• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.2
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• pp.112-121
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• 2013

The calibration of resistance factor in reliability theory for limit state design of gravel compaction piles (GCP) requires a reliable estimate of ultimate bearing capacity. The static load test is commonly used in geotechnical engineering practice to predict the ultimate bearing capacity. Many graphical methods are specified in the design standard to define the ultimate bearing capacity based on the load-settlement curve. However, it has some disadvantages to ensure reliability to obtain an uniform ultimate load depend on engineering judgement. In this study, a well-fitting nonlinear regression model is proposed to estimate the ultimate bearing capacity, for which a nonlinear regression analysis is applied to estimate the ultimate bearing capacity of GCP and the results are compared with those calculated using previous graphical method. Affect the resistance factor of the estimate method were analyzed. To provide a database in the development of limit state design, the load test conditions for predicting the ultimate bearing capacity from static load test are examined.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.195-203
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• 2001

The purpose of this study is to estimate ultimate uplift capacity of permanent anchor which was cast into weathered rock. The ultimate uplift capacity was estimated from the load-displacement curve of four different anchors which have different bond length. The creep test was performed for 15minutes under the maximum load of each step in order to understand the load-transfer property of permanent anchor and to decide which anchor to choose. The destruction range of soil due to the changes in load was estimated by installing dial gauge on the ground which was cast into the weathered rock. Ultimately, the study on the behavior of the anchor case into the weathered rock was performed by comparing and analyzing the estimated result of the UUC obtained by the full scale pull out test in the field with the exsting theoretical and practical results of soil and rock anchor.

• Journal of Industrial Technology
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• v.17
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• pp.111-118
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• 1997

This thesis is an experimental research of investigating behavior of single pile, subjected to the vertical compression loads, using the centrifuge facility located in the geotechnical engineering laboratory in Kangwon National University. Centrifugal model experiments of model pile were carried out changing diameter of model pile, relative density of sandy ground and the gravitational level applied in the centrifuge. Thus, their effects on the load-settlement behavior and the ultimate bearing capacity of pile were investigated. Experimental results obtained from centrifuge model tests were compared with the theoretical or semi-empirical equations to analyze values of ultimate bearing capacity of model pile. When we compare the ultimate bearing capacity of experimental results with the ultimate bearing capacity of theorical results, the experimental results appear more higher in the De Beer method and Meyerhof. Expecially, Terzaghi method is very same as the experimental results normally.

• Journal of Bio-Environment Control
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• v.10 no.3
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• pp.148-154
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• 2001

The uplift capacity of a pile for improving the wind resistance of the 1-2 W type plastic film pipe on greenhouses was tested using the plane and corrugated piles with various shapes and diameters. First, the resistant uplift capacity was measured by using the uplift loading on plane piles. As the uplift loading on plane piles increased, the resistant uplift capacity also increased until the loading was reached to ultimate uplift capacity. After ultimate uplift capacity was appeared the uplift displacement, the uplift capacity was decreased gradually. Secondly, the resistant uplift capacity was measured by using the uplift loading on corrugated piles. After the uplift capacity was reached the uplift displacement, the uplift capacity was continually increased or decreased. In general, the ultimate uplift capacity was independent of pile shapes, pile diameter length, and embedded pipe depth. However, the ultimate uplift capacity of a corrugated pile was twice more than that of a plane pile without regard to its diameter and embedded depth. The ultimate uplift capacity per unit pile area was increasing in deeper embedded depth. However, the longer a pile diameter was, the less ultimate uplift capacity. The uplift capacity of a plane pile, used in conjunction with the design wind velocity (26.9m.s$^{-1}$ ) of the project area, was unsatisfiable without regard to diameters and embedded depths of piles, while most of corrugated piles were well appeared uplift capacity under various experimental conditions.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.369-374
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• 1999

A practical approach of calculating the ultimate strength of composite beams with unreinforced web opening is proposed. In this method, the slab shear contribution at the opening is calculated as the smaller of the shear strength of the slab and the pullout capacity of the shear connectors at the high moment end. A simple interaction equation is used to predict the ultimate strength under simultaneous bending moment and shear force. Strength prediction by the proposed method is compared with previous test results and the predictions by other analytical method. The comparison shows that the proposed method predicts the ultimate capacity with resonable accuracy.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.3
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• pp.92-100
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• 2002

The advent or high-strength steel has enabled the arch structures to be relatively light, durable and long-spanned by reducing the cross sectional area. On the other hand, the possibility of collapse may be increased due to the slender members which may cause the stability problems. The limit analysis to estimate the ultimate load is based on the concept of collapse mechanism that forms the plastic zone through the full transverse sections. So, it is not appropriate to apply it directly to the instability analysis of arch structures that are composed with compressive members. The objective of this study is to evaluate the ultimate load carrying capacity of the parabolic arch by using the elasto-plastic finite element model. As the rise to span ratio (h/L) varies from 0.0 to 0.5 with the increment of 0.05, the ultimate load has been calculated fur arch structures subjected to uniformly distributed vertical loads. Also, the disco-elasto-plastic analysis has been carried out to find the duration time until the behavior of arch begins to show the stable state when the estimated ultimate load is applied. It may be noted that the maximum ultimate lead of the parabolic arch occurs at h/L=0.2, and the appropriate ratio can be recommended between 0.2 and 0.3. Moreover, it is shown that the circular arch may be more suitable when the h/L ratio is less than 0.2, however, the parabolic arch can be suggested when the h/L ratio is greater than 0.3. The ultimate load carrying capacity of parabolic arch can be estimated by the well-known formula of kEI/L$^3$where the values of k have been reported in this study. In addition, there is no general tendency to obtain the duration time of arch structures subjected to the ultimate load in order to reach the steady state. Merely, it is observed that the duration time is the shortest when the h/L ratio is 0.1, and the longest when the h/L ratio is 0.2.

• Proceedings of the Korean Geotechical Society Conference
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• 1997.10a
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• pp.73-80
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• 1997

• Journal of the Korean Geotechnical Society
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• v.25 no.2
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• pp.37-44
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• 2009

In this study, estimation methodology for the pile of ultimation lateral resistance, pu, and ultimate lateral capacity, Pu, is based on the CPT cone resistance $q_c$. Preexistent methodologies for ultimate lateral resistance and ultimate lateral capacity have been generally represented with relative density, vertical effective stresses, and various $K_0$ values which are important for analyzing sandy soil. These methodologies, however, did not consider the horizontal effective stress and the effects of construction site conditions. Therefore, CPT-based methodology for the estimation of the ultimate lateral pile load capacity Hu was proposed. Calibration chamber test results were analyzed and compared with calculated results. The proposed estimation methodology for the pile of $p_u$ can be effectively utilized as alternative to preexistent methods.

• Structural Engineering and Mechanics
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• v.39 no.3
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• pp.383-398
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• 2011

This paper investigates the nonlinear analysis of concrete-filled steel composite columns subjected to axial loading to predict the ultimate load capacity and behaviour of the columns. Finite element software LUSAS is used to conduct the nonlinear analyses. The accuracy of the finite element modelling is verified by comparing the result with the corresponding experimental result reported by other researchers. Nonlinear analyses are done to study and develop different shapes and number of cold-formed steel sheeting stiffeners with various thicknesses of cold-formed steel sheets. Effects of the parameters on the ultimate axial load capacity and ductility of the concrete-filled steel composite columns are examined. Effects of variables such as concrete compressive strength $f_c$ and cold-formed steel sheet yield stress $f_{yp}$ on the ultimate axial load capacity of the columns are also investigated. The results are shown in the form of axial load-normalized axial shortening plots. It is concluded from the study that the ultimate axial load capacity and behaviour of the concrete-filled steel composite columns can be accurately predicted by the proposed finite element modelling. Results in this study demonstrate that the ultimate axial load capacity and ductility of the columns are affected with various thicknesses of steel sheets and different shapes and number of stiffeners. Also, compressive strength $f_c$ of the concrete and yield stress $f_{yp}$ of the cold-formed steel sheet influence the performance of the columns significantly.

• Steel and Composite Structures
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• v.42 no.2
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• pp.173-190
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• 2022

With the development of spatial structures, the joints are becoming more and more complex to connect tubular members of spatial structures. In this study, an approach is proposed to establish high-efficiency finite element model of multiplanar KTX-joint with the weld geometries accurately simulated. Ultimate bearing capacity the KTX-joint is determined by the criterion of deformation limit and failure mechanism of chord wall buckling is studied. Size effect of fillet weld on the joint ultimate bearing capacity is preliminarily investigated. Based on the validated finite element model, a parametric study is performed to investigate the effects of geometric and loading parameters of KT-plane brace members on ultimate bearing capacity of the KTX-joint. The effect mechanism is revealed and several design suggestions are proposed. Several simple reinforcement methods are adopted to constrain the chord wall buckling. It is concluded that the finite element model established by proposed approach is capable of simulating static behaviors of multiplanar KTX-joint; chord wall buckling with large indentation is the typical failure mode of multiplanar KTX-joint, which also increases chord wall displacements in the axis directions of brace members in orthogonal plane; ultimate bearing capacity of the KTX-joint increases approximately linearly with the increase of fillet weld size within the allowed range; the effect mechanism of geometric and loading parameters are revealed by the assumption of restraint region and interaction between adjacent KT-plane brace members; relatively large diameter ratio, small overlapping ratio and small included angle are suggested for the KTX-joint to achieve larger ultimate bearing capacity; the adopted simple reinforcement methods can effectively constrain the chord wall buckling with the design of KTX-joint converted into design of uniplanar KT-joint.