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Historically, it has been demonstrated that bridges may be vulnerable to fire, and in many circumstances, resulting damage might not be apparent, and bridges could maintain acceptable levels of serviceability. In the absence of proven assessment tools and given the limited research that addresses bridge fire, research that better understands response and strives to improve highway bridge resiliency to fire is needed. Extending the work carried out during an earlier research stage, the present study focused on investigating performance of bridge pier columns that survive fire under coupled vehicle collision and air blast. Numerical models of single reinforced concrete columns supported by a pile foundation system and surrounded by air and soil volumes were created using LS-DYNA. As explicit solvers such as those available in LS-DYNA are infrequently used for fire analysis, an indirect two-step approach that integrated heat transfer and structural analyses was developed and validated against published fire-induced impact and blast test results. A parametric study that examined the effects of various fire exposure conditions and column diameters was completed. Performance was comprehensively assessed based on various structural response parameters, which included failure modes, lateral displacement, residual axial capacities, and shear demand-to-capacity ratios. Column damage was then categorized into six levels to qualitatively assess column performance under the aforementioned multi-hazards. The developed modeling approach was shown to be viable, and results indicated that larger column diameters could potentially remain in service in their final damage states after being repaired for fire durations of less than 120 min. [ABSTRACT FROM AUTHOR]

Pile foundations frequently endure dynamic loads, necessitating an in‐depth examination of the cyclic shear properties at the pile–soil interface. This study involved a series of cyclic direct shear (CDS) tests conducted on sand and concrete with irregular surface, utilizing varying displacement amplitudes (1, 3, 6, and 10 mm) and joint roughness coefficients (0.4, 5.8, 9.5, 12.8, and 16.7). Discrete Element Method (DEM) models, informed by experimental data, facilitated mesoscopic mechanical response analyses. Findings indicate that the sand–concrete interface undergoes softening, with hysteresis loops' morphology dependent largely on displacement amplitude. A maximum ultimate shear stress corresponds to a specific critical surface roughness, while the initial tangent modulus escalates with increased concrete roughness. Volume variations of the specimen inversely correlate with displacement amplitude and directly with surface roughness. As displacement amplitude expands, there is a reduction in the maximum shear stiffness and an elevation in the maximum damping ratio. Empirical formulas for the surface roughness and normalized shear stiffness were proposed. Larger displacement amplitudes result in more substantial shear bands and heightened energy dissipation, yet the incremental energy ratio remains largely unaffected. Predominant energy dissipation mechanisms include both slip and rolling slip, with the former surpassing the latter in energy dissipation capacity. The anisotropy directions of contact normal, normal contact forces, and tangential contact forces consistently fluctuate with shear direction alterations. [ABSTRACT FROM AUTHOR]

Many instances of severe damage to pile foundations and pile-supported infrastructures have been caused by liquefaction-induced lateral spreading during major earthquakes, particularly in coastal areas. The current study conducted a series of shaking table experiments to determine the differences between the responses of a free- and a fixed-head group pile under lateral spreading in the presence of finned and circular protection piles. The results indicated that the maximum bending moment tolerated by nonprotected free-head piles was more than that by fixed-head piles. Also, reductions in bending moments were more significant in free-head piles in the presence of protection piles than in fixed-head piles. The bending moments of front and rear piles under restricted pile head conditions were reduced by about 31% and 21%, respectively, when finned piles were used as protection piles, while they were 34% and 42%, respectively, under free-head conditions. Furthermore, modification factors of recommended lateral pressure distribution along a pile per the current design code were determined for the protected and nonprotected free- and fixed-head pile groups of the current study and it was observed that this modification factor (CL) was highly dependent on the location of piles in a group, pile head conditions, and the presence of protection piles in the lateral spreading analysis. [ABSTRACT FROM AUTHOR]

The shear creep characteristics of the contact surface between the permafrost and the structure play an important role in the study of the law of deformation and the measures for the prevention and control of pile foundations. In order to study the creep law and the development tendency of the contact surface between permafrost and concrete, it is necessary to establish an accurate creep model. In this study, based on the Nishihara model, a nonlinear element and damage factor D were introduced to establish an intrinsic model of permafrost-concrete contact surfaces considering the effect of shear stress. Creep tests with graded loading of concrete and frozen silt with different roughness at -1°C were conducted using a large stress-controlled shear apparatus. The adequacy of the model was checked using the test data and the regularity of the parameters of the model was investigated. The results show that the creep curves of the contact surface obtained with the improved Nishihara model agree well with the test results and can better describe the whole process of creep of the contact surface of frozen concrete. The analysis of the experimental data shows that: the roughness of the concrete has an inhibiting effect on the creep deformation of the contact surface, When the roughness R varies from 0 mm to 1.225 mm, the specimen corresponds to a long-term strength of 32.84 kPa to 34.57 kPa. For the same roughness and creep time, the creep deformation of the contact surface is more significant with the increasing shear stress τ. The results of the study can provide a theoretical basis for the design and numerical simulation of pile foundations in permafrost regions. [ABSTRACT FROM AUTHOR]

The foundation is the lower part of a structure used as a load distributor for the loads generated by the upper structure, which are then transmitted into the hard soil layers. The selection of foundation types in building construction must consider the type and characteristics of the soil at the construction site to avoid construction failures. This analysis is conducted to determine the bearing capacity of pile foundations using analytical and finite element methods. The type of foundation used in this analysis is a pile foundation with a pile length of 8 meters and a pile diameter of 0.4 meters. For the analytical calculation, Standard Penetration Test (SPT) data obtained from PT. Adhi Karya (Persero) for the Infrastructure Green House Biodiversity LIPI Cibinong-Bogor project are used, employing the analytical method (Alpha Method) and the finite element method with the assistance of Plaxis 2D V.8 software. The results of the analysis show that the bearing capacity of the group pile foundation (Qg) for a pile diameter of 0.4 meters and a pile length of 8 meters on clayey soil, based on SPT data using the analytical method (Alpha Method), is 60.432 tons. Meanwhile, the bearing capacity of the horizontal pile foundation using the Broms method is 6.03 tons. The bearing capacity obtained using the Finite Element Method yields an ultimate load on the group pile (Qq) of 57.89 tons. The bearing capacity of the group pile foundation (Qg) from both sets of data, with a difference of 2.5%, meets the requirement, being greater than the axial load (P) of 42.6 tons that must be supported. [ABSTRACT FROM AUTHOR]

This paper investigates the interference effect of closely spaced foundations on the modulus of subgrade reaction (k) and provides an insight into some of the factors affecting the k-value of a raft foundation when other foundations (isolated footings or other identical rafts) are closely placed on both sides. The investigation adopted a three-dimensional, non-linear, finite-element numerical analysis based on a case study of a residential project with several multi-storey buildings constructed on sand underlain by weathered limestone. A site-specific ground investigation was conducted to determine soil properties, which were used to construct three-dimensional numerical models to simulate different arrangements of foundations and estimate the corresponding k-values. The results show that the k-value starts to decrease when the spacing between the foundations becomes less than three times the raft width, and the percentage of reduction in k-value increases in a non-linear way as the spacing decreases further. In addition to spacing, the study revealed that the effect of adjacent foundations depends on their size and the magnitude of their applied pressure. The case study provides a framework for developing a correction factor that can be applied to k-value for improving the structural and geotechnical design of closely spaced shallow foundations. [ABSTRACT FROM AUTHOR]

In projects such as highway bridges and offshore wind farms, understanding the kinematics of soil layers and their displacement is important for accurately predicting the behavior of caissons and monopiles under lateral loads. To better predict the distribution of soil deformation around the foundations, this paper presents an extensive usage of the energy-based variational method in laterally loaded deep foundations (caissons or monopiles) with very large diameters. By adding an assumption of soil deformation in multilayered soils, the displacement distribution around the foundations can be better described. The responses of deep foundations were obtained by minimizing the potential energy and virtual work of the foundation-soil system. After that, static lateral loading tests on two caissons with the same embedment depth of 36 m and the same diameter of 6 m were performed, and the displacement field in soils and the deflection profiles of the caissons were measured. Results show that the lateral displacement and the decay distribution fields calculated from the theory in this paper agree with the measured data from the static loading tests and the corresponding finite differential method (FDM) results. At last, a series of case studies performed by MATLAB and FDM analyses were also conducted to study the influence of uz on the response of foundations, as well as the influence of foundation parameters and soil modulus on the value of ϕz. [ABSTRACT FROM AUTHOR]

Pile foundations are still the preferred foundation system for high-rise structures in earthquake-prone regions. Pile foundations have experienced failures in past earthquakes due to liquefaction. Research on pile foundations in liquefiable soils has primarily focused on the pile foundation behavior in two or three-layered soil profiles. However, in natural occurrence, it may occur in alternative layers of liquefiable and non-liquefiable soil. However, the experimental and/or numerical studies on the layered effect on pile foundations have not been widely addressed in the literature. Most of the design codes across the world do not explicitly mention the effect of sandwiched non-liquefiable soil layers on the pile response. In the present study, the behavior of an end-bearing pile in layered liquefiable and non-liquefiable soil deposit is studied numerically. This study found that the kinematic bending moment is higher and governs the design when the effect of the sandwiched non-liquefied layer is considered in the analysis as opposed to when its effect is ignored. Therefore, ignoring the effect of the sandwiched non-liquefied layer in a liquefiable soil deposit might be a nonconservative design approach. [ABSTRACT FROM AUTHOR]

Exosomes continue to attract interest as a promising nanocarrier drug delivery technology. They are naturally derived nanoscale extracellular vesicles with innate properties well suited to shuttle proteins, lipids, and nucleic acids between cells. Nonetheless, their clinical utility is currently limited by several major challenges, such as their inability to target tumor cells and a high proportion of clearance by the mononuclear phagocyte system (MPS) of the liver and spleen. To overcome these limitations, we developed "Smart Exosomes" that co-display RGD and CD47 p110–130 through CD9 engineering (Exo Smart ). The resultant Exo Smart demonstrates enhanced binding capacity to αvβ3 on pancreatic ductal adenocarcinoma (PDAC) cells, resulting in amplified cellular uptake in in vitro and in vivo models and increased chemotherapeutic efficacies. Simultaneously, Exo Smart significantly reduced liver and spleen clearance of exosomes by inhibiting macrophage phagocytosis via CD47 p110–130 interaction with signal regulatory proteins (SIRPα) on macrophages. These studies demonstrate that an engineered exosome drug delivery system increases PDAC therapeutic efficacy by enhancing active PDAC targeting and prolonging circulation times, and their findings hold tremendous translational potential for cancer therapy while providing a concrete foundation for future work utilizing novel peptide-engineered exosome strategies. Schematic illustration of ExoSmart enhances pancreatic cancer (PDAC) targeting while increase of evasion of mononuclear phagocyte system (MPS) clearance. (A) Diagram of ExoSmart; (B) Schematic diagram of ExoSmart working model; (C) Fluorescence imaging of liver, spleen and tumors of PDAC orthotopic mice that receive DiR stained exosomes via i.v. injection; (D) Immunofluorescence analysis of exosome in liver, spleen and tumors using anti-hemagglutinin (HA) antibody. [Display omitted] • A "Smart Exosome" that co-display RGD and CD47 p110–130 through CD9 engineering (Exo Smart ) was created. • The Exo Smart enhanced binding capacity to αvβ3 on PDAC cells, resulting in amplified cellular uptake in PDAC. • The Exo Smart significantly reduced liver and spleen clearance of exosomes by inhibiting macrophage phagocytosis. • The Exo Smart drug delivery system significantly increased PDAC therapeutic efficacy. [ABSTRACT FROM AUTHOR]

Functionally graded materials (FGMs) are commonly utilized in construction projects. They enhance the performance of functionally graded beams (FGBs) under various loading conditions. Therefore, the incorporation of variable-section FGBs theory into the analysis of structural and soil interactions is crucial for advancing engineering applications. Employing the variational principle and the transfer-matrix method, and considering the shear stiffness of the axially FGB structure itself, along with the continuity and shear strength of the soil, a semi-analytical solution for displacement and internal force of axially FGBs on Pasternak foundation (termed as P–T model) is derived in this paper. The semi-analytical solution is subsequently compared with finite difference solution results from prior studies, affirming the accuracy and precision of the proposed computational theory. The P–T model degenerates to the Winkler–Timoshenko model (W–T model) when the foundation's shear layer stiffness is set to zero. Additional analysis is conducted on displacement and internal force variation when the beam stiffness follows different distribution along the axial direction. The results indicate that an asymmetrical distribution of stiffness on either side of the midpoint could increase the displacement at the middle section. Furthermore, when the beam stiffness adheres to a Gaussian distribution along the axial direction of the beam, a significant increase in displacement at the boundary position of the beam is observed. The proposed method is then integrated with the Mindlin stress solution to evaluate construction impact on an existing tunnel within a foundation pit project in Shenzhen. A comparative analysis of theoretical calculations, monitoring data, and numerical simulation results exhibits substantial concurrence across the three methods. The tunnel's overall deflection adopts an "M" shape, and the computation using the variable-section FGB portrays the existing tunnel's deformation trend with heightened accuracy, diminishing the calculation error from 35 to 8.3% compared to the conventional normal section beam. [ABSTRACT FROM AUTHOR]

This study investigates the ultimate bearing capacity (UBC) of an eccentrically loaded strip footing of width, B, resting above circular dual cavities in the rock mass using the Generalized Hoek–Brown (GHB) yield criteria for the rock mass. The stability number (Ns) is determined using upper and lower-bound finite element limit analysis (FELA), incorporating an adaptive meshing technique. The study considers two configurations: symmetrical and parallel outlines based on the relative positions of the dual cavities and the footing. The effects of the numerous governing parameters, including the load eccentricity (e/B), the vertical distance of dual cavities from the ground surface (δ/B), the spacing between dual cavities (β/B), the uniaxial compressive strength of intact rock, ( σ ci /γB), geological strength index (GSI), and material constant for intact rock (mi) on the Ns are studied. The study finds that the magnitude of e/B significantly affects Ns. For symmetrical outline, Ns improves with increasing δ/B, and the effect of δ/B is insignificant when δ/B ≥ 3, corresponding to β/B = 4 irrespective of e/B. Moreover, Ns increases with β/B for δ/B ≤ 3 and e/B ≤ 0.2. However, the effect of β/B on Ns is insignificant beyond δ/B > 3, irrespective of e/B. For the parallel outline case, the strip footing achieves maximum Ns under centrally placed load (i.e., e/B = 0), regardless of β/B and δ/B values. The study presents potential failure envelopes that might include all representative cases to provide insights into the possible failure mechanism of such foundation systems. [ABSTRACT FROM AUTHOR]

In this manuscript, the long-term behaviour of piled-raft foundations (PRFs) due to the consolidation of clayey soils has been investigated by 3D finite element analysis. The validation of the numerical prototype has been carried out using the field test outcomes performed in the field laboratory and other reported results. The ultimate load capacity of the PRFs has been assessed by varying the number of piles, diameter of piles, width of raft and ground water level. Compressive loads are provided starting from an increment of 10% of the ultimate load till the ultimate load capacity of the PRFs. Settlements of PRFs have been observed till a time period of 1 month for each increment of loading and for a period of 1 year after the ultimate load capacity has been applied. The influence of load sharing behaviour, interaction effects and factor of safety on consolidation settlement of PRFs have been analysed, and predicted expressions are suggested. Average, differential and reference settlements are evaluated. Multiple linear regression analysis is implemented for estimating consolidation settlement. The proposed design equation has been validated using an example. It is inferred that load sharing ratio increased by about 34–48%, 6–19% and 11–20% with increase in the number of piles, pile diameter and width of raft in the PRF, respectively. The reduction rate of factor of safety of PRFs is insignificant and nearly minimizes to a constant value at higher settlement magnitude. The reference settlement increases from 49 to 54% as the value of load sharing ratio decreases. [ABSTRACT FROM AUTHOR]

This paper intends to investigate the effect of tunnelling on the response of a framed building on different types of foundations with the help of shake table test. For the test, effect of utility tunnel on response of scaled prototype steel building has been determined with the help of accelerometer mounted at different floors. For experimental tests, three types of foundation (isolated foundation, mat foundation, and pile foundation) and two different heights of scaled prototype steel building frame have been considered. The analysis was performed in Heavy Structural Engineering Lab at N.I.T Patna, and soil has been excavated from the campus. To consider the ovalling effect of tunnel, shake table was vibrated perpendicular to the axis of tunnel by taking El Centro N-S as input motion. After the analysis it was found that ovalling effect of circular tunnel mostly affects the displacement of building when the tunnel was situated just below the centre axis of building. Same result was found for all types of foundation. Influence of ovalling effect of circular tunnel diminished as the distance between the building frame and tunnel increases. Response of building, constructed over isolated foundation was found to be the mostly effected as compared to the building constructed over other two types of foundation, while building constructed over pile foundation was the least affected. Shake table results show that high-rise prototype scaled steel building is much affected as compared to low-rise prototype scaled steel building frame. The results help in acknowledging the fact that foundation type should be considered for investigating the effect of tunnels during seismic excitation. [ABSTRACT FROM AUTHOR]

Energy piles are gaining popularity worldwide as both pile foundations and ground source heat producers. While considerable research has been conducted on energy pile design and evaluation, implementing these approaches effectively remains challenging for engineers. This study presents a novel approach based on Load and Resistance Factor Design (LRFD) with First-Order Second-Moment (FOSM) reliability analysis and target reliability ( β T ) for energy pile design. Additionally, three soft computing techniques, namely 1D-CNN, LSTM, and Bi-LSTM, were employed to enhance the design process. To conduct this research, datasets from each model were analyzed using various statistical indices, including R2, RMSE, RMSLE, MAPE, BF, AARD, NSE, U 95 , t-stat, TIC, and PI. The results indicated that the Bi-LSTM model demonstrated superior performance for heating operations, with R2, RMSE, and RMSLE values of 0.975, 0.021, and 0.007 for training and 0.984, 0.019, and 0.006 for testing datasets, respectively. For cooling operations, the LSTM model exhibited the most suitable predictive capabilities, achieving R2, RMSE, and RMSLE values of 0.969, 0.022, and 0.008 for training and 0.982, 0.019, and 0.007 for testing datasets, respectively. Comparative analyses, including rank analysis, Williams plot, accuracy matrix, and Taylor's diagram, were performed to assess the accuracy of the proposed models. The results demonstrated that the Bi-LSTM model for heating and the LSTM model for cooling outperformed other soft computing models within the reliability-based LRFD approach for energy pile design. This research contributes to the advancement of energy pile design methodologies, providing engineers with a more efficient and reliable LRFD-based framework. The successful application of soft computing techniques further enhances the accuracy of predictions for both heating and cooling operations. Overall, the findings of this study hold significant implications for the design and evaluation of energy piles, contributing to sustainable and energy-efficient construction practices. [ABSTRACT FROM AUTHOR]

This paper aims to analyze and describe the geotechnical behavior of a piled raft foundation of a tall building (53 floors, 172.4 m high) through the monitoring of strains in the building's columns and piles, the stresses at the raft–soil interface, and the foundation settlements. Field and laboratory tests were performed, and associated with axisymmetric and three-dimensional finite element analysis to the assessment of the measured data. The monitoring of the pile strains suggests the occurrence of soil expansion, caused by the raft excavation process, up to approximately 6 months after the excavation was completed. The presence of different soil profiles under the raft, with different mechanical properties, affected the distribution of the foundation settlements and the pile loads. Initially, the average pile loads were concentrated in the perimeter elements, but, as the construction of the building evolved, they tended to become more uniform. The effect of the superstructure stiffness caused successive load redistributions in the columns, which contributed to the maintenance of the maximum angular distortion of the building within the allowable values and reduced the load difference between the piles positioned in opposite soil profiles. [ABSTRACT FROM AUTHOR]

In any high-rise building construction based on piles, it is essential to correctly evaluate their response when subject to high loads to avoid oversizing and consequently high costs. This work falls within the framework of the FONDASILEX project, which studies the behaviour of the pile foundations and the soil within the 'Silex2' tower project built in the Part-Dieu district in Lyon, France. This paper presents the geotechnical instrumentation executed for the foundations and the soil to enable the real-time monitoring of their behaviour. It details its conception, execution and limits. Five different types of electrical and unconventional sensors, including the fibre optic technique, which is based on reflectometry by Rayleigh scattering, were employed. This instrumentation allowed us to measure the soil settlement, the applied load at the head of the pile and the induced deformation in the concrete. The obtained measurements showed good agreement between all the sensors and were compatible with the real applied load. The results of this monitoring completed with an additional specific study to characterize the soil will be used in a future study to calibrate numerical models simulating the behaviour of high-rise building foundations. [ABSTRACT FROM AUTHOR]

In excavation engineering, most of the retaining structures are subjected to asymmetrical loads, including in asymmetrical excavation and asymmetrical overloading. However, a theoretical solution to, and deformation-controlling method for, this problem has remained elusive to date. In this work, a semianalytical solution for determining the deformation of retaining structures subjected to asymmetrical loads was derived based on the principle of minimum potential energy. The retaining structures were viewed as flexible, and the overall deformation of the retaining system was evaluated by our proposed theoretical model. This model was verified by comparing it with practical monitoring data. Subsequently, the theoretical solution was applied to analyze the stress and deformation characteristics under the conditions of asymmetrical excavation and asymmetrical overloading, which can be controlled to ensure the safety of a project. Finally, because of the requirement for a small amount of deformation in the foundation pit retaining piles, the earth pressure on the retaining piles is close to the static earth pressure. Reducing the length of the retaining pile on one side had a greater influence on the deformation on that side, but less of an influence on the other side. Thus, the proposed model can be used for optimizing the asymmetrical design of a retaining structure in order to balance the economy and safety of a project. Our design theory can be applied to a variety of engineering projects. A typical case is the Guangzhou Baiyun District Comprehensive Transportation Hub Project in China. The method was used to analyze the status of the subway foundation pit, offering a new design scheme to reduce the design length of the retaining piles, which resulted in great economic benefits in its practical application. The findings provided in this paper can be applied to the engineering of any long, narrow foundation pit that can be simplified into a two-dimensional plane–strain calculation model, being used to realize more accurate deformation control over the foundation pit envelope. The core of this calculation method is that it can accurately describe the magnitude of the earth pressure. The distribution of the earth pressure is worthy of further study. [ABSTRACT FROM AUTHOR]

Although three-dimensional finite-element analysis has been introduced to foundation design for years, simplified computer-based calculations based on the spring analogy of soils and structural elements are also frequently used in many engineering projects. Using coefficients of subgrade reactions and pile stiffness is a straightforward way to design and analyze a piled raft foundation. This paper discusses the determination of the coefficients of pile reactions for embedded piled raft foundations in soft clays subjected to vertically uniform loads through a series of finite-element analyses. The geologic property was assumed to be composed of homogeneous soft clays with the shear-wave velocities varying at 100–140 m/s. The foundations with a square raft ranging from 16 to 36 m and embedment depths of 8 and 12 m were studied. Load intensity approximating 1.5 times the excavated soil pressures was considered where the maximum uniform load was applied to the foundation. The foundation settlements and reactions of the piles were obtained first from a three-dimensional finite-element analysis. For design convenience, the dimensionless pile displacements, pile reactions, and coefficients of pile reactions were developed and presented in plots. The embedment depth-to-raft size ratio, pile slenderness ratio, and pile-to-pile spacing distance-to-pile diameter ratio were examined to find their optimized correlation. Finally, a design example was given to verify the proposed suggestions. We conclude that the proposed method can be an alternative to the piled raft foundation design. [ABSTRACT FROM AUTHOR]

The seismic design of pile foundation–supported structures has gained significant attention in the last few decades; there have been several failures during moderate to severe earthquakes. Seismic soil–pile foundation–structure interaction (SSPSI) was reported as the governing phenomenon behind the failure mechanism of such structures. In this context, in this study an attempt is made to investigate the influence of SSPSI (mainly the inertial part of the interaction) in a pile-supported structural system with variation in dynamic characteristics and the ratio of superstructure stiffness to pile foundation stiffness (Ks/Kp) through physical model experiments using a shake table. The primary aim in this study is to assess the extent of the effect of dynamic soil–structure interaction in a scaled-down pile foundation–supported bridge structure in nonliquefied ground with the help of a simplistic normalized parameter, i.e., Ks/Kp, for different ranges of the period of the superstructure system. The study primarily highlights variation of the normalized lateral period of the whole interaction between the superstructure and pile foundation as a function of the practicable range of Ks/Kp, which may be helpful for designers in predicting the dynamic characteristics of the system as a first step in seismic design. Similarly, the trend of normalized spectral acceleration and displacement response at the superstructure and pile head with respect to Ks/Kp is presented for the prediction of design forces. Finally, an idealized case study prototype design problem is used to verify the outcome of the study and illustrates simplified design steps for pile foundation–supported structures in general. [ABSTRACT FROM AUTHOR]

Existing simplified procedures for evaluating soil liquefaction potential or for estimating excess pore pressures during earthquakes are typically based on undrained cyclic tests performed on saturated soil samples under controlled loading and boundary conditions. Under such conditions, the effect of excess pore pressure (ue) dissipation and redistribution to neighboring soil layers cannot be accounted for. Existing simplified procedures treat liquefiable layers as isolated soil layers without any boundary conditions even if dense and loose layers are very thin, permeable, and adjacent to each other. However, redistribution is likely to increase and decrease ue in the neighboring dense and loose layers respectively. Until now, no procedure short of fully coupled numerical analysis is available to estimate the importance of redistribution. This paper presents an approximate analytical procedure for assessing the effects of ue redistribution in (1) soil layers that would have liquefied if they were undrained, and (2) soil layers that would have not liquefied even if undrained. It is found that a layer that is initially assumed liquefied under undrained conditions might not even liquefy accounting for the ue redistribution to neighboring layers. On the other hand, a layer initially assumed to not liquefy can develop significant ue and can even liquefy due to pore pressure migration from the neighboring layers. Thus, accounting for redistributed ue is important for liquefaction consequence assessment quantification, particularly in systems that span the depth of these effects like deep foundations. Migration of u toward the tip of a pile can reduce its capacity, even if the tip is embedded in a dense sand layer. On the other hand, if redistribution can result in the reduction of ue in initially assumed liquefied layers, risks associated with liquefaction might be avoided. A criterion is also developed to evaluate the thicknesses of a layer below which redistribution could prevent liquefaction even if the layer is deemed liquefied according to the existing liquefaction-triggering procedures. Finally, the proposed procedure is illustrated by application to selected shaking events of centrifuge tests involving liquefaction of layered soil profiles. The predictions from the procedure matched the centrifuge test results reasonably. [ABSTRACT FROM AUTHOR]

Pile foundations supporting high-rise buildings are generally subject to cyclic loading because of dynamic loading. The corrosion of steel materials in pile foundations is another major concern, especially for piles in a marine environment. In this study, a series of cyclic and static loading tests on model piles made of fiber-reinforced polymer (FRP) and seawater–sea sand concrete (SSC) and ended in a rock socket were reported. Three structural configurations (FRP tube–confined, FRP rebar cage–reinforced, and centered FRP rebar–reinforced) were adopted for the model piles. Strain along the depth of the piles was measured using fiber Bragg grating (FBG) optic sensors and an advanced distributed optical sensing technique known as optical frequency domain reflectometry (OFDR). Strain distribution, axial cyclic stiffness, and shaft friction mobilization of the piles under static and different modes of axial cyclic loading were analyzed and explored in detail. The test results indicated that the FRP tube–confined model pile showed higher confinement and cyclic capacity and lower stiffness degradation, leading to relatively more stable behavior. A high level of cyclic loading can cause microcracks to form and grow within the pile material, thereby decreasing pile stiffness. The strain profile of all the piles along the depth appeared to follow a similar trend, and fluctuations at certain points led to failure. Cyclic stiffness showed gains initially when cyclic load conditions were below a certain threshold level but degraded when loading was increased beyond it. Moreover, shaft resistance gradually increased with cycles, causing higher mobilization in the upper portion of the socket. The experimental results have provided the first systematic study on the performance of the FRP-SSC composite model piles ended in rock sockets under axial cyclic and static loadings. This will contribute to development of a potential predictive method for pile settlement and capacity for the better design of rock-socketed piles. [ABSTRACT FROM AUTHOR]

Soil improvement is originally an economical solution to make soil buildable, particularly compared to deep foundation methods using piles. The object of this research is the understanding of the behavior of soil-mixing material, in particular, what concerns the effect of environmental parameters, whether: temperature, water table level, chemical attacks, the phenomenon of aging etc. on the mechanical and physical characteristics (resistance to simple compression, resistance to simple bending, modulus of elasticity, porosity, density, etc.), of a soil-mixing column, in the short term and long term. The big problem is how to carry out experiments in the laboratory, which will be representative of the different phenomena that take place on a real scale (on site). To do this, our approach consists of studying different soil-mixing mixtures composed of «artificial» soils (clay and sand) and a CEM III/C cement, and with a variable W/C ratio. After making the test pieces, with the different dosages of cements and a ratio between clay and fixed sand, they were kept under normal temperature conditions, in order to reach a maturation age (180 days), to be able to begin the series of experiments. Once the specimens were subjected to the aging test, let’s begin to crush them with simple compression and simple bending. The parametric study highlights a percentage of clay beyond of which the resistance decreases and the rigidity of the material can pose a problem for certain structural uses. The different results obtained show that for a low cement dosage, the humidification-drying cycle influences both the resistance to simple compression and to bending simple, as well as the number of cycles affects the resistance values in a significant way. On the other hand, for a greater or lesser dosage of cement, the resistance values are not affected. Based on the results obtained, it is possible to conclude that the choice of cement dosage depending on the nature of the soil influences the soil-mixing column and plays an important role on the lifespan of the column; therefore, it is necessary to give primary importance to the choice of cement dosage depending on the nature of the soil treated. [ABSTRACT FROM AUTHOR]

In current engineering practice, the torsional effects of ground motions are only considered implicitly through "accidental eccentricity coefficients". In seismic design codes, these coefficients account for not only the unintended (or uncertain) asymmetric distributions of structural mass and stiffness in the plan but also the torsional components of ground motions. The torsional effects may develop due to wave passage effects or the incoherency of translational ground motions along the foundation systems. While it is possible to obtain torsional components of ground motions directly from seismic records with modern instruments, such sensors are uncommon. Therefore, several numerical procedures have been proposed in the literature for estimating torsional components of ground motions from translational measurements. In this study, the Single Station Procedure (SSP)—based on the deconstruction of translational ground motions into body waves and the subsequent reconstruction of rotational ground motions—is employed to obtain torsional ground motions for seven different seismic events in Turkey. Additionally, the corresponding accidental eccentricity coefficients that can cause the same response modification with torsional ground motions are determined. First, a conventional procedure is utilized to obtain the corresponding accidental eccentricity coefficients. Various drawbacks of the conventional procedure, such as negative eccentricity coefficients, are addressed. Then, a relatively obscure definition of accidental eccentricity is revived to propose a novel procedure for determining accidental eccentricity coefficients. It is observed that the proposed procedure yields higher values for the accidental eccentricity coefficients than the conventional procedure. It also observed that the torsional spectrum provided in Eurocode 8 provisions requires higher eccentricity values than those implied by the recorded ground motions from Turkey. [ABSTRACT FROM AUTHOR]

The aim of the small-scale regional engineering geological study of the Czech Republic was to evaluate the relationship between slope gradient and engineering geological zones. The research motivation was to determine the average slope gradient, 25%, 50% (median) and 75% quantiles related to the different engineering geological zones. This scientific information is critical from the perspectives of engineering geology, geotechnical engineering, and foundation engineering because an increasing slope gradient evokes the need to create a cut respectively foundation excavation or another excavation in the geological structure, which increases the probability of occurrence of the problem in terms of differential settlement and bearing capacity of the structures. The research was carried out in the territory of the Czech Republic in 8 Quaternary zones with soil foundation ground and 10 pre-Quaternary zones with rocks and semi-rocks and their eluvia. A significant difference in the statistical characteristics of slope gradients was found in the group of Quaternary engineering geological zones (evaluated group I) compared to the group of pre-Quaternary zones (evaluated group II). The value range of the average slope gradient was 1.65° (16.9%) to 5.89° (60.3%) for the Quaternary engineering geological zones (soil foundation ground), representing 43.4% difference. Whereas for the over-quaternary engineering geological zones (rocks, semi-rocks and their eluvia), the difference was much higher, 3.59° (36.8%) to 9.76° (100%—value determined as a referential because it was the maximum), which is also reflected in a more significant percentage difference of 63.2%. [ABSTRACT FROM AUTHOR]

To assess the sensitivity of impulse response testing to potential poor support zones or voids beneath the foundation slabs, numerical simulations were performed using the finite element method. These simulations covered a range of scenarios, including soil-loosening zones, sub-slab cavities, and slab cracks. The analysis of the simulation results employed two distinct techniques: the normalized acoustic response method and the ASTM C1740 mobility spectrum approach. These methods allowed the parameters and attributes derived from changes in input signals to be described in relation to the specifications within the synthetic models. [ABSTRACT FROM AUTHOR]

This study discusses the issues in increasing the reliability of buildings and structures on Type II loess-like collapsible soils through the construction of basement floors. This study also analyses the effectiveness of using pile foundation options for buildings with basement floors made from driven and bored piles up to 50 m long that cut through collapsible soil of 10–32 m. Results showed that foundations made of driven and augered piles are the most effective in terms of cost, labour intensiveness, and concrete consumption, whereas options using barrettes are the least effective. [ABSTRACT FROM AUTHOR]

Rafts are frequently used to design foundations on soft soils to minimize the overall and differential settlements of structures built on them. In many cases, the raft alone can offer sufficient bearing capacity and all that is needed to restrict foundation settlements to a predetermined level with a few widely spaced piles. Granular piles (GPs) can be used due to their several advantages over steel or concrete piles. An annular raft foundation is generally provided for overhead water tanks, chimneys, etc. The provision of granular piles underneath the annular raft foundation not only increases the capacity of the foundation but also minimizes the settlement to an acceptable level. The present study deals with a rigorous analysis of annular raft foundation supported by GPs based on the continuum approach. A new numerical method is developed with geometric considerations for excluding the loaded pile portion from the region of the raft area by considering two distinct zones. This article introduces a novel approach, the annular raft over granular piles, which represents an innovative solution in geotechnical engineering. This innovation has the potential to improve the efficiency and effectiveness of foundation design in various construction projects. The response of annular raft foundation with GPs is evaluated in terms of settlement influence factor (SIF), load shared by granular piles (in %), and normalized shear stress variation along the GP–soil interface. The present study reveals that the presence of the pile influences the stress distribution locally. The stiffness of GP, relative length of GP, relative size of the raft influence the settlement and load sharing of annular raft with GPs. [ABSTRACT FROM AUTHOR]

Foundation pit excavation can cause settlement and displacement of surrounding existing buildings and roads. In order to study the influence of soil unloading on the surrounding buildings during pit foundation excavation, the application of a pile-anchor retaining structure in a deep foundation pit was studied, with the deep foundation pit project of Anhui Bright Pearl Mall as the research subject. Through theoretical analysis, field measurements, and FLAC3D numerical simulations, the supporting structure was comprehensively analyzed. A comparison was made between the measured displacement data and the numerical simulation results of the supporting structure and the surrounding environment during the excavation process of the foundation pit. The results indicate that the model results, obtained through the use of the FLAC3D software for numerical simulations, generally align with the field data. This approach can more accurately reflect the evolutionary laws of soil pressure and deformation during the excavation of the foundation pit. The maximum displacement of the horizontal displacement monitoring point in this project's foundation pit is 25.96 mm, which is less than the monitoring alarm value of 30 mm. The horizontal displacement monitoring of the sidewall of the foundation pit is crucial among them. An analysis of the three major causes of numerical deviation provides valuable insights for the design of deep foundation pit supporting structures. [ABSTRACT FROM AUTHOR]

This paper assesses trending AI foundation models, especially emerging computer vision foundation models and their performance in natural landscape feature segmentation. While the term foundation model has quickly garnered interest from the geospatial domain, its definition remains vague. Hence, this paper will first introduce AI foundation models and their defining characteristics. Built upon the tremendous success achieved by Large Language Models (LLMs) as the foundation models for language tasks, this paper discusses the challenges of building foundation models for geospatial artificial intelligence (GeoAI) vision tasks. To evaluate the performance of large AI vision models, especially Meta's Segment Anything Model (SAM), we implemented different instance segmentation pipelines that minimize the changes to SAM to leverage its power as a foundation model. A series of prompt strategies were developed to test SAM's performance regarding its theoretical upper bound of predictive accuracy, zero-shot performance, and domain adaptability through fine-tuning. The analysis used two permafrost feature datasets, ice-wedge polygons and retrogressive thaw slumps because (1) these landform features are more challenging to segment than man-made features due to their complicated formation mechanisms, diverse forms, and vague boundaries; (2) their presence and changes are important indicators for Arctic warming and climate change. The results show that although promising, SAM still has room for improvement to support AI-augmented terrain mapping. The spatial and domain generalizability of this finding is further validated using a more general dataset EuroCrops for agricultural field mapping. Finally, we discuss future research directions that strengthen SAM's applicability in challenging geospatial domains. [ABSTRACT FROM AUTHOR]

This study introduces an innovative approach to improving speaking proficiency among Korean EFL learners through the use of vlogs, further evaluating their impact on learners' foreign language speaking anxiety (FLSA) and willingness to communicate (WTC). In this semester‐long experiment, 49 university students were divided into an experimental group (n = 25) and a control group (n = 24). The former engaged in vlogging activities, while the latter received traditional instruction devoid of social networking. Data were collected via pre‐ and post‐questionnaires on FLSA and WTC, coupled with pre‐ and posttests assessing speaking skills. Vlogging significantly decreased FLSA and bolstered WTC in Korean EFL learners, demonstrating a marked improvement when contrasted with the control group. Additionally, the experimental group, engaged in vlogging, displayed superior advancement in vocabulary, comprehension, fluency and task proficiency. However, no discernible enhancements were observed in speaking accuracy when compared to the control group. With the evidence of reduced anxiety, increased communication willingness and enhanced speaking proficiency in the vlogging group, this study provides a concrete foundation for EFL teachers to consider integrating vlogging and similar social media‐based activities into language instruction. This approach could contribute to creating more engaging and comfortable learning environments, aiding learners in overcoming affective barriers and improving their language skills. Practitioner notesWhat is already known about this topic Prior research in second language acquisition probed the impact of social media on diverse language learning areas: vocabulary, intercultural learning, speaking skills, pronunciation and writing skills.Social media‐integrated language learning demonstrated potential in enhancing oral proficiency among English as a Foreign Language (EFL) learners.Limited research exists exploring the influence of social media, especially vlogging, on EFL learners' speaking skills and affective factors such as Willingness to Communicate (WTC) and speaking anxiety.What this paper adds This study demonstrates that a learning environment cultivated via social media, particularly vlogging, improves speaking proficiency and positively influences affective factors like Foreign Language Speaking Anxiety (FLSA) and WTC.The findings suggest that social media‐integrated speaking activities, specifically vlogging, offer a beneficial and effective pedagogical strategy to ameliorate speaking proficiency, FLSA, and WTC in supportive and non‐intimidating contexts.Implications for practice and/or policy This study offers crucial insights for EFL teachers planning courses to enhance speaking proficiency:The integration of vlogging and similar social media‐based activities into language instruction is strongly supported by the evidence of reduced anxiety, increased communication willingness and enhanced speaking proficiency in the vlogging group. This study provides a concrete foundation for such innovative approaches.The creation of an engaging, interactive and stress‐free learning environment is essential, enabling learners to practice speaking English without anxiety. This approach can also aid learners in overcoming affective barriers and enhancing their language skills.EFL educators should prioritize improving key attitudinal factors, such as anxiety and WTC. These factors significantly contribute to the holistic development of oral proficiency.When incorporating social media‐based speaking activities like vlogging, teachers' targeted feedback on recurring learner mistakes can foster improvements in speaking accuracy.EFL teachers must recognize their critical role in nurturing a supportive, non‐intimidating environment, paving the way for learners to effectively enhance their speaking proficiency. [ABSTRACT FROM AUTHOR]

Corrosion is important in the design, maintenance, and preservation of bridge steel pile foundation systems. It is an inevitable phenomenon when steel is exposed to the environment, as metals tend to return to their lower energy state. While the corrosion rate of steel is predictable for atmospheric exposures, it is highly variable and difficult to predict for steel buried underground because of the high variability of soils. Applying a protective sacrificial layer is a common protection method to prevent corrosion. This study aims to evaluate the efficiency of a galvanized and painted galvanized steel bridge pile for achieving a 100-year service life and to economically compare them for using piles without a coating. To meet this objective, 21 steel coupon samples and nine 30 cm pile samples with galvanized coating, painted-galvanized coating, and no coating were tested in a cyclic corrosion test chamber to investigate the efficiency of each coating. The test was conducted for 600 days simulating a 100-year service life. Results from the experimental test revealed that galvanized and painted-galvanized coating methods show remarkable performance in protecting the piles against corrosion, and both methods can protect the piles from corrosion for 100 years. Further evaluation showed that, while the cost to increase the pile size was determined to be less than the premium for galvanizing or galvanizing and painting the piles for the bridge in this study, a cost–benefit evaluation for each protection measure is suggested, knowing that costs can vary widely depending on specific project requirements, location, market prices, etc. [ABSTRACT FROM AUTHOR]

In this study, we instrument the foundations and towers for two onshore shallow wind turbine generators (WTGs) to evaluate foundation response, quantify in-service loads, and assess the assumptions behind WTG foundation design calculations. Measurements of pressure at the soil–foundation interface, soil strain just below foundation level, and tower moments over long periods provide insights into the operational moments experienced by the tower and the load transfer mechanisms to the foundation system. The results of this study have implications for design practices in three distinct ways: (1) the assessment of rotational stiffness calculation assumptions, (2) the evaluation of pressure distribution used in the bearing capacity formulation, and (3) the estimation of tower loads used in the tower and anchor bolt design. Our observations show that the induced overturning moments correlate well with incipient wind speeds and directions and the associated soil pressure and strain responses. The overturning moments and the response parameters relate linearly within the spectrum of measured magnitudes. However, the pressure distribution across the foundation footprint does not monotonically increase or decrease with distance from the neutral axis of the foundation base (e.g., the pressure sensed at the foundation's center close to the foundation is between 1.5 and 2 times greater than the pressures sensed at the edges). In addition, the measured soil strain as a function of cyclic moments shows that the in-service cyclic shear strains are less than 1.4 × 10−5 (i.e., two orders of magnitude smaller than the assumed design strain level). Finally, the spectrum of cyclic moments follows a semilog trend, thus indicating that operational and nonoperational loads dominate the fatigue load spectrum. Our study suggests that adequately designed WTG foundations on competent fine-grained soil result in very low operational soil shear stresses and strains, which might indicate that the current design practices are too conservative in nature. Field measurements establish load spectrums for cyclic fatigue loads for the long-term operational conditions of WTGs. [ABSTRACT FROM AUTHOR]