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This study investigates the quasi-static bearing stress-settlement response of shallow foundations in monolithic tire derived aggregate (TDA) layers having a total thickness of 3 m using a large-scale container and loading system. Tests were performed on footings having a range of widths, embedment depths, shapes, and loading inclinations. In tests where tilting was restricted, a clear bearing capacity was not observed for settlements up to 1.2B, where B is the footing width, but in tests where tilting was permitted bearing capacity was observed between settlements of 0.2B to 0.7B. Surface settlements indicate a dragdown response of the TDA adjacent to the footing extending out to more than 3B from the footing center, while settlement plates beneath the footing indicate a zone of influence of induced settlements of 14% at a depth of 4B. While bearing capacity theories for frictional geomaterials provided a reasonable prediction of the bearing capacity of footings in TDA for most tests, the corresponding settlements may be excessive for engineering applications. Accordingly, a correlation was developed between the theoretical bearing capacity and bearing stress at a settlement of 0.1B. A test with sustained loading indicates slight creep settlements with some stress dependency with magnitudes consistent with past studies.

To evaluate the axial compressive performance of the hollow sandwich GFRP-concrete-steel double-skin tubular columns (DSTC), 15 composite column specimens were produced to study the effect of various design variables. And the study presents a rational and accurate finite element (FE) model that provides a detailed working mechanism of the DSTCs, leading to the enrichment of parametric research and the creation of an extensive database. Based upon the unified strength theory of double shear, limit equilibrium theory, and superposition theory, the study evaluates and compares the effectiveness of different bearing capacity calculation models. With each added millimeter in the thickness of the GFRP tube, the ultimate bearing capacity of the DSTC specimen increased by 23.6% and 61.8%, respectively, compared to that of the 1.5 mm thick GFRP tube sample. The lower the hollow ratio of the DSTC section, the higher its ultimate bearing capacity. Specimens with a hollow ratio of 0.3 and 0.43 showed an ultimate bearing capacity 1.4 times and 1.25 times higher, respectively, than those with a hollow ratio of 0.6. The study observes a relatively high level of precision in the results of the ultimate equilibrium theory, with an average error rate of 20%. [ABSTRACT FROM AUTHOR]

In recent years, fiber-reinforced polymer-polyvinyl chloride (FRP-PVC) tubular cylinders have been widely used in civil engineering applications. Concrete-filled FRP-PVC tubes possess excellent mechanical behavior and high durability. In this work, a composite reinforcement system with basalt fiber reinforced polymer (BFRP) strips wrapped around the surface of polyvinyl chloride (PVC) tubes is proposed for existing concrete cylinders. In addition, the effectiveness of the composite reinforcement system is evaluated and the working mechanism is studied. Monotonic axial compression tests are conducted on 39 concrete cylindrical specimens, and the parameters studied includs the number of BFRP layers, the net spacing of BFRP strips, and the type of reinforcement. The test results demonstrate that the bearing capacity of specimens with BFRP strips was enhanced by 8.42% up to 45.43% compared to unreinforced concrete cylinders. While, the bearing capability of BFRP-PVC reinforced specimens increase by 26.54% up to 62.30% compared with the control group specimen. Furthermore, a strength model that considers equivalent constraint effect coefficients is proposed based on existing strength models. The difference between the predicted results and the experimental results is within 15%. Research has shown that the reinforcement effect of the composite system is significant, and the research results can provide reference for engineering practice. [ABSTRACT FROM AUTHOR]

A large amount of excavation waste soil will be produced during highway construction, which will lead to environmental pollution and construction site occupation. To make full use of the excavation waste soil, hydraulic pile-forming equipment with a maximum pressure of 200 t is developed based on the principle of building clean transportation infrastructure. In addition, a precast pile with modified waste soil (PPMS) is proposed to achieve the large-scale consumption of the excavation waste soil. The PPMS has the advantages of regular shape, reliable quality, and stable bearing capacity. The relevant production standards and construction processes are proposed in this paper. The static pressure test analysis of the PPMS and lime–soil compaction pile was performed to verify the feasibility of the PPMS in reinforcing soft foundations. The test results show that the bearing capacity of a single PPMS could reach 600 kN. Under the upper load of 400 kPa, the settlement of the PPMS-reinforced soft foundation is 30% smaller than that of the lime–soil compaction pile. The PPMS has the advantages of high bearing capacity and economic and environmental protection, which is suitable for reinforcing soft foundations. [ABSTRACT FROM AUTHOR]

To reveal the impact of erosion environment and age on the strength and deterioration of solidified soil exposed to salty soil, two types of solidified soil, soda residue-ground granulated blast furnace slag-carbide slag solidified soil (S20G10) and cement solidified soil (C10), were eroded by salty soil prepared with kaolin mixed with Na2SO4, MgSO4 or seawater. The unconfined compressive strength tests, X-ray diffraction and scanning electron microscopy analysis were conducted. The results showed that 1% MgSO4 erosion resulted in the most significant reduction in strength. After 28 days of erosion, the strength was approximately 66% to 68% of the standard curing sample. The strength initially increased and then decreased with the erosion age. Numerous needle-like ettringite or thamuasite were generated in the samples, which led to a loose microstructure and decrease in strength. Sample S20G10 showed stronger erosion resistance than sample C10. The bearing capacity of solidified soil exposed to MgSO4 erosion exhibited an initial increase followed by a decrease with erosion age. When considering erosion deterioration for 50 years, it was necessary to increase the pile diameter by 1.1 to 1.7 times if the bearing capacity of the mixing pile was equal to the allowable bearing capacity. [ABSTRACT FROM AUTHOR]

To improve the bearing capacity and optimize the allocation of ring beam connection, a new type of steel reinforced engineered cementitious composite (ECC) ring beam connection linking the reinforced concrete (RC) beam and the concrete‐filled steel tube (CFST) column was presented. The superior tensile property of ECC can significantly solve the cracking problem that weakens the bearing capacity of the ring beam. In this paper, the failure mechanisms, contact press analysis and strain distribution of steel reinforcement for reinforced engineered cementitious composite (RECC) ring beam joints were analyzed by finite element analysis. Moreover, based on the ultimate equilibrium method, a comprehensive study was conducted on the stress transfer mechanism for the RECC ring beam joint. The bearing capacity model and simplified computational method for the beam‐to‐CFST column with RECC ring beam were proposed. Finally, the calculation method was demonstrated with experimental results. Comparison results showed good agreement, proving that the proposed bearing capacity calculation model had reliability and theoretical significance. [ABSTRACT FROM AUTHOR]

In urban areas, shallow foundations are inevitably adjacent to each other. Moreover, the presence of thin, weak layers in these areas is not unanticipated. This study analyzes the combined impact of a thin, weak layer and the interaction of adjacent foundations on bearing capacity. Whereas previous research has separately explored the effects of weak layers and adjacent foundations. To attain the research objective, by utilizing the finite element method, the impact of various parameters, such as spacing between the foundations, the shear strength characteristics of a thin, weak layer, and the depth of this layer from the surface on the behavior of the adjacent shallow foundations studied. The foundation bed and thin-weak layer are assumed to be sandy soil. The analysis result indicates that the thin and weak layers reduce the bearing capacity of the shallow foundations, which is related to the shear strength parameters of the weak layer. Nevertheless, the placement of adjacent foundations at a short distance from each other reduces the negative impact of the existence of the thin, weak layer. This impact depends on the shear strength parameters, the depth of the weak layer, and the distance between the foundations. Compared to a single foundation, interfering footings can increase between 6 and 50% in the bearing capacity. The depth of the impact of the weak layer on the bearing capacity will also be a function of the distance between the adjacent foundations. [ABSTRACT FROM AUTHOR]

Evaluating the bearing capacity of strip footing is a classic problem in geotechnical engineering, which has been investigated by many researchers. As the advancement of technology and urbanization, less and less land area can be available for the construction of facilities, which results in that many buildings must be constructed near slopes. The bearing capacity of strip footing constructed near slopes is usually lower than that on flat land. When the soil strength of slopes is not sufficient to support the external loads, it is often necessary to backfill or reinforces the slopes to make the strength of slope meet application requirements. The discontinuity layout optimization (DLO) method is therefore adopted in this paper to investigate the effects of various factors on bearing capacity and failure mechanism of strip footing on inclined multilayered natural slopes. Two conditions, normal slope and backfilled reinforced slope, are considered in the analysis. In addition, the influence of distance between the strip footing and slope, the number of soil layers, the thickness of the interlayer soil layer and earthquake on the unreinforced slope, and the influence of geosynthetic length and burial depth on the reinforced slopes are investigated. Eventually, the results showed that different factors have different impacts on the slope bearing capacity and failure mechanism. [ABSTRACT FROM AUTHOR]

This paper presents a new analytical solution to predict the ultimate depth and holding capacity of plate anchors based on an integrated analysis of the anchor and mooring system. The configuration equations of the mooring line, both in soil and water, have been solved to obtain the complete line profile. A key advancement is that the mooring line angle at mudline varies compatibly with the whole anchor–mooring system. This is different from the solutions available in literature that neglect the mooring line segment in water and only assume a constant mooring line angle at the mudline. The system of equations is solved by using an iteration scheme, and parametric studies are demonstrated. The effects of line length, water depth, and seabed strength profile are explored by demonstrating the performance of a commercial plate anchor. It is found that neglecting the mooring line in water can significantly overestimate the ultimate embedment and capacity, especially when the mooring line length is relatively short. This paper can be used as an engineering tool to predict the ultimate capacity of an anchor–mooring system considering the integrated behavior of the whole system. [ABSTRACT FROM AUTHOR]

Offshore floating systems are held in position with chains that connect the floater to anchors embedded in the seabed. An essential component for calculating the overall mooring capacity is an accurate assessment of the holding resistance from the anchor chains. Existing studies generally simplify the (complex) chain geometry to that of a cylindrical bar, which does not account for the intricate geometry of the connected chain links. This paper reports on three-dimensional finite-element modeling that defined the capacity of a link of anchor chain in clay soil with consideration of the geometry of the chain links, including the influence from adjacent links. Both stud link and studless links were considered, along with the effect of embedment depth, link direction angle, and interface condition. The soil resistance acting on the chain links, represented by uniaxial bearing capacity factors Nn,max , Ns,max , and Nt,max along the normal, lateral, and axial directions of the chain link, respectively, were derived, and the soil failure mechanisms for these conditions are discussed. Equivalent bearing capacity factors Nq and Na were derived by converting the soil resistance to normal and tangential resistances (q and f) acting on an equivalent cylindrical bar. Ultimately, f/q was calculated to represent the friction coefficient, μ , which ranged from 0.2 to 0.4. [ABSTRACT FROM AUTHOR]

The ultimate bearing capacity of a strip footing placed horizontally over the edge of a sloping rock mass has been determined on the basis of the stress characteristics method (SCM) using the generalized Hoek–Brown yield criterion. The effect of footing–rock interface roughness on the results has also been analyzed. The problem has been solved, in addition, with the usage of the adaptive mesh–based finite-element limit analysis (FELA) method. The results are provided in the form of nondimensional bearing capacity factor (Nσ) as a function of different input material parameters for several slope inclinations. After analyzing all the results, an expression on the basis of the regression analysis has also been generated to compute the factor Nσ as a function of different input variables. The bearing capacity obtained from the SCM has been found to lie between the lower and upper bounds of the FELA, and the failure patterns from the two sets of analyses match quite closely with each other for both smooth and rough footings. The results are also found to be in good agreement with the existing solutions from the literature. [ABSTRACT FROM AUTHOR]

To improve the out-of-plane stability of partially encased composite (PEC) beam webs and enhance the synergy between concrete and section steel, a new type of wavy web PEC beam was designed and fabricated. In this study, the flange thickness and shear–span ratio were varied as key parameters. Low-cycle reversed loading tests were conducted to investigate the effects of these variables on the load-bearing capacity, failure patterns, deformation capacity, hysteretic energy dissipation capacity, and stiffness degradation of the wavy web PEC beams. Numerical simulations were performed using ABAQUS CAE2023, a finite element analysis (FEA) software, under low-cycle reversed loading conditions. The applicability of the ABAQUS software CAE2023 for the corrugated web PEC beam model was validated by comparing test results with finite element analysis results. A detailed parametric analysis was then carried out using the finite element model to further investigate the mechanical properties of the wavy web PEC beams. The research findings are as follows: the wavy web PEC beams exhibited good ductility; a larger shear–span ratio led to a transition in the failure pattern from shear failure to flexural failure; varying the flange thickness significantly affected the failure location and characteristics; and reducing the flange thickness could limit the propagation of concrete cracks, thereby improving toughness and energy dissipation capacity. [ABSTRACT FROM AUTHOR]

As a new type of pile, the bearing characteristics of stepped variable-section DX piles (multi-joint extruded and expanded piles) are quite complicated; thus, their design concepts and pile-forming processes are still in the exploration stage, and their application in actual engineering is not particularly mature. The settlement law and load transfer law of the variable section DX pile have not been studied deeply, and the values of the parameters of engineering design are not clear, which are the problems to be solved for the variable section DX pile. To solve the above problems, the present study on the bearing characteristics of stepped variable-section DX piles under vertical loading is of great scientific significance and engineering practical value. In this study, the bearing capacity of a DX pile with two variable steps was first analyzed experimentally. Then, the bearing capacity of variable cross-section DX piles and equal cross-section piles were simulated under the same soil conditions. Later, the numerical simulation results were compared with the experimental results to verify the validity and accuracy of the numerical models established in ABAQUS software. Finally, the bearing capacity of stepped variable-section DX piles in different soil layers was analyzed numerically to compare the effect of different soils on the compressive bearing capacity of piles. The results indicated that the load-bearing plates had a greater influence on the bearing capacity of the stepped variable-section DX piles. At the optimum variable section ratio, which was close to 0.9, DX piles had a good bearing capacity. The relative errors of the numerical simulation ultimate loads were below 10%, which verified the accuracy of the developed numerical model. The simulated ultimate load of the equal-section pile was the smallest. The vertical compressive bearing capacity and the effect of controlling settlement under the same level of load of the variable section DX pile in sandy soil were both better than those in silt soil. There was little difference between the bearing capacities of the piles with a load-bearing plate. The bearing capacity of the pile with two load-bearing plates was the best, which can be used in practical engineering. [ABSTRACT FROM AUTHOR]

This work aims to provide a comprehensive understanding of the structural impact of micro-texture on the properties of bearing capacity and friction coefficient through numerical simulation and theoretical calculation. Compared to the traditional optimization method of single-factor analysis (SFA) and orthogonal experiment, the multivariate linear regression (MLA) algorithm can optimize the structure parameters of the micro-texture within a wider range and analyze the coupling effect of the parameters. Therefore, in this work, micro-textures with varying texture size, area ratio, depth, and geometry were designed, and their impact on the bearing capacity and friction coefficient was investigated using SFA and MLA algorithms. Both methods obtained the optimal structures, and their properties were compared. It was found that the MLA algorithm can further improve the friction coefficient based on the SFA results. The optimal friction coefficient of 0.070409 can be obtained using the SFA method with a size of 500 µm, an area ratio of 40%, a depth of 5 µm, and a geometry of the slit, having a 10.7% reduction compared with the texture-free surface. In comparison, the friction coefficient can be further reduced to 0.067844 by the MLA algorithm under the parameters of size of 600 µm, area ratio of 50%, depth of 9 µm, and geometry of the slit. The final optimal micro-texture surface shows a 15.6% reduction in the friction coefficient compared to the texture-free surfaces and a 4.9% reduction compared to the optimal surfaces obtained by SFA. [ABSTRACT FROM AUTHOR]

Circular steel pipe concrete can give full play to the combination of steel pipes and concrete, resulting in an improvement in the steel pipe's concrete bearing capacity and ductility. In this study, the axial compression load capacities of nine steel pipe concrete columns, including one traditional steel pipe concrete column and eight steel pipe self-stressed concrete columns, were analyzed using an axial pressure test. The damage patterns and stress–strain curves of all the specimens under axial compression load were analyzed, and a comparison analysis was made between the test results of the different specimens. The test results show that the longitudinal expansion displacement of concrete increases with the increase in the expansion agent content. The greater the self-stress, the higher the bearing capacity of steel-tube concrete columns under axial compressive load within a certain range of the expansion agent, indicating that self-stress can increase the bearing capacity of steel-tube concrete columns under axial compressive load, but the effect of the magnitude of the self-stress on the damage pattern of the specimens is limited. The damage patterns of all the specimens were bulging in the center and concave at both ends. In addition, the existing theoretical calculation method of the bearing capacity of steel pipe concrete columns is modified, and a theoretical calculation method applicable to steel pipe self-stressed concrete columns is proposed to simplify the calculation method of the bearing capacity of steel pipe self-stressed concrete columns, which provides a basis for decision-making in practical engineering. [ABSTRACT FROM AUTHOR]

In this study, the ultimate bearing capacity of shallow strip footings resting on a geosynthetic-reinforced soil mass subjected to inclined and eccentric combined loading is rigorously examined through the well-established method of lower bound limit analysis (LA) in conjunction with finite element (FE) and second-order cone programming (SOCP). Lower bound limit analysis formulation is modified to consider the ultimate tensile force of the geosynthetic layer in the soil mass so as to account for both pullout (sliding) and rupture (structural) modes of reinforcement failure. The effects of several parameters, including the embedment depth (u) and the ultimate tensile strength (Tu) of the geosynthetic layer along with load inclination angle (α) and load eccentricity (e), on the bearing capacity ratio (BCR) and failure envelopes of the overlying shallow foundation are examined and discussed. The results generally show a marked increase in the ultimate bearing capacity of the surface footing against combined loading with the inclusion of a single geosynthetic layer. Results also reveal that a second intermediate reinforcement might be required to bear a dual performance against both vertical concentric and combined loading scenarios so as to more effectively support the footing. [ABSTRACT FROM AUTHOR]

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigates the behavior and capacity of concrete-filled steel tubes (CFTs) with rectangular and circular sections under various loading conditions: axial loads, pure-bending, and combined axial load-bending moments. A finite element-based numerical model is developed and validated against existing experimental data. Using an extensive databank generated from finite element analysis, this research proposes analytical empirical relations for determining the bearing capacity of rectangular and circular composite beams, columns, and beam–columns. These relations provide a direct, concise, and efficient method for calculating the ultimate strength of CFT members, making them valuable for engineering design. Comparisons between the proposed analytical results and previous experimental studies demonstrate the high accuracy of this method in analyzing rectangular and circular CFT member behavior. The findings contribute to a better understanding of CFT structural performance and offer practical tools for designers working with these composite elements. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Shallow foundations are used in many scenarios to transmit the loads from the lightly loaded superstructures constructed on expansive soil slopes. Infiltration associated with rainfall and snow melt influence both the foundation and the expansive soil behavior, including its slope. However, several research studies that are available in the literature focus on only one of these challenges. The combined influence of infiltration on the performance of the foundation and the slope in cracked expansive soils has not received the attention it deserves in the literature. In this study, the combined performance is evaluated with the aid of a numerical method considering shallow foundations located on the top of an unsaturated expansive cracked surficial soil slope. The influence of the rainfall intensity, rainfall duration, foundation setback distance, and foundation loading on the foundation bearing capacity and slope stability were investigated. The numerical results of the study highlight that all the parameters have a significant impact on the foundation–slope failure mechanisms associated with different infiltration conditions. [ABSTRACT FROM AUTHOR]

ABSTRACT The long‐core SDCM pile is a typical type of stiffened deep cement mixing (SDCM) pile, it could be widely exploited in coastal geotechnical engineering because of its high bearing capacity, low settlement, green, and economic advantages. The long‐core SDCM pile is constituted by a PHC pipe pile and cemented soil, the height of the PHC pipe pile is upward than the depth of the cemented soil reinforcement. This study implements a theoretical approach to load transfer analysis of the long‐core SDCM pile under vertical load in layer soil. Herein, the shear constitutive models of the DCM pile‐PHC pipe pile interface and the fictitious soil pile‐PHC pipe pile interface are double exponential models, the compression constitutive model of the soil under the pile and the shear constitutive models of the DCM pile–soil interface and the fictitious soil pile–soil interface are ideal elastic–plastic models. The results obtained from this calculation model can match well with the data from on‐site tests and other analytical solutions. The theoretical model is used to analyze the key parameters LD/LP, DD/DP, Ec, and Ep of the long‐core SDCM pile. The LD/LP and DD/DP are the critical parameters affecting the bearing characteristics, and the minor settlement is affected by the changes of Ec and Ep. [ABSTRACT FROM AUTHOR]

In offshore pile engineering, the installation of jacked piles generates compaction effects within soil, thus further affecting previously installed adjacent piles. This study proposes a three-dimensional numerical model for pile group installation, soil consolidation, and loading analysis. Subsequently, the effect of pile spacing and pile length-to-diameter ratio on the deformation, internal forces, and vertical bearing capacity of adjacent piles are investigated. The results indicate that with an increase in pile center distance, the peak lateral displacement of the adjacent piles decreases, whereas the peak vertical displacement increases. As the pile length-to-diameter ratio increases, the peak vertical and lateral displacements of the adjacent piles are enhanced. In addition, the peak axial force of the adjacent piles initially decreases and then increases with the penetration depth of the subsequent pile, whereas the peak bending moment initially increases and then decreases. The vertical bearing capacity of the subsequent pile is significantly superior to that of the adjacent piles. Therefore, the effects of pile installation on adjacent piles should be included in pile engineering. The impact of the subsequent pile installation on the bearing capacity of adjacent piles can be significantly reduced by increasing the pile center distance and pile length-to-diameter ratio. The findings provide useful guidance for pile group engineering. [ABSTRACT FROM AUTHOR]

In recent years, with the rapid development of cities, the utilization rate of underground space has gradually increased, and anti‐pull piles have also been widely used in practical engineering. In this paper, the failure surface form of the anti‐pull pile was assumed, the soil parameters of each soil layer in the layered foundation and the Poisson effect generated by the anti‐pull pile under the action of the uplift force was considered, and the calculation formula for the bearing capacity of the anti‐pull long pile in the layered foundation was obtained, which was verified by on‐site test data. Finally, the parameter range of the calculation method was analyzed. The results show that when the aspect ratio of the anti‐pull pile is large, and the elastic modulus of the anti‐pull pile is small, the Poisson effect of the anti‐pull pile is obvious, and the increment of pile side friction caused by the Poisson effect is also large. When the value range of parameter N is 50 ≤ N ≤ 100, the calculation results are more reasonable. The average error of the lower limit N = 50 is 11.7%, and the average error of the upper limit N = 100 is 5.3%. [ABSTRACT FROM AUTHOR]

Skirted foundations are critical components in offshore applications where combined loads are common in deep‐water environments. Their ultimate capacity under VH (vertical‐horizontal) combined loading is traditionally determined using VH failure envelopes, which are primarily constructed using numerical methods. These methodologies, however, frequently ignore the spatial variability inherent in seabed soils due to geological formations. This paper investigates the effect of spatial variability of undrained shear strength and embedment ratio impact on the capacity of skirted foundations subjected to VH combined loading. For this, OptumG2 software is used to perform Monte Carlo simulation combined with random finite element limit analysis. This paper investigates the stochastic analysis of bearing capacity and failure envelopes, with a particular emphasis on understanding the effect of spatial correlation on undrained shear strength. The study focuses on the horizontal scale of fluctuation and the soil strength heterogeneity index, shedding insight on previously undiscovered areas. Novel findings highlight how a rigid base affects VH failure envelopes and offer insights into evaluating the vertical bearing capacity of skirted foundations. [Correction added on 8 July 2024, after first online publication: The above statement has been updated in this version.] [ABSTRACT FROM AUTHOR]

Footing on slope is a prevalent construction encountered in geotechnical engineering, and its safety is receiving increased attention. A natural rainfall event will inevitably have adverse influences on the stability and bearing capacity of strip footings lying on slopes; however, the conventional practice to simulate the rainfall is realized by varying the soil moisture content and the actual rainfall characteristics cannot be fully reflected. As a result, the finite element (FE) software ABAQUS is employed in this study to model the temporally varying rainfall, and the bearing capacity, as well as failure mode of the strip footing placed at the top of slopes, is estimated accordingly. A series of FE analyses are carried out to quantify the influences of rainfall pattern, rainfall intensity, soil strength properties (i.e., effective cohesion c′ and effective friction angle φ′) and several geometric parameters associated with the location of embedded footing with B in width, such as the edge distance ratio L/B and the embedded depth ratio D/B. Results show that the bearing capacity will be decreased and the failure mode evidently changes under rainfall condition. Moreover, it is noted that the rainfall pattern produces less substantial impact on the bearing capacity and failure mode, compared with the rainfall intensity. [ABSTRACT FROM AUTHOR]

A rigorous solution aimed at accounting for the superposition and flow rule assumptions in the assessment of the bearing capacity of shallow strip footings under plane strain conditions has been developed using the method of characteristics and the finite element method. With reference to the Hill and Prandtl failure mechanisms, a bearing capacity factor Nγq and a superposition corrective coefficient μ that allow to directly obtain the actual bearing capacity of shallow strip foundations have been proposed. The geometry of the plastic volume involved in the failure mechanism has been also investigated, highlighting the influence of the superposition and flow rule assumptions. Starting from the numerical results obtained using the method of characteristics, several empirical relationships have been proposed for an accurate estimate of Nγq and μ as well as for the lateral extension and depth of the plastic volume. The accuracy of the numerical results has been checked through finite element analyses under the assumption of associated and non-associated flow rule showing that the proposed superposition corrective coefficient μ is not influenced by the flow rule assumption. Thus, a general bearing capacity equation for shallow strip footings has been provided which accounts for superposition approximation and non-associated flow rule. [ABSTRACT FROM AUTHOR]

Deep, large-diameter caisson shafts are a popular means of constructing underground storage and attenuation tanks and pumping stations for the water and wastewater industry. One of the key design concerns for these structures is resistance to flotation during periods when the tanks are only partially filled or empty. In this paper, two-dimensional numerical analysis is used to explore the undrained uplift resistance provided by under-reaming the walls of the caisson shaft to create an enlarged base. The primary aim of the study is to assess the influence of the taper angle of the anchor (i.e. the protruded base) on the resulting uplift resistance. The effects of the anchor–soil interface roughness factor, soil weight, surcharge pressure and caisson radius are also investigated. The results indicate that the effect of the taper angle on both the uplift bearing capacity and the developed horizontal reaction can be very significant. The numerical output informs the development of a closed-form approach for application in routine design. The new design method is shown to provide an excellent agreement with both finite-element and additional finite-element limit analysis calculations. By way of example, the proposed design method is applied to a hypothetical design scenario. [ABSTRACT FROM AUTHOR]

This study investigates clayey soil from a road project situated in the district of Lodhran, Punjab, Pakistan. The subgrade prepared with the soil distorted due to heaving after a certain period of its construction. First, laboratory tests were conducted to explore the reason for this problem, examining the fundamental engineering properties of soil. The test results show that the soil acts as a soft material when water content reaches 30%, significantly reducing its strength. The soft soil is generally considered unsuitable for civil work due to its poor performance behaviour. So, the performance of clayey soil was examined in the study at its soft state by coupling it with stronger materials, such as polyethylene polymeric reinforcement and sand, developing laboratory-scale foundation models. Based on the model studies, the study proposes a sustainable polyethylene–sand–soft soil model, which shows 155 and 56% higher ultimate bearing capacity (BC) than soft soil and sand-reinforced soft soil foundations. The changes in BC occur due to the reinforcement action of the polyethylene reinforcement, which is associated with its tensile membrane action effects and interlock bonding at the soil-reinforcement interface. Practically, the study can reduce the dependency of industry practitioners on sand materials. Using polyethylene in civil work is viable for environmental sustainability. [ABSTRACT FROM AUTHOR]

In this article, a kind of original bamboo-fiber reinforced phosphogypsum composite wall was proposed. The axial compression tests of eight walls and finite element analysis were carried out. The failure modes and mechanical properties of the walls were explored, the influence of parameters on the axial compression performance of the walls was studied, and the calculation methods of the axial compression capacity and stiffness of the composite walls were proposed. The results show that the phosphogypsum cracked first in the composite walls during the loading process, the cracks gradually spreaded through and widened, and the bamboo tubes inside the composite walls were crushed. The buckling failure occurred in the pure original bamboo wall. The bearing capacity of the composite wall control specimen is 140% and 38.46% higher than that of the pure phosphogypsum wall and the pure original bamboo wall, respectively. The number of dovetail nails has no significant effect on the axial compression performance of the composite wall. The bearing capacity and stiffness of composite wall increase with the increase of bamboo number, wall thickness, bamboo wall thickness and phosphogypsum strength. The calculation method of axial bearing capacity and stiffness of composite wall based on bamboo content is proposed. The finite element simulation results are in good agreement with the experimental and theoretical calculation results. The theoretical calculation method has high accuracy. The composite wall realizes the complementary advantages of original bamboo and phosphogypsum, which provides reference for the development and application of green buildings. [ABSTRACT FROM AUTHOR]

This paper aims to study the effects of the non-stationary soil property on the horizontal bearing capacity of three-dimensional monopile in spatially variable soils. The soil undrained shear strength is assumed to obey lognormal distribution and is simulated as non-stationary random fields. The mean value of the undrained shear strength linearly increases with depth, while the standard deviation keeps constant. The random finite-element method is applied to analyze the reliability of the bearing capacity. The influence of the correlations and non-stationary property on the mean and coefficient of variation of the bearing capacity are discussed. It is found that the correlation distance has no obvious effect on the bearing capacity and the bearing capacity increases with the increase of non-stationary coefficient. The results can guide the reliability-based design of horizontally loaded piles embedded in spatially variable soil. [ABSTRACT FROM AUTHOR]

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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The investigation of the ultimate bearing capacity (UBC) of shallow foundations has consistently been a significant area of study within the realm of geotechnical engineering. Estimating the UBC is a challenging and intricate task due to the influence of various factors, including soil qualities, foundation depth, and shape. Consequently, this subject gained considerable interest from researchers during the past century. Due to the rapid advancement of AI techniques, numerous models have been effectively utilized in foundation engineering, resulting in a significant rise in the number of related research publications. Despite considerable advancement in recent years, there is still a lack of a comprehensive overview of this topic. In order to comprehensively summarize the most recent developments and offer insights into future investigations, the objective of this review is to present a detailed analysis of AI applications in the evaluation of UBC of shallow foundations. By analyzing the recently published articles concerning the application of AI techniques in UBC prediction, the advantages and disadvantages of the established techniques are clearly outlined. According to the investigation, the choice of input parameters and the quantity and types of datasets used in AI systems determine their accuracy and success. Upon analysis of the considered publications, it was observed that the utilization of AI techniques for evaluating the UBC of shallow foundations has produced acceptable and encouraging outcomes. [ABSTRACT FROM AUTHOR]

The critical aspect of the seismic bearing capacity of footings holds significant importance in the field of geotechnical engineering. Past research has primarily focused on deterministic analyses, mainly neglecting or ignoring the spatial variability of the soil. This study aims to address this gap by employing a probabilistic approach to assess the seismic bearing capacity of foundations while considering the seismic force effect by adopting the pseudo-static approach. To achieve this goal, this study utilizes the random adaptive finite element limit analysis technique and Monte Carlo simulations to cover a wide range of potential outcomes, taking into account the uncertainties in the parameters. This research investigated the influence of soil strength variability on three key factors: the horizontal seismic coefficient, coefficient of variation, and dimensionless correlation length. The study revealed that an increase in the coefficient of variation of the undrained shear strength (COVsu) and the dimensionless correlation length (Θsu) leads to a reduction in the mean of the random seismic bearing capacity factor (μNran). Conversely, the horizontal seismic coefficient (kh) negatively impacts the seismic bearing capacity, thereby diminishing the overall soil stability. Additionally, the factor of safety must be selected with caution to ensure that the probability of failure is less than a specified value, particularly when the coefficient of variation of the undrained shear strength (COVsu) is high. To establish surrogate models capable of predicting the random seismic bearing capacity, multivariate adaptive regression spline (MARS) models have been developed. Utilizing the proposed MARS surrogate models offers a more convenient and computationally efficient means of evaluating the impact of variability in soil strength properties on geotechnical stability calculations. [ABSTRACT FROM AUTHOR]

Although soil stabilization with cement and lime is widely used to overcome the low shear strength of soft clay, which can cause severe damage to the infrastructures founded on such soils, such binders have severe impacts on the environment in terms of increasing emissions of carbon dioxide and the consumption of energy. Therefore, it is necessary to investigate soil improvement using sustainable materials such as byproducts or natural resources as alternatives to conventional binders—cement and lime. In this study, the combination of cement kiln dust as a byproduct and zeolite was used to produce an alkali-activated matrix. The results showed that the strength increased from 124 kPa for the untreated clay to 572 kPa for clay treated with 30% activated stabilizer agent (activated cement kiln dust). Moreover, incorporating zeolite as a partial replacement of the activated cement kiln dust increased the strength drastically to 960 and 2530 kPa for zeolite ratios of 0.1 and 0.6, respectively, which then decreased sharply to 1167 and 800 kPa with further increasing zeolite/pr to 0.8 and 1.0, respectively. The soil that was improved with the activated stabilizer agents was tested under footings subjected to eccentric loading. The results of large-scale loading tests showed clear improvements in terms of increasing the bearing capacity and decreasing the tilt of the footings. Also, a reduction occurred due to the eccentricity decreasing as a result of increasing the thickness of the treated soil layer beneath the footing. [ABSTRACT FROM AUTHOR]

Skirted anchors are often used as temporary or permanent anchoring foundations for underwater pipelines and floating platforms. A series of model tests and finite element simulations were conducted to study the bearing capacity of square skirted anchors with different mooring points. Based on the test results, two failure modes of square skirted anchors with different mooring points were analyzed. It was found that, when the mooring point was located at the top of the side skirt, the square skirted anchor was more prone to rotation and had a lower bearing capacity. The numerical method was validated by the model tests. In total, 140 numerical calculation results show that, when the mooring point position (normalized depth of mooring point) h/H = 0.5~0.75 and the load inclination angle θ = 0°~30°, the bearing performance of the square skirted anchor is optimal. As the aspect ratio of the square skirted anchor (H/B) increases from 0.25 to 2.0, the optimal mooring point position h/H moves downward from 0.5 to 0.75. The failure envelopes in the V-H loading space of the square skirted anchor were drawn, and the corresponding fitting equation was obtained. [ABSTRACT FROM AUTHOR]

Dynamic compaction is a method of ground reinforcement that uses the huge impact energy of a free-falling hammer to compact the soil. This study presents a DC method for strengthening coral reef foundations in the reclamation area of remote sea islands. Pilot tests were performed to obtain the design parameters before official DC operation. The standard penetration test (SPT), shallow plate-load test (PLT), and deformation investigation were conducted in two improvement regions (A1 and A2) with varying tamping energies. During the deformation test, the depth of the tamping crater for the first two points' tamping and the third full tamping was observed at two distinct sites. The allowable ground bearing capacity at two disparate field sites was at least 360 kPa. The reinforcement depths were 3.5 and 3.2 m in the A1 and A2 zones, respectively. The DC process was numerically analyzed by the two-dimensional particle flow code, PFC2D. It indicated that the reinforcement effect and effective reinforcement depth were consistent with the field data. The coral sand particles at the bottom of the crater were primarily broken down in the initial stage, and the particle-crushing zone gradually developed toward both sides of the crater. The force chain developed similarly at the three tamping energies (800, 1500, and 2000 kJ), and the impact stress wave propagated along the sand particles primarily in the vertical direction. [ABSTRACT FROM AUTHOR]

An attached cantilever scaffold, which mainly consists of a cantilever horizontal steel beam and a diagonal bar, is a new type of cantilever scaffold. The upper end of the diagonal bar is attached to an upper floor slab by a hinge, while the lower end is connected to a cantilever beam. Therefore, the position of the lower suspension point has a significant impact on the overall mechanical performance. However, current research on this topic is limited. Thus, in this study, we aim to optimize the mechanical behavior by changing the lower suspension point position. An optimization methodology based on the genetic algorithm is proposed. This methodology has been demonstrated to be efficient and accurate enough to determine the optimal lower suspension point position of a diagonal bar. The effects of different beam cross-sections, diagonal bar diameters, and upper suspension point positions are further investigated. The bearing capacity is shown to improve by more than 100% and 30% for hinged and rigidly connected cantilever beams when the proposed optimization methodology is adopted. The analysis in this study can serve as a reference for the optimal design of an attached cantilever scaffold and can provide a theoretical basis for developing related design software. [ABSTRACT FROM AUTHOR]

In the area of ground improvement, the stone columns (SCs) play a definite role. The ground treatment technique has been demonstrated to be effective in improving the embankments’ stability and natural slopes by raising the bearing capacity and decreasing settlements. The objectives of this study are to develop models for predicting the performance of SCs-supported embankment foundations utilizing artificial neural networks (ANN). For the aim of creating ANN models, training, testing, and validation sets comprising 70%, 15%, and 15% of the data, respectively steps were done, making use of available numerical results obtained from the 2D finite element analysis. A dataset including about 200 cases is involved, and the mean square error (MSE) with R-squared value is used as performance metrics of the system. The applied data in ANN models are arranged in the component of 4 input parameters, which cover column diameter d, centre-tocentre spacing S, the internal friction angle of columns material ϕ, and embankment high H. Relating to these input parameters, the selected responses were the bearing capacity of the SC (BC) and the safety factor against the stability (SF). Based on the simulated results, an ideal 4- 14-1 ANN architecture has been settled for the direct prediction. According to the technique used, the forecasted data from the model had a good agreement with the actual datum, where the high regression coefficient (R2) was equal to 0.995 and 0.891 for BC and SF models, respectively. Furthermore, the relative importance of influential variables is examined, which shows that the column diameter is the most effective parameter in the two study models with a significance score of 32.9%. Finally, the outcomes clearly demonstrated that the ANN method is reliable for modelling and optimizing of the SC behaviour. [ABSTRACT FROM AUTHOR]

In this paper, uniaxial tensile testing of semi-grouted sleeve connectors was carried out by controlling the amount of expansive agent in the grout material. The effects of different steel bar diameters and anchorage depths on the failure mode, bearing capacity, and surface strain of sleeve connectors were studied. It is found that there are three failure modes in the specimens--namely, steel bar pullout failure, steel bar slip failure, and screw thread failure. The expansion characteristics of the grout material can partially compensate for the lack of compressive strength. Based on the analysis of the ultimate bearing capacity of different specimens, a design method to prevent the slip failure of the semi-grouted sleeve is proposed. The addition of 5 to 11% expansive admixture can reduce the circumferential strain of the casing from the steel bar anchorage location to the grouting end by 28.57 to 125.30%, with no impact on the longitudinal strain variation pattern. As the depth of steel bar anchorage increases, the expansive effect of the steel bar anchorage and casing longitudinal strain gradually surpasses the shrinkage effect, while the shrinkage effect at the grouting end of the casing gradually outweighs the expansive effect. With an increase in steel bar diameter, the longitudinal strain at the grouting end of the casing only decreases by 1.75% and 2.10%, essentially having no significant impact. [ABSTRACT FROM AUTHOR]

Prestress enables the Glulam beam could make full use of the compression strength, and then increase the span, but it still could not reduce all drawbacks, such as cross-section weakening and small force arm. To avoid slotting and ensure suitable tension and compression couple, one kind of novel anchor has been proposed, which could meet the bearing capacity requirement. And then the bending test of prestressed Glulam beams with a geometric scale ratio of 1: 2 was simulated, to investigate the effect of the force arm on bending capacities, failure modes, and deformation performance. Results show that increasing the force arm could improve the ultimate bending performance of the beam significantly, and the anchor arm length has a certain effect on the performance, but it is not obvious. Finally, based on Finite element method analysis, the practice design suggestions have been offered. Graphic Abstract [ABSTRACT FROM AUTHOR]

In current practice of bolt reaming and anchoring of roadways in soft coal and rock mass, resin cartridges bend easily under the strong pushing and stirring of bolts, and the resin accumulates in the bolt-reamed area and does not participate in the stirring. As a result, bolts encounter high drilling resistance and cannot reach the bottom of drillholes. The effective anchorage length is far less than the actual anchorage length. Bolts are not centered, and the shear is misaligned at the joint surface in the reaming area, which leads to cracking of the whole anchoring solid and large shear deformation of bolts. This study systematically analyzes the characteristics of roadway bolt reaming and anchoring. The influences of resin stirring force, bolt pull-out force, and reaming–anchoring solid strength on reaming–anchoring performance were analyzed theoretically. The main purpose is to develop a device that enhances reaming and anchoring. The mechanism through which the device strengthens the reaming–anchoring solid was analyzed theoretically. Numerical simulation and experiments were carried out to verify the improved performance of the small-pore reaming and anchoring using the proposed technology. The results showed that the stirring migration rate of the resin cartridge is greatly improved by adding the device to bolts. The reaction rate of the anchoring mixture, stirring pressure, pull-out force of the reaming and anchoring system, bolt concentricity, and shear and compressive strengths of the anchoring solid are also enhanced in the reaming area. This ensures that the resin cartridge in the reaming area is completely stirred, which greatly improves the shear resistance of the reaming–anchoring solid. Meanwhile, the drilling performance, torsional force, and stirring efficiency of bolts are maximized and prevail over those of conventional bolts.

The assessment of the load-bearing capacity of piles holds significant importance in the design of pile foundations. This paper presents hybridized support vector regression (SVR) models by utilizing the Artificial Rabbit Optimization (ARO) and the Black Widow Optimization Algorithm (BWOA) to predict the bearing capacity of concrete piles. A repository comprising 472 reports on static load tests conducted on driven piles was employed for the study. The dataset was allocated into three parts: the training set (70%), the validation set ( 15% ), and the testing set ( 15% ). Multiple criteria for assessing quality were utilized to evaluate the effectiveness of the models. The first rank belonged to the SVR model integrated with the ARO algorithm, where it could gain the higher value of R^2 in all of training (R^2 = 0.9876), validating (R^2 = 0.9778), and testing sections (R^2 = 0.9874), and the lowest value of RMSE in all the training ( RMSE = 39.393 ), validating ( RMSE = 53.727 ) and testing sections ( RMSE = 38.082). The findings indicate that the suggested model is highly appropriate for predicting the capacity of concrete piles.

[Introduction] The construction process of pile insertion and removal for installing offshore wind turbines on mobile platforms is risky, which can easily affect the working performance of adjacent infrastructure, and even lead to its instability and failure. [Method] In order to clarify the mechanism of the influence of pile shoe insertion and removal on adjacent foundation, this paper used CEL large deformation method to simulate the insertion and removal process of similar rectangular pile shoe in homogeneous and heterogeneous clay, and focused on the analysis of the evolution mechanism of additional overturning angle caused by pile insertion process on adjacent jacket foundation; based on the simulation results of large deformation, the influence of soil softening effect on the ultimate bearing capacity of adjacent buckets after pile shoe removal was further studied by using small deformation. [Result] The results show that under the action of pile shoe compaction, the rotational displacement of the three-cylinder jacket foundation will take place, and it will decrease gradually with the increase of net spacing. At the same time, the soil softening caused by compaction will reduce the bearing capacity of adjacent cylinder. [Conclusion] The overturning angle of three-cylinder jacket in heterogeneous soil is larger and the corresponding penetration depth is deeper due to the influence of pile shoe insertion and removal. The affected area of softening area caused by pile shoe insertion and removal is larger in horizontal direction and smaller in depth direction in homogeneous clay. In homogeneous clay, the average strength loss is small, and the horizontal and angular bearing capacity loss of the three-cylinder jacket is small. In homogeneous and heterogeneous clays, the vertical bearing capacity is reduced obviously, and the maximum reduction factor can reach 0.72.