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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.

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]

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]

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]

With the great development of the construction industry, prefabricated building components have been greatly developed. To study the compressive performance of the new wallboard, the axial compression performance test of six full-scale new lattice wallboards was carried out in this paper. The failure mode, axial pressure-displacement relationship curve, axial compression bearing capacity, and axial pressure-strain relationship of the wallboard were obtained through the experiments. This reveals the influence of the thickness of the concrete surface and the number of ribs on the performance of the wallboard. The test results show that the ultimate bearing capacity of the specimen increases with the increase of the thickness of the concrete surface layer with the same number of ribs. Specimen DW -30 increased by 4% over DW -20 and DW -50 increased by 41.6% over DW -30. The ultimate bearing capacity of the three-ribbed specimens was higher than that of the two-ribbed specimens for the same concrete face thickness, about 1.11 times that of the two-ribbed specimens. The concrete facing thickness and the number of ribs have a restraining effect on the deformation of the wallboard. Additionally, the calculation formula of axial bearing capacity of type latticed wallboard considering the influence of eccentric compression was proposed, which can provide a reference for engineering calculation. [ABSTRACT FROM AUTHOR]

A prediction model for the bearing capacity estimation of strip and ring footing embedded in layered sand is proposed using soft computing approaches, namely, artificial neural network (ANN) and random forest regression (RFR). The required data for the model preparation were generated by performing lower- and upper-bound finite-elements limit analysis by varying the properties of the top and bottom layers. Two types of layered sand conditions are considered in the study: (a) dense on loose sand; (b) loose on dense sand. The investigation for strip footing was carried out by varying the thickness of the top layer, embedment depth of the foundation and friction angles of top and bottom layers. For a ring footing, the internal-to-external diameter ratio forms an additional variable. In total, 1222 and 4204 data sets were generated for strip and ring footings, respectively. The performance measures obtained during the training and testing phase suggest that the RFR model outperforms the ANN. Also, following the literature, an analytical model was developed to predict the bearing capacity of strip footing on layered sand. The ANN and the generated analytical model predictions agreed with the published experimental data in the literature. [ABSTRACT FROM AUTHOR]

In this pioneering study, the performance of an eccentrically loaded strip footing on geocell-reinforced sand was assessed with instrumented laboratory model tests in terms of pressure-settlement response, surface displacement profiles, failure mechanisms and ultimate bearing capacity considering load eccentricity, geocell height, geocell material stiffness and the relative density of the soil. The results indicated that strip footings on the geocell-reinforced sand outperformed those on unreinforced soils, with up to a 6.5-fold increase in the bearing capacity and significant improvements in the initial slope of the pressure-settlement curve. Furthermore, the strip footing under centric loading on the geocell-reinforced loose and dense sand exhibited either only punching or local shear failure while load eccentricity on the strip footing could lead to the shear failures including punching, local and general. In this research, both a design chart for predicting failure modes of geocell-reinforced strip footings and a new interpretation method to evaluate ultimate bearing capacity were proposed. Increasing the relative density of the soil and material stiffness enhanced the ultimate bearing capacity of geocell-reinforced strip footings under both centric and eccentric loading conditions, with stiffer materials resulting up to 25% increase. However, increased geocell height had no significant impact on bearing capacity. • Comprehensive assessment on eccentrically loaded strip footings on geocell-reinforced sand. • Investigated pressure-settlement response, surface displacement profiles, and failure mechanisms. • Proposed a design chart for predicting failure modes of geocell-reinforced strip footings. • Introduced a new method for evaluating the ultimate bearing capacity of geocell-reinforced footings. • Found geocell material stiffness and soil density crucial for bearing capacity, but not geocell height. [ABSTRACT FROM AUTHOR]

Allowing the transitory attainment of bearing capacity of caisson foundations supporting bridge piers during strong seismic events can lead to substantial optimisation in their design and major cost savings. If the approach of capacity design is applied to geotechnical systems, the temporary triggering of plastic mechanisms may be permitted if the resulting permanent displacements are smaller than given threshold values. To validate this design approach, the seismic performance of caisson foundations was assessed through dynamic centrifuge testing on reduced-scale models. This paper presents the results of two tests in which a caisson–pier–deck system was embedded in a typical alluvial deposit and subjected to a series of earthquakes of different intensities. The caissons were founded on soft and very soft clay, to either avoid or induce the attainment of plastic soil behaviour under the same seismic inputs. It is shown that both yielding and failure of the layer of very soft clay limit inertial forces transmitted to the superstructure, validating the design approach and some useful empirical relations available in the literature. In contrast, inelastic soil behaviour implies accumulation of permanent rotation and settlement of the system, which must be carefully evaluated to check for fulfilment of performance requirements. [ABSTRACT FROM AUTHOR]

In the paper, the eccentric compression behavior of the truss-reinforced cross-shaped concrete-filled steel tubular (CCFST) column is investigated. A total of eighteen CCFST columns were tested under eccentric compression, and the key test variables included the reinforced truss node spacing (s = 140 mm and 200 mm), slenderness ratio (λ = 9.2, 16.6, and 23.1), and eccentricity ratio (η = 0, 0.08, and 0.15). The failure mode, deformation characteristic, stress distribution, strain distribution at the mid-span of the steel tube, and the eccentric compression bearing capacity were assessed. The results show that due to the addition of reinforced truss, the steel plates near the mid-span of eccentrically compressed CCFST columns experienced multi-wave buckling rather than single-wave buckling after the peak load was reduced to 85%, and the failure mode of concrete also changed from single-section to multi-section collapse failure. Comparisons were made with the unstiffened specimen. The ductility coefficient of the stiffened specimen with eccentricity ratios of 0.08–0.15 and node spacings of 140 mm~200 mm increased by 70~83%, approaching that of the multi-cell specimens with an increasing steel ratio of 1.8%. In addition, by comparing the test results with the calculation results of four domestic and international design codes, it was found that the Chinese codes CECS159-2018 and GB50936-2014, and the Eurocode 4 (2004) can be better employed to predict the compression bearing capacity of truss-reinforced CCFST columns. [ABSTRACT FROM AUTHOR]

The matric suction in unsaturated soil depends on the type of soil and various flux conditions i.e., infiltration, evaporation and no flow. The shear strength of unsaturated soil changes with change in matric suction leading to varying resistance of soil under various flow conditions. In this study, the bearing capacity of strip foundations resting over unsaturated clay considering variation of matric suction with depth for different surface flux conditions and position of water table, has been obtained using finite element lower bound limit analysis. Modified Mohr-Coulomb yield criteria based on unified effective stress approach has been employed to incorporate the contribution of matric suction stress to the failure condition. A non-dimensional bearing capacity factor was introduced to estimate the bearing capacity of strip foundations and presented as a function of different influencing parameters such as foundation width, water table depth, soil properties, various flow conditions and their flow rate, and surcharge pressure. The influence of variation of unit weight of soil in the unsaturated zone, air entry and pore size distribution parameters, residual degree of saturation of soil, specific gravity of soil solids, and foundation-soil interface roughness on the bearing capacity has also been examined and found to be insignificant. [ABSTRACT FROM AUTHOR]

The present study examines the efficacy of the thickness of recycled construction and demolition waste (RCDW) layer (0.4D, 0.6D, 0.8D, 1D and 1.2D; D: diameter of footing) prepared at different relative densities (30%, 50% and 70%) overlaying on loose sand. Two sizes of RCDW, 5 mm named RCDW-I and 10.6 mm named RCDW-II, were used in this investigation. The plate load test and finite element analysis using ABAQUS were carried out on different combinations. Moreover, a large box direct shear test was conducted to determine the angle of internal friction (α) of RCDW-I and RCDW-II at relative densities (ID) of 30%, 50% and 70%. With the usage of RCDW layer over sand, the ultimate bearing capacity increases by 640% for RCDW-I and 597% for RCDW-II, and the corresponding decrement in the settlement was 36.86% and 33.54% (at ID = 70% and u = 1.2B), respectively. The conjoined analysis shows that RCDW-II performs better than RCDW-I at lower ID. Whereas the opposite trend is witnessed at higher ID. The experimental results were compared to the numerical model created in ABAQUS 3D. In addition, regression analysis was performed using SPSS software to build empirical expressions of the given results. [ABSTRACT FROM AUTHOR]

Coir-geotextile plays a significant role in the reinforcement of red clay foundation. The present study was envisaged to investigate the effect of the length, reinforced depth, and embedment depth of the first layer of coir-geotextile as well as the vertical spacing of coir-geotextile on the bearing capacity and distribution of Earth pressure along the depth of a red clay foundation using plate loading tests and numerical simulation. The results revealed that the bearing capacity of the red clay foundation increased with an increase in the length of coir-geotextile and the reinforced depth of coir-geotextile. The bearing capacity of the red clay foundation was inversely proportional to the embedment depth of the first layer of coir-geotextile and the vertical spacing of the coir-geotextile. The optimal length, reinforced depth, and embedment depth of the first layer of coir-geotextile were found to be 3B , 2B , and 0.25B , respectively (B is the width of strip footing). The optimal vertical spacing of the coir-geotextile was found to be 0.25B. The Earth pressure in the red clay foundation reinforced with the coir-geotextile showed a gradual reduction along the depth of foundation. However, it dropped slowly within the reinforced depth of coir-geotextile due to the stress concentration caused by the coir-geotextile and dropped faster outside the reinforced depth of coir-geotextile. The red clay foundation reinforced with the coir-geotextile failed by punching. Based on the punching failure, the calculated values of the bearing capacity ratio of the simplified calculation method were observed to be close to the measured values in the model tests. The results obtained by the small-scale model tests in the present study can provide a reference for the bearing capacity and Earth pressure distribution of the red clay foundation reinforced by coir-geotextile under similar test conditions. [ABSTRACT FROM AUTHOR]

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The necessity for moderate improvements in the stress-strain behavior of soft soil is common in geotechnical engineering. One effective method for stabilizing such soil involves the installation of a granular trench. This experimental study examines the performance of strip footings supported by granular trenches in soft soil, focusing on the effects of trench size, shape, and the friction angle of the trench material on bearing capacity and settlement. Results indicate that a significant enhancement in bearing capacity, up to four times, and a settlement reduction of approximately 54% were achieved when the trench depth and width were 4 and 2.5 times the footing width, respectively. Beyond these dimensions, improvements in load-bearing capacity and reductions in settlement became negligible. It was also observed that the greatest settlement reduction occurred when trench sides were inclined outward by 30o from the vertical, whereas the maximum bearing capacity improvement was noted with vertical trench sides. The friction angle of the trench material had a substantial impact on settlement and a moderate effect on bearing capacity. This investigation provides valuable insights for optimizing granular trench design to enhance the performance of strip footings on weak clay. [ABSTRACT FROM AUTHOR]

The bearing capacity of shallow foundations on geocell-reinforced sand (GRS) depends not only on the soil characteristics but also on the geometries and properties of geocell. The geometry characteristics of GRS comprise height, length and cell aperture size of geocell as well as the sand layer thickness engaged between footing and GRS layer. Using the design-of-experiments (DOE) method the trends of bearing capacity ratio (BCR) as a function of selected geometry parameters of geocell are systematically visualized. Furthermore, trends of BCR as a function of geocell-selected geometry parameters are analysed. To this end, the study deploys the response surface methodology (RSM) to identify several configurations of geocell by conducting only twenty-seven laboratory tests. The results show that the DOE-RSM method gives an efficient interpretation of the variable's interaction while it lessens the number of tests. In addition, it has been found that the geocell height is the most influential parameter on BCR of footings on GRS. Moreover, an interaction between geocell aperture size and geocell height is recognised. The results are formulated and compared with the literature, resulting in good agreement. [ABSTRACT FROM AUTHOR]

Soil–rock mixture, a non-homogeneous medium with discrete characteristics, is commonly used in high-fill projects. This study analyzes the impact of rock morphology and distribution on the ultimate bearing capacity and sliding failure surface morphology of soil–rock embankments using the discrete element method (DEM). The results indicate that the embankment's ultimate bearing capacity increases with higher rock content. A larger ultimate bearing capacity is observed when rocks aggregate at the top of the sliding zone and the slope's toe. The influence of rock inclination angle on the ultimate bearing capacity follows this order: 30° > 45° > 60° > 0°. The rotation of block stones mainly occurs in the roadbed's shear zone. This study examines the shear zone morphology of the roadbed influenced by the stone content and spatial distribution of block stones. In this paper, we establish a sliding surface equation that considers the stone content and spatial distribution, providing guidance for assessing roadbed stability using the limit equilibrium method. [ABSTRACT FROM AUTHOR]

The ultimate bearing capacity of stone columns is very important in the design of soil improvement. The bulging failure mechanism is the most common failure mechanism reported. However, it depends on the surrounding soil at the site, necessitating a site-specific study of single-stone column bearing capacity. The current paper presents the full-scale plate load test of the single stone column in the Long Son Petrochemical Project, Vietnam in order to verify the bearing capacity of single stone column. A single stone column of 800 mm diameter was installed at the site by vibroflot. An 800 m circle full-scale plate test was carried out on site. The stone properties followed the Vietnamese standard TCVN 7572. The settlement result of the plate load test verifies the single stone column bearing capacity of 882.5 kPa. [ABSTRACT FROM AUTHOR]

Investigations on the changes in pore water pressures and stress during the construction of stiffened deep cement mixing (SDCM) piles are scarce, resulting in an unsatisfactory understanding of the bearing capacity formation process. Thus, this paper presents a preliminary field study to investigate the variation characteristics of pore water pressures, total stress and effective stress during the construction of SDCM piles derived from field tests. In the meantime, cone penetration tests (CPTs) were conducted before and after the construction of SDCM piles. The results show that the variation ranges of pore water pressure, total stress and effective stress of soils around piles decreased with increasing distance between the measuring point and piles when the depths of the measuring points were the same. During the piling process, the effective stress increased by approximately 53–103%, and the pile side frictions increased accordingly, while the tip resistance and side resistance values of soils around piles increased by 27–106% and 2–145%, respectively. Additionally, SDCM piles successively formed different load-bearing components with decreasing bearing capacity along the pile diameter direction, which realized a better bearing efficiency than conventional piles made with homogeneous materials. In essence, they were also the source of significant economic advantages of SDCM piles. Through this study, we expect to provide a reference for further studies on the bearing mechanism of SDCM piles in soft soil regions. [ABSTRACT FROM AUTHOR]

A large number of concrete-filled CFRP steel tube structures are widely used in practical engineering at current. Considering that as a column structure, compressive-shear loading is a more important bearing capacity method. 12 specimens are designed to study the comperssive-shear performance of concrete filled CFRP steel tube. The shear loading- displacement (V-Δ) curves and the collaborative work performance between the steel tube and CFRP are tested. Based on the tests, a numerical simulation method is firstly proposed to estimate the compressive-shear performance of concrete-filled CFRP steel tube stub column, and then validated against the representative tests results.Parametric study is conducted to explore the influence of principle factors on compresive-shear behaviour by verified numerical models. The experimental results show that the steel tube and CFRP can work together. As the axial compression ratio increases, the shear displacement of the specimen is constrained, resulting in increase of bearing capacity. Additionally, the increase of steel ratio, CFRP layers and materials strength for specimens enhance not only the bearing capacity but also the initial stiffness. The simulation results of the established finite element model are in good agreement with the experimental results. Finally, Based on experimental and finite element results, the bearing capacity correlation equation for concrete-filled square CFRP steel tublar stub columns when subjected to compressive-shear loading is presented. [ABSTRACT FROM AUTHOR]

The multi-line anchor achieves the "anchor sharing" goal by allowing multiple floating devices to be moored, such that the total number of anchors in a floating device array can be reduced significantly. This study proposes a dynamically installed anchor with the potential of resisting uplift loading from varied directions. The multi-line anchor is dynamically installed with the aid of a booster. The installation performance of the hybrid anchor (i.e., multi-line anchor + booster) is first examined by field tests. Then, finite-element analyses are performed to investigate the uplift capacity of the anchor under V-H-M-T combined loading conditions. Based on the numerical results, yield envelopes are established for assessing the ultimate bearing capacity of the anchor. Additionally, model tests are conducted to quantitatively study the installation and setup effects on the uplift capacity of the anchor, indicating that the vertical and torque capacities are sensitive to the installation effect. Finally, a design framework is proposed to assess the stability of the multi-line anchor under combined loading conditions. [ABSTRACT FROM AUTHOR]

In order to reveal the mechanical behavior of short concrete columns reinforced with hybrid steel and glass FRP bars, 10 specimens were designed for eccentric compression tests. The effect of eccentricity and load–displacement/strain of the specimens was studied. Test results indicate that the damage process and failure mode of these hybrid RC columns was similar to those in the conventional steel-reinforced concrete columns. The mode of failure for all specimens is characterized as large eccentricity compression failure, and the ultimate bearing capacity of the columns decreases with the increase in eccentricity. However, the impact of the varying axial stiffness ratio between GFRP and steel bars on the bearing capacity can be considered negligible. In addition, based on theoretical analysis, two boundary states for distinguishing failure mode and the formulae for calculating ultimate bearing capacity in different failure modes of eccentrically loaded hybrid RC columns are proposed. The computed results agree well with test results. [ABSTRACT FROM AUTHOR]

In saline environments, it is difficult for reinforced concrete structures to meet normal durability requirements, which in turn affects the mechanical properties of the members. In this context, this paper proposes a reinforcement method that involves wrapping corroded reinforced concrete columns with CFRP (carbon fiber reinforced polymer) cloth. By conducting axial compression tests on four specimens, key mechanical performance indicators such as failure mode, ductility, and bearing capacity during the entire stress process of the specimens were analyzed, revealing the failure mechanism of CFRP-confined corroded reinforced concrete columns. A refined finite element model of CFRP-confined corroded reinforced concrete columns was established using ABAQUS software. The influence of key parameters such as the number of CFRP wrapping layers, longitudinal reinforcement corrosion rate, and axial compression ratio on the mechanical properties of the specimens was studied, and the influence of each parameter was determined. Furthermore, a formula for the axial compression bearing capacity of CFRP-confined corroded reinforced concrete columns was proposed. The results indicate that in the presence of corroded steel reinforcement, specimens confined with CFRP undergo substantial lateral constraints during the mid to late stages of loading. This approach effectively alleviates the transverse deformation of the concrete. The specimen demonstrated yield bearing capacities and peak loads of 1441 KN and 1934 KN, respectively, representing a 2.2-fold and 2.5-fold increase compared to the non-reinforced specimen. With the increase in the transverse strain of concrete, CFRP begins to play a restraint role, and a more obvious restraint role in the failure stage of members. It is recommended to apply 1–3 layers of CFRP wrapping for a longitudinal reinforcement corrosion rate of 5%, 3–5 layers for a rate of 10%, and 6–8 layers for an overall corrosion rate of 15%. This paper establishes a theoretical framework for investigating the performance characteristics of such columns and offers technical assistance for practical engineering purposes. [ABSTRACT FROM AUTHOR]

To investigate the axial compression behavior of composite columns with high-strength concrete-filled steel tube flanges and honeycombed steel web (STHHC) under load during freeze–thaw cycles, 48 full-scale composite column specimens were designed with different parameters: the restraint effect coefficient (ξ), concrete strength (fcu), number of freeze–thaw cycles (nd), slenderness ratio (λ), space–height ratio (s/hw), and hole–height ratio (d/hw). The finite element models of STHHC composite columns were simulated using ABAQUS finite element software (Version: 2021). The modeling method's rationality was verified by comparing simulation results with experimental outcomes. Based on the finite element model, a parametric analysis of the composite columns under freeze–thaw cycles was conducted, analyzing their failure modes and load-bearing processes. The results indicate that the bearing capacity of the STHHC increased with increases in ξ and fcu, and decreased with a rise in λ. In contrast, the influence of s/hw and d/hw on the ultimate bearing capacity of the composite columns was relatively minor. An equation for calculating the axial bearing capacity of the STHHC composite columns under freeze–thaw cycles was derived using statistical regression methods and considering the impact of different parameters on the axial compressive performance of the composite columns, laying the foundation for the promotion and application of this type of composite column in practical engineering projects. [ABSTRACT FROM AUTHOR]

The suspender is a crucial and vulnerable component of large-span cable bridges, and its service performance inevitably degrades under environmentally corrosive media and traffic load. The long loading area of a large-span bridge provides the possibility for continuous traffic flow braking on the bridge. This study proposes a continuous braking model of traffic flow based on the driver's emergency braking reaction time and a steel wire degradation model considering the stress distribution characteristics of steel wire bending in the cross-section to analyze the safety of degraded cable components. The degradation process and bearing capacity variation of the cable are accurately quantified, and the reliability of the degraded cable under the action of traffic flow braking is determined. The results show that the traffic flow braking action causes a remarkable bending stress response in the bridge cable that reaches 450 MPa, which is much larger than the normal acting time. Moreover, differences in the bending stress of the cross-sectional steel wire cause significant differences in the fatigue process of the steel wire in different layers of the suspender. The outermost steel wires begin to fail after 12 years, and their service life is considerably different from that of the interlayer wires. The severely degraded steel wires on the outside can easily break under the traffic flow braking action, but they have no noticeable effect on the suspender's ultimate bearing capacity because of the Daniels effect. The increase in the cable force caused by traffic flow braking and the stress redistribution after the steel wires break have the most evident influence on the reliability of the structure. Due to the effects of traffic flow braking, the timing of suspender maintenance is advanced by 8 years. [ABSTRACT FROM AUTHOR]

In construction projects, conducting dynamic load tests on all piles proves impractical. Selective testing estimates bearing capacity, while the remaining piles rely on penetration depth for management. This approach, however, faces reliability issues due to varying conditions among piles. Technological advancements, such as non-contact hammers and sensors, have enhanced the accuracy of penetration depth measurements during final driving. Nonetheless, relying solely on penetration depth for construction and quality management remains problematic. This study, therefore, focuses on enhancing the use of driving formulas to improve pile quality management, particularly for the widely used pre-stressed high-strength concrete (PHC) piles. To improve pile quality management, existing driving formulas underwent review and refinement. Utilizing 258 dynamic load test data from various sites, the Hiley, Gates, and Danish formulas underwent validation through statistical analysis and graphical comparison. Enhancements to the Gates formula, achieved through curve fitting with actual data and the application of segment-based coefficients, demonstrated increased accuracy in bearing capacity estimation. These improvements offer a more reliable approach to pile quality management in construction projects. [ABSTRACT FROM AUTHOR]

Foundation treatment piles are crucial for enhancing the bearing capacity and stability of weak foundations and are widely utilized in construction projects. However, owing to the complexity of geological conditions, traditional construction methods fail to meet the demand for low-carbon development. To address these challenges, this study introduced a comprehensive decision-making approach that considers the impact of stratum variability on greenhouse gas (GHG) emissions and pile bearing capacity from the design phase. During the design process, the GHG emissions and bearing capacities of deep cement mixing (DCM) and high-pressure jet grouting (HPJG) piles were quantitatively assessed by analyzing the environmental and performance impacts of foundation treatment piles related to materials, transportation, and equipment usage. The results suggest that the bearing capacity of piles in shallow strata is highly susceptible to stratum variability. Using piles with a diameter of 800 mm and a length of 20 m as an example, compared with DCM piles, HPJG piles demonstrated a superior bearing capacity; however, their total GHG emissions were 6.58% higher, primarily because of the extensive use of machinery during HPJG pile construction. The GHG emissions of foundation treatment piles in shallow strata were influenced more by geological variability than those in deep strata. Sensitivity analysis revealed that the pile diameter is a critical determinant of GHG emissions and bearing capacity. Based on the bearing capacity–GHG emission optimization framework, a foundation treatment strategy that integrates overlapping and spaced pile arrangements was introduced. This innovative construction method reduced the total GHG emissions by 22.7% compared with conventional methods. These research findings contribute to low-carbon design in the construction industry. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) 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.)

In this paper, low circumferential reciprocating load foot-scale tests were performed on two nontruncated PHC B 600 130 tubular piles with bearing nodes to characterize the damage process and morphology of the specimens and to investigate the load-carrying performance of the members. The test results reveal that under the action of tensile-bending-shear loading, the bearing concrete in the node area buckles and is damaged, the anchored reinforcement in the node area yields, the constraint is weakened, an articulation point is formed, and the node rotational capacity increases. When the embedment depth increases from 200 mm to 300 mm, the ultimate bearing capacities of the positive and negative nodes increase by 31.04% and 36.16%, respectively. A numerical simulation is used to verify the test results. Considering the four types of piles without truncated nodes, the numerical simulation is used to analyze the node-bearing capacity at different embedment depths. Finally, a preferred node type is proposed as follows: a terminal plate welded anchor bar and pipe pile core-filled longitudinal reinforcement anchored into the bearing node, with a preferred embedment depth of 250 mm. [ABSTRACT FROM AUTHOR]

The aim of the paper is to propose design tools for pile groups when vertical and moment loads are applied simultaneously. This is done by presenting a method to derive the exact solution for the failure locus in the generalized force space, including a vertical load and a moment with components along two axes, to employ for capacity requirements which helps to get rid of overconservative assumptions usually adopted in design. Moreover, closed-form solutions for performance-based interaction domains are also provided allowing to detect all the combinations of external loads associated with a given value of settlement and/or rotation of the foundation that is extremely useful when the design is ruled by serviceability requirements. The application of these straightforward formulae provides results which are in very good agreement with the more rigorous solutions derived from a numerical procedure developed ad hoc for the problem at hand. [ABSTRACT FROM AUTHOR]

This study investigates soil–steel composite structures, emphasizing the role of stiffening ribs and geotextile reinforcement through comprehensive numerical modeling. This study presents a two-dimensional finite element analysis (FEA) and compares the influence of stiffening rib and geotextile on the ultimate bearing capacity of the soil–steel composite structures. The results of this study demonstrate a significant enhancement in load capacity. Specifically, a notable 47% improvement was observed with a stiffening rib, and a 26% increase was noted with the use of a single layer of geotextile. Under peak load, the vertical displacement at the crown exceeds the permissible standard for all models except for one model, while bending moments reach their limits, marking a failure mode of composite system considered. Structures with stiffened ribs reach their load capacity due to the creation of a plastic hinge around the shoulder and haunch of the shell. On the other hand, in structures without stiffening ribs, the crown and haunch section of the shell becomes fully plastic under peak load. The maximum axial thrust is shown in geotextile-reinforced structure, reaching 78% of the shell maximum capacity due to compression. Eventually, stiffening rib substantially improves overall load-bearing capacity of the soil–steel composite structures, and geotextile placement in the upper part of the backfill reduces shell deflection due to bending. [ABSTRACT FROM AUTHOR]

The usage of screw piles is one of the increasingly widespread ground improvement methods. In this study, the behaviour of linear, triangular, and square pattern screw piles in groups under tensile and compressive forces is investigated. The model experiments in the literature on screw piles were modelled by finite element method and a reasonably accurate agreement with the experimental results was obtained. Then, the number of helixes and helix diameters of the screw piles used in the experimental study were changed and the effect of the change in the number of helixes and diameter on the bearing capacity was investigated. Also, the behaviour and failure surfaces of screw piles under load were investigated. In conclusion, increasing the number of helixes significantly increased the bearing capacity. In fact, it was observed that the increase in the number of helixes was sufficient to reduce the number of piles as a result of the increase in the bearing capacity up to 100%. In addition, the increasing the diameter of the helixes by 1.8 times resulted an increase in the bearing capacity values between 80% and 100%. However, it was determined that the bearing capacity increases were different in each pattern. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ground Improvement is the property of Journal of Ground Improvement Editorial Office 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 paper addresses the critical gap of uncertainty quantification in existing geotechnical models predicting bearing capacity for shallow foundations on cohesionless soils. The developed Bayesian regression model improves point estimate accuracy by 30% compared to traditional models while introducing a robust method for quantifying prediction uncertainty. Utilizing extensively studied literature data, we demonstrate the model's closed-form structure, allowing the direct calculation of both the most probable bearing capacity and its uncertainty. This transparency distinguishes the proposed model from black-box machine learning alternatives. Furthermore, we illustrate its practical applicability by integrating it into reliability-based design, specifically showcasing its utility in incorporating applied load distributions. In essence, this research enhances predictive accuracy and establishes a comprehensive framework for addressing uncertainty in bearing capacity models, with direct implications for reliability-based design practices. [ABSTRACT FROM AUTHOR]

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office 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.)

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe 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 paper proposed a theoretical solution to predict the bearing capacity of a new horizontal-vertical (H-V) geogrid reinforced foundation under strip footing, incorporating the key mechanism including the friction and the interlock between soils and the horizontal plane of H-V geogrid, and the confinement of the vertical plane of the H-V geogrid. The input to the equation includes soil properties (e.g., unit weight, soil friction angle, Terzaghi's bearing capacity coefficient) and H-V geogrid properties (e.g., tensile strength, geometry, aperture size, and dimension of the geogrid). The results showed that the theoretical equation accurately predicted the bearing capacity of the H-V geogrid as well as the conventional geogrid-reinforced foundation. Contrary to the traditional geogrid, the vertical component of the H-V geogrid offered effective soil resistance. When the height of the vertical element of the H-V geogrid increases from 0 to 0.04 m, the bearing capacity of the H-V geogrid foundation was increased about 1.44 times compared to the conventional one. When the vertical element spacing is reduced from 1.60 to 1.33 times the width of strip footing, the bearing capacity rise from 1.20 to 2.63 times compared to a traditional geogrid-reinforced foundation. [ABSTRACT FROM AUTHOR]

Cured-in-place pipe (CIPP) technology is used to repair deformed municipal polyethylene (PE) pipes caused by design flaws, construction issues, or external loads. However, research on CIPP for PE pipes is limited, restricting its broader application. This research focuses on the mechanical response characteristics and failure modes of the composite PE pipe–CIPP liner structure under external loads. Using experimental setups involving comparative test groups with different diameters and wall thickness ratios (DR values, defined as the ratio of the pipe's outer diameter to its wall thickness), this study evaluates the effects of the liner's elastic modulus, the bonding effectiveness at the PE pipe–CIPP liner interface, and the initial ovality of the pipes on the load-bearing capacity. The experimental results reveal that CIPP liners substantially enhance the stiffness and load-bearing capacity of PE pipes, with improvements ranging from 200% to nearly 500% depending on the pipe's DR value. A novel ring stiffness prediction model is also introduced and validated against the experimental data. This model provides a theoretical framework for understanding the complex interactions at the PE pipe–CIPP liner interface and aids in designing more resilient urban drainage systems. [ABSTRACT FROM AUTHOR]

To address the issue of local buckling in thin-walled steel tube concrete columns, a form of helical stiffening ribs was proposed. Axial compression tests were conducted on five sections of square steel tube concrete column specimens. The research revealed that, compared to ordinary steel tube concrete columns, the axial compression bearing capacity and deformation capacity of steel tube concrete columns with helical rib constraints increased by 18.5% and 7.7%, respectively. The helical ribs effectively enhanced the buckling resistance of the thin-walled steel tube concrete components. The failure pattern of this new type of component was characterized by diagonal cracks in the encased concrete aligning with the direction of the helical ribs, and the buckling of the steel tube walls was concentrated between the helical stiffening ribs. Based on the experiments, an analysis of the buckling performance of thin-walled steel tubes with helical rib constraints was conducted, and this was incorporated into the bearing capacity calculation. The test, simulation, and theoretical calculations showed that the bearing capacity error of the composite columns for each specimen was within 10%. Ultimately, a formula for the critical buckling bearing capacity of the helical rib steel tubes was proposed. The research findings provide a foundation for the engineering application of this new type of component. [ABSTRACT FROM AUTHOR]

Metro transit construction has begun to develop rapidly in northwest China because of the acceleration of urbanization. Accordingly, metro depots are also regarded as an essential auxiliary facility for stopping, operation, and maintenance of trains. Meanwhile, many commercial buildings are constructed over metro depots to improve the utilization rate of land due to the increasingly scarce urban land resources, known as transit-oriented development (TOD). These buildings have a large covered area and transfer concentrated loads to the bases. Therefore, pile bases under metro depots have the bearing characteristics of undertaking large concentrated loads, while lesser loads are placed on the soil between the adjacent pile bases. Additionally, the main ground in northwest China is collapsible loess, so the collapsibility should also be considered. Based on the above background, this research performed static loading tests with and without immersion in a reduced scale of adjacent pile bases under a metro depot in Xi'an. The remolding process of natural loess could destroy its structure and the anisotropy of natural loess could also affect the test results. Therefore, four kinds of artificial collapsible loess with different mass ratios of barite powder, kaolin, river sand, cement, industrial salt, and calcium oxide were made by the free-drop method. This method could make the artificial loess simulate the structure of natural loess reasonably. Then, the artificial loess with the most similar properties to intact loess was selected by comparison. Finally, static loading tests with this artificial loess were implemented. The results showed that the ultimate bearing capacity was 4.5 kN. At the same time, the axial force decreased along depth, since the pile shaft friction was positive, and the load sharing ratio of pile tip force increased to 0.58 when the load exceeded 4.5 kN in the situation without immersion; the settlement of pile bases increased significantly after immersion, while the negative shaft friction occurred at the depth of −8 cm~−35 cm, and the load sharing ratio of pile tip force reached 0.92. [ABSTRACT FROM AUTHOR]

This study presents an engineering geological investigation aimed at assessing the bearing capacity of the proposed site for the Meli gold processing plant (GPP) located in the northwestern region of Tigray, Ethiopia. The geological composition of the site predominantly comprises low-grade metamorphic rocks, with intermediate metavolcanic rocks being the most prevalent. This research utilized an innovative combination of empirical methodologies, including the Hoek–Brown and Mohr–Coulomb criteria, to evaluate the strength and elasticity characteristics of the rock mass. Additionally, the rock mass foundation for the GPP was rigorously classified using renowned systems such as the rock mass rating (RMR), quality index (Q), and geological strength index (GSI). Employing five different empirical equations to estimate bearing capacity, this study significantly advances our understanding by comparing these diverse methodologies, which is a novel approach in this geological context where engineering property data are scarce or non-existent. The bearing capacities determined using the Hoek–Brown and Mohr–Coulomb criteria ranged from 11.6 to 46.2 MPa and 7.9 to 10.5 MPa, respectively. These findings not only offer valuable insights into the assessment of bearing capacity in metamorphic rock formations but also underscore the effectiveness of combining multiple empirical approaches to enhance the reliability of geological assessments. This research contributes to the advancement of construction practices and enhances project planning strategies in comparable geological environments, particularly highlighting the utility of robust empirical data in the absence of extensive drilling data. By integrating comprehensive empirical analyses, the study provides a methodological framework that significantly aids in informed decision-making for future projects located in similar geological settings. [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]

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]