Papers by Keyword: CFS

Abstract: This article aims to study the calculation for shear capacity of SRHC (Steel Reinforced High-Strength Concrete) members restrained with CFS (Carbon Fiber Sheet). Experimental study, theoretical analysis and calculation simulating are integrated in this article for the research of the shear failure characteristics and effect of various parameters on their behavior of SRHC members restrained with SFC on the basis of existed SRHC members tested results. The shear strength formula of steel reinforcement high-strength concrete short columns restrained with CFS is put forward, which based on the superposed strength method. This method on the basis of the load-deformation process of CFS is similar to hooping. The results indicate that the shear capacity of SRHC columns restrained with CFS is higher than SRHC columns. And, due to the axial compression ratio, shear span ratio and the amount of reinforcement influence the shear capacity of the FRP materials. So, these three kinds of factors are also the influencing factors of shear capacity of SRHC members restrained with CFS. The effect of the internal concrete restrained with CFS is good because of the function of CFS is equal to hooping and the strain of CFS is bigger than the strain of steel, so this simple calculation method is safe , which may be useful for further study and engineering design.

Abstract: Unreinforced masonry buildings have significant portion of existing and historical buildings around the world. Recent earthquakes have shown the needs of seismic retrofitting for these types of buildings. There are many types of retrofitting materials for URM(unreinforced masonry buildings) such as shotcrete, ECC and FRPs. Many engineers use many types of fiber reinforced polymers because these types of material enhance the shear strength of wall without expansion of wall sectional area and additional weight of total structure. However, the complexity of mechanical behavior of masonry shear wall and the lack of experimental data of masonry wall which was retrofitted by FRPs may cause the problem that engineers hard to determine the retrofitting level. Determining and providing the information for retrofitting effect of FRPs for masonry shear wall, this paper investigate in-plane shear behavior of URM and retrofitted masonry shear walls using two types of different FRP materials. Specimens were designed to idealize the wall of low rise apartment which was built in 1970s Korea with no seismic reinforcements and have 1 aspect ratio. Retrofitting materials were carbon FRP and Hybrid sheet which have different elastic modulus and ultimate strain. Consequently, this study will evaluate the structural capacity of masonry shear wall and retrofitting effect of FRP sheet for in plane shear behavior comparing with evaluation method for reinforced concrete beam which was retrofitted by FRPs.

Abstract: The dielectric properties of -SiAlON and various cations doped -SiAlON bulk ceramics prepared by a hot-press method were investigated. The dielectric properties (dielectric constant and tangent loss) were characterized by a post-resonator method (Hakki-Coleman method) at room temperature in the microwave frequency range. The effect of z-values about -SiAlON was examined, and also the effects of various interstitial cations on dielectric properties of -SiAlON were studied. Dielectric properties of -SiAlON were compared with those of Si3N4 and -SiAlON and their relationship between the dielectric properties and the cationic species of SiAlON were discussed.

Abstract: A series of five shear wall specimens were tested under constant axial stress and reversed lateral cyclic loading in order to evaluate the seismic retrofit methods that had been proposed for shear walls with new openings. The test results showed that the failed specimens had shear fractures and two different retrofit methods had different effects on the strengths of each specimen.