• Proceedings of the Korean Geotechical Society Conference
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• 1997.10a
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• pp.197-202
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• 1997

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.433-438
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• 2005

This study was carried out to analyze the effect of the variation of a wind speed on the stability of a container crane. The wind load according to 'The Requirement of Port Facilities and Equipments / Specification for the design of crane structures (KS A 1627)' and 'Load Criteria of Structures' enacted by the ministry of construction & transportation was evaluated. And the uplift forces of a container crane under this wind load were calculated by analyzing reaction forces at each supporting point and compared with each other. The analytic model was a container crane with uplift capacity of 50ton which was widely used in port.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.227-243
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• 2003

To find the structural characteristics of non-slip device in connecting method B between steel pipe pile and concrete footing, compression and uplift test was performed for full sized specimens not having non-slip device, those having non-slip device with two curved steel plate bars welded inside the steel pipe pile(standard method), and those having non-slip device with serveral curved steel plate bars bolted inside the steel pipe pile(new method). As a result, specimens not having non-slip device had chemical debonding failure at 15.6tonf of peak uplift load and 27.57tonf of peak compression load. And the standard method and the new method showed about 8.9 times of peak uplift load and 6.2 times of peak compression load higher than specimens not having non-slip device. The load transfers of lower non-slip devices of the standard method and the new method were similar in behavior, while the higher non-slip device of the new method showed higher ratio of load transfer than that of the standard method. And these two methods had nearly the same composite action and structural capacity caused by non-slip devices.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.25-27
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• 2010

Helical steel piles are being widely used in foundation for the buildings in urban areas because of their high compressive and tensile capacities. Helical steel piles have many advantages; ease installation, a vibration-free and low level of noise process, and so on. However, the most researches are about the capacity of helical steel piles under uplift condition. Therefore, this paper focuses on the capacity under compressive loading according to the soil condition. The bearing capacity of helical steel piles varies with the diameter of the helix and shaft and the bearing area of helical steel piles is not always identical with the sum of helix and shaft area due to the difference of each bearing mechanism. Therefore, the experiment with the parameters of the ratio of helix and shaft diameter and soil condition will be carried out to survey the effective helix area under a given soil condition for the bearing capacity of helical steel piles.

• Earthquakes and Structures
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• v.7 no.6
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• pp.1001-1024
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• 2014

The size of spread footings was found to be unnecessarily large from some actual engineering practices constructed in Taiwan, due to the strict design provisions related to footing uplift. According to the earlier design code in Taiwan, the footing uplift involving separation of footing from subsoil was permitted to be only up to one-half of the foundation base area, as the applied moment reaches the value of plastic moment capacity of the column. The reason for this provision was that rocking of spread footings was not a favorable mechanism. However, recent research has indicated that rocking itself may not be detrimental to seismic performance and, in fact, may act as a form of seismic isolation mechanism. In order to clarify the effects of the relative strength between column and foundation on the rocking behavior of a column, six circular reinforced concrete (RC) columns were designed and constructed and a series of rocking experiments were performed. During the tests, columns rested on a rubber pad to allow rocking to take place. Experimental variables included the dimensions of the footings, the strength and ductility capacity of the columns and the intensity of the applied earthquake. Experimental data for the six circular RC columns subjected to quasi-static and pseudo-dynamic loading are presented. Results of each cyclic loading test are compared against the benchmark test with fixed-base conditions. By comparing the experimental responses of the specimens with different design details, a key parameter of rocking behavior related to footing size and column strength is identified. For a properly designed column with the parameter higher than 1, the beneficial effects of rocking in reducing ductility and the strength demand of columns is verified.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.3-10
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• 1999

There is an increasing demand for using rock anchors as foundations in many geotechnical engineering structures such as transmission towers, dams, etc. For investigate the behavior and strength of rock anchors, in-situ pull-out tests were carried out. From the tests, various forms of failure of rock anchors were observed. Ultimate capacity of each failure modes of 1) Tendon failure, 2) Interface failure(tendon-grout interface, sheath-grout interface and grout-rock interface), 3) Combined interface failure, was obtained by varying the parameters such as diameter and length of tendon, grout strength, and quality of rock.

• Journal of Environmental Science International
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• v.9 no.1
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• pp.49-55
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• 2000

An EMERGY analysis of the main energy flows driving the economy of humans and life support systems consists of environmental energies, fuels, and imports, all expresses as solar emjoules. Total EMERGY use(720.0 E20 sej/yr) of the Nakdong River Basin is 96 per cent from imported sources, fuels and goods and services. EMERGY flows from the environment such as rain and geological uplift flux accounted for only 4 percent of total EMERGY use. Consequently, the ratio of outside investment to attracting natural resources was large, like other industrialized areas. EMERGY use per person in the Nakdong River Basin indicates a moderate EMERGY standard of living, even though the indigenous resources are very poor. Population of 6.66 million people in 1996 is already in excess of carrying capacity of the basin. Carrying capacity for steady state based on its renewable sources in only 0.226 million people. EMERGY yield ratio and environment loading ratio were 1.07 and 28.52, respectively. EMERGY sustainability index, a ratio of EMERGY yield ratio to environment loading ratio, is therefore less than one, which is indicative of highly developed consumer oriented economies. This study suggests that the economic structure of the Nakdong River Basin should be transformed from the present industrial structure to the social-economic structure based on an ecological-recycling concept for the sustainable use of the Nakdong River.

• Geomechanics and Engineering
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• v.17 no.2
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• pp.165-173
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• 2019

Plate anchors are generally used for structures like transmission towers, mooring systems etc. where the uplift and lateral forces are expected to be predominant. The capacity of anchor plate can be increased by the use of geosynthetics without altering the size of plates. Numerical simulations have been carried out on three different sizes of square anchor plates. A single layer geosynthetic has been used as reinforcement in the analysis and placed at three different positions from the plate. The effects of various parameters like embedment ratio, position of reinforcement, width of reinforcement, frequency and loading amplitude on the pull out capacity have been presented in this study. The load-displacement behaviour of anchors for various embedment ratios with and without reinforcement has been also observed. The pull out load, corresponding to a displacement equal to each of the considered maximum amplitudes of a given frequency, has been expressed in terms of a dimensionless breakout factor. The pull out load for all anchors has been found to increase by more than 100% with embedment ratio varying from 1 to 6. Finally a semi empirical formulation for breakout factor for square anchors in reinforced soil has also been proposed by carrying out regression analysis on the data obtained from numerical simulations.

• Earthquakes and Structures
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• v.21 no.6
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• pp.641-652
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• 2021

Digging well foundation has been widely used in railway bridges due to its good economy and reliability. In other instances, bridges with digging well foundation still have damage risks during earthquakes. In this study, a new type of digging well foundation with prefabricated roots was proposed to reduce earthquake damage of these bridges. Quasi-static tests were conducted to investigate the failure mechanism of the root digging well foundation, and then to analyze seismic behaviors of the new type well foundation. The testing results indicated that these prefabricated roots could effectively limit the rotation and uplift of the digging well foundation and increase the lateral bearing capacity of the digging well foundation. The elastic critical load and ultimate load can be increased by 69% and 36% if prefabricated roots were added in the digging well foundation. The prefabricated roots drived more soil around the foundation to participate in working, the stiffness of the bridge pier with root digging well foundation was improved. Moreover, the root participation could improve the energy dissipation capacity of soil-foundation-pier interaction system. The conclusions obtained in this paper had important guiding significance for the popularization and application of the digging well foundation with prefabricated roots in earthquake-prone zones.

• Geotechnical Engineering
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• v.11 no.3
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• pp.91-112
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• 1995

Drilled shafts are used increasingly as the foundations for many types of structures. However, very little knowledge of drilled shaft behavior under inclined load is available. In this study, a systematic experimental testing program was conducted to understand the undrained behavior of drilled shaft foundations under inclined loads. A semi-theoretical method of predicting the inclined capacity was developed through a parametric study of the variables such as shaft geometry and load inclination. Test parameters were chosen to be representative of those most frequently used in the electric utility industry. Short, rigid shafts with varying depth/diameter(D/B) ratios were addressed, and loading modes were investigated that includes exial uplift, inclined uplift, and inclined compression loads. Capacities were evaluated using the structural interaction formula and an equation developed from this experimental study. This new equation models the laboratory data well and is applicable for the limites field data.