• Title/Summary/Keyword: Coefficient of ground reaction

Search Result 34, Processing Time 0.025 seconds

A Study on Prediction of Moment Developed in Bottom of Foundations between Pile and Heterogeneous Soils (말뚝기초와 이질지반 경계부 기초저판에서의 발생모멘트 예측에 관한 연구)

  • Lim, Hae-Sik;Park, Yong-Boo
    • Land and Housing Review
    • /
    • v.2 no.3
    • /
    • pp.277-285
    • /
    • 2011
  • To reinforce bearing capacity-changed section or different foundation in the same building, empirical or simple tools have been used. To solve this problem, an analytical solution which can evaluate and reinforce the stability of foundation is introduced. To suggest a clue for the problems, current foundation reinforcing method is studied through recent literature studies and the structural analyses of foundation slab are performed on the pile foundation of 49$m^2$, 59$m^2$ and 84$m^2$ I type apartments in 15 story building. The analyses are conducted with SAP 2000, a computer program for ordinary structural analysis. To predict the moments of slab by ground non-uniformity, the structural analysis results for the foundation slab of 3 types 15 story apartment buildings in 49$m^2$, 59$m^2$ and 84$m^2$ I type on non-uniformity ground are shown in the diagrams.

Relationship between Hip Medial Rotation Range of Motion and Weight Distribution in Patients with Low Back Pain

  • Kim, Sang-Kyu;Kim, Won-Bok;Ryu, Young-Uk
    • Journal of the Korean Society of Physical Medicine
    • /
    • v.9 no.3
    • /
    • pp.279-284
    • /
    • 2014
  • PURPOSE: This study intended to verify whether there was actual correlation between weight-bearing asymmetry and a limitation in hip joint rotation range in patients with low back pain. METHODS: Thirty five low back pain patients voluntarily participated this study. For each participant, hip joint medial rotation symmetry rate and the weight-bearing symmetry rate were calculated. The correlation between the two variables was investigated. RESULTS: A decrease in the left hip joint medial rotation range of motion (ROM) was observed more often than a reduction in the right hip joint medial rotation ROM. However, similar number between right and left side was observed in ground reaction force more weighted. The coefficient between the passive hip joint medial rotation symmetry rate and the weight loading symmetry ratio was -0.19 (p < 0.05). CONCLUSION: The present study demonstrated a weak correlation between the hip joint medial rotation ROM and the weight distribution of both feet. Such result suggests that careful evaluation by separating each element is needed in treating patients with low back pain. Future research should take into account asymmetric alignment and abnormal movement in different joints of the body as well as asymmetry in the bilateral hip joint rotation and the unilateral weight supporting posture.

Correlation Between BBS, FRT, STI, TUG, MBI, and Falling in Stroke Patients (뇌졸중 환자에서 BBS, STI, MBI, TUG, FRT, 낙상과의 상관관계)

  • Lee, Han-Suk;Choi, Jin-Ho
    • The Journal of Korean Physical Therapy
    • /
    • v.20 no.4
    • /
    • pp.1-6
    • /
    • 2008
  • Purpose: We studied the correlation between BBS (Berg Balance Scale), Functional Reach Test (FRT), Timed-Up & Go test (TUG), Stability Index (STI), MBI (Modified Barthel Index), and Fall History. Methods: We recruited 20 stroke patients from the Gang Dong Gu Health Care Center in Seoul, Korea. All subjects could walk with or without an assisting device. Subjects first completed a questionnaire pertaining to their fall history and Activity of Daily Living (MBI), and then were evaluated with BBS, TUG, FRT, and STI. We used the Tetrax posturography system that calculates a STI based on fluctuations in vertical ground reaction forces. The data were analyzed using a Pearson Correlation Coefficient. Results: The BBS and FRT (p<0.05) and MBI (p<0.01) showed a significant positive correlation. BBS negatively correlated with STI and TUG (p<0.01). Fall history and BBS, TUG, MBI, FR, STI did not correlate. Conclusion: The BBS helps predict weight shifting, walking, and ADL, but is not good for predicting fall risk. So, we need to study about factors that affect falling.

  • PDF

Biomechanical Analysis of the Non-slip Shoes for Older People (미끄럼방지 노인화에 대한 생체역학적 분석)

  • Lee, Eun-Young;Sohn, Jee-Hoon;Yang, Jeong-Hoon;Lee, Ki-Kwang;Kwak, Chang-Soo
    • Korean Journal of Applied Biomechanics
    • /
    • v.23 no.4
    • /
    • pp.377-385
    • /
    • 2013
  • Fall is very fatal accident causes death to older people. Shoe may affect to fall. Shoe influences risk of slips, trips, and falls by altering somatosensory feedback to the foot. The purpose of this study was to investigate the analysis of non-slip shoes for older people and influence on older people's lower extremity. For this study twenty three healthy older people were recruited. Each subjects walked over slippery surfaces (COF 0.08). Four pairs of non-slip shoes (shoe A had the greatest COF, 0.23 while shoe B, C, and D had smaller COF relatively) for older people were selected and tested mechanical and biomechanical experiment. For data collection motion capture and ground reaction forces were synchronized. There were statistically significant differences for slip-displacement, coefficient of friction, braking force, propulsion force, knee range of motion and knee joint stiffness by shoes. It was concluded that shoe A was the best for non-slip function because of the lowest slip displacement, the highest braking and propulsion forces, and the highest mechanical and biomechanical coefficient of friction where as shoe B, C, D were identified as a negative effect on the knee joint than shoe A. To prevent fall and slip, older people have to take a appropriate non-slip shoes such as shoe A.

Optical Characterization of Sensory Rhodopsin II Thin Films using a Near-field Scanning Microwave Microscope (근접장 마이크로파 현미경을 이용한 로돕신의 광학적 특성 연구)

  • Yu, Kyung-Son;Kim, Song-Hui;Yoon, Young-Woon;Lee, Kie-Jin;Lee, Jung-Ha;Choi, Ah-Reum;Jung, Kwang-Hwan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.20 no.1
    • /
    • pp.80-85
    • /
    • 2007
  • We report the electro-optical properties of the sensory rhodopsin II using a near-field scanning microwave microscope(NSMM). Rhodopsin was known as a photoreceptor pigment with a retinal as a chromophore via a protonated Schiff base and consists of seven ${\alpha}-helical$ transmembrane segments. The sensory rhodopsin II, expressing E. coli UT5600 with endogenous retinal biosynthesis system and purified with $Ni^{-2}-NTA$ affinity chromatography in the presence of 0.02 % DM (Dodecyl Maltoside) from Natronomonas pharaonis. We measured the absorption spectra and the transients difference of sensory rhodopsin II from Natronomonas pharaonis using a UV/VIS spectrophotometer with Nd-Yag Laser (532 nm). The absorption spectra of NpSR II showed a typical rhodopsin spectrum with a left shoulder region and the photointermediates spectra of NpSR II-ground state (${\lambda}max=498\;nm$), NpSR II-M state (${\lambda}max=390\;nm$), and NpSR II-O state (${\lambda}max=550\;nm$) during the photocycle. The observed photocycle reaction was confirmed by measuring the microwave reflection coefficient $S_{11}$ at an operating frequency of f=3.93-3.95 GHz and compared with the results of a photocycle of NpSR II.

Dynamic Behavior Characteristics of Group Piles with Relative Density in Sandy Soil (건조 모래지반의 상대밀도에 따른 무리말뚝의 동적거동특성)

  • Heungtae Kim;Hongsig Kang;Kusik Jeong;Kwangkuk Ahn
    • Journal of the Korean GEO-environmental Society
    • /
    • v.24 no.9
    • /
    • pp.33-40
    • /
    • 2023
  • The lateral load which is applied to the pile foundation supporting the superstructure during an earthquake is divided into the inertia force of the upper structure and the kinematic force of the ground. The inertia force and the kinematic force could cause failure to the pile foundation through different complex mechanisms. So it is necessary to predict and evaluate interaction of the ground-pile-structure properly for the seismic design of the foundation. The interaction is affected by the lateral behavior of the structure, the length of the pile, the boundary conditions of the head, and the relative density of the ground. Confining pressure and ground stiffness change accordingly when the relative density changes, and it results that the coefficient of subgrade reaction varies depending on each system. Horizontal bearing behavior and capacity of the pile foundation vary depending on lateral load condition and relative density of the sandy soil. Therefore, the 1g shaking table tests were conducted to confirm the effect of the relative density of the dried sandy soil to dynamic behavior of the group pile supporting the superstructure. The result shows that, as the relative density increases, maximum acceleration of the superstructure and the pile cap increases and decreases respectively, and the slope of the p-y curve of the pile decreases.

Kinetics of the Reaction of Benzyl Chlorides with Pyridine in Methanol Solvent under High Pressure (고압하의 메탄올 용매내에서 염화벤질류와 피리딘과의 반응에 대한 반응속도론적 연구)

  • Oh Cheun Kwon;Young Cheul Kim;Jin Burm Kyong;Kee Joon Choi
    • Journal of the Korean Chemical Society
    • /
    • v.31 no.5
    • /
    • pp.413-418
    • /
    • 1987
  • Rates of the reaction for p-nitro benzyl chloride, benzyl chloride and p-methyl benzyl chloride with pyridine in methanol solvent have been measured by an electric conductivity method at 40$^{\circ}$C and 50$^{\circ}$C under various pressures (1∼2000bar). Pseudo first-order rate constants and second-order rate constants were determined. Rates of these reactions were increased in the order p-NO$_2$ < p-H < p-CH$_3$ and increased with temperature, pressure and concentration of pyridine. From those rate constants, the activation parameters were evaluated. The activation volume and the activation compressibility coefficient are both negative values, but the activation enthalpy is positive and the activation entropy is large negative value. From the evaluation of the ground state and transition state which was resulted from substituents and pressure, it was found that this reaction proceeds through S$_N$2 reaction, and S$_N$2 fashion is slightly disappeared as pressure increases.

  • PDF

Genetic Relationship among Sedum Species Based on Morphological Characteristics and RAPD Analysis (한국산 Sedum속 식물의 형태적 특성과 RAPD에 의한 유연관계 분석)

  • Kwon, Soon Tae;Jeong, Jeong Hag
    • Horticultural Science & Technology
    • /
    • v.17 no.4
    • /
    • pp.489-493
    • /
    • 1999
  • This study was conducted to investigate the potentiality of various Korean Sedum species as ornamental plants based on morphological characteristics and to analyze the genetic relationship among the Sedum species. S. kamtschaticum and S. takesimense possessing splendour flowercluster with yellow color could be suggested for garden plant, S. routundifolium having pink flower-clusters with round leaf shape for pot flower or garden plant and S. sarmentosum, S. polystichoides and S. oryzifolium with creeping stem and low plant height for ground cover plant or floral carpet. Eighteen oligonucleotide random primers were used to amplify genomic DNA of Sedum species using polymerase chain reaction (PCR). Ninety five polymorphic bands among 125 different DNA fragments in the range of 224 to 3,675 base pairs were obtained from RAPD analysis. Similarity matrix of RAPD profiles was generated by coefficient value of variation, and the data were subjected to be cluster analysis. Fifteen lines of Sedum species analyzed were classified into 3 groups with the similarity coefficient value of 0.418, and 12 groups with the value of 0.328. RAPD results showed similar trends as the morphological characteristics of the plants.

  • PDF

Bending of a rectangular plate resting on a fractionalized Zener foundation

  • Zhang, Cheng-Cheng;Zhu, Hong-Hu;Shi, Bin;Mei, Guo-Xiong
    • Structural Engineering and Mechanics
    • /
    • v.52 no.6
    • /
    • pp.1069-1084
    • /
    • 2014
  • The long-term performance of plates resting on viscoelastic foundations is a major concern in the analysis of soil-structure interaction. As a powerful mathematical tool, fractional calculus may address these plate-on-foundation problems. In this paper, a fractionalized Zener model is proposed to study the time-dependent behavior of a uniformly loaded rectangular thin foundation plate. By use of the viscoelastic-elastic correspondence principle and the Laplace transforms, the analytical solutions were obtained in terms of the Mittag-Leffler function. Through the analysis of a numerical example, the calculated plate deflection, bending moment and foundation reaction were compared to those from ideal elastic and standard viscoelastic models. It is found that the upper and lower bound solutions of the plate response estimated by the proposed model can be determined using the elastic model. Based on a parametric study, the impacts of model parameters on the long-term performance of a foundation plate were systematically investigated. The results show that the two spring stiffnesses govern the upper and lower bound solutions of the plate response. By varying the values of the fractional differential order and the coefficient of viscosity, the time-dependent behavior of a foundation plate can be accurately captured. The fractional differential order seems to be dependent on the mechanical properties of the ground soil. A sandy foundation will have a small fractional differential order while in order to simulate the creeping of clay foundation, a larger fractional differential order value is needed. The fractionalized Zener model is capable of accounting for the primary and secondary consolidation processes of the foundation soil and can be used to predict the plate performance over many decades of time.

Carbonation Behavior of GGBFS-based Concrete with Cold Joint Considering Curing Period (재령 변화에 따른 콜드조인트를 가진 GGBFS 콘크리트의 탄산화 거동)

  • Cho, Sung-Jun;Yoon, Yong-Sik;Kwon, Seung-Jun
    • Journal of the Korean Recycled Construction Resources Institute
    • /
    • v.6 no.4
    • /
    • pp.259-266
    • /
    • 2018
  • In the work, the carbonation behavior and strength characteristics in cold-joint concrete are evaluated for OPC(Ordinary Portland Cement) and GGBFS(Ground Granulated Blast Furnace Slag)concrete considering three levels of curing age (28, 91 and 365 days). The compressive strength in GGBFS concrete is level of 86% of OPC concrete at the 91 days of curing period, but is level of 107% at 365 curing days due to hydration reaction. Carbonation velocities in both OPC and GGBFS concrete significantly decease after 91 curing days. The effect of cold joint on carbonation is evaluated to be small in GGBFS concrete. The increasing ratios of carbonation velocity in cold joint are 1.06 and 1.33 for 28-day and 365-day curing condition, respectively. However they decreases to 1.08 and 1.04 for GGBFS concrete for the same curing conditions.