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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]

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]

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]

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]

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]

Piles are commonly used under partial head-restraint conditions. Currently, quantification of the lateral capacity of partially head-restrained piles is an open problem. This paper reports the results of a comparative study on the partially head-restrained behaviours of single piles in virgin sites and new piles in sites with existing piles. The lateral performance of new piles affected by pile-head restraints was examined and compared with that of single piles in virgin sites, and the characteristics of new and single pile capacities with respect to pile-head restraints were evaluated. An intrinsic H–δδ correlation (the lateral pile capacity and the factor linking partially head-restrained piles to pure free- and fixed-head piles) is discussed, which enables the calculation of capacities of partially head-restrained piles based on those of pure free- and fixed-head piles. In addition, analytical models of the δδ–λ correlation (λ represents the pile-head restraint percentage) are deduced. By combining the δδ–λ and H–δδ correlations, the lateral pile capacities for arbitrary pile-head restraints in virgin sites and sites with existing piles are calculated. The proposed method is comprehensively validated by numerical and literature examples, showing significant advantages in the determination of the lateral pile capacity considering head restraints. [ABSTRACT FROM AUTHOR]

To investigate the axial compressive behavior of reinforced concrete-filled square glass-fiber-reinforced polymer(GFRP) tubular (RCFSGT) columns, 17 specimens were designed with variations in GFRP tube wall thickness, spiral reinforcement yield strength, and spiral reinforcement ratio. A detailed model was developed using the finite element software ABAQUS, enabling in-depth mechanistic analysis and expanded parameter studies. The results indicate that the failure types of the specimens are all manifested as GFRP square tube cracking, and the core concrete is subjected to crushing or shear failure. The inclusion of a reinforcement cage can significantly enhance the load-bearing capacity and ductility of the specimen. Furthermore, as the yield strength and reinforcement ratio of the spiral reinforcement increase, so does the load-bearing capacity of the specimen. The finite element simulation results align well with the experimental findings. As the wall thickness of the GFRP square tube increases from 2 mm to 6 mm, the load-bearing capacity improves by approximately 19.69%. With the yield strength of the spiral reinforcement rising from 200 MPa to 400 MPa, the specimen's load-bearing capacity shows an increase of approximately 7.55%. However, as its yield strength continues to increase, there is minimal change in the load-bearing capacity. When the stirrup ratio of spiral reinforcement rises from 0.33% to 2.26%, the specimen's load-bearing capacity experiences an increase of approximately 56.90%. [ABSTRACT FROM AUTHOR]

A new approach based on the limit equilibrium method to calculate the ultimate bearing capacity of a strip shallow foundation is presented in this paper. The bearing capacity estimated with Terzaghi's three-term basic formula using the superposition method has proven to be conservative. A proposed failure mechanism to determine the bearing capacity coefficients of the three parameters, namely, the cohesion (Nc), the surface surcharge (Nq) and the soil weight (Nγ), is developed. The 'individual minimum' of each coefficient is determined using different failure mechanisms; hence, a new analytical approximation is suggested for calculating the 'global minimum' of the bearing capacity with a single failure mechanism without superposition. The rationality of the results of the analytical solutions (bearing capacity and failure mechanism) is verified using finite element analysis with the program PLAXIS 2D and kinematical analysis with the program FIDES-GeoStability. [ABSTRACT FROM AUTHOR]

The bearing capacity of shallow foundation is significantly affected by stratum uncertainty, mainly including geological uncertainty and spatial variability of soil properties. This paper aims to develop a general framework of shallow foundation to characterize the influence of two types of uncertainties on bearing capacity quantitatively. The geological uncertainty is simulated by Markov random field with different borehole schemes. The spatial variability is characterized using random field theory considering variations of the vertical scale of fluctuation. The bearing capacity of shallow foundation analysis is then conducted based on the proposed calculation framework. Borehole data and soil properties collected from Shenzhen Mawan are adopted as an example to illustrate the proposed framework. A reduction factor is developed to reveal the relationship of two category uncertainties on bearing capacity. A contribution rate indicator is defined to quantitatively evaluate the impact of two category uncertainties. Results show that the geological uncertainty greatly influences the calculation results when boreholes are sparse. However, spatial variability dominates in two kinds of uncertainties when having relatively more boreholes. [ABSTRACT FROM AUTHOR]

The bearing capacity of shallow foundations is often calculated using the classical three-term bearing capacity equation, containing bearing capacity factors and correction factors for embedment depth and footing shape. The available solutions for the determination of these factors were obtained using primarily limit analysis and the method of characteristics, with the assumption that soil is a perfectly plastic material following an associated flow rule. However, in reality, sands are neither perfectly plastic nor do they follow an associated flow rule. The unit bearing capacity of footings in sand depends on (1) the representative friction angle mobilized within the zone encompassing the footing's collapse mechanism, and (2) the size, shape, and embedment depth of the footing. This paper presents the results of load tests on model strip and square footings of different sizes installed in clean silica sand samples pluviated to produce different densities inside a calibration chamber. The test results for the footings placed on the sand surface show that the bearing capacity factors depend on the relative density of the sand sample and the geometry of the footing. For the embedded footings, the unit bearing capacity of the footing is shown to depend on its embedment depth. Insights into the footing collapse mechanism are provided by plotting the maximum shear strain contours for different stages of footing loading; the contours were obtained using the digital image correlation technique. Finally, we determined the shape and depth factors by analyzing the results of the load tests performed for surface and embedded strip and square footings in dense sand using procedures that account for stress level, loading path, and flow rule nonassociativity. [ABSTRACT FROM AUTHOR]

The bearing capacity of large rectangular foundations on soil subjected to combined loading [simultaneously subjected to vertical load (V), overturning moment (M), and horizontal or lateral load (H)] is one of the central topics of interest to geotechnical engineers as it relates to the design of foundations such as ground anchorages of bridges, offshore structures, and gravity dams. To solve this problem, a combination of numerical simulation and theoretical research was used, and a stability evaluation model of large rectangular foundations on soil subjected to combined loading was established. First, an empirical equation for the failure envelope in the V‒M‒H loading space of rectangular foundations was developed. Second, the safety factor for load-path dependency (LPD) was established by considering the combined effects of V, M, and H, the stability evaluation model for large rectangular foundations on soil subjected to combined loading was constructed by proposing a method for calculating the LPD safety factor based on the V‒M‒H failure envelope. Last, the accuracy and effectiveness of the stability evaluation model proposed was verified. The proposed model provides a convenient means of calculating the stability of large rectangular foundations on soil under combined loading. The model was applied to the optimal design of a gravity anchorage project of a suspension bridge, which proves that the proposed model is rational and efficient. [ABSTRACT FROM AUTHOR]

Cavities are common subsurface anomalies that have a significant impact on the bearing capacity of footings. While cavities behave three-dimensionally, in previous studies, the analysis of cavities has been limited to two-dimensional plane-strain analysis because of the time-consuming nature and complexity of three-dimensional modeling. However, this study demonstrates that the bearing capacity factor derived from three-dimensional modeling can be up to 10 times higher than that obtained from plane-strain analysis, highlighting the importance of considering three-dimensional effects. The present paper conducted three-dimensional simulations to investigate the impact of spherical cavity on the failure mechanisms and bearing capacity of footings under undrained conditions. An extensive parametric study was performed to investigate the influential parameters, including footing width to cavity dimension ratio (B/D), cover depth ratio (C/D), overburden factor (γD/Su), and void eccentricity ratio (S/D) for both circular or square footings. The results indicate that increasing the overburden factor and void eccentricity ratio leads to a decrease and increase in the bearing capacity of the footing, respectively. Furthermore, changes in other parameters can either increase or decrease the bearing capacity depending on the characteristics of the cavity (size and location) and footing (size and shape). General solutions for the bearing capacity factor are provided for different variations of the dimensionless parameters. This study also examined various failure mechanisms, including both cavity-independent and cavity-dependent failure mechanisms, associated with circular and square footings and influential parameters. These mechanisms are categorized into three zones for cavity-independent failures and four zones for cavity-dependent failures. The changes in the influential parameters including B/D, S/D, γD/Su, and C/D lead to changes in the type of failure mechanism and the size of the failure zones, while the foundation shape does not have a significant effect on the failure mechanism. Sinkholes and underground cavities annually contribute to infrastructure damage and financial losses. The 1981 incident in Winter Park, Florida, exemplifies the real-world consequences. Previous investigations have been limited to two-dimensional models due to the time-consuming nature and complexity of three-dimensional modeling, but the real-world nature of cavities in three dimensions requires a more comprehensive understanding. This study directly addresses this need by investigating the impact of three-dimensional cavities on the bearing capacity of circular and square building foundations, also known as footings. This study thoroughly investigated the factors influencing the results, encompassing cavity size, depth, soil weight, and off-center position. It extensively explored potential footing failures, providing detailed discussions. Our findings are presented as easy-to-understand maps and charts covering a broad range of potential scenarios. These visual tools can help engineers and researchers accurately estimate the stability of a building's foundation when a cavity is present underneath. In simpler terms, this research has created a handy tool for professionals to predict the potential danger posed by hidden cavities to buildings and infrastructure. This knowledge can then be applied to ensure safer building practices, potentially saving a significant amount of money and preventing accidents in the future. [ABSTRACT FROM AUTHOR]

AbstractThis study proposes guidelines for predicting the failure mechanism of a shallow strip footing resting on geosynthetic-reinforced granular deposit at different stages of footing settlement. Physical model tests are performed on footings resting on unreinforced and geosynthetic-reinforced soil. The reinforcement parameters varied include the depth between consecutive reinforcements, number of layers and the depth of the reinforced zone. Additionally, contours of deformation and maximum shear strain of soil and mobilised tensile strain in reinforcement with increasing footing settlement are studied. The improvement of bearing capacity ratio and the peak tensile strain in the reinforcement was monitored for three normalised settlement ratios of 5% (low), 10% (medium) and 25% (high). The reinforced soil models were found to depict primarily a punching shear failure limited solely within the reinforced zone at s/B of 5%. This was supplemented with a well-formed triangular wedge in the underlying unreinforced soil at s/B of 10%. In addition to above mechanisms, the radial shear zones were prominent at s/B of 25%. Failure mechanisms have been proposed eventually for each s/B value investigated, including guidelines on the upper and lower bounds of the load dispersion angle in the reinforced soil and wedge angle of the underlying unreinforced soil. [ABSTRACT FROM AUTHOR]

AbstractThe effect of consolidation on the undrained capacity of two interfering footings has not been investigated previously in a systematic manner, although this is particularly interest for offshore foundations, where consolidation will occur as a result of working load or preload. This paper presents results of a numerical investigation into the consolidated undrained bearing capacity of two interfering footings resting on heterogeneous clays. Finite difference code FLAC with the modified Cam Clay soil model is applied to couple the effect of consolidation and strength gain of clay beneath the footings. The results are expressed in dimensionless form of the gain in capacity, accounting for the coupling effects of the spacing between two footings, the magnitude and duration of applied preloads, and the clay strength heterogeneity. A design approach based on the data-fitting equations of the obtained solutions is proposed, and the failure mechanisms of the two adjacent footings after consolidation are also discussed. [ABSTRACT FROM AUTHOR]

Village classification is an important foundation for preparing village planning and formulating development strategies. This study takes a typical plateau mountain area-Yulong County, Yunnan Province as the research object. First, the analytical hierarchy process is used to build a “three evaluations” (ecological sensitivity, development potential, and construction suitability)indicator system. Second, spatial correlation analysis of the “three evaluations” was carried out to obtain the initial village classification results. Finally, the state space method was used to calculate the village bearing capacity, which could be used to correct the initial village classification. Thus, the final village classification could be obtained. The results show that a significant plateau mountain space distribution of heterogeneity was shown in the villages of the research area, and the spatial autocorrelation coefficients of the “three evaluations” were 0.343, 0.253, and 0.110, respectively; more than 60% of the villages were in a bearing state and the higher bearing capacity was concentrated in the southeast, northwest, and central regions of the research area. After the comprehensive carrying capacity was calculated and corrected, the special protection category accounted for 23%, the suburban integration category accounted for 4%, the relocation and withdrawal category accounted for 15%, the agglomeration and promotion category accounted for 40%, and the temporary unclear category accounted for 18%. For different types of villages, the layout optimization strategy should be proposed according to the carrying capacity calculation results. The results of this research can provide a reference and basis for the formulation of township(town)-level territorial spatial planning and the implementation of “multi-planning” practical village planning. [ABSTRACT FROM AUTHOR]

Large seabed trenches have recently been found adjacent to suction caissons with taut and semi-taut moorings. Seabed trenching leads to loss of soil support and additional caisson rotation, and can therefore significantly decrease geotechnical capacity. In this paper, upper-bound solutions are presented that enable calculation of the reduction in ultimate load-carrying capacity of a suction caisson in a trenched seabed compared to optimal capacity in an intact seabed. Failure mechanisms for caissons embedded in an intact seabed are augmented to incorporate a kinematically admissible mechanism for a trench extending from the mudline. The rate of work dissipation is calculated to determine the optimised solution of the inclined capacity of suction caissons. Comparisons of the results of the upper-bound solutions with finite-element analyses show that the failure mechanisms and the calculated load-carrying capacities derived from the two methods agree well. Therefore, the analytical upper-bound method presented in this paper can be employed for efficient routine calculations of suction caisson capacity under inclined load considering seabed trenches, which are increasingly encountered in engineering practice. [ABSTRACT FROM AUTHOR]

Soil spatial variability is a common situation in marine geotechnical engineering, while most studies have primarily focused on evaluating the uniaxial vertical (V), horizontal (H), or moment (M) bearing capacity of foundations in spatially variable clay. Whereas the process of combined bearing capacity analysis by probe method is complex, resulting in low efficiency. As a result, the simplified modified swipe (SMS) method is proposed in this paper, which can represent the capacity in any direction of the load space accurately and takes just 6.5 times the duration of a single probe loading for a half-failure envelope. Based on the established three-dimensional random finite element models, the effectiveness of this method is demonstrated by analyzing the combined bearing capacity of five kinds of foundations in spatially variable clay. Furthermore, Monte Carlo simulations revealed that the spatial variability of the soil cause various failure envelopes, and the response of the combined bearing capacity is not identical in all directions. The VHM failure envelopes with different probabilities are given and could be found that the safety factors recommended by the guidelines are insufficiently conservative for structures susceptible to soil spatial variability. Finally, a strategy for applying different safety factors to both load directions is proposed, which could be helpful for the design of foundations in spatially variable clay. [ABSTRACT FROM AUTHOR]

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

The monopile-friction wheel hybrid foundation withstands various loads in the marine environment, such as the vertical load (V) transmitted from the superstructure, horizontal loads (H) caused by wind or wave, torsional loads (T) caused by rotating structures. In this article, 1 g model tests are used to investigate the behavior of the monopile-friction wheel hybrid foundation under independent horizontal load (H) or torsional load (T), and combined loads (H-T) in sand soil, respectively. The failure envelopes of H-T loading plane are obtained from the measured load-displacement data with the simplified calculation equations presented as well. Finally, we also discuss quantitatively the influences of the pre-vertical loads, foundation geometry and loading eccentricity on the bearing capacity of the hybrid foundation via the three-dimensional finite element method. The results indicate that the displacement response of the hybrid foundation under independent loading is significantly different from that subjected to combined loads (H-T). The torsional bearing capacity of the hybrid foundation can be significantly improved by 6.6-33.34% under pre-horizontal load. The horizontal bearing capacity of the hybrid foundation decreases sharply after the pre-torsional load reaches a certain value, which decreases by about 20%. The presence of a friction wheel improves the torsional/bending moment distribution of pile shaft. [ABSTRACT FROM AUTHOR]

Load‐bearing capacity tests on large scale test specimens for modular polygon tower sections of wind turbines The verification for stability and fatigue of steel towers for onshore wind‐turbines require large dimensions due to the high static and dynamic loads. Since, the rated power as well as the hub height will further increase for wind turbines in the future, also the dimensions of the tower must be increased. Some kind of turbines will require a tower base diameter of > 4.5 m. Tubular steel sections with this dimensions cannot be transported (economically) by road. Therefore modular construction methods have been developed, whereby the tubular steel sections consist of longitudinally divided segments, which will finally assembled on site. Furthermore, the detail design of the connections between the structural components is also a challenge when planning wind turbines for the next generation. As a technical alternative to the existing tower configurations, a concept for a modular polygon tower made of steel is presented, where single plate segments can be connected along the longitudinal edges using extruded profiles so that no further bolted or welded connections are required for the final assembly on site. This technical proposal allows a longitudinal manufacturing of tower segments with steel plates but without any formwork with rolling and bending machines. As part of a research project, the technical feasibility of a modular polygon tower for a hub height of 200 m and a wind turbine class with 10 MW rated power was analysed to offer technical solutions for the next generation of onshore wind turbines. Load cases were generated for a fictitious reference wind turbine to carry out a pre‐design for the tower sections. A test programme was created on the basis of the calculated tower dimensions and ultimate load bearing tests were carried out on test specimens at a scale of 1 : 10. This paper presents the results of the experimental investigations, comparing the load‐bearing capacity of the various tower configurations and the observed failure mechanisms are explained. [ABSTRACT FROM AUTHOR]

This study presents a new solution algorithm to calculate the bearing capacity coefficient Nγ for a fully rough strip footing located on an infinite slope considering different soil friction angles φ and ground slopes β° using the stress characteristics method. The results showed that Nγ coefficients decreased with an increase in slope inclination, and roughness contribution prevented further reduction, particularly for higher φ values. The higher contribution of the upside-sloping ground for footing laid on the infinite slope led to a lower reduction of the Nγ coefficients compared with the footing placed at the slope vicinity in terms of a larger area affected by the stress field, and a larger plastic region of the downface slope. The reduction value was more eminent for steeper slopes β ≥ 20° due to the tendency for nonsymmetrical failure pattern, especially for higher φ values. The findings of the current research and those described in the literature were in good agreement, so much so that the lower-bound limit analysis and the current solution technique virtually reflect the same trend. The load inclination values for footings located adjacent to the slope with β ≤ 30° were not meaningful, whereas for footing resting on an infinite slope with β ≥ 25° it exceeds 15°, which reflects the fact that its effect should not be neglected, especially for ground slopes greater than 20°. By increasing β°, the maximum values of plastic length and plastic depth on the left and right sides of the footing decrease and increase, respectively. The maximum depth of the plastic region for β ≥ 20° from around the right side of the footing shifts toward the downward-sloping face. The maximum width of the elastic wedge gradually reduces, and the intersection point of the left and right plastic regions slowly shifts to the left and upside of the footing. [ABSTRACT FROM AUTHOR]

The strength anisotropy and strain softening of natural soil can significantly impact the bearing capacity of shallow foundations on clay. In this article, we present a nonlocal numerical method to study the coupled rotation of the maximum normal stress axis and strain softening on the bearing capacity of shallow foundations on clay through a Cosserat strain softening constitutive model. The strength anisotropy and strain softening characteristics were numerically implemented into a finite-element (FE) program by dynamically updating the anisotropic cohesion in global Newton–Raphson iterations. Due to its nonlocal feature, the proposed nonlocal numerical method can overcome the mesh dependence in simulating the progressive failure of clay through the classical FE method. We first validated the efficacy of this method against the results of the plane strain test and numerical results in the literature. We then study the bearing capacity of a strip footing over anisotropic and strain-softening clay through the implemented numerical method. The results indicated that the deposition angle has an important effect on the bearing capacity and failure mode. The effects of the degree of anisotropy and strain softening on the ultimate bearing capacity are quantified through the numerical method. It is found that (1) the proposed method can effectively reflect the characteristics of the maximum normal stress axis rotation on the failure surface of the footing; (2) the ultimate bearing capacity of a footing (Pu) on anisotropic clay could increase linearly with an increase in the anisotropy ratio k (i.e., k is the ratio between C1 and C2) and decreases with an increase in the softening modulus; and (3) the strength anisotropy and strain softening are strongly coupling factors impacting the bearing capacity of anisotropic clay. [ABSTRACT FROM AUTHOR]

Karst caves should be avoided as far as possible during pile foundation construction, but sometimes it is unavoidable. Therefore, research on the bearing characteristics of pile foundations in karst areas is a problem that must be faced. The current status of research on the bearing characteristics of pile foundations in karst areas from three aspects: theoretical research, physical experiments, and numerical simulation was analyzed. The following conclusion was drawn. The existing bearing capacity calculation formulas have insufficient consideration of influencing factors, and subsequent theoretical research should consider the derivation of single pile ultimate bearing capacity calculation formulas under the synergistic influence of multiple factors. The variables in physical model tests are relatively single, and the influence of water on the bearing characteristics of pile foundations is often ignored during the testing process. Subsequent research should focus on the synergistic effect of groundwater and multiple factors. There are few in-situ experiments conducted, and the accuracy of the data obtained through detection needs to be improved. In the future, more in-situ experiments and in-site damage experiments should be carried out to obtain more comprehensive experimental data on the bearing characteristics of pile foundations. Most of the cave models are built with standard size in numerical simulation, which is inconsistent with the three-dimensional geometric size of the actual stratum cave. The establishment of a more realistic Geometric modeling of the cave is a key development direction in the future. [ABSTRACT FROM AUTHOR]

In order to study the effect of high temperatures on the thermomechanical properties of reinforced concrete (RC) beams, fire and mechanical tests were carried out on four fully dimensioned simply supported beams. A numerical analysis model based on the measured information was developed, and validated through experimental tests and theoretical calculations. The effects of fire exposure time, different physical parameters and concrete spalling parameters on the thermodynamic properties were further analysed. The results show that the measured vibration frequencies exhibit a fluctuating trend of decay with increasing fire exposure time. The simulated frequency decays as a power function of fire exposure time. The frequency decreases with increasing span-to-height ratio and increases with section width, elasticity modulus of the concrete and reinforcement ratio. Cross-sectional temperature field is most significantly affected by spalling depth, and increases rapidly with an increase in this parameter. With the increase in spalling area ratio, the increase in the temperature field gradually becomes smaller. The effect of spalling area ratio was relatively stable after more than 15%. Flexural bearing capacity shows a linear trend of decrease with increase in spalling depth. With the increase in spalling area ratio, it shows a power function of the decreasing trend. [ABSTRACT FROM AUTHOR]

An experimental and numerical study of hollow reinforced concrete-filled glass-fibre-reinforced polymer tubular beams was carried out. Based on bending tests, the working mechanism and failure modes were studied. A finite-element model was established and the validity was assessed by comparing the experimental and numerical results. The main parameters included the wall thickness of the fibreglass tube, reinforcement ratio, hollow ratio, concrete strength and fibre winding angle. The results indicated that the composite beams failed gradually with considerable ductility. The bending capacity increased by about 12% with every 1 mm increment of the fibreglass tube thickness, increased by about 40% as the reinforcement ratio increased from 2.28% to 4.56%, and increased by about 6% with every 5 MPa increment of the concrete strength. The bending capacity decreased and then increased as the fibre winding angles ranged from 10° to 90°, and a small fibre winding angle was preferable for the flexural member. A hollow ratio of 0.375 is proved to be applicable to obtain lighter member self-weight with minimal decrease in strength. [ABSTRACT FROM AUTHOR]

This study will look for the ultimate bearing capacity value of bored pile foundation and foundation subsidence, based on SPT data and loading test calculated empirically with SPT data using equations provided by O'Neil and Reese while loading test data using curve interpretation Davidson Method, Mazurkiewich Method, Chin Method and finite element method using 2D Plaxis software with all types of medium mesh. After analysis, the ultimate bored pile carrying capacity value of ø 80 cm based on SPT data using the O'neill and Reese equations was 1242 tons, then analysis using the Davisson method of 875 tons, using the Mazurkiewiech method of 960 tons and the Chin method of 876 tons. While the ultimate carrying capacity based on PLAXIS 2D calculations is 1364 tons. 5. Based on SPT data, the carrying capacity of a single bored pile axial permit (Qi) was obtained at 497 tons with SF = 2.5. And for the value of the decrease that occurs in the bored pile foundation based on analytical results is 22.85 mm, based on the loading test is 7.95 mm and based on the PLAXIS 2D program is 14.12 mm. Based on the results of the analysis, it can be concluded that the O'Neil and Reese equations provide a greater value than the interpretation of load testing so that it will provide a large safety value if used when design and descent analysis that is closest to the results in the field is analysis with 2D PLAXIS with the Mohr-Coulomb modeling type. There are differences in carrying and lowering capacity analysis results with several methods used, but the use of analytical methods and finite element methods with PLAXIS 2D meets the safety requirements of bored pile foundations. [ABSTRACT FROM AUTHOR]

The state of meadow vegetation in areas with different ages of experimental spring burnout (from 1 to 12 years ago) was studied in the Tomsk region for 3 years. On experimental plots of 1 m2 and 100 m2 (small- and middle-scale levels, respectively), the dynamics of species richness, total projective cover of vegetation, and aboveground phytomass reserves were characterized, and the structure of communities was analyzed. It was revealed that a single fire in the spring significantly reduces species richness for small-scale plots and increases the total projective cover for middle-scale plots. Structural differences from control plots can be traced from 1 to 4 years for different characteristics. The effects of fire are more prominent for small-scale plots. To suppress tree growth and maintain the existence of meadows, grass fires seem to be a less effective practice than mowing. At the same time, the results obtained potentially allow us to consider prescribed burning as a tool for maintaining the stability of meadow plant communities in the south of Western Siberia, preventing them from becoming overgrown with tree undergrowth, in cases with a controlled frequency of burning and the use of appropriate fire safety measures. [ABSTRACT FROM AUTHOR]

A new type of UHPC‐NC (normal concrete) structure in the negative moment zone was proposed to improve the bearing capacity of the connection structure in the negative moment zone of prefabricated prestressed concrete (PC) beam bridges. First, the distribution characteristics of the crack, cracking load, ultimate moment, and ductility coefficient of the new structure were obtained by the 1:4 scale model tests. The feasibility of the connection structure is verified. Then, the value ranges of critical structural parameters affecting the bearing capacity of the connection structure based on the plane section assumption analysis, including the reasonable thickness of the UHPC layer, the reinforcement ratio of the longitudinal tensile reinforcement, and the diameter of the reinforcement, are obtained. At the same time, based on the verification of the finite element model, the influence of crucial research parameters on the bending capacity of the connection structure is obtained by using the finite element method. Finally, a theoretical method for the bending moment capacity of the connection structure of the UHPC‐NC structure is proposed, considering the high ductility characteristics of UHPC materials. The average relative error between the calculation results and the finite element method is within 7.2%, which verifies the reliability of the calculation method in this paper and provides a reference for its design and engineering application. [ABSTRACT FROM AUTHOR]

The section K0 +785 -K0 +988 on the north shore of the Dalian Bay immersed tunnel, which is higher than the original seabed surface, is susceptible to ship collision risks and requires anti-collision measures. Taking into account factors such as construction difficulty, environmental protection, and cost, a permeable gravity pier foundation composed of circular caissons, column piles, and cast-in-place piers was proposed as the anti-collision structure, while meeting the requirements of the construction period. Combined with the structural form and main loads of the anti-collision pier, the overall stability of the anti-collision pier structure and the bearing capacity of the column piles were analyzed and calculated using finite element method and specification method. The results show that the permeable gravity pier anti-collision structure can meet the requirements of engineering use in all aspects, and can provide design reference for the construction of similar structures in the future. [ABSTRACT FROM AUTHOR]

This paper presents the results of field tests performed to investigate the bearing capacity of Drilling with a prestressed concrete (DPC) pipe pile under different end sealing and side grouting conditions. The High Strain Dynamic Testing (HSDT) was conducted to evaluate the bearing characteristics of full-scale DPC pipe piles. Moreover, base resistance theoretical formula considering end sealing effect and shaft resistance theoretical formula considering side grouting effect are presented. The theoretical results were compared with the recommended values of specification for traditional pipe piles and tested values to demonstrate the rationality of theoretical formulas and the superiority of end sealing and side grouting. Furthermore, the effects of sediment under the sealing concrete and grouting conditions on the bearing capacity of a single pile were discussed in detail to reveal the influencing mechanisms of end sealing and side grouting. The result showed that the presented base resistance theoretical formulas can estimate the effect of end sealing on the ultimate base resistance of DPC pipe piles with good accuracy. For 1 m pipe piles, end sealing increases the base resistance by up to 103.5% at most compared to unsealing pipe piles; total shaft resistance of piles with double or multi-pipe grouting is more than 37% higher than the recommended maximum value of traditional pipe piles in the pile foundation specification. In addition, the base resistance was significantly affected by the sediment thickness under the sealing concrete. The hole wall time-dependent deformation caused by drilling and unloading affected the side grouting significantly. [ABSTRACT FROM AUTHOR]

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

Large stone porous asphalt mixes (LSPMs) have the characteristics of large gaps, large content of coarse aggregate, and large particle size of coarse aggregate. Compared with the traditional asphalt-treated base (ATB), LSPM forms a more obvious skeleton structure in the process of bearing load. In this study, the discrete element method (DEM) model of LSPM is established, and an evaluation method for studying the bearing capacity and high-temperature performance of LSPM through an internal skeleton network is proposed. Firstly, the DEM model of asphalt mixture with different gradations is established, and the virtual uniaxial penetration test is carried out. Then, the performance of the skeleton network inside the asphalt mixture is analyzed, and the contribution of each group of aggregates to the skeleton network is further studied. The experimental results show that the bearing capacity of an asphalt mixture is closely related to the performance of internal skeleton network. The skeleton network inside the asphalt mixture is extracted by the value of the contact force, the angle between the contacts, and the contact continuity. When the skeleton network has better bearing capacity and load-transfer capacity, the asphalt mixture can bear more external load in the virtual penetration test. The contribution of different coarse aggregates to the skeleton network is analyzed from four perspectives: total contact force, vertical work, contact number, and effective coordination number. The aggregates of 19–26.5 and 4.75–9.5 mm constitute the main body of the load-transfer path and play a major role in bearing and transmitting the load in the skeleton network. [ABSTRACT FROM AUTHOR]

In the Chengdu-Chongqing economic circle in China, the recommended bearing capacity of a medium-weathering mudstone foundation is less than the capacity of the rock structure to withstand loads. The aim of this paper was to perform plate loading tests (PLTs) with binocular vision measurement (BVM) to obtain the accurate deformation of the foundation under vertical loading. The results revealed that vertical load–bearing foundations have a failure mode that can be reduced to that of thrust failures for thin bedded structures of mudstone foundations. By analyzing the differences in results between the PLTs and the uniaxial compressive strength tests under the same conditions, a new formalism for calculating foundation-bearing capacity was proposed; there is only a 5% difference compared to in situ tests. The results of this research provide theoretical support and a practical benchmark for the full development of the load-bearing capability of soft red rocks. As the Chengdu-Chongqing economic circle progresses toward the international urban cluster, inevitably, soft rock is used as a foundation retaining layer in the construction of superhigh and super-rise buildings in the region. However, owing to antiquated testing methods and poor intelligibility of the testing equipment, the bearing capacity of such a mass of rock has yet to be fully developed and cannot meet the dual-carbon economic goals and sustainable development of architectural design. Based on this, the study introduces a noncontact method to measure the bearing capacity of soft rock within the traditional method of in situ testing and combines the concept of big data analysis to advance an empirical method for calculating the bearing capacity accurately. Based on the results of this study, the concept of natural foundations can be adopted and the engineering dilemma that the treatment of building foundations cannot be economical and practical can be solved. [ABSTRACT FROM AUTHOR]

To investigate the flexural performance of Steel-FRP Composite Bars (SFCBs) reinforced Ultra-High Performance Concrete (UHPC) beams, eight concrete beams with different reinforcement ratio, types of concrete were designed and fabricated. Flexural performance tests were conducted to examine the effect of various parameters on bearing capacity, deflections, crack patterns, ductility, and failure modes. The results indicate a significant enhancement in the flexural capacity of tested beams with UHPC. The bearing capacity of SFCB–UHPC beam is higher than that of steel-reinforced UHPC beams, but less than that of FRP (Fiber-Reinforced Polymer) reinforced UHPC beams. The deformation and crack resistance ability of SFCB–UHPC beams fall between those of steel-reinforced UHPC beam and BFRP-reinforced UHPC beam. Increasing the concrete strength and SFCB reinforcement ratio can significantly enhance the deformation and crack resistance ability of SFCB–UHPC beam. All tested specimens exhibited ductile failure. At the serviceability limit state controlled by deflection/crack, the steel-reinforced UHPC beams and BFRP-reinforced UHPC beams exhibit the highest and lowest utilization factors of flexural capacity, respectively, and that of SFCB–UHPC beams falling in between. High-ductility UHPC enhances energy absorption, ductility, initial and secant stiffness. The reinforcement type has a minor impact on the energy dissipation of flexural beams. SFCB, on the other hand, enhances the ductility, initial and secant stiffness of specimens. Based on a simplified material constitutive model and fundamental assumptions, three failure modes for the SFCB–UHPC beam under bending were defined, along with their respective criteria. This enables the establishment of a simplified load capacity calculation formula. With reference to ACI440.1R-03, a stiffness calculation formula was developed to predict the deformation of SFCB–UHPC beams. This research can provide a technological reference for the design and analysis of SFCB-reinforced UHPC beams. [ABSTRACT FROM AUTHOR]