Estimation Of Bearing Capacity Research Articles

Enhancing pile bearing capacity estimation through random forest-based hybridization approach

Enhancing pile bearing capacity estimation through random forest-based hybridization approach

A comparative study on the estimation of ultimate bearing capacity of rock masses using finite element and limit equilibrium methods

Most rock masses are excellent foundation materials due to their bearing capacities of MPa. However, the ultimate bearing capacity of rock masses should be accurately estimated in the design of structures with high foundation loads. In this study, the ultimate bearing capacities of a strip footing built on rock masses with different geotechnical properties are determined using the finite element method (FEM) and the failure criterion of Hoek & Brown. The results of FE-analyses are compared to those obtained from the limit equilibrium methods (LEM) in the literature. It has been shown that the FEM with associated flow rule and Terzaghi`s limit equilibrium method give similar failure surfaces for most cases, and the ratio of ultimate bearing capacities determined according to the Terzaghi´s method to FEM varies between 1.5 and 4. In cases, in which the failure surfaces obtained from both methods differ, this ratio can rise up to 11.aring capacities determined according to the Terzaghi´s method to FEM varies between 1.5 and 4. In cases, in which the failure surfaces obtained from both methods differ, this ratio can rise up to 11.

Estimation of bearing capacity and serviceability of a floor slab after high-temperature exposure

Estimation of bearing capacity and serviceability of a floor slab after high-temperature exposure

Geotechnical and structural assessment on estimated bearing capacity of strip footing resting on silty sand incorporating moisture content effect

This paper aims to assess the ultimate bearing capacity of a strip footing on the ground surface of a silty sand soil layer. It considers structural failures and geotechnical changes, including the impact of moisture content, using numerical simulation in PLAXIS 3D V21. The structural damage assessments on a student center building located in the northern part of Peninsular Malaysia were performed by visual inspection, and thirty-six sub-points of rebound hammer tests were conducted on three selected different points (Point 1, 2, 3) of the building to evaluate concrete strength and record crack characteristics for severity classification. Subsequently, an extensive geotechnical laboratory tests were performed to investigate the effects of moisture content on physical and mechanical properties of silty sand including, soil compositions, Atterberg limits, compaction characteristics and unconfined compressive strength (UCS) from the building area which resulted to structural damage caused by differential settlement beneath the building. The visual inspection assessment has shown the student center building experienced severe damage category at Point 1 with crack width and length are 25 mm and 3 m respectively. At Point 2, there was minimal damage to the surface structure, with a crack measuring 1 mm in diameter and 0.1 m in length. Furthermore, crack width and length are 1 mm and 0.2 m respectively are recorded for Point 3. The study fills in a gap in the research by combining geotechnical and structural tests on the bearing capacity of silty sand with moisture content. The effect of soil saturation, matric suction, and the unsaturated strength of soil are affected by these factors in the analysis of the bearing capacity of the foundation. The exact solution gives us 568.213 kPa for a zero degree of saturation and 385.34 kPa for a 100 percent degree of saturation. The incorporation of geotechnical and structural assessments aims to find reliable strategies for failure remediations for instance patched and sealed with a concrete patching compound.

Seismic performance and estimation of flexural bearing capacity of prefabricated engineered cementitious composite shell–reinforced concrete composite column with grouted sleeve connection

Engineered cementitious composites (ECCs) have excellent crack control capacity and pseudo-strain-hardening behaviour. They can be used to improve the damage-tolerant capacity of vulnerable parts of structures. To improve the seismic performance of a traditional prefabricated column connected with grouted sleeves (GSs), an innovative prefabricated ECC shell–reinforced concrete (RC) composite column with GSs (ECC–PRC–GSs) is proposed in this paper. Then, three-dimensional nonlinear finite element models of the ECC–PRC–GSs are established and validated with previous experimental results. Subsequently, parametric analysis of the ECC–PRC–GSs is systematically performed to assess the seismic performance of ECC–PRC–GSs. Notably, certain important design suggestions for the ECC–PRC–GSs are proposed. Finally, a theoretical model is developed to predict the flexural bearing capacity of ECC–PRC–GSs based on the strain compatibility and force equilibrium conditions. The effectiveness of the model is verified through finite element analysis and experimental results.

Estimation of ultimate bearing capacity of circular footing resting on recycled construction and demolition waste overlaying on loose sand

Estimation of ultimate bearing capacity of circular footing resting on recycled construction and demolition waste overlaying on loose sand

An extreme learning neural network approach for seismic bearing capacity estimation of planar caissons in nonhomogeneous clays

An extreme learning neural network approach for seismic bearing capacity estimation of planar caissons in nonhomogeneous clays

Bearing Capacity Equation for Shallow Foundations on Unsaturated Soils

For shallow foundations resting on unsaturated soils, matric suction increases effective stresses, resulting in enhanced bearing capacity. However, this boost in bearing capacity is ignored in practice for the sake of simplicity, thus compromising economy. That is why this study aims to consider the beneficial effect of unsaturated conditions on bearing capacity. This is achieved by applying limit analysis using the finite element method on unsaturated soils and investigating the problem parametrically for shallow foundations. The suction effect is taken into account in the formulation of the limit analysis based on effective stress principle. The numerical outcomes are verified by comparing them with available experimental data from the literature. The findings from the parametric study emphasize that the influence of suction on bearing capacity is determined by the friction angle. Moreover, the effects of a varying suction profile are contingent on the foundation width. Based on the results derived from the numerical analyses, a modified bearing capacity equation is introduced. This equation showcases a very good coefficient of determination, effectively encompassing the effects of the soil suction profile. Consequently, the proposed procedure can be considered as a convenient yet precise tool for estimating bearing capacity in engineering practice.

Numerical modelling of skirted foundations under vertical loads

In the construction of civil structures, the strength of the foundation is of high importance. Thus, engineers face many challenges, such as bearing capacity, settlement and high groundwater level, particularly if the structure is on sandy soil. To deal with these problems, solutions have been proposed, one of which is the use of skirted foundations. In this method, walls skirt the surface foundation and are buried deep in the soil. In this study, numerical analysis, taking into account the parameters of different lengths of skirted foundation walls, different percentages of soil densities and wall thickness, has been used to investigate skirted foundations under static loads. On the basis of the obtained results, a series of charts are presented for estimating bearing capacity improvement. Skirted foundations resting on denser sand provide better results in terms of bearing capacity than foundations resting on medium and loose sand.

Using GIS for the allowable soil bearing capacity estimation according to the Terzaghi (1943) equation in Eskişehir city center, Türkiye

In foundation engineering, it is necessary to calculate the bearing capacity of soils. The allowable soil bearing capacity required for foundation design is calculated through various empirical methods using geotechnical parameters such as specific gravity and angle of internal friction. Standard Penetration Test (SPT) values of the soil are used in these calculations. Therefore, soil tests which engineers need, are costly and time-consuming. This study aims to determine the soil bearing capacity of Eskişehir city according to the Terzaghi (1943) equation and present soil bearing capacity maps for shallow foundations. The geotechnical parameters of the soil were obtained from 40 borehole data made in the field. Within the scope of the study, according to the Terzaghi (1943) equation bearing capacity maps were created for 0-5 m depth to provide an overview of the bearing capacity of Eskişehir soil. These maps were made in the Geographic Information System (GIS), which has a database that stores and analyses regular data. In addition, these maps can assist engineers working on shallow foundation design on the site.

Comparative study of homogenization techniques for evaluating the bearing capacity of bimsoils under shallow foundations

Bimsoils, characterized by discrete blocks within a finer-grained matrix, pose challenges in evaluating the bearing capacity of shallow foundations due to their spatial variability. To address this, a binary random field coupled with a Finite-Element model is used to simulate the variability of bimsoils. This study focuses on investigating the effect of the blocks spatial fraction (γ), the isotropic and anisotropic spatial correlations, and the undrained shear strength (cu) ratio between the matrix and the blocks. The results reveal that the coefficients of variation (CV) for the bearing capacity (qu), at a given γ, reach nearly 20% due to the diverse spatial configurations. This dispersion is attributed to the development of distinct failure mechanisms. However, optimizing the local average area used to evaluate γ can help reduce these CV values. The average qu for a given γ can be accurately determined using the Bruggeman symmetric effective medium (BEM) equation, ensuring safe design compared to traditional homogenization techniques. The BEM equation considers γ and the cu ratio, providing an accurate estimation of bearing capacity for an equivalent homogeneous model suitable for probabilistic analyses.

Retracted: Quantitative Estimation of Ecocultural Bearing Capacity of Urban Agglomerations in Britain

Retracted: Quantitative Estimation of Ecocultural Bearing Capacity of Urban Agglomerations in Britain

Bearing Capacity Estimation of Ring Footing on Layered Sand with Geogrid at the Interface Using FELA and MARS

Bearing Capacity Estimation of Ring Footing on Layered Sand with Geogrid at the Interface Using FELA and MARS

Influence of Spring Stiffness on the Loading Speed of the Falling Weight Deflectometer (FWD) in Bearing Capacity Evaluation of Cement Concrete Pavement

Introduction: The bearing capacity evaluation of cement concrete runway pavement is one of the most important contents in the airfield operation. Among the methods for estimating bearing capacity, the Falling Weight Deflectometer (FWD) is the most widely used method because it does not damage the pavement structure and spends so much time. The equipment for evaluation should have suitable parameters, such as. magnitude and loading speed, to the actual operating loads. Aims and Objectives: Currently, the equipment to assess the bearing capacity of cement concrete pavements of highways and airports by falling weight has been widely used in the world and is being applied in Vietnam. The loading system consists of a falling block through a spring system acting on the pressure plate under the pavement with a certain falling height. In particular, the spring system plays an important role in controlling the speed of the load on the pavement. In Vietnam, the test standards (Industry Standard 22TCN335-06, Vietnamese Standard TCVN 11365-2016) for assessing the pavement bearing capacity by FWD equipment do not specify the selection of spring stiffness corresponding to different operating speeds of the vehicle. Therefore, it is difficult to use the equipment for pavements with operating speeds different from the standard. In this paper, we study the effect of spring stiffness on the loading speed when considering different loading speeds corresponding to different speeds of vehicles moving in reality. This research is only limited to laboratory experiments. This study aims to determine the dependence of the loading magnitude and loading time on the damping spring stiffness of the dynamic loading equipment, that is, used as a basis for choosing the appropriate damping stiffness of FWD corresponding to actual vehicles. Methods: Among the methods for estimating the bearing capacity, the Falling Weight Deflectometer (FWD) is the most widely used method as it does not cause any damage to the pavement structure and spends much time. The equipment for evaluation should have suitable parameters, such as magnitude and loading speed, to the actual operating loads. Results: This paper presents the results of experimental research that determines the influence of the damping spring stiffness on the loading speed of the dynamic loading equipment on the model of the concrete slab in the laboratory. Conclusion: Based on the comparison of the FWD loading speed when using 02 damping springs with different stiffness, we propose the basis for choosing the damping system that conforms to the evaluation needs of different types of vehicles.

Second-Order Generalized Plastic Hinge Method for Ultimate Bearing Capacity Estimation of Unbraced Steel Frames

The traditional first-order plastic hinge method (FPHM) utilizes the proportionality property to rapidly estimate the external load increment between any two adjacent plastic hinges, with superior computational efficiency. However, the FPHM cannot consider the influence of second-order effects and residual stresses. Although the refined plastic hinge method (RPHM) overcomes these problems, it must solve the nonlinear structural stiffness equation, resulting in low computational efficiency. In this paper, the second-order generalized plastic hinge method (sGPHM) is proposed to evaluate the ultimate bearing capacity of unbraced steel frames on the basis of using the proportionality property to estimate the external load increment. First, the element bearing ratio (EBR) that considers second-order effects and residual stresses is defined. Since the EBR and the external load are proportional, the plastic yield degree of the cross-section can be easily obtained. Then, the displacement increment and the load increment between any two adjacent plastic hinges can be rapidly estimated through the proportionality property between the EBR and the external load. Accumulating all load increments can determine the ultimate bearing capacity of frames. Finally, several benchmark frameworks in the literature are compared and analyzed with different methods to verify the superior calculation accuracy and efficiency of the proposed sGPHM.

Performance assessment of borehole arrangements for the design of rectangular shallow foundation systems

This study proposes a framework to evaluate the performance of borehole arrangements for the design of rectangular shallow foundation systems under spatially variable soil conditions. Performance measures are introduced to quantify, for a fixed foundation layout and given soil sounding locations, the variability level of the foundation system bearing capacities in terms of their mean values and standard deviations. To estimate these measures, the recently proposed random failure mechanism method (RFMM) has been adopted and extended to consider any arrangement of rectangular foundations and boreholes. Hence, three-dimensional bearing capacity estimation under spatially variable soil can be efficiently performed. Several numerical examples are presented to illustrate the applicability of the proposed framework, including diverse foundation arrangements and different soil correlation structures. Overall, the proposed framework represents a potentially useful tool to support the design of geotechnical site investigation programs, especially in situations where very limited prior knowledge about the soil properties is available.

Bearing Capacity of Karst Cave Roof under Pile Foundation Load Using Limit Analysis

Reducing the computational workload by simplifying the analysis of karst foundations into a plane strain problem can yield significant advantages. Yet, such an approach fails in reproducing the engineering situation in a rigorous manner. In this regard, this paper proposes an upper-bound method that can effectively analyze the bearing capacity of three-dimensional karst foundations. This method is utilized to investigate the impact of various pile diameters, the ratio of roof thickness to pile diameter, and the ratio of cave width to pile diameter on the stability of karst foundations. The validity of this method is established through an illustrative example. The outcomes illustrate that when subjected to both tensile and compressive horizontal stresses if the maximum horizontal stress surpasses the tensile strength of the rock mass, the roof rock mass may suffer damage. Increasing the ratio of roof thickness to pile diameter can bring down the horizontal stress value. The stability factor is largely influenced by the ratio of roof thickness to pile diameter. The most prominent growth trend of the stability factor is observed when the ratio is less than 3. If the ratio of the roof thickness to pile diameter exceeds 3, the prediction of the bearing capacity estimation for the karst foundation in three-dimensional circumstances is more conservative than that in two-dimensional circumstances.

Experimental determination of the tightening coefficient of bolts according to the din standard

The use of slip-critical connections is very common in the design of critical steel structures and is seen as an effective way to transfer the force in conditions of dynamic loading. The limit state of the connection occurs when the calculated shear stress is reached, which depends on the friction coefficient of the contact planes and the value of the clamping force, equal to the bolt tension stress. In order to ensure the necessary bolt tensioning force, it is necessary to know the bolt tightening coefficient, because according to the current understanding of the slip-critical connection performance, the designed functioning of the bolt connection is ensured when the bolt tensioning force arising at the necessary torque value is achieved. Otherwise, the actual work of the connection will be different from the calculated, because only a given tension force provides the estimated bearing capacity of the bolted connection with friction planes. This article focuses on tensile testing of a bolt and determining the tightening factor of a bolt made of high-strength10.9 M14 steel. The tightening factor is determined with strain gauges by measuring the relative strain of the bolt when the nut is tightened. This method requires specialized equipment and a test bench and can be used in the study of bolt performance in the absence of a certificate or the need to verify or clarify the available data. The results show that the proposed method can provide a stable determination of the coefficient value. The examined bolts were made according to the German standard DIN931, strength 10.9 size M14x220, nuts according to the German standard DIN934, strength 10 size M14. An Instron 1000HDX tensile testing machine was used to plot the performance of the bolt steel. Nut tension control was determined with the use of NOGRAU NTW24-034R torque wrench, and bolt elongation control with FLA 5-11 strain gauges and National Instruments data acquisition system. On the basis of the conducted research, a method for determining the tightening factor of high-strength bolts has been tested and proposed. The proposed method of determining the tightening factor of a high-strength bolt can be used in research work and allows to determine the coefficient in the absence of an appropriate certificate or the need to clarify (verify) the stated value of the coefficient.

Model and field tests of drilled displacement system piles

Drilled Displacement System (DDS) and Continuous Flight Auger (CFA) piles are two popular techniques used for building pile foundations that offer advantages over traditional pile systems, including improved load-carrying capacity, reduced installation time, and less spoil generation. This article presents laboratory-scaled model tests conducted on model piles installed using the Drilled Displacement System (DDS) and Continuous Flight Auger (CFA) technologies on a test tank setup filled with soil. Model piles considering a scaling factor of 1/20 with a diameter of 20 mm and a length of 300 mm were adopted for the study. Static loading is applied to the model piles and the corresponding displacements are measured during each loading phase. The results of the analysis were compared for load-settlement curves and ultimate bearing capacity estimates for both DDS and CFA piles. Based on the study, the DDS piles were observed to perform well in terms of load-carrying capacity compared to the CFA piles. Further, full-scale field tests under static load conditions were carried out on DDS-drilled piles of diameter 400 mm and length 6 m. The load-settlement response from the field test shows good agreement with the model tests. Overall, the results of the study provide valuable insights into the behavior and performance of DDS piles that can be used to optimize their design and installation in different soil types.

Bearing capacity prediction of strip and ring footings embedded in layered sand

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.