• Structural Engineering and Mechanics
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• v.19 no.4
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• pp.381-399
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• 2005

Base isolation technologies have been proven to be very efficient in protecting structures from seismic hazards during experimental and theoretical studies. In recent years, there have been more and more engineering applications using base isolators to upgrade the seismic resistibility of structures. Optimum design of the base isolator can lessen the undesirable seismic hazard with the most efficiency. Hence, tracing the nonlinear behavior of the base isolator with good accuracy is important in the engineering profession. In order to predict the nonlinear behavior of base isolated structures precisely, hundreds even thousands of degrees-of-freedom and iterative algorithm are required for nonlinear time history analysis. In view of this, a simple and feasible exact formulation without any iteration has been proposed in this study to calculate the seismic responses of structures with base isolators. Comparison between the experimental results from shaking table tests conducted at National Center for Research on Earthquake Engineering in Taiwan and the analytical results show that the proposed method can accurately simulate the seismic behavior of base isolated structures with elastomeric bearings. Furthermore, it is also shown that the proposed method can predict the nonlinear behavior of the VCFPS isolated structure with accuracy as compared to that from the nonlinear finite element program. Therefore, the proposed concept can be used as a simple and practical tool for engineering professions for designing the elastomeric bearing as well as sliding bearing.

• Steel and Composite Structures
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• v.13 no.6
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• pp.501-519
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• 2012

As an alternative to current conventional force-based assessment methods, the energy-based seismic performance of a code-designed 20-storey high-rise steel building is evaluated in this paper. Using 3D nonlinear dynamic time-history method with consideration of additional material damping effect, the influences of different restoring force models and P-${\Delta}/{\delta}$ effects on energy components are investigated. By combining equivalent viscous damping and hysteretic damping ratios of the structure subjected to strong ground motions, a new damping model, which is amplitude-dependent, is discussed in detail. According to the analytical results, all energy components are affected to various extents by P-${\Delta}/{\delta}$ effects and a difference of less than 10% is observed; the energy values of the structure without consideration of P-${\Delta}/{\delta}$ effects are larger, while the restoring force models have a minor effect on seismic input energy with a difference of less than 5%, but they have a certain effect on both viscous damping energy and hysteretic energy with a difference of about 5~15%. The paper shows that the use of the hysteretic energy at its ultimate state as a seismic design parameter has more advantages than seismic input energy since it presents a more stable value. The total damping ratio of a structure consists of viscous damping ratio and hysteretic damping ratio and it is found that the equivalent viscous damping ratio is a constant for the structure, while the equivalent hysteretic damping ratio approximately increases linearly with structural response in elasto-plastic stage.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.1
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• pp.154-162
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• 2019

Large scale damage has been globally increased due to natural disasters such as earthquake. Although a variety of studies secured seismic performance of buildings, casualties and economic loss have occurred because of poor security of seismic performance in non-structural components. Structure's location on which non-structural components are installed and characteristics of vibration occurring on each position of structures are varied, so a response spectrum is required for each position of structures. In addition, a response spectrum occurring in a structure is different, depending on the form of it and positions on which it is installed. Therefore, selection of a response spectrum is important, so a definite method for calculating the response spectrum which acts on non-structural components is necessary. A method for choosing a response spectrum is suggested in this paper, and a structural analysis was conducted with the suggested method, by selecting a ground response spectrum and a structural system, which may occur in Korea. Moreover, it helps create a response spectrum necessary for a seismic test of non-structural components, by suggesting the method for deduction it, with a simple formula.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.8
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• pp.77-86
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• 2018

The purpose of this study is to examine the condition of the architectural location and the history of Yeongbojeong and investigate the motivation which formed the YuSik space and the poetical circles of it. And another purpose of the study is to discover how Yeongbojeong, located in a military camp in Western coast, displayed the poetic scenery so to be the poetic summer house among so many Nujeongs in Joseon. Yeongbojeong is currently located in Soseong-ri, Ocheon-myeon, Boryeong City, Chungnam. Yeongbojeong has the biggest size among all the summer houses in the country with 24 architectural rooms. And Yeongbojeong is not only the summer house in which people could simply see its scenery, but beyond the poetic space of Joseon, it was the unique poetic summer house which enables poets and calligraphers to enjoy imaginary freedom. The time range of the study was from the building of Yeongbojeong in 1504 to its demolish in 1901, and its space range was taken focused on the particular scenery which was seen from around Yeongbojeong. To investigate the architectural aspect of Yeongbojeong, the existing records about the summer houses, "OcheonGoonJi" and the landscape paintings etc. were referred. The travel records and poems in the work collection of the famous poets who explored Yeongbojeong were referred to examine the formation of the Yeongbojeong poetical circles. The result of the study shows the process that Yeongbojeong had become the famous national place with scenery and how it became the most visited YuSik space. And this study figured out the full account of Yeongbojeong poetical circles which had been formed by so many poets of the country for 4 hundred years.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.11
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• pp.13-24
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• 2019

The history of tall buildings begins in 1853with the development of elevators. After the Industrial Revolution of the 18th century, the development of high-rise buildings will be carried out in earnest as a means to efficiently use the limited land of cities. The development, which began around Chicago, extended over a long period of time to Asia, maximizing the high competition. However, in the 2000s, not only was it high due to the development of construction and digital technology, but it also became competitive in eco-friendly elements and unstructured forms. High-rise building plans that have gained elemental and morphological diversity are completed by the interrelationships of various plans. Among them, it is important that the core plan has a reasonable approach from the initial planning stage as the basis for the vertical copper plan linking vertically-intensive functions. The cores should be designed to be clear and adequately responsive to changes in the shape of the building. This study aims to provide designers with a reasonable understanding of core planning by identifying core characteristics of irregular high-rise. In particular, we want to analyze the shape of the ground layer core and the relationship between the area and components of the ground layer core. The analysis results are as follows, classified according to the type or use of the building. Of the atypical forms composed of double bending, the TAPER-Curve and TWIST forms are the most distributed, and the plane and core shapes of the ground floor are the most commonly used. Based on the analysis of the validity of the ground floor cores by shape of the cores, the most commonly used forms for core shapes in the planning of the atypical high-rise are square, circular and Oval, and the most efficient oval cores and relatively inefficient ones when planned.

• Journal of Korean Biological Nursing Science
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• v.23 no.1
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• pp.64-71
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• 2021

Purpose: This study was conducted to examine the effects of an educational program based on mobile SMS and counseling for colonoscopy in elderly people. Methods: The study utilized a non-equivalent control group with a non-synchronized design as a quasi-experimental research. The study subjects consisted of 72 elderly people (36 elderly people in the experimental group and 36 in the control group). Among the subjects, 49 were male (68.1%) and 23 were female (31.9%), and the age was 69.04±6.14 years. Forty-five subjects (62.5%) answered that they had underlying diseases, eight subjects (11.1%) had a family history of colon disease, and 61 subjects (84.7%) had undergone a colonoscopy. The experimental group was provided with an educational program based on mobile SMS and counseling when three days and one day before the test. The control group received verbal explanations using information sheet. The data were analyzed using descriptive statistics, the Chi-squares test, and the independent t-test with SPSS/WIN 21.0. Results: Significant differences were found in bowel cleanliness scores (t= 3.60, p= .003) between the groups. No significant differences were seen between the groups in the sedation drug dosage (propofol (t= 1.02, p= .730), midazolam (t= 0.66, p= .380)) and time for colonoscopy (t= 1.08, p= .235). Conclusion: Based on the results of this study, an educational program based on mobile SMS and counseling for colonoscopy was proposed as an educational program before colonoscopy.

• Earthquakes and Structures
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• v.20 no.1
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• pp.55-70
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• 2021

In urban cities, buildings were built in the neighborhood, these buildings influence each other through structure-soilstructure interaction (SSSI) and seismic pounding due to limited separation distance in-between. Generally, the effects of the interaction between soil and structure are disregarded during seismic design and analysis of superstructure. However, the system of soil-base adversely changes structural behavior and response demands. Thus, the vibration characteristics plus the seismic response of a building are not able to be independent of those in adjacent buildings. The interaction between structure, soil, and structure investigates the action of the attendance of adjacent buildings to the others by the interaction effect of the sub-soil under dynamic disturbances. The main purpose of this research is to analyze the effects of SSSI and seismic pounding on the behavior of adjacent buildings. The response of a single structure or two adjacent structures with shallow raft base lying on soft soil are studied. Three dimensions finite element models are developed to investigate the effects of pounding; gap distance; conditions of soil; stories number; a mass of adjacent building and ground excitation frequency on the seismic responses and vibration characteristics of the structures. The variation in the story displacement, story shear, and story moment responses demands are studied to evaluate the presence effect of the adjacent buildings. Numerical results acquired using conditions of soil models are compared with the condition of fixed support and adjacent building models to a single building model. The peak responses of story displacement, story moment, and story shear are studied.

• Computers and Concrete
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• v.27 no.5
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• pp.457-472
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• 2021

Reinforced concrete (RC) buildings in Taiwan have suffered failure from strong earthquakes, which was magnified by the non-ductile detailing frames. Inadequate reinforcement as a consequence of the design philosophy prior to the introduction of current standards resulted in severe damage in the column and beam-column joint (BCJ). This study establishes a finite element analysis (FEA) of the non-ductile detailing RC column, BCJ, and three-story building that was previously tested through a tri-axial shaking table test. The results were then validated to laboratory specimens having the exact same dimensions and properties. FEA simulation integrates the concrete damage plasticity model and the elastic-perfectly plastic model for steel. The load-displacement responses of the column and BCJ specimens obtained from FEA were in a reasonable agreement with the experimental curves. The resulting initial stiffness and maximum base shear were found to be a close approximation to the experimental results. Also, the findings of a dynamic analysis of the three-story building showed that the time-history data of acceleration and displacement correlated well with the shaking table test results. This indicates the FEA implementation can be effectively used to predict the RC frame performance and failure mode under seismic loads.

• Structural Engineering and Mechanics
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• v.76 no.6
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• pp.751-763
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• 2020

Available records of recent earthquakes show that near-field earthquakes have different characteristics than far-field earthquakes. In general, most of these unique characteristics of near-fault records can be attributed to their forward directivity. This phenomenon causes the records of ground motion normal to the fault to entail pulses with long periods in the velocity time history. The energy of the earthquake is almost accumulated in these pulses causing large displacements and, accordingly, severe damages in the building. Damage to structures caused by past earthquakes raises the need to assess the chance of future earthquake damage. There are a variety of methods to evaluate building seismic vulnerabilities with different computational cost and accuracy. In the meantime, fragility curves, which defines the possibility of structural damage as a function of ground motion characteristics and design parameters, are more common. These curves express the percentage of probability that the structural response will exceed the allowable performance limit at different seismic intensities. This study aims to obtain the fragility curve for low- and mid-rise structures of reinforced concrete moment frames by incremental dynamic analysis (IDA). These frames were exposed to an ensemble of 18 ground motions (nine records near-faults and nine records far-faults). Finally, after the analysis, their fragility curves are obtained using the limit states provided by HAZUS-MH 2.1. The result shows the near-fault earthquakes can drastically influence the fragility curves of the 6-story building while it has a minimal impact on those of the 3-story building.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.3
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• pp.1-12
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• 2021

The purpose of this paper is to study of the applicability of the current response spectrum analysis method by grasping the dynamic behavior characteristics of soil-pile and pier-crane in pile mooring facilities. To this end, time history analysis was performed using Abaqus as a design variable for various soil types, pile-ground modeling, and structure specific cycles. The results were compared with the analysis results of the response spectrum. Subsequently, a problem has been found in the current response spectrum analysis and the improvements are needed when considering the dynamic behavior of the ground-pile and pier-crane of the pile mooring facility.