Applied Mechanics and Materials Vols. 764-765

Abstract: Taiwan, located in subtropical areas, relies heavily on air-conditioning to adjust the environment to maintain occupant comfort and work efficiency. Among numerous indicators that measure living comfort, the one corresponding to the change of temperature and relative humidity is the most felt by people. This study will investigate data on changes in the atmospheric environment in Taiwan over the years, and will correlate them to temperature and relative humidity within the comfort range for human beings. The Heat Index will also be examined and applied in this research in order to help air-conditioning systems better adapt to more volatile weather patterns and variable human needs. A simultaneous and precise control of temperature and relative humidity with reference to the Heat Index can reduce the load for air-conditioning without compromising environmental comfort.

Abstract: This paper deals with the application of Glass Fiber Reinforce Polymer (GFRP) to shear reinforcement for deep beam. Instead of steel stirrup, GFRP shear reinforcement was fabricated in the form of plate with openings and embedded in concrete. An experimental study was performed to evaluate the shear behavior of eight shear reinforced concrete deep beam. Shear test was conducted in which the shear span-to-depth ratio were 1.1, 1.3 and 1.6. Also, shear reinforcement area, and effective depth were considered as variables. Crack patterns, failure modes, and load-displacement were compared in order to evaluate shear strength of the specimens. The effects of these variables on the shear strength of the deep beam were examined. The test results in terms of the shear span-to-depth ratio showed that shear strength increased when the ratio decreased. Also, it showed that shear strength increased as the reinforcement area and the effective depth increased.

Abstract: During seismic hazards, offshore wind turbine structures do not have direct effects on people's safety; however, the seismic design is still important to prevent heavy damage on structure. The seismic design of offshore wind turbine has been discussed in some previous studies. Based on the result of those studies, we further modified the seismic source, especially on active faults in west foot hill zone. Of all the active faults in this area, we choose five which lie nearby the sites to make the modification. A logic tree has been set to avoid overlapping and derive an accurate recurrence model of the seismic source used in PSHA. This study is just a preliminary result of PSHA in wind turbine sites, Chunan and Chanbin, there are still several adjustments need to be done.

Abstract: Geopolymer concrete (GPC) is a new construction material in which cement is totally replaced by calcined source materials fly ash and GGBS. Geopolymer utilization reduces or eliminates the use of cement whose production produces a lot of carbon dioxide. Usually fly ash as a source material for the geopolymer. The behavior of GPC has to be studied in detail to check its suitability in construction industry. In the present study, the fracture behavior of geopolymer concrete is investigated and compared. Three-point bending test on notched prisms with a/d (notch depth/beam depth) ratios 0.1, 0.15, 0.2 are considered. The values of Critical load, fracture toughness, fracture energy and ductility are presented. The test results of total of 27prisms, 6cubes, 18 cylinders with M30 grade geopolymer concrete and conventional concrete (OPC) of same grade are presented in this paper. The test results indicated that the characteristic length of GPC is about 25% more than that of conventional concrete.

Abstract: This study focuses on 53 villages located in the slopelands of Pingtung County. Remote sensing image interpretation techniques are used to identify geologic hazard areas. GIS map overlay analysis of environmental geologic maps, landslide susceptibility maps and potential debris flow torrent maps provided by local and regional governments are used to further interpret and correctly identify the extent of the geologic hazard zone. This study successfully combines both GIS and GPS techniques, and according to data analysis results, constructs a slopeland village geologic hazard assessment method.

Abstract: The current thesis proposed the integration of air conditioners that exhaust heat with solar energy to enhance the overall efficiency of thermal energy conversion. The analysis of thermal storage tanks of different volumes revealed that a two-ton air conditioner operating for an hour produced double energy than normal sunshine for a day. With thermal storage tanks of fixed volume, the integration of air conditioners of different tons with solar energy indicated that air conditioners of less tons produced faster and more efficient energy conversion. Therefore, the current thesis proposed that the modification of condenser in domestic air conditioner into water-cooled condenser not only enhanced the energy efficiency of air conditioners but also increased hot water supplies since hot water from air conditioners could be integrated into solar water heaters. By doing so, energy conservation and carbon reduction could be achieved.

Abstract: The large deformation of cold-formed steel bolted connection has become a significant research interest in order to construct a reliable and safe light steel frame. This paper presents a study on the influence of column flange thickness for cold-formed steel top-seat flange cleat joint using finite element method. The verified and validated modelling technique for cold-formed steel top-seat flange cleat connection is applied to the column component study. The failure of the joint is fixed at column component and the bolt pull-out from column was observed at the top tension bolt row. The increment of the thickness of column flange has improved the load-carrying characteristic by the best representation of polynomial equations at both elastic and plastic regions. The cubic polynomial equation has a good representation of initial and secant rotation stiffness in the function of the column flange thickness for cold-formed steel top-seat flange cleat joint. For relative thin cold-formed column, the thickness of open section for column flange is an important variable in the design of bolted joint in light steel framing.

Abstract: Experimental tests have been conducted to investigate the performance of Concrete Filled Carbon Fiber Reinforced Polymer Sheet Tube (CFCST) columns. The main variables of this experimental program were the number and wrapping angles of CFRP sheets. In the first stage, stress versus strain characteristic of CFCST specimens was investigated by uni-axial tests. In the second stage, six full-scaled CFCST columns subjected to quasi-static lateral loading, as well as constant axial compression, were tested. The test results showed that the response of CFCST was seriously influenced by these two variables. This test results could be utilized for establishing the analytical models.

Abstract: Pile foundation is the practical method to enhance earthquake-resistant ability for structures located in liquefiable soil sites. Soil liquefaction impact has been occurred such as Kashiwazaki-Kariwa NPP in 2007 Chūetsu offshore earthquake because of the soft backfill soil. To understand the behavior of pile foundations in liquefied soil during earthquake attack and conform to nuclear standard, seismic analysis with soil-structure interaction considering liquefaction using the finite difference program FLAC3D is developed to renew the traditional method used in nuclear industry. The models are verified according to a series of centrifuge model test results conducted in National Central University, Taiwan, to show the accuracy of seismic response prediction, and it provides the more advanced tool to demonstrate the detail of seismic response so that the utility and authority can easily decide the disaster prevention strategy.

Abstract: This study is aimed to investigate the seismic behavior of the freestanding dry storage cask for spent fuel, several shaking table tests were conducted using a scaled cask model for a real assessment of the characteristics of the seismic response of the cask. First, the harmonic excitation test on the pedestal of the cask was performed to estimate the friction coefficient at the interface between the cask and the pad according to the sliding acceleration response of the pedestal. Then, tests for the seismic response of the cask were conducted for two different setups, the vertical cylindrical concrete cask (VCC) and the concrete cask with an add-on shield which has a square pedestal (VCC+AOS), respectively, using the artificial earthquakes compatible to the design spectrum. In order to verify the often-used analysis method for the seismic response of the cask in engineering practice, the explicit finite element software LS-DYNA was adopted to generate the finite element model of the scale cask with the cask/pad interface modeled by Coulomb’s law of friction and to simulate the shaking table tests. Results indicate that the utilized method gave reasonable cask responses if the variation of the friction coefficient at the cask/pad interface was small during the sliding process.