• Computers and Concrete
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• 제13권3호
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• pp.389-409
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• 2014

Precast hollow core slabs (HCS) are technically advanced products in the precast concrete industry, widely used in the last years due to their versatility, their multipurpose potential and their low cost. Using three dimensional FEM (Finite Element Method) elements, this study focuses on the stresses induced by the prestressing of steel. In particular the investigation of the spalling crack formation that takes place during prestressing is carried out, since it is important to assure the appropriate necessary margins concerning such stresses. In fact, spalling cracks may spread rapidly towards the web, leading to the detachment of the lower part of the slab. A parametric study takes place, capable of evaluating the influence of the tendon position and of the web width on the spalling stress. Consequently, after an extensive literature review on the topic of soft computing, an optimization of the HCS is performed by means of Genetic Algorithms coupled with 3-D FEM models.

• Structural Engineering and Mechanics
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• 제65권1호
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• pp.1-7
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• 2018

This paper reviews the mechanical effects produced by reinforcement corrosion of prestressed concrete beams. Specifically, modifications in the bonding of the tendon to the concrete that reduce service life and load bearing capacity are studied. Experimental information gathered from previous works has been used for the theoretical analysis. Relationships between bond stress loss and reinforcement penetration in the concrete, and concrete external cracking were established. Also, it was analysed the influence that has the location of the area affected by corrosion on the loss magnitude of the initial prestress.

• 한국재난정보학회 논문집
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• 제5권2호
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• pp.124-137
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• 2009

The research on the effect of the prestressing force on the frequency of PSC(Prestressed Concrete beam) has been conducted theoretically and experimentally, and a few theory has been presented. However, the presented theories show no agreement in predicting the effect of the prestressing force. In this paper, the theories on the effect of the prestressing force on the frequency of PSC beam are presented and evaluated using the experimental result. To obtain the experimental result, two PSC beam specimens were manufactured, and the modal test and analysis were performed. The modal analysis results revealed that the prestressing force increased the natural frequency of the PSC beam. Comparing predicted results using existing theories show that Kim's model, which substitutes the prestressing tendon with the equivalent beam, gives the best prediction result.

• Clinics in Shoulder and Elbow
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• 제6권2호
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• pp.115-126
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• 2003

Although painful conditions of varying degrees of severity involving the soft tissues (i .e., muscles, tendons, ligaments, periosteum and peripheral nerves) occur frequently, their underlying pathogenesis is poorly understood. The term peripheral neuropathic pain has recently been suggested to embrace the combination of positive and negative symptoms in patients whose pain is due to pathological changes or dysfunction in peripheral nerves or nerve root. The spinal nerve root, because of its vulnerable position, is very easily prone to injury from pressure, stretch, angulation, and friction. Therefore, not a few of musculoskeletal chronic pains are result of nerve root dysfunction. Neuropathic changes due to nerve root dysfunction are primarily in soft tissue especially muscle, tendon and joint. It shows tenderness over muscle motor points and palpable muscle contracture bands and restricted Joint range. Careful palpation and physical examination is the important tool that, be abne to detect all of these phenomena.

• 대한견주관절학회:학술대회논문집
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• 대한견주관절학회 2006년도 제14차 학술대회
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• pp.50-53
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• 2006

• Smart Structures and Systems
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• 제19권5호
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• pp.463-472
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• 2017

In a previous study, the potential of damping suspension bridges with active stay cables has been evaluated on a numerical model of a suspension bridge, and demonstrated experimentally on a laboratory mockup. In this paper, we extend our study to explore two different configurations of the active stay-cables: one classical configuration, corresponding to attaching the active stay-cables between the top of the pylons and the deck (configuration I) and, another configuration, consisting of attaching the stay-cables between the base of the pylons and the catenary (configuration II). The analysis confirmed that both configurations are effective with a slight superiority of the second configuration. The study is conducted numerically and experimentally on a suspension bridge mock-up, by considering two types of active stay-cables. The experimental results confirmed the numerical predictions, and demonstrated the effectiveness of the second configuration.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.195-201
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• 2003

A fibered element for the material and geometric nonlinear analysis of three-dimensional reinforced and prestressed concrete frame is presented. The fibered frame element is idealized as an assemblage of concrete and reinforcing steel fibers in order to account for varied material properties within the cross section of the frame element through elastic, cracking and ultimated stages of materials. Prestressing tendon is modeled as an assemblage of multilinear prestressing steel segments each of which spans a frame element. The contribution of each prestressing steel is added directly to the fibered frame element. Numerical results from the ultimate analysis of three-dimensional PSC box girder are compared with those obtained from other investigator. The validity and the capability of the present nonlinear analysis model is well demonstrated.

• 한국구조물진단유지관리공학회 논문집
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• 제5권4호
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• pp.147-153
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• 2001

The major objectives of this study are to investigate experimental and analytical behavior of composite steel plate strengthened by external post prestressing method and to study the increasing magnitude of load carrying capacity by the external post prestressing method. With installed strain gauges and LVDT, the change of structural behaviors according to the amount of prestressing force is measured and the effects of shear strengthening according to the degree of angle in tendon are studied. The analytical structural behavior according to the amount of prestressing force is also investigated using finite element method. The effectiveness of strengthening of external post prestressing method is proved and an efficient FEM model is suggested by comparing the test results and analyzing results.

• Computers and Concrete
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• 제13권1호
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• pp.1-16
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• 2014

To evaluate the behavior of the advanced unbonded pre-stressed concrete containment vessel (UPCCV) for one typical China nuclear power plant under Japan's March 11 earthquake, five nonlinear time history analysis and a nonlinear static analysis of a 1:10 scale UPCCV structure have been carried out with MSC.MARC finite element program. Comparisons between the analytical and experimental results demonstrated that the developed finite element model can predict the earthquake behavior of the UPCCV with fair accuracy. The responses of the 1:10 scale UPCCV subjected to the 11 March 2011 Japan earthquakes recorded at the MYG003 station with the peak ground acceleration (PGA) of 781 gal and at the MYG013 station with the PGA of 982 gal were predicted by the dynamic analysis. Finally, a static analysis was performed to seek the ultimate load carrying capacity for the 1:10 scale UPCCV.

• 한국전산구조공학회논문집
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• 제28권5호
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• pp.523-533
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• 2015

원자로 격납건물은 냉각재상실사고와 같이 내부의 과도한 압력이 유발되는 사고에 있어서도 방사성 물질이 외부로 누출되지 않도록 막는 최종의 방벽이다. 이러한 격납건물의 기능적 중요성에 기인하여, 건설 초기 구조건전성시험(SIT)을 수행한다. 신고리 3호기 SIT 시험 당시 계측된 변위를 예측하기 위한 초기 해석 모델은 일부 위치에서 실제 변위를 과소 평가하는 경향을 보임에 따라 이를 개선하고자 하는 연구가 수행되었다. 해당 연구의 결과를 I 편과 II 편의 논문으로 정리하였으며, 본 I 편에서는 초기 해석모델을 개선해가는 과정에서의 해석모델 구성 시의 주요 고려사항의 분석 및 예비해석 결과를 제시하고 있다. 우선적으로 콘크리트 자체의 해석요소(mesh) 구성과 라이너, 철근, 텐던 등의 요소간의 연결 설정이 중요함을 확인하였다. 또한, 다양한 예비해석의 결과를 통해 비부착식 텐던으로 시공된 구조물에서 덕트관에 의한 강성 저감 효과 및 덕트관을 사이에 둔 텐던과 콘크리트간의 밀착 여부에 따른 강성 영향을 적절히 고려하는 것이 중요함을 확인하였다.