• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.525-530
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• 2007

Although just developed in recent years, curved box girder has widely used in modern highway system due to their load resistance capacity as well as aesthetic considerations. According to recent literature reviews on curved box girder designs, distortional load was not considered as much as it deserves to be. In practice, the effect of distributional force is very small in straight bridge systems but yet unknown how it is in curved bridge systems. For the reason, this paper will show up an extensive parametric study on distortional behavior of curved box girder with trapezoidal section. Based on Dabrowski formulas, using finite element method, various bridges were investigated. In this study, following parameters will be included: span length, curvature radius, section height, section width, and internal section angle (web slope). From the obtained results, some initial geometric parameters are proposed for curved box girder bridges.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.1
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• pp.53-60
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• 2010

In constructing ILM(Incremental Launching Method) bridges, a launching nose is generally used in order to absorb temporary stress occurring during launching. The sectional forces of superstructure of ILM bridges, which occurs during launching, varies significantly according to the length, weight and stiffness of the launching nose. Thus in order to guarantee the safety of section of ILM bridges, the change of stress according to interaction behavior between launching nose and superstructure should be considered. However, the span division and span length are often decided based on previous cases in practice. It makes the design sections of launching nose are similar in spite of different projects. The designer's anxiety to optimize the launching nose to affect the optimum design of superstructure is also weak. In this study, an design formular to optimize the nose is proposed by using the analysis formular of nose-deck interaction and the design level of ILM bridges constructed on 00 Expressway is examined. According to the result of this study, the proposed design formulas are expected to make a significant contribution to section design that is economically efficient and at the same time guarantees the safety of the superstructure and launching noses of ILM bridges regardless of span length.

• Journal of Korean Society of Steel Construction
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• v.20 no.1
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• pp.1-8
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• 2008

This research carried out to optimize crossbeams and stringers of steel box girder bridges, which are parts of floor system and support loading from the bridge deck. In the current design practice, the crossbeam is densely deployed with a spacing of 6 meters, and the stringer is placed between the crossbeams. The crossbeams and stringer are connected to the deck through slab anchors but the allowable stress of the compression flange is determined by the lateral-torsional buckling. To increase economic efficiency of the steel box girder bridges. the increased spacing of the crossbeam was studied. The study shows that the spacing can be increased up to 10 meters. However, higher strength steel plates are necessary. Shear studs rather than slab anchors are also recommended to prevent lateral-torsional buckling strength of the crossbeams and stringer.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.4
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• pp.1-6
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• 2002

The structural safety required in general design is to be proved with safety factors provided for structural members in elastic range. But, for the safety requirement in the earthquake resistant design, a specific ductile failure mechanism in plastic range should be verified according to the structural configuration. Therefore such verifications should be done in the preliminary design stage by comparing various design alternatives. In the main design stage only a confirmation of the ductile failure mechanism is required. In this study typical roadway bridges are selected and analysis models are presented for the preliminary and main design. For the two models, vibration periods and mode shapes are compared and the multi-mode spectrum method is applied to determine failure mechanisms. The failure mechanisms obtained with the two models are compared to check the properness of the model used for the preliminary design, which may well be used as an earthquake resistant analysis model in practice.

• Anatomy and Cell Biology
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• v.49 no.2
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• pp.143-150
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• 2016

Understanding of morphological structures such as the sphenoid spine and pterygoid processes is important during lateral transzygomatic infratemporal fossa approach. In addition, osseous variations such as pterygospinous and pterygoalar bridges are significant in clinical practice because they can produce various neurological disturbances or block the passage of a needle into the trigeminal ganglion through the foramen ovale. Two hundred and eighty-four sides of Korean adult dry skulls were observed to carry out morphometric analysis of the lateral plate of the pterygoid process, to investigate, for the first time among Koreans, the incidence of the pterygospinous and pterygoalar bony bridges, to compare the results with those available for other regional populations, and to discuss their clinical relevance as described on literatures. The mean of maximum widths of the left and right lateral plates of the pterygoid process were 15.99 mm and 16.27 mm, respectively. Also, the mean of maximum heights of the left and right lateral plates were 31.02 mm and 31.01 mm, respectively. The ossified pterygospinous ligament was observed in 51 sides of the skulls (28.0%). Ossification of the pterygospinous ligament was complete in four sides (1.4%). In 47 sides (16.6%), the pterygospinous bridge was incomplete. The ossified pterygoalar ligament was observed in 24 sides of the skulls (8.4%). Ossification was complete in eight sides (2.8%) and incomplete in 16 sides (5.6%). This detailed analysis of the lateral plate of the pterygoid process and related ossification of ligaments can improve the understanding of complex clinical neuralgias associated with this region.

• Journal of Korean Society of Steel Construction
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• v.23 no.2
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• pp.199-210
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• 2011

The cables in cable-stayed bridges are under high stress and are very sensitive to vibration due to their small section areas compared with other members. Therefore, it is reasonable to evaluate the cable impact factor by taking into account the dynamic effect due to moving-vehicle motion. In this study, the cable impact factors were evaluated via moving-vehicle-load analysis, considering the design parameters, i.e., vehicle weight, cable model, road surface roughness, vehicle speed, longitudinal distance between vehicles. For this purpose, two steel composite cable-stayed bridges with 230- and 540-m main spans were selected. The results of the analysis were then compared with those of the influence line method that is currently being used in design practice. The road surface roughness was randomly generated based on ISO 8608, and the convergence of impact factors according to the number of generated road surfaces was evaluated to improve the reliability of the results. A9-d.o.f. tractor-trailer vehicle was used, and the vehicle motion was derived from Lagrange's equation. 3D finite element models for the selected cable-stayed bridges were constructed with truss elements having equivalent moduli for the cables, and with beam elements for the girders and the pylons. The direct integration method was used for the analysis of the bridge-vehicle interaction, and the analysis was conducted iteratively until the displacement error rate of the bridge was within the specified tolerance. It was acknowledged that the influence line method, which cannot consider the dynamic effect due to moving-vehicle motion, could underestimate the impact factors of the end-cables at the side spans, unlike moving-vehicle-load analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.1
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• pp.61-68
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• 1988

This study is intended to propose an approach to reliability-based safety evaluation as well as LRFR(Load and Resisitance Factor Rating) type capacity classification of military or civilian bridges based on the limit state models which are delived by incorporating all the uncertainties of resistance and load random variables including deterioration, and are used in a practical AFOSM (Advanced First Order Second Moment) method. The proposed methods for the assement of safety and load carrying capacity are applied for the evaluation of rating and classifications of several practical bridges against the crossing of military vehicles. Based on the observation of the numerical results, it can be concluded that the current NATO classification method which is based on the traditionl allowable stress concept can not provide real load carrying capacity but results in nominal classification, and therefore the reliability-based safety evaluation and LRFR-classification method or the corresponding rational allowable stress method proposed in this paper may have to be introduced into the classification practice.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.504-509
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• 2011

Recently, construction projects are very complicated and diverse such as high-rise buildings and big bridges, etc. These complicated projects call for a system which can effectively generate productive ideas and activities. Value Engineering (V.E.) activity within construction projects is a necessity for systematic design management and to improve construction ability. This need in the construction industry has required a regular implementation of VE into construction projects. For this reason; America, South Korea, and some other nations have adopted VE applications which control the baseline investments of the construction projects. The process of VE activity is a preferred system and a reasonable alternative. In particular, idea generation within these projects is an important stage in the VE job plan. In this study, VE idea patterns are extracted through best practice analysis from VE cases of road construction projects. Next, we suggest an idea hierarchy model to be used in conjunction with VE idea patterns. This model is supported by reasonable idea generation in VE activity of construction projects. Finally, this model could possibly be the outcome of successful VE results.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.285-292
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• 2000

Though there has been increasing use of large diameter drilled shaft as a foundation structure of bridges, current practice for quality control is to confirm the minimum required load carrying capacity during construction stage. For economic and appropriate design of drilled shaft, it is necessary to evaluate the load transfer mechanism by pile load tests during initial stage of construction and to use the test results as a feedback to a revision of initial design. In this paper, results of load tests peformed at several domestic sites are presented to investigate the load transfer characteristics of large diameter drilled shaft. It was found that most of the load on piles is sustained by shaft friction and that only small portion of the load reaches the bottom of the drilled shaft. Some test results of drilled shaft by Pile Driving Analyzer performed at same sites are also presented to compare the load transfer characteristics interpreted from static pile load tests.

• Korean Institute of Interior Design Journal
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• v.24 no.2
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• pp.42-49
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• 2015

The aim of this study is to review the background and characteristics of Pallasmaa's architectural phenomenology. As a prominent architect, educator and phenomenologist, Pallasmaa criticizes the contemporary architecture that has been commercialized and intended to addict superficial images. He suggests the restoration of essentials of architecture related to human existence. His architectural phenomenology shows a solution to problems of contemporary architecture through focusing on architectural experiences. Pallasmaa argues 'multi-sensory architecture' to criticize architecture based on visual images and emphasizes the importance of tactile sense for architectural experiences. His phenomenology of architecture has significant meaning in that it bridges between theory and practice but also has limits in depth rather than width of theory. Pallasmaa believes that the essence of architecture can be explained as existential activities to maintain existence of our lived space.