Foundation System Research Articles

Geotechnical seismic isolation based on high-damping polyurethane: centrifuge modelling

Geotechnical seismic isolation (GSI) is a new category of low-damage resilient design methods that are in direct contact with geomaterials and of which the isolation mechanism primarily involves geotechnics. Various materials have been explored for placing around the foundation system in layer form to facilitate the beneficial effects of dynamic soil-foundation-structure interaction, as one of the GSI mechanisms. To reduce the thickness of the GSI foundation layer and to ensure uniformity of its material properties, the use of a thin and homogeneous layer of high-damping polyurethane (HDPU) was investigated in this study via centrifuge modelling. HDPU sheets were installed in three different configurations at the interface between the structural foundation and surrounding soils for realising GSI. It was found that using HDPU for GSI can provide excellent seismic isolation effects in all three configurations. The average rates of structural demand reduction amongst the eight earthquake events ranged from 35 to 80%. A clear correlation between the period-lengthening ratio and the demand reduction percentage can be observed amongst the three GSI configurations. One of the configurations with HDPU around the periphery of the foundation only is particularly suitable for retrofitting existing structures and does not require making changes to the structural systems or architectural features.

Elastic foundation-introduced defective phononic crystals for tunable energy harvesting

Defective phononic crystals offer the advantage of concentrating elastic waves, thereby enhancing the potential for piezoelectric energy harvesting (PEH). However, a key limitation is their reliance on a fixed operating frequency, rendering them susceptible to the prevailing vibration environment. To surmount this constraint, this study introduces a novel approach involving a tunable elastic foundation system for defective phononic crystal structures. The newly developed phononic crystal is fashioned by integrating a periodically elastic foundation beneath a uniform beam. A defect is induced by selectively removing specific elastic foundations and integrating piezoelectric components. Explicit analytical solutions are established through the transfer matrix method and the spectral element method, which are subsequently corroborated via comparison with finite element results. The findings underscore that the periodic elastic foundations impart bandgaps in the elastic wave band structure. The absence of specific elastic foundations results in the emergence of distinct defect modes. Additionally, frequency response analysis exposes the potential for energy enhancement, albeit with inherent variations. Noteworthy is the revelation that manipulating the stiffness of the elastic foundation triggers shifts in the resonant frequency of the output voltage. Therefore, the proposed tunable elastic foundation system exhibits promising potential to engender versatile and adaptive phononic crystal configurations, thereby advancing the domain of PEH.

Liquefaction and performance of foundation systems in Iskenderun during 2023 Kahramanmaras-Turkiye earthquake sequence

On February 6, 2023, two devastating earthquakes occurred on the East Anatolian Fault, Turkiye. The earthquakes had severe impacts on civil engineering structures in Iskenderun, Hatay. Reconnaissance studies were performed in Iskenderun to document and evaluate the performances of the different foundation systems and improved ground. Several soil liquefaction cases, including a boulevard, a mosque complex, fishing shelter, and military quarters were observed and documented along with the ground conditions and surface ejecta characteristics. The site observations during the reconnaissance study showed that the application of the unreinforced concrete piles was not a proper foundation solution against seismic loading and did not perform well. Whereas foundation systems including reinforced barrette piles and improved sites with jet grout columns were observed to perform quite well with negligible/no deformations. Observations at several structures indicate that conventional pile foundations also performed well, however structures built on deep foundation systems together with prior jet grout improved sites performed notably better.

Geosynthetic-encased columns (GEC): A proven case study over 30 years

The construction of embankments on very soft soils is a challenge due to the low shear strength, low permeability, high compressibility, and high-water content of the subsoil. The surcharge load imposed by the embankment can result not only in a local or total loss of stability but also in unacceptable settlements and horizontal deformations or thrusts, which could endanger nearby structures. To overcome these problems, different construction methods are applicable. One particularly interesting and still innovative foundation system is the use of geotextile encased granular columns, which can be considered “State-of-the-Art” in Europe. It was developed and introduced in 1994, and since then many major projects have been realised using geotextile encased columns (GEC). The overall loads and stress concentrations above the column heads induce outwardly directed radial horizontal stresses in the columns. The particularity of the GEC system is that these stresses are counteracted not only by the inwardly acting pressure of the soft soil but also –most importantly – by the radial resistance of the tensile stiff geotextile casing. This paper briefly describes the GEC system and includes the description of a few notable projects using GEC as a foundation system: land reclamation at the Airbus site in Hamburg, Germany, and the Second Niger Bridge in Africa. The geotechnical challenges, design basis, and what can be considered the most important findings of each of these projects are also discussed in this paper.

Основні вектори розвитку зеленої енергетики в Україні: тарифна політика

The aim of the article is to form a scientific and practical basis for determining the main vectors of development of green energy in Ukraine, related to the definition of tariff policy. According to the results of the carried out study, it is proved that the prospects for the development of the world energy sector and the associated threats of irreversible negative impact on the environment are among the most pressing problems of the globalization process. All countries of the world are faced with the practical task of changing the paradigm of development, changing the system of basic ideological foundations for the use of industrial energy and «transparency» of resource management that meet the requirements of open and transparent activities based on innovative and progressive knowledge and technologies. All this requires the development of alternatives that will ensure the transition of world economies to sustainable development. Programs for the development of renewable and alternative energy sources are formed and implemented in almost all developed countries. However, the unresolved number of methodological issues regarding the introduction of renewable and alternative energy sources, the lack of relevant experience, the insufficient development of the regulatory framework at all levels and bureaucratic obstacles hinder the introduction of renewable and alternative energy sources in Ukraine, which justifies the relevance of this study. The article states that the problems of renewable energy development are discussed at different institutional levels. The constant threat of a crisis in the supply of oil, the threats associated with the development of nuclear energy, and the concern of modern society about environmental, and therefore climate problems, have led to the emergence of modern energy policy, the purpose of which is to create renewable green energy without greenhouse gas emissions into the atmosphere. The most important role for the sustainable development of the world economy be played by energy, which is the basis for the functioning of the economy and society and should ensure the growth of the world’s population and economic development with an average annual GDP growth rate.

Smarter Aging: Developing A Foundational Elderly Activity Monitoring System with AI and GUI Interface

Smarter Aging: Developing A Foundational Elderly Activity Monitoring System with AI and GUI Interface

Machine learning model based on radiomics features for AO/OTA classification of pelvic fractures on pelvic radiographs.

Depending on the degree of fracture, pelvic fracture can be accompanied by vascular damage, and in severe cases, it may progress to hemorrhagic shock. Pelvic radiography can quickly diagnose pelvic fractures, and the Association for Osteosynthesis Foundation and Orthopedic Trauma Association (AO/OTA) classification system is useful for evaluating pelvic fracture instability. This study aimed to develop a radiomics-based machine-learning algorithm to quickly diagnose fractures on pelvic X-ray and classify their instability. data used were pelvic anteroposterior radiographs of 990 adults over 18 years of age diagnosed with pelvic fractures, and 200 normal subjects. A total of 93 features were extracted based on radiomics:18 first-order, 24 GLCM, 16 GLRLM, 16 GLSZM, 5 NGTDM, and 14 GLDM features. To improve the performance of machine learning, the feature selection methods RFE, SFS, LASSO, and Ridge were used, and the machine learning models used LR, SVM, RF, XGB, MLP, KNN, and LGBM. Performance measurement was evaluated by area under the curve (AUC) by analyzing the receiver operating characteristic curve. The machine learning model was trained based on the selected features using four feature-selection methods. When the RFE feature selection method was used, the average AUC was higher than that of the other methods. Among them, the combination with the machine learning model SVM showed the best performance, with an average AUC of 0.75±0.06. By obtaining a feature-importance graph for the combination of RFE and SVM, it is possible to identify features with high importance. The AO/OTA classification of normal pelvic rings and pelvic fractures on pelvic AP radiographs using a radiomics-based machine learning model showed the highest AUC when using the SVM classification combination. Further research on the radiomic features of each part of the pelvic bone constituting the pelvic ring is needed.

Dynamic soil-structure interaction analyses of a foundation system based on rigid inclusions

Dynamic soil-structure interaction analyses of a foundation system based on rigid inclusions

Available methods for the identification of the foundation system and depth in case of existing bridges

The new Italian “Guidelines for classifying and managing the risk, assessing the safety and monitoring existing bridges” (LLG) are based on a multi-level and multi-risk approach. The Level 0 of this approach is focused on collecting the basic information about both the bridge under consideration and the environment in which it is located (for the assessment of seismic, hydraulic and landslide hazards). These can be retrieved in the project documentation, via available seismic/hydraulic/landslide hazard maps, accelerometric and hydraulic monitoring stations and interferometric data. The Level 1, instead, consists of carrying out visual inspections and compiling some inspection forms for each risk (structure-foundation, seismic, hydraulic and landslide). Then, in the Level 2 all the collected data are organized and used for defining the so-called Class of Attention (5 classes: low, low-medium, medium, medium-high, high) for each risk and the overall Class of Attention. Based on the experiences gained in the last three years by the geotechnical staff of the University of Pisa (member of the FABRE Consortium) one of the main issues encountered in the Levels 0 and 1 (and therefore in the Level 2) was the difficulty to properly identifying the type, geometry, layout, material, and depth of the foundation system of existing bridges. This contribution is focused on describing Non-Destructive Tests, such as Low-Strain Surface tests, Low-Strain Down-hole tests, Parallel Seismic testing (PS) and Electrical Resistivity Tomography (ERT) with the aim of showing main capabilities, limitations, and field of application. These techniques can be useful to improve the classification of existing bridges according to the new Italian Guidelines.

Using shear modulus to predict the bearing capacity of strip foundations on sand

This paper reports results of a study to predict load-settlement behaviour of strip foundations on a dry uncemented sand using only soil stiffness data, under both working loads and extreme loads. This involved predicting the strength of a foundation system without using any strength parameters. A non-linear stepwise load-settlement prediction algorithm was utilised, which used the small-strain shear modulus of layers below the footing, a suitable stiffness modulus reduction curve and elasticity theory. The algorithm was adapted to predict the ultimate bearing capacity, as well as to construct astress-settlement curve and determine the bearing pressure experienced beneath a foundation at any particular settlement. The method was evaluated using two different sets of modulus reduction curves, for small-scale model foundations on loose, medium dense and dense sand. Model tests were conducted at 1g. Particle Image Velocimetry (PIV) was used to observe strains within the soil during loading. These strains were used to calculate the shear modulus of discrete layers throughout loading and back-estimate the layer small-strain shear moduli. Additionally, the mode of shear failure for each test at ultimate bearing capacity was observed using PIV. Modulus reduction curves that initially degrade shear modulus rapidly beyond the elastic threshold strain (0.001%) gave superior predictions under the given conditions. Using such curves, ultimate bearing capacity predictions produced errors of 0.4% to 10.8%. Using the same input parameters, stresssettlement predictions were of satisfactory accuracy over the entire settlement range.

One‐Dimensional‐Convolutional Neural Network (1D‐CNN) Based Reliability Analysis of Foundation Over Cavity Incorporating the Effect of Simulated Noise

This paper presents a thorough reliability assessment of cavity foundation systems involving the generation of 272 datasets using Plaxis 2D automation. The parameters were systematically varied across feasible ranges, and Sobol‐based sensitivity analysis identified the negligible influence of the soil modulus of elasticity (E) on subsequent reliability analyses. A robust 1D‐CNN surrogate model was developed to predict the critical foundation responses by integrating Gaussian white noise to simulate real‐world uncertainties. A log transformation with 1,000 bootstrap samples was chosen for resampling non‐normally distributed data. This study employed a novel approach utilising 1D‐CNN regressor models for bearing capacity (BC) prediction, achieving promising results with R2 values of 0.953 and 0.945 for BC in the training and testing phases, respectively. Bootstrapping resampling facilitates reliability analysis preparation and ensures robustness in handling complex data. Simulated noise varied with specific variance (p) from 0.01 to 0.5, allowing the examination of model efficacy under varying noise levels. Both the Monte Carlo Simulation (MCS) and first‐order reliability method (FORM) were employed, revealing a reliability index (β) of 2.046 for FORM and 2.066 for MCS. This indicates a 0.976% increase in β and a 75% increase in the probability of failure transitioning from FORM to MCS, underscoring the model’s sensitivity to analytical methods.

Three-Dimensional Analyses of Long-Term Settlement of Storage Tanks Supported by a Large Piled-Raft Foundation System

Three-Dimensional Analyses of Long-Term Settlement of Storage Tanks Supported by a Large Piled-Raft Foundation System

Geotechnical Preliminary Design of Onshore Wind Turbine Foundations

A simplified geotechnical design procedure for foundations of onshore wind turbines is often beneficial because it can provide the types and sizes of foundations required to perform financial feasibility analysis of a project, and can also be used for preliminary design. This study presents a simplified method for designing onshore gravity-based foundations based on limited required data, namely, loads acting on foundations, data provided by manufacturers, and soil properties. The detailed design issues that may be essential for the final design are also discussed. A flowchart of the design process is also presented to visualize the geotechnical design of such foundations. The required calculation procedures can be easily carried out either through a series of spreadsheets or simple hand calculations. An example problem explaining the design of onshore wind turbine foundations was presented to demonstrate the proposed calculation procedure. The data used for the calculations were obtained from the literature. The proposed flowchart provides a quick way for the preliminary design of foundations of onshore wind turbine foundations. The foundation system obtained from the preliminary geotechnical design was numerically modeled using Plaxis 3D software. The global stability of the foundation system under Ultimate Limit State (ULS) loads and soil pressure developed under the foundation were calculated. The soil pressure beneath the foundation under Serviceability Limit States (SLS) loads and the total settlement and rotation of the foundation were calculated. The results obtained from the Plaxis 3D software and those obtained from the preliminary design were in agreement.

PENGEMBANGAN MANAJEMEN SEKOLAH BERBASIS SISTEM INFORMASI MANAJEMEN MELALUI APLIKASI MY IRSYADUL IBAD

This study aims to analyze the implementation of an integrated information system in all schools under the Irsyadul Ibad Foundation and the impact of implementing an education management information system on student attitudes covering moral and social attitudes. This study was conducted by 6 educational units of the Irsyadul Ibad Foundation, Kab. Pandeglang Banten Province. This study uses qualitative methods with observation techniques, interviews and document studies. The results of this study illustrate that the application of the my Irsyadul Ibad education information system can assist educational institutions in assisting student learning activities, relationships with parents, tidying up the management and financial system of school units and foundations. By using this information system application, students' learning activities can be controlled by parents and their progress can be recorded in real time. The existence of this information system also makes it easier for parents to meet their financial obligations to the institution. The application of this management and administrative information system makes it easy for teachers to identify attitudes and develop students' attitudes.

TABAKALI ZEMİNLERDE TÜNEL AÇMANIN KAZIKLI TEMEL ÜZERİNDEKİ ETKİSİ

It is believed that tunnel construction will have significant and intricate effects on structures supported by piles. One of the most popular approaches to research is numerical modeling. This study looked into how tunnel placement affected piled foundation systems in layered soil. In sixteen models utilizing PLAXIS 2D finite element analysis, a square foundation with dimensions of 26×26×2 meters and a load of 200 kPa was applied to the soil profile representing Istanbul's Avcilar district. In the 11×7 formation, two groups of piles were created, each with a fixed spacing of 2.4 meters and varying diameters of 0.8, 1.2 with 30 meters in length. The piles were placed 4 meters out of the plane and 1 meter from the edges. For every pile group, a 10-meter-diameter tunnel was examined at two various Z⁄D and four various X⁄D from the foundation's center to determine the influence of the tunnel location. According to the results, the surface total settlement values decrease, and the differential settlements increase as the tunnel is positioned farther in the x direction from the foundation center axis. The pile's bending moment slightly decreases as the tunnel's horizontal location gets farther away from it. The tunnel's effect decreases with increasing distance within the influence zone. Tunnel settlement cannot be significantly reduced by deepening the tunnel or increasing the pile's diameter.

Reliability Analysis of Bearing Capacity of Soil of Combined Pile Raft Foundation (CPRF) of Historic Dharahara

When the raft foundation alone does not fulfil the design requirement, it may be possible to enhance the performance of the raft by economical addition of piles to transfer the heavy load to soft soil with a rather low total or differential settlement called a combined pile raft foundation (CPRF). The proposed twenty-one storey Dharahara tower at Sundhara, Kathmandu is being constructed with CPRF.This paper focuses on the reliability index, the probability of failure and reliability of Dharahara. Statistical analysis is carried out to determine the mean and variance of log-normally distributed geotechnical uncertainty parameters cohesion, unit weight, friction angle and the normally distributed loading on the foundation. First, the limit equilibrium performance function equation of bearing capacity is prepared using a First Order Reliability Method (FORM) and then solving the value of reliability index by coding on C Programming Language. Obtained value is validated with Euro Code-Basis of Structural Design. The results show that the reliability of the designed foundation system of Dharahara is 0.99999872% and the probability of failure is 0.00000128%. Sensitivity analysis is performed by varying uncertainty parameters and the result shows that friction angle is more sensitive than the other three parameters.

Load Test on Combined Pile and Cap / Pad Foundation System on Compressible Calcareous Sand and Comparison with FEM Modelling

An optimum type of foundation is expected to support 2 – 3 stories residential house on reclamation area to avoid deep foundation. The foundation will sit on engineering fill that constructed with calcareous sand which is classified as compressible sand. Below that part, at the original ground medium density sand and very soft marine clay is found stratified. Typical column in the residential building will have about 100 tons load intensity and based on this project, the design load for a single pile is 32 ton. Since no additional compression on soft clay layer is expected after building construction, than combine cap/pad foundation with short pile 6.5 m length is proposed. Load test with stress cell for this combine pile and cap/pad foundation was performed. The load test result show that interpretation using Chin’s and Mazurkiewicz’s Method obtained that the combined pile and cap/pad foundation’s ultimate bearing capacity of 112 – 119 tons. Analysis using stress cell data shows that the cap/pad carry about 31.8 % of the total load. Finite element analysis with axisymmetric condition conducted to study load distribution on combine pile and cap/pad foundation system. Analysis result was show that the cap or pad can carried about 38.1% of design load during testing. The 6.3% deviation between the stress cell and FEM results could be attribute by the assumption when calculating the load acting on cap/pad foundation. The stress cell analysis used the assumption that the load carried by the cap/pad foundation was uniform while the FEM results showed a non-uniform load.

Did It Go Accordingly? A Case of Community-Based Learning Sulam on Stock Trading in Malaysia

Community-based learning (CBL) has become an integral part of educational methodologies, consistently being incorporated into teaching, and learning pedagogies. This approach has proven effective in broadening the scope of learning, particularly when integrated within the local community. This research examines the feedback received from members of the community engaged in the CBL stock trading project. Underpinned by Kirkpatrick’s Four-Level Model, this paper assessed (1) the community’s reactions and learning, (2) the community’s learning, (3) the community’s behavior, and (4) the results. A total of 94 participants were coached by 179 bachelor’s degree students in applied investment management. The students delivered five modules to the respective participants within three months. The findings show that the participants had a positive outlook on the project, although there was a poor response that potentially posited a loophole in CBL. This research provides more insight into the study of community-based learning at Service-Learning Malaysia-University for Society (SULAM) derived from High-Impact Educational Practices. Furthermore, it is suggested by this research that a foundational system of regulatory guidelines must be implemented across the program. This would serve to establish checks and balances, enhancing both student adherence to the program and community engagement.

COMBINED SLAB-PILE FOUNDATION

Solid reinforced concrete slab foundations are commonly employed in the construction of multi-story frame and panel buildings on natural grounds, as well as in industrial structures such assilos, elevators, chimneys, steel reactors, and more.One significant advantage of monolithic foundations is their ability to be used on weak and uneven ground bases. These foundations can distribute uneven loads over a considerable area, redistributingthem to equalize the inevitable differential settlements of individual foundations. On soft and uneven soils, slab foundations are not only used to mitigate deformations but also to protect against highgroundwater, creating what is known as a "floating" foundation.It has been demonstrated that the combined slab pile foundation (CSPF) is an effective development in the field of foundation construction. CSPF constitutes a foundation system comprising a "pile field – slab grillage – soil base," where piles bear a portion of the building load, and the slab grillage functions as a foundation slab. CSPF can be interpreted as a monolithic slab supported by piles of various types arranged in the form of a pile field, strips,clusters, or individual piles. Various types of piles, including "barrette" piles, can be used for CSPF foundations.Considering the soil resistance beneath the slab grillage in the deformation calculations and loadbearing capacity of combined slab-pile foundations provides a reserve for enhancing their economic efficiency. This includes reducing the number ofpiles, lowering the consumption of steel reinforcement, and decreasing the thickness of the grillage.However, the implementation of CSPF in construction is hindered by the limited theoretical research, necessary regulatory framework, and design experience for such structures.The determination of design parameters for CSPF is carried out using the method of successive approximations. By specifying the area of the slab grillage and defining the pile length and spacing, the number of piles in the foundation, the settlement ofan individual pile, and the design load on the pile are calculated (initially assuming that all piles bear 70-80% of the total load).

Experimental and Numerical Analysis of Laterally Loaded Single- and Double-Paddled H-Piles in Clay

An efficient foundation system of single- or double-paddled H-piles (PHPs), which comprises steel H-piles fitted with specially configured steel plates (paddles), is proposed to support sound walls subjected to wind loading. The lateral responses of single-paddled (SPHPs) and double-paddled H-piles (DPHPs) installed in clay is evaluated using a comprehensive assessment of the foundation performance via a full-scale lateral load testing program, alongside extensive three-dimensional (3D) nonlinear finite element (FE) analysis. The comparison between the calculated and measured responses of the PHPs demonstrates that the developed numerical model accurately depicts the response of the PHPs under lateral load. The validated numerical model is then used to evaluate the effect of the soil consistency on the lateral response and capacity of the PHPs. The influence of the paddles’ configuration on the lateral response and capacity of the PHPs is also evaluated. Furthermore, the change in the PHP lateral stiffness due to adding a second paddle is also examined. Finally, the influence of the plates on the surrounding soil is investigated by analyzing the formation of the strain field around the pile and evaluating the extent of the soil influence zone at different plate-width-to-pile-flange-width ratios (Wp/Wf). The result of this study indicates that adding plates contributes significantly to the lateral capacity of PHPs in clay and reduces the maximum bending moment. The parametric study reveals that the top 5–6 Wp of the soil have a significant effect on the lateral response of the proposed H-pile. Based on the outcomes of the field tests and numerical analysis, optimal geometrical parameters for paddles are proposed.