• Title/Summary/Keyword: eccentric

Search Result 893, Processing Time 0.053 seconds

An Evaluation of Structural Performance of Reinforced Concrete Column Retrofitted with Grid Type Unit Details of Jacketing Method under Loading Patterns (격자형 유닛 상세를 가진 단면증설공법으로 보강된 철근콘크리트 기둥의 하중가력패턴에 따른 구조성능평가)

  • Moon, Hong Bi;Ro, Kyong Min;Lee, Young Hak
    • Journal of Korean Association for Spatial Structures
    • /
    • v.22 no.2
    • /
    • pp.29-37
    • /
    • 2022
  • The collapse of reinforced concrete (RC) frame buildings is mainly caused by the failure of columns. To prevent brittle failure of RC column, numerous studies have been conducted on the seismic performance of strengthened RC columns. Concrete jacketing method, which is one of the retrofitting method of RC members, can enhance strength and stiffness of original RC column with enlarged section and provide uniformly distributed lateral load capacity throughout the structure. The experimental studies have been conducted by many researchers to analyze seismic performance of seismic strengthened RC column. However, structures which have plan and vertical irregularities shows torsional behavior, and therefore it causes large deformation on RC column when subjected to seismic load. Thus, test results from concentric cyclic loading can be overestimated comparing to eccentric cyclic test results, In this paper, two kinds of eccentric loading pattern was suggested to analyze structural performance of RC columns, which are strengthened by concrete jacketing method with new details in jacketed section. Based on the results, it is concluded that specimens strengthened with new concrete jacketing method increased 830% of maximum load, 150% of maximum displacement and changed the failure modes of non-strengthened RC columns.

Seismic Performance of an Inverted V-type Eccentrically Braced Steel Frames with Slit Dampers Using Shape Memory Alloy (형상기억합금을 이용한 슬릿댐퍼 적용 역V형 편심가새골조의 내진 성능)

  • Jang, Han Ryul;Kim, Joo-Woo
    • Journal of Korean Association for Spatial Structures
    • /
    • v.22 no.4
    • /
    • pp.39-48
    • /
    • 2022
  • The energy dissipation of inverted V-type eccentric steel braced frames can be achieved through the yielding of a slit link, through yielding of a number of strips between slits when the frame is subjected to inelastic cyclic deformation. On the other hand, the development of seismic resistance system without residual deformation is obtained by applying the superelasdtic shape memory alloy (SMA) material into the brace and link elements. This paper presents results from a systematic three-dimensional nonlinear finite element analysis on the structural behavior of the eccentric bracing systems subjected to cyclic loadings. A wide scope of structural behaviors explains the horizontal stiffness, hysteretic behaviors, and failure modes of the recentering eccentric bracing system. The accurate results presented here serve as benchmark data for comparison with results obtained using modern experimental testing and alternative theoretical approaches.

Effects on Functional Recovery of Eccentric Exercise-Induced Muscle Damage by Phonophoresis of Piroxicam Gel (피록시캄 겔의 음파영동이 원심성 운동-유발 근 손상의 기능회복에 미치는 효과)

  • Choi, Sug-Ju;Kim, Tae-Youl;Song, Myung-Soo;Kim, Young-Il;Moon, Sung-Ki
    • Journal of the Korean Academy of Clinical Electrophysiology
    • /
    • v.1 no.1
    • /
    • pp.17-29
    • /
    • 2003
  • This study was investigated the effects on functional recovery of eccentric exercise-induced muscle damage by phonophoresis transdermal permeation of piroxicam gel and observed the change of amplitude at muscle action potential. Through eccentric exercise-induced muscle damage, performed healthy men and women take eccentric resistance exercise and measured action, potentials. The subjects were divided into three groups of four men each 24 hour, 48 hour, 72 hour. The results of this were as follows: 1. Change of maximal action potential at maximal voluntary contraction : The phonophoresis group was increase more than control group and gel group. 2. Change of average action potential at maximal voluntary contraction : The gel group was increase more than control group and phonophoresis group. 3. Change of maximal action potential at pain subthreshold voluntary contraction : The phonophoresis group was increase more significantly than control group and gel group. 4. Change of average action potential at pain subthreshold voluntary contraction : The phonophoresis group was increase more significantly than control group and gel group. In conclusion, the change of muscle action potential amplitude by eccentric exercise-induced muscle damage showed that the phonophoresis by pulsed ultrasound of piroxicam gel was improved the recovery of muscle function.

  • PDF

Load-carrying Capacity of Thermal Prestressed Steel Beam with Eccentric Bracket (편심 브라켓 설치 온도프리스트레싱 강재보의 하중저항 성능)

  • Kim, Sang-Hyo;Jung, Chi-Young;Choi, Kyu-Tae;Ahn, Jin-Hee
    • Journal of Korean Society of Steel Construction
    • /
    • v.22 no.6
    • /
    • pp.563-572
    • /
    • 2010
  • This study evaluates the load-carrying capacity of a thermal prestressed steel beam with an eccentric bracket. The steel beam that is proposed in this study has an eccentrically installed cover plate through application of the eccentric bracket. The eccentric bracket helps the steel beam achieve greater sectional stiffness and more efficiently induces prestress. A material non-linear characteristic applied finite element analysis was also conducted to check the validity of the experiments. The results of this study showed that the structural stiffness, yield load, and ultimate strength of the TPSM-applied steel beam with the eccentric bracket increased due to the eccentricity of the cover plate.

Reproducibility of Mandibular Eccentric Movements in Patients with Temporomandibular Disorders (측두하악장애환자에서 하악의 편심운동재현성에 관한 연구)

  • 서명석;한경수
    • Journal of Oral Medicine and Pain
    • /
    • v.22 no.2
    • /
    • pp.295-307
    • /
    • 1997
  • This study was performed to investigate the reproductibility of eccentric mandibular movements according to preferred chewing side, range of mouth opening, type of lateral guidance and involvement of temporomandibular disorders. 50 patients with temporomandibular disorders and 65 dental students without any signs and symptoms were randomly selected for this study as the patients group and the control group, respectively. For recording and observation of eccentric mandibular movement trajectory, BioEGN$^\textregistered$ of Biopak$^\textregistered$ system (Bioresearch Inc., USA) was used. Each eccentric movement to anterior, right and left side was performed three times similar to the movement pattern for Pantronic Reproducibility Index. mandibular path was analyzed by three dimensional positional change and the three paths from one direction were compared with one another. From this, reproducibility index of one-directional lateral movement could be calculated, and total reproducibility index, named BioEGN reproducibility index(BERI), was also computed from three-directional eccentric movement likewise. BioEGN reproducibility Index could have four value of score by small or large scale, and by outgoing or incoming movement. The data were analyzed by SAS/stat program and the results obtained were as follows: 1. Right side chewing subjects showed more consistent pattern In reproducibility index in comparison between patients group and control group than left chewing subjects have done, and reproducibility was low in patients group. However, there was no difference between the two stoups in bilateral chewing subjects. 2. There were no difference in reproducibility index between preferred chewing side and contralateral side in unilateral chewing subjects whereas reproducibility index in left side on outgoing movement were higher than in right side in bilateral chewing subjects. 3. Difference in total reproducibility index(BERI) between canine guidance group and non-canine guidance group were not observed though difference in reproducibility index on lateral movement were observed in part. 4. There were no difference in reproducibility index between affected side and contralateral side in unilaterally affected patients, and between unilaterally affected patients and bilaterally affected patients in patients group. 5. Highly significant positive correlationship were shown among the four 쇼pes of total reproducibility index(BERI) in total subjects, and range of clinical mouth opening was negatively correlated with BEBI on outgoing movements and with index on outgoing movement to preferred side.

  • PDF

Comparison of the Duration of Maintained Calf Muscle Flexibility After Static Stretching, Eccentric Training on Stable Surface, and Eccentric Training on Unstable Surfaces in Young Adults With Calf Muscle Tightness

  • Jang, Hee-Jin;Kim, Suhn-Yeop;Jang, Hyun-Jeong
    • Physical Therapy Korea
    • /
    • v.21 no.2
    • /
    • pp.57-66
    • /
    • 2014
  • The objective of this study was to determine the duration of maintained calf muscle flexibility gained in young adults with calf muscle tightness, as measured by increases in ankle active and passive dorsiflexion range of motion (DFROM) after three stretching interventions. Twenty subjects (5 men and 15 women) with calf muscle tightness received the following three stretching interventions in one leg (assigned at random): static stretching (SS), eccentric training on stable surface (ETS), and eccentric training on unstable surfaces (ETU). The subjects received all three interventions to the same leg, applied in a random order. Each intervention had a break of at least 24 h in-between, in order to minimize any carryover effect. Each intervention used two types of stretching: with the calf muscle stretched and both knees straight, and with the knee slightly bent in order to maximize the activation of the soleus muscle. All three interventions were performed for 200 seconds. We measured the duration of maintained calf muscle flexibility through active and passive ankle DFROM before intervention, immediately after intervention (time 0), and then 3, 6, 9, 15, and 30 min after intervention. We found a difference in the duration of maintained calf muscle flexibility between the three interventions. In the ETS and ETU interventions, a significant improvement in calf muscle flexibility, both ankle active and passive dorsiflexion ranges of motion (ADFROM and PDFROM), was maintained for 30 min. In the SS intervention, however, ADFROM before 9 min and PDFROM before 6 min were statistically different from the baseline. Our results suggest that ETS and ETU may be more effective than SS for maintaining calf muscle flexibility in young adults.

A study on eccentric load acted on cut and cover tunnel by numerical approach (복개 터널구조물에 작용하는 편토압 고려를 위한 수치해석적 연구)

  • Bae, Gyu-Jin;Chung, Hyung-Sik;Lee, Gyu-Phil
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.5 no.3
    • /
    • pp.227-239
    • /
    • 2003
  • For environment-friendly construction, cut-and-cover tunnels have been constructed, thereby leading to embankment slopes with a number of steps. The slopes cause eccentric load on concrete lining of the tunnel. Nevertheless, uniform vertical and horizontal earth pressures, which are determined by considering a self-weight of embankment and $K_0$, are routinely used in structural calculation. Distribution of the earth pressures applied to the lining will lead to a biased calculation far from the actual behavior of the lining. In this study, basic study, therefore, was performed to consider the eccentric load properly in design and analysis of a cut-and-cover tunnel. A method capable of considering the eccentric load in design was proposed and its applicability was numerically examined through a number of examples.

  • PDF

Critical Review on Theory of "Eccentric Diseases are Due to Phlegm" (괴병다속담(怪病多屬痰) 이론에 대한 비판적)

  • Bae, Sung-Jin;Choi, Jun-Yong;Kim, Kibong;Ha, Ki-Tae
    • Journal of Physiology & Pathology in Korean Medicine
    • /
    • v.34 no.6
    • /
    • pp.279-284
    • /
    • 2020
  • The theory of "eccentric diseases are generally due to phlegm (怪病多屬痰)" means that phlegm is a major cause for intractable diseases including cerebrovascular accident, depression, insanity, and shock from strange things or evil sprint. It has been a key foundation for the diagnosis and treatment of phlegm in traditional Korean medicine. However, the origin of the theory is not clear and controversial. In this study, we critically reviewed the origin and developing process of the theory in the viewpoints of philology and pathology in Korean medicine. Wang Yin-Jun (王隱 君) did not claim that eccentric diseases are generally due to phlegm in Taidingyangshengzhu-lun (泰定養生主論). The miscitation by following medical literature caused the misunderstanding in the meaning of Taidingyangshengzhu-lun, that phlegm can cause variable symptoms and signs. In the Ming dynasty, some poor medical doctors had tended to diagnose any difficult case as phlegm syndrome and to use Kuntan-huan (滾痰丸) as a standard herbal formula for treating phlegm syndrome. However, the tendency to categorize delicate cases easily to phlegm syndrome is not desirable. Besides, the tendency to use Kuntan-huan as a basic formula for the phlegm syndrome might cause diverse and severe adverse effects. Thus, we cannot accept the theory of eccentric diseases is generally due to phlegm without a doubt. In conclusion, this theory might be a valuable aphorism in terms of considering the possibility of the secondary pathologic factors including phlegm and blood stasis which should be considered first in case of intractable diseases.

The Effects of Eccentric Training Applied to Calf Muscles on Muscle Tone, Muscle Strength and Gait of Patients with Chronic Stroke (만성 뇌졸중 환자의 종아리 근육에 적용한 편심성 훈련이 근긴장도와 근력 및 보행에 미치는 영향)

  • Ji-Hyun Bae;Young-Keun Woo;Yong-Wook Kim;Kyue-Nam Park
    • PNF and Movement
    • /
    • v.22 no.1
    • /
    • pp.113-128
    • /
    • 2024
  • Purpose: This study aimed to investigate the effects of eccentric training applied to the calf muscles on muscle tone, muscle strength, and gait variables in patients with chronic stroke. Methods: Twenty-two participants were divided into experimental (n=12; eccentric training) and control (n=10; static stretching and stretching board) groups. The participants completed 30-minute physical therapy sessions five times a week for three weeks. Calf muscle tone, muscle strength, and gait variables were measured using MyotonPRO, a hand-held dynamometer, and Optogait, respectively, before and after each intervention. Results: Two-way analysis of variance (ANOVA) indicated a significant interaction effect between measurement points and groups in frequency, stiffness, and decrement of the lateral gastrocnemius, medial gastrocnemius, and soleus muscles (p<.05). Paired t-tests showed that the experimental group exhibited significantly decreased frequency and stiffness scores for the lateral gastrocnemius, medial gastrocnemius, and soleus muscles (p<.05), as well as significantly increased decrement and muscle strength scores, gait speed, step length, and stride length (p<.05). Conclusion: The application of eccentric training to the calf effectively reduced muscle tone, increased muscle strength, and improved the gait speed, step length, and stride length of patients with chronic stroke.

Functionally Graded Piezoelectric Strip with Eccentric Crack Under Anti-plane Shear

  • Shin, Jeong-Woo;Kim, Tae-Uk
    • Journal of Mechanical Science and Technology
    • /
    • v.17 no.6
    • /
    • pp.854-859
    • /
    • 2003
  • In this paper, we examine the singular stresses and electric fields in a functionally graded piezoelectric ceramic strip containing an eccentric crack off the center line under anti-plane shear loading with the theory of linear piezoelectricity. It is assumed that the properties of the functionally graded piezoelectric ceramic strip vary continuously along the thickness. Fourier transforms are used to reduce the problem to the solution of two pairs of dual integral equations, which are then expressed to a Fredholm integral equation of the second kind. Numerical values on the stress intensity factor and the energy release rate are obtained.