Articles

  1. Impact Resistance of Shear-strengthened RC Beams with Sprayed GFRP Download Article

    Sayed Mohamad Soleimaniand and Nemkumar Banthia
    • Article Type: Research Article
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    • Pages (83-87)
    • No of Download = 727

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    The use of Sprayed Glass Fiber Reinforced Polymer (GFRP) was investigated as a potential technique for improving the impact resistance of reinforced concrete (RC) beams strengthened in shear. Reinforced concrete beams with a small number of stirrups as shear reinforcement were retrofitted. Different configurations and thicknesses of Sprayed GFRP with a random distribution of chopped fibers, at a fiber content of about 25% by volume, were applied on two or three sides of the RC beams. These specimens were then subjected to impact using a fully instrumented 14.5 kJ drop weight impact machine. A frequency of 100,000 Hz was used to collect the dynamic data. Results indicate that RC beams with the Sprayed GFRP coating were highly resistant to impact. RC beams with the sprayed GFRP coating were found to possess a higher load carrying capacity, and were found to absorb much greater energy compared to those without the coating, under both static and impact loading.

  2. Quantifying Macrodispersion in Stratified Porous Formations Using Image Processing and Spatial Moment Analysis Download Article

    Katsutoshi Suzuki, Kazuya Inoue, Tsutomu Tanaka and Akira Kobayashi
    • Article Type: Research Article
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    • Pages (88-94 )
    • No of Download = 635

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    Laboratory dye tracer experiments with a pulse source were conducted under saturated unidirectional flow conditions in a two-dimensional and vertically placed water tank. In tracer experiments, homogeneous and stratified porous formations, which were comprised by a few combinations with three types of soil particles, were of concern to examine the effect of variation of pore structure on macrodispersion phenomena. A new methodology using spatial moment analysis linked with image processing of a dye tracer behavior was developed to estimate macrodispersivities both in longitudinal and transverse directions. These results demonstrated that the ratio of the longitudinal macrodispersivity to the longitudinal microdispersivity ranged from about 2 to about 40. Moreover, it was indicated that the layering of stratified porous formations had an effect on the degree of longitudinal and transverse macrodispersions.

  3. Thermally Modifying Bentonite For Construction Industry Download Article

    Abdoullah Namdar
    • Article Type: Research Article
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    • Pages (95-98)
    • No of Download = 846

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    The application of geology in civil engineering create possibility of ground improvement. This paper present thermally modification of construction material based on changing micro and macro characteristics. The heat can modify the soil shape, size and chemical composite as well as crystal structure. In this research work the bentonite subjected to the heat for 6 hours from 100 ºC to 500 ºC in increment of 100 ºC. The different techniques and methods have been used for changing soil micro and macro characteristics. And also the different technique validated this research investigation and the result has been shown that heat has significant affect on controlling geotechnical engineering problem. There is still more scope for continuing this research work on several natural soil and mineral in applying heat for different time and level  for approaching better results.

  4. Landslide Susceptibility Mapping by Using Logistic Regression Model with Neighborhood Analysis: A Case Study in Mizunami City Download Article

    Liangjie Wang, Kazuhide Sawada and Shuji Moriguchi
    • Article Type: Research Article
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    • Pages (99-104)
    • No of Download = 943

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    Landslides which affect human lives and economic losses are always attracted a lot of concerning in modern society. In order to identify the potential hazardous areas related to landslides, three methods have been used, such as qualitative or knowledge-based method, deterministic method and quantitative-based method. Geographical information system (GIS) technology and high computing ability provide a convenient tool to deal with landslide triggering factors and make the quantitative-based method achieve effectively. In this study, landslide-related factors such as topographical elevation, slope angle, slope aspect, topographical wetness index (TWI) and stream power index (SPI), were employed in the landslide susceptibility analysis. The logistical regression was used to obtain the relationships for landslide susceptibility between landslides and causative factors. The distributions of observed landslides were used to evaluate the performance of the susceptibility map. The approaches described in this paper showed us that the logistical regression and neighborhood can be used as simple tools to predict the potential landslide locations. This map will be helpful for city planning, infrastructure construction and agriculture developments in the future.

  5. Effect of Geological Succession on Macrophyte and Microbiota in Aquifer Ecosystem in Urban Coastal Zone Download Article

    Kazuhito Murakami and Akiko Inoue-Kohama
    • Article Type: Research Article
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    • Pages (105-110)
    • No of Download = 497

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    This study was conducted to investigate the effect of geological succession of sediment on macrophyte and microbiota in aquifer ecosystem. The research field was selected as Yatsu Tidal Flat where located in urban coastal zone in Tokyo Inner Bay. This tidal flat has been registered under Wildlife Protection Area of Japan in 1988 and the Ramsar Convention in 1993, and just as the tidal flat that was left from reclamation of waterfront zone of urban area. It is very important to obtain some information about these ecosystem characteristics of such nature left in urban area, because creation of artificial tidal flat is recognized as one of important enterprises to construct urban ecosystem. In recent years, a large chlorophyceae, Ulva spp. (mainly Ulva pertusa and Ulva japonica) which is recognized as a biotic indicator of eutrophicated sea area, has become observed in Yatsu tidal flat, and it is considered that Ulva spp. give a large effect to water quality. Ulva spp. has high absorbent potential of nutrient salts at its growth phase, so this macrophyte is considered to place the microbiota such as zooplankton and phytoplankton under its control. In the first place, the geological succession as muddy to sandy occurred because of water quality change as fresh water to sea water. This water change resulted from the decrease of drainage with the sewer system service in basin area, and lead oligotrophication of the sediment. Ulva spp. is one of the biological indicater for sea water and sandy sediment and eutrophicated environment. Because of the irregular growth of Ulva spp., the quantity of phytoplankton decreased drastically, and the dominant species of phytoplankton and zooplankton transited from ideal to unsuitable food organisms for macrobenthos which is important food for the migratory birds, and the production potential of this aquifer ecosystem became in fragility.

  6. Experimental Investigation for Nitrate Reduction Using Iron Powder in Porous Media Download Article

    Haruka Shimada, Kazuya Inoue, Ikko Ihara, Katsutoshi Suzuki and Tsutomu Tanaka
    • Article Type: Research Article
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    • Pages (111-116)
    • No of Download = 791

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    This paper assessed the potential of iron powder as a nitrate reduction and retardation material in porous media. Under saturated and unsaturated flow conditions, column experiments were conducted in silica sand with a mixture of two kinds of iron powders. Experimental breakthrough curves were analyzed using temporal moments not only to estimate the retardation factor and the degradation rate but to quantify mass recovery fractions associated with nitrate and ammonium ions. The results showed the increase of the amount of iron powder resulted in the increase of the degradation rates and the retardation factor estimates. Moreover, the production of ammonium occurred by nitrate reduction was confirmed. A mixture of iron powder with soil has a potential to reduce the concentration of nitrate by the reduction of nitrate to ammonium and to retard a nitrate.

  7. Determination of Organophosphoric Acid Tiesters from Different Landfill Sites and Sewage Plants in Japan Download Article

    Haruki Shimazu
    • Article Type: Research Article
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    • Pages (117-121)
    • No of Download = 502

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    Seven organophosphoric acid triesters (OPEs) were measured in the water emissions from five active landfill sites and three closed inactive landfill sites. Many kinds of OPEs were detected and the highest concentration levels are 10,000ng/L orders of magnitude. The OPE concentration levels for the closed inactive landfill sites were almost same with those for the active landfill sites. It will be necessary for the closed inactive landfill sites to do continuous monitoring and further maintenance. The same OPEs were measured in the inlet waters and the outlet waters from two sewage plants. The OPE concentration levels in the inlet waters were almost same with those for the landfill sites. The OPE concentrations in the outlet waters were lower than those in the inlet waters. Some OPEs could be removed in the treatment process of sewage plants. It is probably effective for OPE reduction to introduce the treatment process into landfill sites.

  8. Impact Analysis of Water Price Reform of Zhangye, China Download Article

    Atsushi Koike, Zhongmin Xu, Kang Wang and Bunei Itoga
    • Article Type: Research Article
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    • Pages (122-129)
    • No of Download = 623

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    The Hei River Basin is located in northwest region of China. This region belongs to arid zone, and water resources are one of the main limiting factors of harmonizing the development of ecology, economy and society. Due to the economic growth and the population increase, water consumption has grown rapidly since 1970s in this region especially in the Zhangye district. The rapid increase of water demand has degraded the ecosystems of the whole watershed. Water pricing is very important instrumentally in balancing water supply and demand. Appropriate water price is a very effective countermeasure in changing the social behavior towards water resource conservation, promoting economic efficiency and investment in more efficient equipments. The aims of this study are to analyze the comprehensive impacts of Water Price Reform of the Zhangye district by using an operational Computable General Equilibrium (CGE) model based on building a social accounting matrix (SAM).

  9. Behavior of Collapsible Loessic Soil After Interparticle Cementation Download Article

    Arrúa P., Aiassa G.; Eberhardt M. and Alercia Biga C.
    • Article Type: Research Article
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    • Pages (130-135)
    • No of Download = 545

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    The water content, shape and roughness of soil particles are related to the strength and stiffness of loessic soil samples under remolded conditions. When soil sample are under undisturbed condition, the cementation level between particles by the presence of water-soluble carbonates, govern the soil macroscopic behavior. Soil stiffness depends on the rigidity of the link. To control the mechanical collapsible behavior usually compaction and stabilization are made by Geotechnical Company with cementations agents. This work presents the hydration process of cement without mixing water and how geotechnical index and other parameter are modified. Those variables influence the resistance have been evaluated using unconfined compression tests. Results showed that resistance depend on the initial water content of hydration. Optimal conditions for generation cementing bridges are established.

  10. Evaluation of Stamps and Latex Shell Influence on Stabilometer Testing Results, Modeled with Simulia Abaqus Download Article

    A Dmitriy Volik
    • Article Type: Research Article
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    • Pages (136-139)
    • No of Download = 570

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    Triaxial tests are often used, along with other research methods, in order to define parameters of geotechnical data. The main topic being conferred in work is analysis of influence, exerted by stamp and latex shell, upon the results of triaxial machine soil tasting. The stabilometer modeling and verification was produced. Calibration of soil model parameters, derived from triaxial tests, is brought in work. The necessity of three dimensional simulation of soil testing process is pointed out in order to take into account stamp and shell influence.