Assessment Of Bearing Capacity Research Articles

Bearing capacity of constrained grouting expansion bored pile based on CPTU and expansion tests

Bored Pile of Constrained Grouting Expansion (BPCGE) is a new type of pile that combines grouting, compression, and expansion technologies. However, there is still insufficient understanding of its bearing characteristics and strength degradation, especially when the surrounding mass is located in soft cohesive soil layers. To address the issues mentioned above, analysis of bearing capacity and strength assessment of BPCGE based on piezocone penetration test (CPTU) and expansion tests are taken into account. Firstly, based on the similarity between the pile prototypes and models, constrained grouting expansion tests are conducted to study the borehole expansion and soil consolidation effects, and analyze the influence on effective stress of soil around the pile and stress relaxation characteristics of cohesive soil. Secondly, CPTU tests and numerical simulations were carried out to investigate the size effect of BPCGE, and a conversion relationship between lateral friction resistance of pile and CPTU friction resistance was established. Finally, the ultimate bearing capacity of BPCGE is proposed. In an application of a high-rise residential project, the calculation method based on CPTU data can effectively predict the ultimate bearing capacity of BPCGE, saving 262 ordinary piles.

Development of Rapid Evaluation and Analysis Cloud System for Bearing Capacity of Highway Bridges

Abstract In order to address and optimize the issues in the current assessment of bridge bearing capacity, such as the heavy workload associated with processing bridge data, the tedious modeling process, the inability to automatically calculate sub-item correction coefficients, and the lack of automatic report output and key data analysis functions, this paper has developed a cloud-based rapid calculation and analysis system for highway bridge bearing capacity. Firstly, the system is capable of quickly establishing finite element models and conducting detailed finite element calculations and analyses. Subsequently, based on field test data, it automatically calculates checking coefficients for each item and compares and analyzes the bridge’s bearing capacity. Utilizing a cloud network platform enables more convenient and rapid creation of bridge tasks and projects, key data statistical analysis, automatic report output, among other functions. Examples demonstrate that the system achieves data fusion, statistics, result verification which shifts highway bridge bearing capacity evaluation towards networking and automation while enhancing efficiency and quality in carrying capacity evaluation work.

Hybrid deep learning and isogeometric analysis for bearing capacity assessment of sand over clay

Hybrid deep learning and isogeometric analysis for bearing capacity assessment of sand over clay

Static and dynamic load test on concrete hollow-core slab bridge

In this paper, dynamic and static load test were carried out on a multi-span reinforced concrete simply supported hollow core slab bridge in Shenyang, Liaoning Province. Through the static load test, the quality and reliability of the project are evaluated, and the results show that under the action of 0.88 times of highway-classⅠload, the deflection and strain check coefficients of the control section of the tested condition are less than 1, which meets the specification requirements, and the measured relative residual deformation and relative residual strain are less than 20%, and the bridge structure is basically in the elastic working state. And combined with the finite element analysis model, the comparison between measured data and calculated data is carried out. Through the dynamic load test, the self-oscillation frequency and damping ratio of the superstructure were tested, and the results showed that the measured damping ratio was 0.690%, the first-order measured vibration pattern conformed to the variation rule of the vibration pattern of the simply supported girder bridge, and the measured self-oscillation frequency was 13.594 Hz, and the measured self-oscillation frequency (fundamental frequency) was greater than the calculated frequency, and the structural actual stiffness was greater than the theoretical stiffness, and the working condition was good. This study is of great significance for the assessment of bearing capacity and quality control of concrete hollow core slab bridge, and provides a useful reference for bridge design and operation.

Dualistic effect of the deformation of protective structures made of broken rock in mine workings under static load

Purpose is to reveal physical essence of the dualistic (double) nature of deformation effects and their influence on the mechanical properties of protective structures made of broken rock while unloading coal-bearing mass to ensure stability of side rocks and operational conditions of the development mine working within the working areas of coal mines. Methods. The deformation properties of protective structures made of broken rock was modeled on experimental samples during their static load in terms of uniaxial compression with the possibility of lateral expansion of the original material or its compressive stress. Findings. A dualistic effect of deformations for the conditions of uniaxial compression of protective structures was revealed. Under the effect, a complex transformation of volume and shape occurs in the structures caused by the process of relative changes in the backfill material volume. The observed phenomenon occurs within the range of 0.12 ≤δV ≤ 0.32 and the values of the compaction coefficient of broken rock being 1.13≤k con. ≤ 1.47, depending on the granulometric composition of the source material and its bulk density. It was established that under conditions when broken rock is compressed, there is an effect of forming the bearing capacity of protective structures, which is observed when a relative change in the volume of backfill material is 0.14 ≤ δV ≤ 0.38, and its compaction factor reaches 1.16 ≤ kcon. ≤ 1.59. Depending on the homogeneity degree of the backfill material of protective structures, when comparing the values of kcon., a dualistic (double) effect is manifested in the difference of deformation characteristics of broken rock under uniaxial and compressive stress, reaching two or more times. Originality. A regularity was established that determines the relationship between compaction factor kcon. of broken rock and a relative change in the volume (δV) of backfill material, which makes it possible to evaluate bearing capacity of protective structures, being under static load in a stress-strain state. Practical implications. The research results can be used to substantiate the selection of a method to protect development mine working with flexible supports made of broken rock. To clarify the assessment of bearing capacity of such structures, it is advisable to carry out specific field studies in mine conditions.

Probabilistic assessment of bearing capacity of skirted foundation under combined loadings with a rigid base

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

Assessment of ultimate bearing capacity of rock-socketed piles using hybrid approaches

Assessment of ultimate bearing capacity of rock-socketed piles using hybrid approaches

Assessment of Ultimate Bearing Capacity of Static Loading Pile Based on Cusp Catastrophe Theory

Determining the ultimate bearing capacity of pile is important for reasonable design of the pile. In this paper, a cusp catastrophe theory-based method was proposed for assessing the ultimate bearing capacity of static loading pile. Firstly, a three-parameter quartic polynomial in accordance with the standard form of cusp catastrophe model is proposed and used to fit the experimentally obtained Q–S curve. The parameters which allow the polynomial to produce best fitting to the Q–S curve are taken to identify the stability of the pile following a simple procedure. Then, the proposed method was verified against 10 Q–S curves obtained from field tests at Jinqiao-Meiya and Jinqiao-Chunyu areas of Shanghai. Results show that the ultimate bearing capacities of the piles identified by the proposed method were comparable to those identified by the JGJ 106-2014 standard method. Finally, it is found that the stability of the pile identified by the proposed method and the mechanical state of the pile identified by the Golden Section approach were correlated closely.

Assessment of Flexural Strengths and Flexural Load Bearing Capacity of Bamboo Grids-Reinforced Soil Beam

Soil improvement techniques have become a major solution to soil related problems. Thus, this paper aims to determine the flexural strengths and flexural load bearing capacity of bamboo grids-reinforced soil beam using standard methods and experiments at 7 days, 14 days, 21 days and, 28 days curing ages. The findings of this study showed that the mean flexural strength of uniaxial bamboo grid reinforced soil beam gave 3.50 N/mm² while flexural strength of biaxial bamboo grid reinforced soil beam gave 3.86 N/mm². The result indicates that biaxial bamboo reinforced soil beam has the tendency to maximize the flexural load bearing capacity of soil beams when compared with the use of uniaxial bamboo grid orientation technique. This paper, therefore, recommends that flexural strength and flexural load bearing capacity of inorganic clays of low to medium plasticity should be improved using biaxial grid type of bamboo grid orientation technique.

Assessment of rock mass properties and load-bearing potential in low-grade metamorphic rocks: A study from the Tigray region, Ethiopia

<p>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.</p>

Structures of bored piles: features of installation technology

Currently, pile foundations are often used in engineering practice. Among the modern types of piles used for foundation structures, the option of foundations made of bored piles is definitely popular. They are used for various types of structures: bridges as part of highways, urban ring roads or high-rise buildings. The main problem in these cases is related to a reliable assessment of the bearing capacity of the pile and the development of a cost-effective design solution for foundation structures.
 The studies carried out in this direction confirm that the issue of determining the load-bearing capacity of piles remains relevant both at the stage of developing reliable design solutions and in the process of searching for an economically efficient option of the foundation constructions of buildings and structures.
 Taking into account the design features of bored piles and their installation technology add certain difficulties to the analytical methods of determining the soil bearing capacity of a single pile.
 The practice of using bored piles on construction sites followed by observation of deformations showed that the soil bearing capacity of the piles, determined by the analytical method of standards used at the stage of developing design solutions for foundations, is underestimated. Therefore, the total number of piles in the foundation needs to be optimized according to the results of further field tests. Geometric parameters of piles, such as length and diameter, in some cases can also be reduced at the stage of rationalization of the design solution of the pile foundation, based on the results of field tests. So, as a result, the underestimated value of the load-bearing capacity of bored piles causes an increase in the cost of construction materials, an increase in the cost of installing foundation structures and an increase in the cost of housing for the end consumer.
 The problem of reliable assessment of the soil bearing capacity of piles remains a relevant issue at the moment, as evidenced by the practice of designing foundation structures.
 The paper presents the results of the analysis of the structural features of bored piles, which are aimed at increasing their bearing capacity. Also, the paper examines the features of the technology of installing bored piles, which are determined by both the hydro-geological conditions of the construction site and the need to install the constructive features of the bored pile.

Corrosion evolution and axial mechanical performance degradation of corroded M24 high-strength bolts

To investigate the axial static performance degradation of high-strength bolts subjected to long-term atmospheric corrosion in coastal environments, a neutral salt spray accelerated corrosion test was performed on M24 high-strength bolts over a period ranging from 0 to 330 days. Microscopic morphology observations and axial tensile tests were conducted after corrosion. A linear relationship between mass loss rate and corrosion period was established, and the evolution of pit depth and aspect ratio was proposed. Based on the tensile test, the failure modes of corroded high-strength bolts were categorized as bolt breakage and thread shear-out. The critical mass loss rate for the transition between these two modes was found to be 7.05% (corrosion period of 180 days). Equations characterizing the degradation of residual ultimate strength and relative stiffness as a function of mass loss rate were derived. Furthermore, based on average thickness loss and pit loss, a theoretical analysis on ultimate strength degradation was conducted, and its results were compared to the refined numerical simulations. Both methods were found to provide acceptable outcomes, and numerical results demonstrated more precise and conservative. With numerical method, parametric analysis was conducted, involving 5 groups and 222 models, leading to the formulation of a general ultimate bearing capacity assessment equation concerning bolt diameter and thread pitch.

Flexural properties of low-height prestressed T-beams: tests and numerical simulations

PurposeThis paper presents the experimental and numerical results of the bending properties of low-height prestressed T-beams. The purpose is to study the bearing capacity, failure state and strain distribution of low-height prestressed T-beams.Design/methodology/approachFirst, two 13 m-long full-size test beams were fabricated with different positions of prestressed steel bundles in the span. The load–deflection curves and failure patterns of each test beam were obtained through static load tests. Secondly, the test data were used to validate the finite element model developed to simulate the flexural behavior of low-height prestressed T-beams. Finally, the influence of different parameters (the number of prestressed steel bundles, initial prestress and concrete strength grade) on the flexural performance of the test beams is studied by using a finite element model.FindingsThe test results show that when the distance of the prestressed steel beam from the bottom height of the test beam increases from 40 to 120 mm, the cracking load of the test beam decreases from 550.00 to 450.00 kN, reducing by 18.18%, and the ultimate load decreases from 1338.15 to 1227.66 kN, reducing by 8.26%, therefore, the increase of the height of the prestressed steel beam reduces the bearing capacity of the test beam. The numerical simulation results show that when the number of steel bundles increases from 2 to 9, the cracking load increases by 183.60%, the yield load increases by 117.71% and the ultimate load increases by 132.95%. Therefore, the increase in the number of prestressed steel bundles can increase the cracking load, yield load and ultimate load of the test beam. When the initial prestress is from 695 to 1,395 MPa, the cracking load increases by 69.20%, the yield load of the bottom reinforcement increases by 31.61% and the ultimate load increases by 3.97%. Therefore, increasing the initial prestress can increase the cracking load and yield load of the test beam, but it has little effect on the ultimate load. The strength grade of concrete increases from C30 to C80, the cracking load is about 455.00 kN, the yield load is about 850.00 kN and the ultimate load is increased by 4.90%. Therefore, the improvement in concrete strength grade has little influence on the bearing capacity of the test beam.Originality/valueBased on the experimental study, the bearing capacity of low-height prestressed T-beams with different prestressed steel beam heights is calculated by finite element simulation, and the influence of different parameters on the bearing capacity is discussed. This method not only ensures the accuracy of bearing capacity assessment, but also does not require a large number of samples and has a certain economy. The study of prestressed low-height T-beams is of great significance for understanding the principle and application of prestressed technology. Research on the mechanical behavior and performance of low-height prestressed T beams can provide a scientific basis and technical support for the design and construction of prestressed concrete structures. In addition, the study of prestressed low-height T-beams can also provide a reference for the optimization design and construction of other structural types.

Quantitative method for evaluating corrosion defects and residual bearing capacity of bridge structural steel via MMM technique

The quantitative assessment of corrosion defects and residual bearing capacity is essential to ensure the safe operation of bridge steel structures. In this study, Q345qD steel was selected as the research object, and specimens with different corrosion levels were prepared using the electrochemical corrosion method. Metal magnetic memory (MMM) detection experiments and uniaxial tensile experiments on corroded steel plates were performed. A three-dimensional magnetic charge model of a corroded steel plate considering the end effect was built to explain the variation of the MMM signals. The finite element simulation results of the corroded steel plates were consistent with the experimental and theoretical results. Based on experimental and finite element data, the quantitative relationship between the corrosion depth h and the magnetic characteristic parameter Hn(z) is established with a relative error within 15 %. A quantitative relationship between the nominal tensile strength σu and the magnetic characteristic parameter Hn(z) is proposed with an evaluation accuracy within ±5 MPa. It is suggested that the proposed evaluation method is feasible in quantitatively evaluating the defects and residual tensile strength of corroded steel plates using the MMM technique.

Numerical study on erosion of mono-pier in hyper concentrated flow environment

To study the erosion characteristics of mono-pier in hyper concentrated flow environment, a three-dimensional numerical model describing the pier erosion process is established based on the finite element method. First, the effectiveness of the new erosion model is validated through existing laboratory tests. Then, using this model, the influences of flow conditions, sediment concentration, particle diameter and pier characteristics on the erosion behavior of mono-pier and the evolution of the mono-pier bearing capacity in the erosion process are studied in detail. Finally, an erosion prediction method under the multiple influencing factors is established through orthogonal regression experiments. The numerical results demonstrate that there is a positive correlation between the flow velocity, particle diameter, and sediment content and the mono-pier erosion rate. However, the mono-pier erosion rate is inversely associated with compressive strength and water depth. In addition, the influences of flow velocity, particle diameter and sediment content on erosion of mono-pier are more obvious than other factors, and the ultimate bearing capacity of mono-pier gradually decreases with the development of erosion. This study can provide scientific reference for the bearing capacity assessment of mono-pier in sediment laden flow environment.

Distributed bending stiffness estimation of bridges using adaptive inverse unit load method

Bending stiffness has important applications in bridge damage detection, model updating, and load bearing capacity assessment. However, accurately predicting bending stiffness is a challenging task. In this paper, a two-phase methodology named the adaptive inverse unit load method (AIULM) is developed for distributed reconstruction of bending stiffness from onboard deflection data. In the first phase, the bending stiffness is roughly estimated by uniform discretization. A global stiffness smoothing method is applied to eliminate nonphysical discontinuities of stiffness at interelement boundaries. Then, the smoothed results are applied in the second phase to define a node optimization function to adaptively adjust the element node distribution. An accurate bending stiffness distribution is provided by performing AIULM analysis again based on optimized discretization. Since only real bridge deflection influence lines (DILs) are utilized in the formulation, the AIULM provides a C0-continuous stiffness distribution without any information on internal force. The adaptive optimization of the node distribution allows the practical application of AIULM to different bridges, especially old bridges. Numerical and experimental validation cases, which demonstrate the excellent predictive capability and practical usefulness of the AIULM, have been performed.

Predicting compressive strength of RCFST columns under different loading scenarios using machine learning optimization

Accurate bearing capacity assessment under load conditions is essential for the design of concrete-filled steel tube (CFST) columns. This paper presents an optimization-based machine learning method to estimate the ultimate compressive strength of rectangular concrete-filled steel tube (RCFST) columns. A hybrid model, GS-SVR, was developed based on support vector machine regression (SVR) optimized by the grid search (GS) algorithm. The model was built based on a sample of 1003 axially loaded and 401 eccentrically loaded test data sets. The predictive performance of the proposed model is compared with two commonly used machine learning models and two design codes. The results obtained for the axial loading dataset with R2 of 0.983, MAE of 177.062, RMSE of 240.963, and MAPE of 12.209%, and for the eccentric loading dataset with R2 of 0.984, MAE of 93.234, RMSE of 124.924, and MAPE of 10.032% show that GS-SVR is the best model for predicting the compressive strength of RCFST columns under axial and eccentric loadings. It is an effective alternative method that can be used to assist and guide the design of RCFST columns to save time and cost of some laboratory experiments. Additionally, the impact of input parameters on the output was investigated.

Analysis and Evaluation of Bearing Capacity of Distributed Photovoltaic Connected to Hunan Power Grid

The development of distributed power in Hunan Province is mainly photovoltaic, with an average annual growth rate of 16.4% in the past five years. By the end of October 2022, Hunan’s distributed photovoltaic installed capacity is 3.06 million kilowatts, accounting for 54.6% of the total photovoltaic installed capacity, which exceeds the centralized photovoltaic installed capacity. Due to the rapid large-scale development of distributed photovoltaics, it is common that the actual operation scale exceeds the contemporaneous planning. In addition, Hunan distributed photovoltaic access is concentrated in northern and southern Hunan, while in southern Hunan, due to a large number of local clean energy, a large number of distributed photovoltaic access will increase the output of terminal power supply, which can seriously cause the grid power flow to reverse. This paper takes the power grid topology in southern Hunan as an example of carrying out the bearing capacity assessment of regional distributed photovoltaic access to the power grid. This method guides the rational layout of distributed photovoltaics and stably ensures the operation of the Hunan power grid.

Analysis of Complex Tests of the Module Piles in Difficult Soil Ground

The purpose of the scientific work is comparative analysis using Static compression load test (SCLT) and Dynamic load test (DLT) methods to determine of bearing capacity of pile foundations in difficult soil ground. Mega project is the construction site of Cargo offloading facilities (COF) in Atyrau region. In project used 2 consists module piles. Precast concrete module piles have 16 meter piles and 11.5 meter (9.5 m) piles with joint a total length of 25.5 m and 27.5 m, cross section 40×40 cm. The design of pile foundations was carried out in accordance with the requirements of regulatory standards. DLT testing method is also need for assessment of bearing capacity for module piles. Numerical modeling of piles was carried out in the Plaxis 2D program. The interaction of module piles with difficult of soil ground of West Kazakhstan is presented.

Risk Assessment of Three-Dimensional Bearing Capacity of a Circular Footing Resting on Spatially Variable Sandy Soil

Risk Assessment of Three-Dimensional Bearing Capacity of a Circular Footing Resting on Spatially Variable Sandy Soil