• 제목/요약/키워드: Transverse

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유한요소해석을 이용한 연속철근콘크리트 포장의 횡방향 철근 설계 검토 (Review of Transverse Steel Design in Continuously Reinforced Concrete Pavement through Finite Element Analysis)

  • 최판길;하수준;전범준;길용수;원문철
    • 한국도로학회논문집
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    • 제16권2호
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    • pp.25-34
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    • 2014
  • PURPOSES : This paper numerically evaluates the contribution of transverse steel to the structural behavior of continuously reinforced concrete pavements to understand the role of transverse steel. METHODS : Two-lane continuously reinforced concrete pavements with and without transverse steel were analyzed through finite element analysis with the aid of commercial finite element analysis program DIANA; the difference in their structural behavior such as deflection, joint opening, and stress distribution was then evaluated. Twenty-node brick elements and three-node beam elements were used to model concrete and steel, respectively. Sub-layers were modeled with horizontal and vertical tensionless spring elements. The interactions between steel and surrounding concrete were considered by connecting their nodes with three orthogonal spring elements. Both wheel loading and environmental loading in addition to self-weight were considered. RESULTS : The use of transverse steel in continuously reinforced concrete pavements does not have significant effects on the structural behavior. The surface deflections change very little with the use of transverse steel. The joint opening decreases when transverse steel is used but the reduction is quite small. The transverse concrete stress, rather, increases when transverse steel is used due to the restraint exerted by the steel but the increase is quite small as well. CONCLUSIONS : The main role of transverse steel in continuously reinforced concrete pavements is supporting longitudinal steel and/or controlling unexpected longitudinal cracks rather than enhancing the structural capacity.

Evaluation of multi-lane transverse reduction factor under random vehicle load

  • Yang, Xiaoyan;Gong, Jinxin;Xu, Bohan;Zhu, Jichao
    • Computers and Concrete
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    • 제19권6호
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    • pp.725-736
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    • 2017
  • This paper presents the two-, three-, and four-lane transverse reduction factor based on FEA method, probability theory, and the recently actual traffic flow data. A total of 72 composite girder bridges with various spans, number of lanes, loading mode, and bridge type are analyzed with time-varying static load FEA method by ANSYS, and the probability models of vehicle load effects at arbitrary-time point are developed. Based on these probability models, in accordance to the principle of the same exceeding probability, the multi-lane transverse reduction factor of these composite girder bridges and the relationship between the multi-lane transverse reduction factor and the span of bridge are determined. Finally, the multi-lane transverse reduction factor obtained is compared with those from AASHTO LRFD, BS5400, JTG D60 or Eurocode. The results show that the vehicle load effect at arbitrary-time point follows lognormal distribution. The two-, three-, and four-lane transverse reduction factors calculated by using FEA method and probability respectively range between 0.781 and 1.027, 0.616 and 0.795, 0.468 and 0.645. Furthermore, a correlation between the FEA and AASHTO LRFD, BS5400, JTG D60 or Eurocode transverse reduction factors is made for composite girder bridges. For the two-, three-, and four-lane bridge cases, the Eurocode code underestimated the FEA transverse reduction factors by 27%, 25% and 13%, respectively. This underestimation is more pronounced in short-span bridges. The AASHTO LRFD, BS5400 and JTG D60 codes overestimated the FEA transverse reduction factors. The FEA results highlight the importance of considering span length in determining the multi-lane transverse reduction factors when designing two-lane or more composite girder bridges. This paper will assist bridge engineers in quantifying the adjustment factors used in analyzing and designing multi-lane composite girder bridges.

Three-dimensional morphometric study on the retromolar pad

  • Min-Sang Cha;Dae-Gon Kim;Yoon-Hyuk Huh;Lee-Ra Cho;Chan-Jin Park
    • The Journal of Advanced Prosthodontics
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    • 제15권6호
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    • pp.302-314
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    • 2023
  • PURPOSE. The aim of this study was to classify the shapes of retromolar pads and assess their morphometric differences using a 3D model. MATERIALS AND METHODS. Two hundred fully edentulous or Kennedy Class I partially edentulous patients (400 retromolar pads) were enrolled. Scan data of the definitive mandibular casts produced through functional impressions were obtained using a 3D laser scanner. Seven parameters (transverse diameter, longitudinal diameter, transverse-contour length, longitudinal-contour length, longitudinal/transverse diameter ratio, longitudinal/transverse-contour length ratio, and angle of the retromolar pad line to the residual alveolar ridge line) were measured using image analysis software. Subsequently, the pads were classified according to the shape. Statistical analyses were performed using 95% confidence intervals. RESULTS. Classifying the retromolar pads into three shapes led to high intra-examiner reliability (Cronbach's alpha = 0.933). The pear shape was the most common (56.5%), followed by oval/round (27.7%) and triangular (15.8%) shapes. There were no significant differences between the left and right sides according to the shape and no significant differences in any parameter according to age. The transverse diameter and longitudinal/transverse diameter ratio differed between sexes (P < .05). The triangular shape had a significantly different transverse diameter, transverse-contour length, longitudinal/transverse diameter ratio, and longitudinal/transverse-contour length ratio compared with the pear and oval/round shapes (P < .05). CONCLUSION. From a clinical reliability standpoint, classifying retromolar pads into three shapes (oval/round, pear-shaped, and triangular) is effective. The differences in the sizes among the shapes were attributed to the transverse measurement values.

$L^2$-transverse fields preserving the transverse ricci field of a foliation

  • Pak, Jin-Suk;Shin, Yang-Jae;Yoo, Hwal-Lan
    • 대한수학회지
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    • 제32권1호
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    • pp.51-60
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    • 1995
  • Let $(M,g_M,F)$ be a (p+q)-dimensional connected Riemannian manifold with a foliation $F$ of codimension q and a complete bundle-like metric $g_M$ with respect to $F$. Let $Ric_D$ be the transverse Ricci field of $F$ with respect to the transverse Riemannian connection D which is a torsion-free and $g_Q$-metrical connection on the normal bundle Q of $F$. We consider transverse confomal (or, projective) fields of $F$. It is clear that a tranverse Killing field s of $F$ preserves the transverse Ricci field of $F$, that is, $\Theta(s)Ric_D = 0$, where $\Theta(s)$ denotes the transverse Lie differentiation with respect to s.

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Infantile Dural Arteriovenous Fistula of the Transverse Sinus Presenting with Ocular Symptoms, Case Reports and Review of Literature

  • Sultan, Ahmed Elsayed;Hassan, Tamer
    • Journal of Korean Neurosurgical Society
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    • 제59권3호
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    • pp.296-301
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    • 2016
  • Dural arteriovenous fistula (DAVF) of the transverse sinus with ophthalmic manifestations in young children are rare. We reviewed two cases of direct AVF of the transverse sinus with ocular manifestations managed at our institution. The first, a 2.5 years old male child presented with left exophthalmos. Angiography revealed AVF between the occipital artery and the transverse sinus. The second, a 2 years old female child, complained of left exophthalmos. Imaging studies showed bilateral direct AVFs of the transverse sinus with bilateral dysmaturation of the sigmoid sinus. Transarterial embolization was done in both cases. Clinical and radiological follow up revealed complete cure. This report suggests that DAVF of the transverse sinus supplied by the external carotid branches can present with ophthalmic manifestations especially if there is distal venous stenosis or obliteration involving sigmoid sinus. Transarterial embolization using coils and liquid embolic agents could be safe and feasible to obliterate the fistula.

장 가성 폐쇄 증상을 동반한 횡단성 척수염 환아 1예에 대한 고찰 (The Clinical Study on 1 Case of Patient with Interstinal Pseudoobstruction Secondary to Transverse Myelitis)

  • 한재경;김윤희
    • 대한한방소아과학회지
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    • 제16권1호
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    • pp.203-216
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    • 2002
  • Objective : There were few reports on the treatment of 'Intestinal pseudoobstruction secondary to Transverse Myelitis'. This study about the Oriental medical treatment conducted on the 'Intestinal pseudoobstruction secondary to Transverse Myelitis' shows the possibility of healing 'Intestinal pseudoobstruction secondary to Transverse Myelitis'. Methods : The acupuncture and herbal medicine therapies were applied for improving the function of stomach & spleen and harmonizing energy & blood. Results : After treatments, the symptoms (abdominal pain, vomiting, constipation, oral intake unable) of 'Intestinal pseudoobstruction secondary to Transverse Myelitis' were improved. Conclusion : The more study about the Oriental medical treatment and conception on 'Intestinal pseudoobstruction secondary to Transverse Myelitis' is needed.

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Transverse earthquake-induced forces in continuous bridges

  • Armouti, Nazzal S.
    • Structural Engineering and Mechanics
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    • 제14권6호
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    • pp.733-738
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    • 2002
  • A simplified rational method is developed to evaluate transverse earthquake-induced forces in continuous bridges. This method models the bridge as a beam on elastic foundation, and assumes a sinusoidal curve for both vibration mode shape and deflected shape in the transverse direction. The principle of minimum total potential is used to calculate the displacements and the earthquake-induced forces in the transverse direction. This method is concise and easy to apply, and hence, offers an attractive alternative to a lengthy and time consuming three dimensional modeling of the bridge as given by AASHTO under its Single Mode Spectral Analysis Method.

PMFBG 센서를 이용한 횡방향 변형률 측정 (Measurement of Transverse Strain Using PMBG Sensor)

  • 윤혁진;김대현;홍창선;김천곤
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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    • pp.27-30
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    • 2002
  • PMFBG sensor was fabricated using phase mask and Excimer laser. The reflected wavelength of PMFBG sensor had dual peaks due to intrinsic birefringence. To discover the polarization axes, peak sensitivity was measured under compression test. The signal characteristics of PMFBG sensor were also examined in embedding condition. The embedded PMFBG sensor in epoxy block was loaded for the transverse strain measurements. Experiments showed that the PMFBG sensor could successfully measure the transverse strain. This PMFBG sensor is useful for the structures that require measuring transverse stram.

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고속도로 영업소 광장의 횡방향 럼블스트립으로 발생되는 소음 조사 (A Noise Investigation of Transverse Rumble Strip at Toll Plaza of Highway)

  • 안덕순;서영찬;권수안;이재준;엄병식
    • 한국도로학회논문집
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    • 제15권3호
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    • pp.31-36
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    • 2013
  • PURPOSES: This study is to investigate a generated traffic noise when vehicle pass over a transverse rumble strip at toll plaza of highway. METHODS: To investigate traffic noise at toll plaza of highway, Pass-by method which is the most common used for measuring traffic noise was adopted and the traffic noise at toll plaza was measured for 10 min per hour for 11hours(13:00~24:00). RESULTS: The measured traffic noise by pass-by method was changed as function of the transverse rumble strip configuration. Generally, the maximum difference among three noise measurement sections was 7 dB(A). It might be related with traffic speed. Also, the measured traffic noise was strongly generated from a passenger car which was 2 axle. It means that the most of traffic noise on the road is generated at tire/pavement interface of the passenger car. CONCLUSIONS: The traffic noise was strongly related with vehicle speed and transverse rumble strip configuration on the road. For driver safety, the transverse rumble strip is definitely necessary. However, the complaints from residents near highway was increased by traffic noise from transverse rumble strip. Therefore, To satisfy both safety and reduction of traffic noise, the development of configuration of transverse rumble strip is necessary in the further study.

Effects of joint aspect ratio on required transverse reinforcement of exterior joints subjected to cyclic loading

  • Chun, Sung Chul
    • Earthquakes and Structures
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    • 제7권5호
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    • pp.705-718
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    • 2014
  • This paper presents an analytical model for determining the transverse reinforcement required for reinforced concrete exterior beam-column joints subjected to reversed cyclic loading. Although the joint aspect ratio can affect joint shear strength, current design codes do not consider its effects in calculating joint shear strength and the necessary amount of transverse reinforcement. This study re-evaluated previous exterior beam-column joint tests collected from 11 references and showed that the joint shear strength decreases as the joint aspect ratio increases. An analytical model was developed, to quantify the transverse reinforcement required to secure safe load flows in exterior beam-column joints. Comparisons with a database of exterior beam-column joint tests from published literature validated the model. The required sectional ratios of horizontal transverse reinforcement calculated by the proposed model were compared with those specified in ACI 352R-02. More transverse reinforcement is required as the joint aspect ratio increases, or as the ratio of vertical reinforcement decreases; however, ACI 352R-02 specifies a constant transverse reinforcement, regardless of the joint aspect ratio. This reevaluation of test data and the results of the analytical model demonstrate a need for new criteria that take the effects of joint aspect ratio into account in exterior joint design.