• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.4
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• pp.109-120
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• 2001

Live load data were collected with a systematic manner from a survey of a refrigeration stores. Using the collected floor live load survey data, the basic statistics, a histogram of the uniformly distributed loads, and the equivalent uniformly distributed loads are computed for various structural members. Based on the above results, the maximum values of a combined live loads during the design life have been estimated and compared with current design live loads. The ultimate goals of this study are to develop probabilistic live load models to analyze survey data of domestic refrigeration stores, and to propose design live loads for structural types.

• Journal of Korean Society of Steel Construction
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• v.23 no.6
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• pp.679-690
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• 2011

Since the elastic buckling problem of the plate has been studied both experimentally and theoretically, the buckling loads with various boundary conditions and loads can be easily determined. Currently, flange and web design specifications are based on the buckling stress and the post-buckling strength and include a safety-factor. Therefore, this study extended suchresearch to the linear buckling theory with ideal conditions and to the ultimate state with post-buckling. The current specifications are based on elastic buckling stress; and therefore, further research on the ultimate behavior of the plate is required. The ultimate strength design concept, which allows finite deflection, is used in this studyto maximize the post-buckling strength in a steel box. An empirical equation, which provides the ultimate strength of the steel box due to the change in the slenderness and optimum rigidity, are suggested based on the experiment results. Moreover, the appropriateness of the current design specifications was analyzed and discussed.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.2
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• pp.161-168
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• 2018

This paper presents the design procedure of the suction bucket used to support a subsea manifold. The soil-suction bucket interaction numerical analysis technique was verified by comparing the present results with a reference data. In order to simulate the soil-bucket interaction analyses of a subsea manifold structure, various material data such as undrained shear strength, elastic modulus, and poisson ratio of soft clay in Gulf of Mexico were collected from reference survey. We proposed vertical and horizontal design loads based on system weights and current-induced drag forces. Under the assumption that diameter of the suction bucket was 3.0 m considering real dimension of the subsea manifold frame structures, aspect ratio was decided to be 3.0 based on reference survey. The ultimate bearing load components were determined using tangent intersection method. It was proved that the two design load components were less than ultimate bearing loads.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.52-60
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• 2002

Failure criterion is a parameter to represent the resistance to failure of locally wall thinned pipe, and it depends on material characteristics, defect geometry, applied loading type, and failure mode. Therefore, accurate prediction of integrity of wall thinned pipe requires a failure criterion adequately reflected the characteristics of defect shape and loading in the piping system. In the present study, the finite element analysis was performed and the results were compared with those of pipe experiment to develop a sound criterion for failure of internally wall thinned pipe subjected to combined pressure and bending loads. By comparing the predictions of failure to actual failure load and displacement, an appropriate criterion was investigated. From this investigation, it is concluded that true ultimate stress criterion is the most accurate to predict failure of wall thinned pipe under combined loads, but it is not conservative under some conditions. Engineering ultimate stress estimates the failure load and displacement reasonably for al conditions, although the predictions are less accurate compared with the results predicted by true ultimate stress criterion.

• Steel and Composite Structures
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• v.29 no.6
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• pp.735-748
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• 2018

In this paper, the cyclic behavior of steel beam-concrete encased steel (CES) column joints was investigated experimentally and numerically. Three frame middle joint samples with varying concrete slab widths were constructed. Anti-symmetrical low-frequency cyclic load was applied at two beam ends to simulate the earthquake action. The failure modes, hysteretic behavior, ultimate load, stiffness degradation, load carrying capacity degradation, displacement ductility and strain response were investigated in details. The three composite joints exhibited excellent seismic performance in experimental tests, showing high load-carrying capacity, good ductility and superior energy dissipation ability. All three joint samples reached their ultimate loads due to shear failure. Numerical results from ABAQUS modelling agreed well with the test results. Finally, the effect of the concrete slab on ultimate load was analyzed through a parametric study on concrete strength, slab thickness, as well as slab width. Numerical simulation showed that slab width and thickness played an important role in the load-carrying capacity of such joints. As a comparison, the influence of concrete grade was not significant.

• Steel and Composite Structures
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• v.43 no.6
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• pp.689-706
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• 2022

Thin-walled square concrete-filled double steel tubular (CFDST) columns composed of the inner circular tube filled with concrete can be used to carry the large axial loads or strengthen existing CFST columns in composite constructions. This paper reports an experimental program carried out on short square CFDST columns loaded concentrically. The influences of important column parameters on the post-buckling performance of such columns are investigated. Test results exhibit that the inner circular tube significantly improves the ultimate loads and the ductility of such columns compared to conventional concrete-filled steel tubular (CFST) and double-skin CFST (DCFST) columns with an inner void. A mathematical model developed is used to simulate the ultimate strengths and load-strain curves of such columns loaded axially. Furthermore, the ultimate strengths of such columns are predicted using existing codified design models for conventional CFST columns as well as the formulas proposed by previous researchers and compared against a large database comprising 500 CFDST columns. Lastly, an accurate artificial neural network model is developed for the practical applications of such columns under axial loading.

• Steel and Composite Structures
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• v.5 no.2_3
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• pp.203-233
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• 2005

This paper presents the findings of a design development project for perforated beams fully integrated with building services. A unified design approach for both steel and composite beams with large rectangular web openings is proposed which is based on plastic design methods and formulated in accordance with analytical structural design principles. Moreover, finite element models are established after careful calibration against test data, and comparison on the predicted ultimate loads of two composite beams with rectangular web openings from the finite element models and the proposed design method is also presented. It is demonstrated that the proposed design method is able to predict the ultimate loads of composite beams with rectangular web openings against 'Vierendeel' mechanism satisfactorily.

• KCI Concrete Journal
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• v.14 no.1
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• pp.8-14
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• 2002

This is the first of two part series on experimental studies of grout type transverse joints. In this study, grout type transverse joints between precast concrete slabs are statically tested to determine the cracking loads and ultimate shear capacities of the grout type transverse joints. The tests are performed with a loading equipment designed and constructed especially in the lab to induce shear failures on the joints of the test specimens. Shape of the transverse joints, grouting materials and amount of prestress are selected as test parameters for the study. The results indicate that epoxy is an excellent grouting material which can be used in limited locations where large tensile stress is acting on the slab. Longitudinal prestressing is also an effective method to increase the shear strength of the transverse joints. A rational method to estimate the cracking and ultimate loads for the design of grout type transverse joints is proposed based on the static loading tests. Success of the tests with shear loading equipment allowed continuing the research further onto the fatigue strength of the grout type joints, which will be presented in the second part of the paper.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.409-413
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• 2007

To assure the structural integrity for the hub and low speed shaft (LSS) of the drive train, it is necessary to obtain the ultimate aerodynamic loads acting on the wind turbine blade. The aim of this study is to predict the time histories of 3 forces and 3 moments at the hub and the LSS based on the design load case of the IEC 61400-1. From the calculated results most of the load components have rotor revolution frequency whereas thrust and torque of the LSS show blade passage frequency. It turns out that the EWM wind condition involves the maximum ultimate loads at both hub and LSS of the horizontal axis wind turbine.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.4
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• pp.92-103
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• 1999

Recently structural damage has been frequently observed in reinforced concrete brdiges due to repeated loads such as vehicular traffic an due to continual overloads by heavy duty trucks. Therefore, the purpose of this experimental stduy is to investigate the damage mechanism due to fatigue behavior of high-strength reinforced concrete beams under repeated loads. From the test results, the relation of cycle loading to deflection is on the mid-span , the crack growth and the modes of failure according to cycle number, fatigue life and S-N curve were observed through the fatigue test. Based on the fatigue test results , high-strength reinforced concrete beams failed to 57 ∼66 percent of the static ultimate strength . Fatigue strength aobut two million cycles from S-N curves was certified by 60 percent of static ultimate strength.