• Magazine of the Korea Concrete Institute
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• v.6 no.5
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• pp.193-202
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• 1994

In this study, an equation for modelling the shear strength of reinforced concrete member with web reinforcement is proposed. Although the general formulas for shear strength of reinforced concrete member with small a /d are obtained based on the experimental results, the proposed equation herein is derived from lower bound theorem of limit analysis. The proposed model takes into account arch mechanism and truss mechanism. And ir provides the values of divided shear strength ratio of each mechanism as well as visual understanding of the mechanism on how the given load is transfered to the support. Also, the model takes into account the effect of a /d. longitudinal reinforcement ratio, and web reiriforcement ratio quantitively. Based on the comparisons of the result of this model with previous, test results, it shows good agreements.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1007-1013
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• 2004

A three-arch NATM tunnel with a total length of 53.5m has been constructed for a metropolitan subway station in Daejon, Korea. The tunnel, whose crown is located 22m below the ground, crosses the old Daejon station underneath. Since the tunnel comprises a very large section (10${\times}$28 m; largest in Korea), it shows complicated mechanical behaviors, especially near portal, due to its short length relative to width. As far as its construction step is concerned, the center tunnel is excavated with pre-excavated pilot tunnel, which is a unique feature of this tunnel (first in Korea) to secure safety during construction and prevent excessive settlements. The both side tunnels are then excavated along with the center tunnel. Since significant amount of settlement was predictable from the design stage, extensive monitoring was performed during construction. During excavation of the side tunnels, unexpected large settlements up to ${\~}$140mm (estimated 41.8 mm at design stage) was measured at the center tunnel. In this paper, we study the causes of this unusually large ground settlement. We believe that the extra-wide tunnel excavation increases the stress influence zone of portal in longitudinal direction and consequently add more settlements to the existing due to excavation and consolidation.

• Journal of International Academy of Physical Therapy Research
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• v.10 no.4
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• pp.1934-1939
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• 2019

Background: Flexible flat foot is that the medial longitudinal arch collapses in weight bearing and returns normal arch when weight is removed and the weight bearing shifts toward medial part of the foot, which can cause pathological problems in the alignment of the lower extremities and the entire body. Objective: To compare the foot pressure for adults with flexible flat foot. Design: Quasi-Experimental Study Methods: 24 participants with flexible flat foot were recruited and were randomly divided into Visual feedback Short Foot Exercise (VSFE) group and Short Foot Exercise (SFE) group. To compare changes of foot pressure about pre and post intervention, the contact pressure measurement was conducted. Results: In the VSFE, significant differences were observed for the foot pressure of the 1^st toe, 1^st, 3^rd and 4-5^th metatarsal, midfoot, medial and lateral heel (p<.05). The foot pressure of the 3^rd and 4-5^th metatarsal, midfoot showed significant differences in the SFE (p<.05). The contact pressure of the 1^st toe, 3^rd metatarsal showed significant differences between the groups. Conclusions: Visual feedback short foot exercise can be useful for moving the pressure from medial to lateral part, and can prevent possible pathological problems.

• Journal of Korean Foot and Ankle Society
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• v.9 no.1
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• pp.9-12
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• 2005

Purpose: This study is to compare the medial longitudinal arch between heel pain group and normal painless group. Materials and Methods: Heel pain group 242 feet and normal group 140 feet were evaluated through the radiographic images of standing foot-ankle lateral view. Four radiographic indices, talo-1stmetatarsal angle (TMA), calcaneal-1st metatarsal angle (CMA), calcaneal pitch angle (CPA), and arch ratio (AR), were used as well as BMI. Results: There was no difference between heel pain group and normal group in the TMA, CMA, CPA, and AR. But in the BMI, heel pain group showed $1.7\;kg/m^2$ (p=0.0002) higher than normal group. To eliminate the sexual error, male and female were evaluated separately. Male heel pain group showed 2.9 degrees more dorsiflexion (p=0.001) in the TMA, 3.1 degrees greater (p=0.007) in the CMA, 0.01 lower (p=0.028) in the AR, and $1.0\;kg/m^2$ greater (p=0.033) in the BMI than normal male group. There were no difference in the CPA. Female heel pain group showed 3.6 degree greater (p=0.035) in the CMA, and $1.9\;kg/m^2$ greater (p=0.002) in the BMI than normal female group. But other indices demonstrated no differences. Conclusion: talo-$1^{st}$ metatarsal angle, calcaneal-$1^{st}$ metatarsal angle and arch ratio were radiographic indices related with heel pain.

• Anatomy and Cell Biology
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• v.57 no.2
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• pp.288-293
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• 2024

The temporal fascia is a double lamina sandwiching a thick fat layer above the zygomatic bony arch. To characterize each lamina, their developmental processes were examined in fetuses. We observed histological sections from 22 half-heads of 10 mid-term fetuses at 14-18 weeks (crown-rump length, 95-150 mm) and 12 near-term fetuses at 26-40 weeks (crown-rump length, 215-334 mm). The superficial lamina of the temporal fascia was not evident at mid-term. Instead, a loose subcutaneous tissue was attached to the thin, deep lamina of the temporal fascia covering the temporalis muscle. At near-term, the deep lamina became thick, while the superficial lamina appeared and exhibited several variations: i) a mono-layered thick membrane (5 specimens); ii) a multi-layered membranous structure (6) and; iii) a cluster of independent thick fasciae each of which were separated by fatty tissues (1). In the second and third patterns, fatty tissue between the two laminae was likely to contain longitudinal fibrous bands in parallel with the deep lamina. Varying proportions of the multi-layered superficial lamina were not attached to the zygomatic arch, but extended below the bony arch. Whether or not lobulation or septation of fatty tissues was evident was not dependent on age. The deep lamina seemed to develop from the temporalis muscle depending on the muscle contraction. In contrast, the superficial lamina developed from subcutaneous collagenous bundles continuous to the cheek. Therein, a difference in development was clearly seen between two categories of the fasciae.

• Structural Engineering and Mechanics
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• v.24 no.1
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• pp.107-136
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• 2006

The present paper proposes a semi-empirical analytical expression that is capable of determining the shear strength of reinforced concrete beams with longitudinal bars, in the presence of reinforcing fibers and transverse stirrups. The expression is based on an evaluation of the strength contribution of beam and arch actions and it makes it possible to take their interaction with the fibers into account. For the strength contribution of stirrups, the effective stress reached at beam failure was considered by introducing an effectiveness function. This function shows the share of beam action strength contribution on the global strength of the beam calculated including the effect of fibers. The expression is calibrated on the basis of experimental data available in literature referring to fibrous reinforced concrete beams with steel fibers and recently obtained by the authors. It can also include the following variables in the strength previsions: - geometrical ratio of longitudinal bars in tension; - shear span to depth ratio; - strength of materials and fiber characteristics; - size effects. Finally, some of the more recent analytical expressions that are capable of predicting the shear strength of fibrous concrete beams, also in the presence of stirrups, are mentioned and a comparison is made with experimental data and with the results obtained by the authors.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.71-79
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• 2008

The concrete track is being used at the Phase II of the Kyeongbu High Speed Railway and New Constructed Honam High Speed Railway. When it makes a decision of bridge type, It has to consider about longitudinal forces of Continuous Welded Rail, Displacement at the end of bridges, Up-lift forces for fastener on the track. If it is installed turnout on the bridge, There is likelihood of the deck twist by applying the each difference longitudinal forces at the 4 each rails and the buckling by concentration of rail stress at the turnout. Moreover, If it is installed turnout on the continuous bridge and REJ(Rail Expansion Joint) on the main track or turnout track. It is hard to keep a safety for rail because of coming to twist or folding at the expansion of deck on the turnout track. Therefore when it is a design of bridge with turnout. It need to take bridge type to minimize an additional axial force and a displacement at the turnout. This paper makes a study of the composite steel arch bridge that is able to resolve criteria requirements of safety for track with turnout and suggest a helpful design method for bridge considering track with turnout by being based on design and construction method of Eonyang Bridge at the north part of Ulsan Station in Phase II of the Kyeongbu High Speed Railway.

• Tunnel and Underground Space
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• v.8 no.1
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• pp.53-66
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• 1998

Considering the mechanical cracking in the concrete lining of tunnels occurring in relatively short period of time after the construction, there is a need for the study on the mechanical behavior and the cracking characteristics of double lining support system(shotcrete and concrete lining). For the proposed study, downscaled lining models of Kyung-Bu High Speed Railway tunnels were tested. Most longitudinal cracks at about 93 percentage developed within 30 arch degree from the vault. Cracking load was about 30 percentage of the failure load and the deflection under the cracking load was 10 percentage of the deflection under the failure load. The overbreak around the vault contributed to the reduction of the capacity for cracking and failure by the percentage greater than the reduced effective depth. Of several rock block types considered in this research, the triangular block was the most critical, and the right triangular block under eccentric load was secondly critical for the stability of the tunnel lining system. The dimensionless support reaction curves were derived from the experimental results for single and double lining. The general equation to compute the designed flexural moment was modified.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.375-378
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• 2005

In the mechanism of beam shear failure, beam action and arch action always exist simultaneously. According to a/d ratio, the proportion and contribution between these two actions to shear capacity are merely changed. Moreover, the current codes recommendations are founded on the experimental results with normal strength concrete, the applicable range of $f'_{c}$ must be extended. Based on this mechanism and new requirement, an analytical equation is proposed for shear capacity prediction of reinforced concrete beams without stirrups. To reflect contribution change of two actions, stress variation in longitudinal reinforcement along the span is considered with Jenq and Shah Model. Dowel action and shear friction are also taken into account. Size effect is included to derive more precise equation. It is shown that the proposed equation is more accurate than other empirical equations and codes. So, it can be possible that wide range of a/d ratio is considered by one equation.

• Journal of Korean Foot and Ankle Society
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• v.20 no.2
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• pp.55-61
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• 2016

The cavus foot is a deformity characterized by an elevated medial longitudinal arch and a hindfoot varus with plantarflexed 1st ray. The etiology of cavus foot is usually related to neuromuscular disease or idiopathic cause. Thorough clinical and radiographic evaluation is required for differentiating etiology of the cavus. Most cases of cavus foot are stable and slowly progressive deformities which can initially be managed with conservative treatment including orthoses and physical therapies. Determining whether the deformity is flexible or rigid, the apex of the deformity and any muscle imbalances in foot and ankle is important for achievement of an adequately balanced plantigrade foot. Treatment should include systematic preoperative planning for selection of appropriate procedures for maintaining a functional and flexible foot with combinations of soft-tissue release, osteotomy, tendon transfer, and arthrodesis.