• Structural Engineering and Mechanics
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• 제86권1호
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• pp.109-118
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• 2023

Any place where exercise is common, such as a club, sports hall, or school, is considered a place for teaching sports. When doing sports, a very safe environment for sports should be chosen. The athlete should consider the safety of sports facilities and equipment, and if there is a defect, he should refrain from exercising in these places. The safety of sports facilities is very effective in creating people's sports activities, with the benefits of staying away from physical harm, enjoying sports, and having mental peace. Everyone has the right to participate in sports and recreation and to ensure that they enjoy a safe environment. The ability to manage and solve issues that may arise plays the most critical role in creating a safe environment. The quality of construction materials used for the construction of sports facilities is of great importance. In this work, the resistance and water repellency of concrete constituents for the construction of sports buildings have been investigated by nanoscience. Nano-concrete material solves the main problem of concrete surfaces, i.e., the entry of water and humidity into the structure. It also gives it a self-cleaning ability with its water repellency. Nanoparticles are placed between pores and cover the cracks, which causes roughness in the surface structure of concrete. The high roughness of the surface of the coated concrete caused its super-hydrophobicity. In hydrophobic surfaces, the higher the contact angle, the more hydrophobic the surface will be. In order to investigate the hydrophobic properties, silica nanoparticles, silica nanoparticles, and fly ash were prepared on concrete, and their properties were analyzed.

• 터널과지하공간
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• 제7권1호
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• pp.51-57
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• 1997

This study provides the results of two different blasting methods applied at the H Telcon construction site in Yeon-dong, Cheju Island. One is the traditional blasting method without bottom-hole stemming and the other with bottom-hole stemming using the materials such as sand, polystyrene and sawdust in 5~10 cm lengths. The effect of these materials on vibration level was studied. Assuming that safety criterion of vibration level be 0.5cm/set, 95% confidence limit line of measured data shows that maximum charge weight per delay could be increased in the following order; traditional methed, polystyrene stemming, sand stemming, sawdust stemming.

• 터널과지하공간
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• 제6권4호
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• pp.326-334
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• 1996

In underground construction the multi-step excavation sequence is commonly adopted for the convenience of the underground work. A numerical simulation method which is capable of analyzing the effects of excavation sequence on the stability of the opening is greatly needed. In this study a two dimensional finite element code was developed based on the effective numerical algorithm for the multistep excavation. The practical applicability of the model was verified for the simplified excavation sequences.

• Fibers and Polymers
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• 제5권3호
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• pp.182-186
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• 2004

The effect of braid construction parameters on yarn cross-sectional shape is presented in this paper. The location of the yam within the braid unit cell is quantified by a compaction factor. A range of braided fabrics were produced and optically measured for actual yarn cross-sectional shape. A comparison of the theoretical and experimental values shows good correlation. Design curves can be produced with the developed model to allow selection of appropriate braid process parameter to create yarns with desired cross-sectional geometries.

• Structural Engineering and Mechanics
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• 제15권1호
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• pp.151-157
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• 2003

A new approach to the analysis of horizontally curved beams is presented in this paper. The proposed method simplifies a two-dimensional structure into a one-dimensional structure just like a normal beam for structural analysis and, therefore, reduces the computational effort significantly.

• Structural Engineering and Mechanics
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• 제45권6호
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• pp.853-865
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• 2013

Inflatable panels made of modern and new textile materials can be inflated at high pressure to have a high mechanical strength. This paper is based on the finite element method as a general solution to determine the characteristics of deformed inflatable panels at high pressure in various end and loading conditions. Proposed method is based on the construction of weak form of formulation and application of Reduced Integration Element method (RIE) to solve the numerical problem of shear locking. The numerical results are validated as an outcome of comparison with other published results.

• 터널과지하공간
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• 제19권3호
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• pp.167-173
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• 2009

지하비축기지는 터널의 규모와 건설공정의 복잡성, 지질 및 지반공학적인 문제들로 인해 가장 난해한 지하공간건설 프로젝트로 알려져 있다. 최근 복잡한 지하구조를 3차원으로 가시화하고, 건설 자원과 지반조건 그리고 공정계획을 고려한 4차원 시뮬레이션을 활용하여 건설공정을 최적화하는 기술이 지하비축기지 건설 프로젝트에 적용되었다. 이 사례연구는 지하구조의 3차원 모델링을 통해 작업자가 복잡한 지하 현황을 쉽게 이해하고, 정확한 3차원 공간상에서 지질자료를 분석하고 검토할 수 있도록 도와줄 수 있음을 보여주고 있다. 또한 건설공정과 실제 공기를 고려한 4차원 시뮬레이션을 활용하여 자재와 버력의 반출입에서 나타날 수 있는 bottle neck의 위치와 시점을 판단하거나 일일 공사비의 변동을 검토하고, 작업조와 투입장비의 수, 터널 시공방향 및 굴착 착수 시점, 버력 및 자재의 운반경로를 검토함으로써 공정의 최적화를 달성할 수 있었다.

• Structural Engineering and Mechanics
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• 제52권2호
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• pp.391-403
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• 2014

In this study an innovative method of earthquake-resistant strengthening of reinforced concrete structures is presented for the first time. Strengthening according to this new method consists of the construction of steel fiber high-strength concrete jackets without conventional reinforcement which is usually applied in the construction of conventional reinforced concrete jackets (i.e., longitudinal reinforcement, stirrups, hoops). The proposed in this study innovative steel fiber high-strength or ultra high-strength concrete jackets were proved to be much more effective than the reinforced concrete jackets and the FRP-jackets when used for the earthquake-resistant strengthening of reinforced concrete structural members.

• Structural Engineering and Mechanics
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• 제14권4호
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• pp.401-416
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• 2002

This paper presents a domain decomposition method for buckling analysis of rectangular Kirchhoff plates subjected to uniaxial inplane load and with mixed edge support conditions. A plate is decomposed into two rectangular subdomains along the change of the discontinuous support conditions. The automated Ritz method is employed to derive the governing eigenvalue equation for the plate system. Compatibility conditions are imposed for transverse displacement and slope along the interface of the two subdomains by modifying the Ritz trial functions. The resulting Ritz function ensures that the transverse displacement and slope are continuous along the entire interface of the two subdomains. The validity and accuracy of the proposed method are verified with convergence and comparison studies. Buckling results are presented for several selected rectangular plates with various combination of mixed edge support conditions.

• Structural Engineering and Mechanics
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• 제20권6호
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• pp.631-653
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• 2005

In this work, the mechanism of damping and its theoretical evaluation for layered aluminium cantilever structures jointed with a number of equispaced connecting bolts under an equal tightening torque have been considered. Extensive experiments have been conducted on a number of specimens for comparison with numerical results. Intensity of interface pressure, its distribution pattern, dynamic slip ratio and kinematic coefficient of friction at the interfaces, relative spacing of the connecting bolts, frequency and amplitude of excitation are found to play a major role on the damping capacity of such structures. It is established that the damping capacity of structures jointed with connecting bolts can be improved largely with an increase in number of layers maintaining uniform intensity of pressure distribution at the interfaces. Thus the above principle can be utilized in practice for construction of aircraft and aerospace structures effectively in order to improve their damping capacity which is one of the prime considerations for their design.