• Title/Summary/Keyword: Design-time history

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Generation of Artificial Acceleration-Time Histories for the Dynamic Analysis of Structures in the Korean Peninsula (구조물(構造物)의 동적해석(動的解析)을 위한 한반도(韓半島)의 인공지진파(人工地震波) 작성(作成))

  • Kim, Won Bae;Yu, Chul Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.10 no.3
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    • pp.39-47
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    • 1990
  • The generation of artificial accelerograms considering the characteristic of earthquakes in the Korean peninsula for a time history analysis of structures is accomplised by the stochastic method. The engineering data such as a representative shape of envelope function and an effective duration are investigated from the instrumental records. The maximum ground acceleration value is based on seismic zoning map which are constructed for the Korean peninsula. The acceleration-time histories are generated for two different types of earthquake motions and two types of soil conditions. In the study, the maximum ground acceleration value of 0.2 g and effective durations of 24 seconds are used. The validity of the artificial accelerograms is obtained by the comparison with the required envelope functions and the design response spectrum.

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Creep analysis of the FG cylinders: Time-dependent non-axisymmetric behavior

  • Arefi, Mohammad;Nasr, Mehrdad;Loghman, Abbas
    • Steel and Composite Structures
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    • v.28 no.3
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    • pp.331-347
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    • 2018
  • In this paper history of stresses, strains, radial and circumferential displacements of a functionally graded thick-walled hollow cylinder due to creep phenomenon is investigated. The cylinder is subjected to an arbitrary non-axisymmetric two dimensional thermo-mechanical loading and uniform magnetic field along axial direction. Using equilibrium, strain-displacements and stress-strain relations, the governing differential equations of the problem containing creep strains are derived in terms of radial and circumferential displacements. Since the displacements are varying with time due to creep phenomenon, an analytical solution is not available for these equations. Thus, a semi-analytical procedure based on separation of variables and Fourier series together with a numerical procedure is employed. The numerical results indicate that the non-axisymmetric loading and the material grading index have significant effect on stress redistributions. Moreover, by proper selection of material for any combination of non-axisymmetric loading, one can arrive suitable response for the cylinder to achieve optimal design. With some simplifications, the results are validated with the existing literature.

Effect of Age on the Voice Onset Time of Korean Stops in VCV contexts (연령에 따른 VCV 문맥에서 한국어 폐쇄음의 성대진동개시시간)

  • Lee, Seulgi;Lee, Youngmee
    • Phonetics and Speech Sciences
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    • v.7 no.3
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    • pp.37-44
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    • 2015
  • This study investigated the effects of the age of Korean speakers, place of articulation, and phonation types on voice onset time (VOT) of stops. Twenty-five preschoolers, 25 schoolers, and 25 adults who had no history of speech and language impairment produced plosives in /VCV/ words in isolation. A three-way ($3{\times}3{\times}3$) mixed design was used with the age of speakers (preschoolers, schoolers, adults) as a between-subject factor, the place of articulation (bilabials, alveolars, velars) and phonation types (plain, tense, aspirated consonants) as a within-subject factor. The dependent measure was the VOT values. Results revealed that three main effects were statistically significant. Preschoolers exhibited longer VOTs than adults (p<.05). There were significant differences in VOTs among the place of articulation, showing that speakers had the longest VOTs for velars (velars > alvelars > bilabials) (all p<.05). In addition, the VOTs for aspirated consonants were longer than those for plain and tense consonants, and the differences were significant among three phonation types (aspirated > tense > plain) (all p<.05). The current results suggested that VOTs would be linked to age and development, and schoolers over the age of 11 years had achieved adult-like VOTs. Moreover, the place of articulation and phonation types in Korean stops showed marked factors in normal speakers' VOT patterns.

A Study on Dynamic Behaviour of Cable-Stayed Bridge by Vehicle Load (차량하중에 의한 사장교의 동적거동에 관한 연구)

  • Park, Cheun Hyek;Han, Jai Ik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.6
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    • pp.1299-1308
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    • 1994
  • This paper is considered on the dynamic behavior and the dynamic impact coefficient on the cable-stayed bridge under the vehicle load. The method of static analysis, that is, the transfer matrix method is used to get influence values about displacements, section forces of girder and cable forces. Gotten influence values were used as basic data to analyse dynamic behavior. This paper used the transfer matrix method because it is relatively simpler than the finite element method, and calculating speed of computer is very fast and the precision of computation is high. In the process of dynamic analysis, the uncoupled equation of motion is derived from simultaneous equation of the motion of cable-stayed bridge and vehicle travelling by using mode shape, which was borne from system of undamped free vibration. The solution of the uncoupled equation of motion, that is, time history of response of deflections, velocity and acceleration on reference coordinate system, is found by Newmark-${\beta}$ method, a kind of direct integral method. After the time history of dynamic response was gotten, and it was transfered to the time history of dynamic response of cable-stayed bridge by linear transformation of coordinates. As a result of this numerical analysis, effect of dynamic behavior for cable-stayed bridge under the vehicle load has varied depending on parameter of design, that is, the ratio of span, the ratio of main span length, tower height, the flexural rigidity of longitudinal girder, the flexural rigidity of tower, and the cable stiffness, investigated. Very good agreements with the existing solution in the literature are shown for the uncracked plate as well as the cracked plate.

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Seismic Fragility Analysis by Key Components of a Two-pylon Concrete Cable-stayed Bridge (2주탑 콘크리트 사장교의 주요 부재 지진 취약도 분석)

  • Shin, Yeon-Woo;Hong, Ki-Nam;Kwon, Yong-Min;Yeon, Yeong-Mo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.4
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    • pp.26-37
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    • 2020
  • This study intends to present a fragility analysis method suitable for concrete cable-stayed bridges by performing an analysis reflecting design criteria and material characteristics from the results of inelastic time-history analysis. In order to obtain the fragility curve of the cable-stayed bridge, the limit state of the main component of the cable-stayed bridge is determined, and the damage state is classified by comparing it with the response value based on inelastic time history analysis. The seismic fragility curve of the cable-stayed bridge was made by obtaining the probability of damage to PGA that the dynamic response of the vulnerable parts to input ground motion would exceed the limit state of each structural member. According to the pylon's fragility curve, the probability of moderate damage at 0.5g is 32% for the longitudinal direction, while 7% for the transversal direction, indicating that the probability of damage in the longitudinal direction is higher in the same PGA than in the transversal direction. The seismic fragility curve of the connections showed a very high probability of damage, meaning that damage to the connections caused by earthquakes is very sensitive compared to damage to the pylon and cables. The cable's seismic fragility curve also showed that the probability of complete damage state after moderate damage state gradually decreased, resulting in less than 30% probability of complete damage at 2.0g.

Study on the Emergency Assessment about Seismic Safety of Cable-supported Bridges using the Comparison of Displacement due to Earthquake with Disaster Management Criteria (변위 비교를 통한 케이블지지교량의 긴급 지진 안전성 평가 방법의 고찰)

  • Park, Sung-Woo;Lee, Seung Han
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.6
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    • pp.114-122
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    • 2018
  • This study presents the emergency assessment method about seismic safety of cable-supported bridges using seismic acceleration sensors installed on the primary structural elements of them. The structural models of bridges are updated iteratively to make their dynamic characteristics to be similar to those of real bridges based on the comparison of their natural frequencies with those of real bridges estimated from acceleration data measured at ordinary times by the seismic acceleration sensor. The displacement at the location of each seismic acceleration sensor is derived by seismic analysis using design earthquake, and the peak value of them is determined as the disaster management criteria in advance. The displacement time history is calculated by the double integration of the acceleration time history which is recorded at each seismic acceleration sensor and filtered by high cut(low pass) and low cut(high pass) filters. Finally, the seismic safety is evaluated by the comparison of the peak value in calculated displacement time history with the disaster management criteria determined in advance. The applicability of proposed methodology is verified by performing the seismic safety assessment of 12 cable-supported bridges using the acceleration data recorded during Gyeongju earthquake.

Seismic Fragility Analysis for Probabilistic Performance Evaluation of PSC Box Girder Bridges (확률론적 내진성능평가를 위한 PSC Box 거더교의 지진취약도 해석)

  • Song, Jong-Keol;Jin, He-Shou;Lee, Tae-Hyung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.2A
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    • pp.119-130
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    • 2009
  • Seismic fragility curves of a structure represent the probability of exceeding the prescribed structural damage state for a given various levels of ground motion intensity such as peak ground acceleration (PGA), spectral acceleration ($S_a$) and spectral displacement ($S_d$). So those are very essential to evaluate the structural seismic performance and seismic risk. The purpose of this paper is to develop seismic fragility curves for PSC box girder bridges. In order to construct numerical fragility curve of bridge structure using nonlinear time history analysis, a set of ground motions corresponding to design spectrum are artificially generated. Assuming a lognormal distribution, the fragility curve is estimated by using the methodology proposed by Shinozuka et al. PGA is simple and generally used parameter in fragility curve as ground motion intensity. However, the PGA has not good relationship with the inelastic structural behavior. So, $S_a$ and $S_d$ with more direct relationship for structural damage are used in fragility analysis as more useful intensity measures instead of PGA. The numerical fragility curves based on nonlinear time history analysis are compared with those obtained from simple method suggested in HAZUS program.

Image Identification Plan for SeJong-City Presidential Archives (세종시 대통령기록관 상설전시 연출을 위한 색채·전시사인 계획)

  • Lee, In-Ho;Lee, Heung-Wu;Kyung, Byung-Pyo;Ryu, Seuc-Ho
    • Journal of the Korea Convergence Society
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    • v.9 no.12
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    • pp.169-174
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    • 2018
  • The museum, run by the archives, should show historical facts about the president through objective records that are not fully evaluated. The wartime atmosphere should maintain solemnity to highlight the evidential value of records about history, but include an interesting element that allows visitors to come comfortably. It would be possible to accommodate 360 viewers at the same time, and it would be an option to limit the number of visitors considering the operation of weekend events and the donor honor hall. In this study, we established and presented an image integration plan centered on the color plan and the signature plan. Although the real image integration plan is a case study that starts with symbols and logos and is conducted through an integrated and systematic system through the basic design and application design system, it is considered to be a meaningful study in terms of practical use.

Performance-based plastic design of buckling-restrained braced frames with eccentric configurations

  • Elnaz Zare;Mohammad Gholami;Esmail Usefvand;Mojtaba Gorji Azandariani
    • Earthquakes and Structures
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    • v.24 no.5
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    • pp.317-331
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    • 2023
  • The buckling-restrained braced frames with eccentric configurations (BRBFECs) are stable cyclic behavior and high energy absorption capacity. Furthermore, they have an architectural advantage for creating openings like eccentrically braced frames (EBFs). In the present study, it has been suggested to use the performance-based plastic design (PBPD) method to calculate the design base shear of the BRBFEC systems. Moreover, in this study, to reduce the required steel material, it has been suggested to use the performance-based practical design (PBPD) method instead of the force-based design (FBD) method for the design of this system. The 3-, 6-, and 9-story buildings with the BRBFEC system were designed, and the finite element models were modeled. The seismic performance of the models was investigated using two suits of ground motions representing the maximum considered earthquake (MCE) and design basis earthquake (DBE) seismic hazard levels. The results showed that the models designed with the suggested method, which had lower weights compared to those designed with the FBD method, had a desirable seismic performance in terms of maximum story drift and ductility demand under earthquakes at both MCE and DBE seismic hazard levels. This suggests that the steel weights of the structures designed with the PBPD method are about 13% to 18% lesser than the FBD method. However, the residual drifts in these models were higher than those in the models designed with the FBD method. Also, in earthquakes at the DBE hazard level, the residual drifts in all models except the PBPD-6s and PBPD-9s models were less than the allowable reparability limit.

Lessons from Haitai Distribution Inc's experience in Korea

  • Cho, Young-Sang
    • Journal of Distribution Science
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    • v.9 no.3
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    • pp.25-36
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    • 2011
  • Owing to the rapid growth of hypermarket/discount store formats since 1996, Korean retailing has suddenly attracted the significant attention from researchers. Before the emergence of large scale retailers such as E-Mart, Lotte Mart and Tesco Korea, there were the two retail formats who led the Korean retailing in the modern retailing history: department store and supermarket formats. Nevertheless, there has been little literature concerned about the two retail formats as a case study, while some authors have paid their attention to hypermarket/discount store formats. In addition, when mentioning the development process of retailing history, it is less likely that authors have made an effort to illustrate supermarket retailing history. In order to regard supermarket retailing as part of the Korean retailing, it is interesting to look at a representative supermarket retailer, Haitai, who was one of the subsidiaries of Haitai chaebol. Based on supermarket retailing, the company which was established as a joint venture in 1974 led a supermarket retailing in the Korean modernised retailing history. Before analysing whether Haitai failed or not, the definition of failure should be illustrated. With regard to the term, failure, in the academic world, authors have interchangeably used the following terms: failure, divestment, closure, organisational restructuring, and exit. To collect research data as a case study, the author adopted an in-depth interview method. The research is based on research interviews with 13 ex-staff who left after Haitai went bankruptcy, from store management department to merchandise department. By investigating Haitai's experiences through field interviews, the research found that Haitai restructured organisational decision-making process at the early stage when companies started to modernise organisational charts, benchmarking sophisticated retailing knowledge through the strategic alliance with a Japanese retailer. In respect of buying system, the company established firmly buying functions by adopting central buying system, and further, outstandingly allocated considerable marketing resources to the development of retailer brands with the dedicated team of retailer brand development. In the grocery retailing, abandoning a 'no-frill' packaging concept, the introduction of retailer brand packaging equal to, or better than national brand packaging design, encouraged other retailers to change their retailer brand development strategies. In product sourcing ways, Haitai organised for the first time the overseas sourcing team with the aim of improving the profit margins of foreign products and providing exotic products for customers, followed by other retailers. Regarding distribution system, the company introduced the innovative idea which delivered products ordered by stores directly to each store withboth its own vehicles and its own warehouse in which could deal with dry foods, chilly foods, frozen food, and non-foods, and even, process produce. In addition, Haitai developed many promotional methods to attract more customers like 'the guarantee of the lowest price', and expanded its own business to US in 1996, although withdrew, because of bankruptcy in 1997. Together with POS introduction in 1994, Haitai made a significant contribution to the development of the Korean retailing, influencing other retailers in many aspects. As a case study, the study has provided a number of lessons from Haitai's experiences for academicians and practitioners, suggesting that its history should be involved in the Korean modernised retailing.

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