• Steel and Composite Structures
• /
• v.27 no.1
• /
• pp.75-87
• /
• 2018

This paper presents a new method to compute the shear strength of composited structural B-C-W members. These B-C-W members, defined as concrete-filled steel box beams, columns and shear walls, consist of a slender rectangular steel plate box filled with concrete and inserted steel plates connecting the two long-side steel plates. These structural elements are intended to be used in structural members of super-tall buildings and nuclear safety-related structures. The concrete confined by the steel plate acts to be in a multi-axial stressed state: therefore, its shear strength was calculated on the basis of a concrete's failure criterion model. The shear strength of the steel plates on the long sides of the structural element was computed using the von Mises plastic strength theory without taking into account the buckling of the steel plate. The spacing and strength of the inserted plates to induce plate yielding before buckling was determined using elastic plate theory. Therefore, a predictive method to compute the shear strength of composited structural B-C-W members without considering the shear span ratio was obtained. A coefficient considering the influence of the shear span ratio was introduced into the formula to compute the anti-lateral bearing capacity of composited structural B-C-W members. Comparisons were made between the numerical results and the test results along with this method to predict the anti-lateral bearing capacity of concrete-filled steel box walls. Nonlinear static analysis of concrete-filled steel box walls was also conducted by using ABAQUS and the results agreed well with the experimental data.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.15 no.6
• /
• pp.114-120
• /
• 2006

Front-end side members of vehicles are structures with the greatest energy absorbing capability in a front-end collision of vehicles. This paper was undertaken to analyze the energy absorption characteristics of spot welded hat and double hat-shaped section members under the axial collapse. The experiments were performed with respect to the various collapse velocities. It was expected that para-closed sections would show collapse characteristics which be quite different from those of perfectly closed sections. The collapse velocities were selected as follows: the velocities in the hat-shaped section members were 0.00017m/sec, 0.017m/sec, 4.7m/sec, 6.5m/sec, 6.8m/sec, 7.2m/sec, and 7.3m/sec those in the double hat-shaped section members were 0.00017m/sec, 0.017m/sec, 6.5m/sec, 6.8m/sec, 7.2m/sec 7.3m/sec, and 7.9m/sec. In the program system presented in this study, an explicit finite element code, LS-DYNA3D, is adopted for simulating complicated collapse behavior of the hat and double hat-shaped section members under the same condition of the collapse test. The validity of simulation was confirmed by the comparison between the simulation result and the collapse experiment.

• International Journal of Concrete Structures and Materials
• /
• v.10 no.2
• /
• pp.237-247
• /
• 2016

Progressive collapse resistance of RC buildings can be analyzed by considering column loss scenarios. Using finite element analysis and a static test, the progressive collapse process of a RC frame under monotonic vertical displacement of a side column was investigated, simulating a column removal scenario. A single-story 1/3 scale RC frame that comprises two spans and two bays was tested and computed, and downward displacement of a side column was placed until failure. Our study offers insight into the failure modes and progressive collapse behavior of a RC frame. It has been noted that the damage of structural members (beams and slabs) occurs only in the bay where the removal side column is located. Greater catenary action and tensile membrane action are mobilized in the frame beams and slabs, respectively, at large deformations, but they mainly happen in the direction where the frame beams and slabs are laterally restrained. Based on the experimental and computational results, the mechanism of progressive collapse resistance of RC frames at different stages was discussed further. With large deformations, a simplified calculation method for catenary action and tensile membrane action is proposed.

• Journal of Ship and Ocean Technology
• /
• v.5 no.3
• /
• pp.36-44
• /
• 2001

The collision energy absorbing characteristics of side structure of the LNG carriers which have the cargo containment systems of the spherical and the membrane types are compared. A failure mechanism of the double hull side structures of 130, 000 $m^3$ class LNG carriers under sideways collision event has been simulated by using the detailed finite element calculations. In ship collision analysis, the finite element method based on explicit time integration has been use[1 with much success. Finite element modeling techniques for detail description of structural members antral ship motion regarding the dynamic behavior allowed to investigate the effect of bow shape and the initial contact position on side shell of collided ship. In the numerical simulations of the ship-to-ship sideways collision, the effect of the colliding bow shapes and the change of the colliding ship draft are investigated. The critical collision energy which is absorbed by a side structure of a collided ship until the fore-end of colliding ship arrives at the boundary of the cargo tank is calculated. The critical speed of specified colliding ships which can not penetrate the boundary of the LNG cargo tank of the collided ship under collision accident if evaluated.

• Journal of Preventive Medicine and Public Health
• /
• v.40 no.4
• /
• pp.291-296
• /
• 2007

Objectives : To explore the information sources and knowledge on infant vaccinations of pro-vaccination community members and anti-vaccination community members on the internet. Methods : An online survey of 245 parents from three pro-vaccination communities and 92 parents from one anti-vaccination community was conducted from June 7 to June 23, 2006. Results : Parents from pro-vaccination communities usually gained the information regarding vaccination efficacy and risk mainly from healthcare providers (49.8%) and mass media (47.7%). Pro-vaccination community members considered healthcare providers as the most credible sources of information on vaccination, whereas the anti-vaccination community members usually gained their information regarding vaccine efficiency and risk from Internet child-care cafes and online vaccination communities. Parents of the anti-vaccination community considered the internet as the most credible information source (77.6% for efficacy, 94.8% for risk). In addition, the major reason why anti-vaccination community members didn't vaccinate and, will not vaccinate, was concern about possible side effects of the vaccine. The knowledge level on infant vaccination, education and economic status was higher in the anti-vaccination community. Conclusions : On-line communities concerned with vaccination are getting popular. The influence of anti-vaccination parents on the Internet is expected to be high. The government and healthcare providers need to increase their efforts to improve the credibility of information about vaccination. Our findings suggest that online communication regarding vaccinations needs to be considered as a means to increase vaccination rates.

• Journal of Preventive Medicine and Public Health
• /
• v.26 no.2 s.42
• /
• pp.192-201
• /
• 1993

Epidemiologic investigation was conducted on January, 1993 in Seoul to identify the cause of an infant methemoglobinemia. Field investigation of the area of outbreak, survey of household and family members, analysis of ground water, and blood tests of involved family members were performed. Following results were obtained On analyzing the quality of the ground water on patient's household high levels of nitrate was found indicating contamination of water as the cause of a methemoglobinemia outbreak. On analysing the quality of the ground waters on seven other places within the neighborhood five were contaminated by nitrate in concentration that exceeded the permissible limit implying presence nearby source of contamination. Sources of contamination were thought to be originating from human waste in conventional bathroom facilities, chicken manure used in nearby orchards and plant fields or fertilizers. But the results of water analysis with presence of bacteria or E.coli, concentration of potassium, phosphate and the past history of diarrhea among family members, chicken manure suggested the most possible source of contamination. To evaluate the health status of members in the neighborhood past history was reviewed revealing no prior existence of patient with cyanosis and 65 people in the neighborhood had normal levels of methemoglobin concentration in their blood. Conclusively, the ground water on patient's household was contaminated with nitrate and despite provision of adequate water supply, family members of the patient along with their distrust in the water supply system had used ground water as their source of drinking water resulting of methemoglobinemia. Many suburban area of Seoul and country side thought to be having similar problems concerning contaminated ground water supply and dormant outbreak of patients as a result of the drinking of the contaminated water. Epidemiologic investigation and water analysis of ground waters are advised.

• Smart Structures and Systems
• /
• v.9 no.3
• /
• pp.253-271
• /
• 2012

Finite element (FE) model updating is a useful tool for global damage detection technique, which identifies the damage of the structure using measured vibration data. This paper presents the application of a finite element model updating method to detect the damage of a small-scale reinforced concrete building structure using measured acceleration data from shaking table tests. An iterative FE model updating strategy using the least-squares solution based on sensitivity of frequency response functions and natural frequencies was provided. In addition, a side constraint to mitigate numerical difficulties associated with ill-conditioning was described. The test structure was subjected to six El Centro 1942 ground motion histories with different Peak Ground Accelerations (PGA) ranging from 0.06 g to 0.5 g, and analytical models corresponding to each stage of the shaking were obtained using the model updating method. Flexural stiffness values of the structural members were chosen as the updating parameters. In model updating at each stage of shaking, the initial values of the parameter were set to those obtained from the previous stage. Severity of damage at each stage of shaking was determined from the change of the updated stiffness values. Results indicated that larger reductions in stiffness values occurred at the slab members than at the wall members, and this was consistent with the observed damage pattern of the test structure.

• Journal of architectural history
• /
• v.26 no.1
• /
• pp.105-116
• /
• 2017

The purpose of this study is to comprehend the change of the terms and the structure of the Pungpanbu in the T-shaped wooden shrines in the later Joseon period through the Salleung-dogamuigwes. Following conclusions have been reached through the study. First, the terms in the Salleung-dogamuigwes were similar to Yeonggeon-dogamuigwes but timing difference was verified. The word about the frame of Pungpanbu was different from the current. Second, in accordance with the extended of Pungpanbu, the members of frame of Pungpanbu had been increased and it had been changed to the lattice. The members of Pungpanbu used as plan dimensions and the size of the members had been gradually increased. Third, the Pungpanbu had been extended to protect the side of T-shaped wooden shrines. At the same time, the range of Chukjungbang had been extended. This was the result of the efforts of the era to reduce the range of plaster. This affected the overall elevation change of T-shaped wooden shrines.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.17 no.1
• /
• pp.86-91
• /
• 2008

The structural members must be designed to control characteristics of energy absorption for protecting passengers in a car accident. Study on collapse characteristics of structural member is currently conducted in parallel with other studies on effective energy absorption capacity of structural members with diverse cross-sectional shapes and various materials. This study concerns the crashworthiness of the widely used vehicle structural members, square thin-walled tubes, which are excellent in the point of the energy absorption capacity. The absorbed energy, mean collapse load and deformation mode were analyzed for side member which absorbs most of the collision energy. To predict and control the energy absorption, controller is designed in consideration of its influence on height, thickness and width ration in this study. The absorbed energy and mean collapse load of square tubes were increased by $15{\sim}20%$ in using the controller, and energy absorbing capability of the specimen was slightly changed by change of the high controller's height.

• Journal of the Korea Safety Management & Science
• /
• v.7 no.3
• /
• pp.1-15
• /
• 2005

Recently in Korean Society, risk and safety has become a central discourse in not only the social and natural science but also political decision making. The efficient organizational management contributes to controlling the risk factors in the workplace. For the management is influenced and improved by the organizational culture, the alternatives more than simply improving the work environment or enforcing the education of safety on each workers are required. This study was the status of safety culture in organizational members(managers and workers, and specialist) including the attitude on the safety atmosphere and risk perception, and experiences, knowledges, motivation etc. For this part, the method of questionnaire and statistical analysis are mobilized. The degree of safety commitment of organization members appears relatively high (3.97 in five scale estimation), but there are variations in this results according to socio-demographic characteristics. At the same time, managers and professionals actively participation in the program related to safety than workers in production/sales. The higher income level and career is the more attention to the safety is. Based on this survey, we make an rough suggestion of several tasks to the policy -makers: improvement of communication on the risk and safety is required and in particular, the workers in the relatively low level in production/sales. The education system about safety which is, with one-side, provided by government or managers turns out to be inefficient. Rather, small group performance of the organizational members which they participate in the communication with interaction in the various discourse are able to provoke the safety mood in workplace.