency.
All these steps point to the importance of integrated design thinking that incorporates civil engineering, architecture, and geology to craft effective solutions for dealing with natural phenomena. Thus, reducing seismic risks becomes a shared responsibility that transcends all disciplines and sectors of architecture.
Source link: https://www.frontiersin.org/journals/built-environment/articles/10.3389/fbuil.2024.1495499/full
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