Bearing Capacity Factors of Flat Base Footing by Finite Elements

Phuor, Ty; Harahap, Indra Sati Hamonangan; Ng, Cheng Yee

doi:10.1061/(asce)gt.1943-5606.0002835

Cited by 3 publications

(17 citation statements)

References 57 publications

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“…In this paper, the number of iterative steps for the stress returning is 500, and convergence is allowed if the ratio between the displacement changes in two consecutive iteration steps and the maximum displacement is less than 0.1%. The penalty scheme, in conjunction with the displacement-controlled technique, is applied, 6,20,39 and consequently, the converged stresses of all interface elements are used to compute the reactions, and then the capacity of the rough and smooth round-shaped footings can be calculated accordingly.…”

Section: Numerical Solution Techniquesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Numerous engineers and researchers have employed various methods to compute the bearing capacity of the footings, for instance, strip footing, [1][2][3][4][5][6][7][8] circular footing, 6,[9][10][11][12][13] and ring footing. 6,[14][15][16][17][18] However, limited studies in the literature for solving the bearing capacity problems of conical footing have been reported. 19,20 As seen in Figure 1, the jack-up structure is utilized for drilling and maintenance works in the oil and gas industry, 21,22 and each of its legs is standing on spudcan, [23][24][25][26][27][28] which has a diameter ranging from 5 to 20 m. 21,29 With the use of the flat base theory, Meyerhof 30 proposed the bearing capacity theory for the conical footing by conducting the loading tests on cones and indicated that when the wedge angle F I G U R E 1 Jack-up rig model (β) increases, the point resistance of a pile with smooth and rough tips are increased and decreased, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…With the employment of the viscoplastic strain in combination with the FEM, the simulations of the smooth flat-base footing (i.e., strip, circular, ring footings) have been successfully conducted by allowing the shear stress to mobilize freely on the footing and soil interface. [6][7][8]20,22,39 In this sense, it does not necessarily require modeling the rigid footing. 7,8 On the contrary, when the footing base is not level, the modeling of the footing and the interface element must be considered.…”

Section: Introductionmentioning

confidence: 99%

“…1,9,20,41 Moreover, at a low friction angle (𝜙 < 10 o ), the overestimated values of the bearing capacity and the convergence problems also occurred. 1,9,20,41 However, these issues might be solved by using the proper magnitudes of the time step and the dilation angle of soil (𝜓) suggested by Phuor et al [6][7][8]20,22 On the other hand, another widely known issue, which is the paging that is the not enough space in the memory for the simulations, might occur, causing the failure of the FE solution for the footings with the large system. For example, for a computed model with around 500000 degrees of freedom or more, the FEM-based computer might crash even with a modern computer having 32GB-RAM.…”

Section: Introductionmentioning

confidence: 99%

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Bearing capacity factors of cone‐shaped footing in meshfree

Phuor

Ganz

Trapper

2022

Num Anal Meth Geomechanics

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Unlike the flat base foundations, the determination of the bearing resistance of the cone-shaped footing in finite element analysis (FEA) might not be carried out without considering the interface model. In addition, the simulations of the FEA is hardly achieved with a large system due to the assembly technique. So, the alternative should be considered. Therefore, this paper proposes a new method for computing the 𝑁 𝑐 , 𝑁 𝑞 and 𝑁 𝛾 factors of the bearing capacity of the rough and smooth cone-shaped foundations by combining the skew boundary condition as the interface model incorporated with the viscoplastic strain method-based meshfree obeying the yield equation of the Mohr-Coulomb (MC). Thus, the factors can be determined exclusively and reported to reach a close agreement with the published data; nevertheless, the discrepancies are also provided. The plastic flow of the soil mechanics is discussed thoroughly. In addition, the effects of soil friction angle (𝜙) and cone-shaped angle (𝛽) on the factors are inspected systematically. Accordingly, the conservation of the Terzaghi's superposition assumption is confirmed, and the bearing capacity factor charts can be established for various combinations of 𝜙 = 5 o -45 o and 𝛽 = 30 o -180 o . Therefore, it may conclude that the results produced by these techniques and the techniques themselves may be applied confidently for solving geotechnical problems, especially for computing the bearing resistance of the soil.

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Section: Numerical Solution Techniquesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Bearing capacity factors of cone‐shaped footing in meshfree

Phuor

Ganz

Trapper

2022

Num Anal Meth Geomechanics

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Eigensensitivity of damped system with distinct and repeated eigenvalues by chain rule

Phuor

Yoon

2023

Numerical Meth Engineering

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In this paper, a novel algorithm for computing the derivatives of eigensolutions of asymmetric damped systems with distinct and repeated eigenvalues is developed without using second‐order derivatives of the eigenequations, which has a significant benefit over the existing published methods. To achieve this, the algorithm is proposed by (1) imposing consistent normalization conditions for both left and right eigenvectors throughout the computational system, and (2) solving sensitivity problems using the chain rule. These contributions add significant value to the proposed method. Additionally, the numerical difficulty is overcome by suggesting justifying Nelson (1976)'s technique based on the normalization conditions. Even though the proposed algorithm is simple and easy to implement, the employment of chain rule with new normalization in this note has never been reported in the literature, especially for the problem of eigensensitivity. Because this new algorithm does not require the second‐order derivatives of the eigenequations, the analytical and numerical solutions for eigensensitivity offered by this method are less complicated than existing available solutions. The validity and applicability of the method are demonstrated through five numerical examples, showcasing its implementation in displacement‐ and state‐space equations (rotordynamic system). Also, verifications are found to be in reasonable agreement with the approximated method.

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An Analytical Expression for the Fundamental Frequency of a Long Free-Spanning Submarine Pipeline

Phuor,

Trapper,

Ganz

2023

Mathematics

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The DNVGL-RP-F105 guidelines provide essential techniques for the preliminary design of undersea pipelines. However, its approximations for static displacement and the natural frequency of the pipe are restricted to cases where the ratio of the pipe’s diameter to its length (L/D) is less than 140. This limitation poses challenges for longer spans, which, although rare, can sometimes be unavoidable. This study introduces a novel analytical method, rooted in the energy method and cable theory, for computing the static deformation and natural frequency of long free-span underwater pipelines. We conducted a comprehensive verification of our proposed method by comparing its outcomes with those of 212 finite element analysis simulations. The results reveal excellent predictions for long spans. However, for shorter spans, traditional methods remain more accurate. Additionally, we explored the influence of pipeline’s diameter, thickness, and boundary conditions on both static displacement and frequency, providing valuable insights for design considerations. We found that the boundary conditions’ impact on the fundamental frequency becomes negligible for long spans, with up to a 10% difference between pinned–pinned and fixed–fixed conditions. In essence, this research offers a vital enhancement to the existing DNV guidelines, becoming particularly beneficial during the preliminary design phases of pipelines with L/D ratios exceeding 140.

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Bearing Capacity Factors of Flat Base Footing by Finite Elements

Cited by 3 publications

References 57 publications

Bearing capacity factors of cone‐shaped footing in meshfree

Bearing capacity factors of cone‐shaped footing in meshfree

Eigensensitivity of damped system with distinct and repeated eigenvalues by chain rule

An Analytical Expression for the Fundamental Frequency of a Long Free-Spanning Submarine Pipeline

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