Articles

  1. PULL-OUT STRENGTH OF AN EXPANSION STUD ANCHOR IN CARBON FIBER REINFORCED CONCRETE Download Article

    Gilford B. Estores and Bernardo A. Lejano
    • Article Type: Research Article
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    • Pages (1-8)
    • No of Download = 713

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    Carbon Fiber Reinforced Concrete (CFRC) is considered as an innovative structural material because of its better performance characteristics when compared to conventional concrete. Its common applications where expansion stud anchor connection is possible are in slabs on grade, wall panel, curtain walls, and pre-cast elements. The design of this stud anchor in CFRC is of great interest to many structural engineers, however, no model is available as basis for its design. To develop such model, this study investigated the pull-out strength of an expansion stud anchor embedded in CFRC as influenced by fiber volume content (Vf), fiber length (Lf), compressive strength and tensile strength. Three compression, three tension, and five pull-out CFRC specimens each of different Vf (0.10%, 0.15%, 0.20%, 0.25%, 0.30%) and different Lf (19 mm, 30 mm, 38 mm) were prepared, tested, analyzed, and compared to control concrete specimens at design compressive strength of 21 MPa. Tests results show that pull-out strength of an expansion stud anchor in CFRC is maximum at Vf = 0.10% and Lf = 38 mm. Among the parameters considered, tensile strength is the most significant contributing factor that could influence the pull-out strength of stud anchor in CFRC. This is further verified numerically by a FEM model with good agreement to the observed tensile strength. Finally, a Response Surface Methodology (RSM) model is proposed to predict the pull-out strength of an expansion stud anchor embedded in CFRC as influenced by the fiber volume content, fiber length, compressive strength, and tensile strength.

  2. STRENGTH AND PERMEABILITY CHARACTERISTICS OF ROAD BASE MATERIALS BLENDED WITH FLY ASH AND BOTTOM ASH Download Article

    Jonathan R. Dungca and Julie Ann L. Jao
    • Article Type: Research Article
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    • Pages (9-15)
    • No of Download = 500

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    The Philippines has an extensive road network which handles most of its passenger and freight movements. Large volumes of aggregate embankment materials of good quality are required to primarily support these transport infrastructures, and this poses threat to the environment. Coal combustion by-products (CCPs) are seen to be its potential alternative mainly due to its vast production and disposal problems in the country. Representative samples of class C fly ash and bottom ash were gathered together with conventional road base materials. Fly ashes were substituted to act as fines; whereas, bottom ash substitutions were varied at different mixture ratios of 0%, 20%, 40%, 60%, 80%, and 100% of fine aggregates. Index properties (i.e. specific gravity, Atterberg limits, and maximum and minimum index densities), compaction characteristics, unsoaked and soaked California Bearing Ratios (CBR), and hydraulic conductivities were obtained for all the blends in order to produce empirical relationships with varying bottom ash content. Results show that the optimum strength can be produced at a blend of 100% bottom ash. However, permeability tests show a considerable decline in hydraulic conductivity with the addition of coal ashes to the typical aggregates. Thus, proper drainage must be carefully applied to these blended embankment materials so as to avoid substantial ingress of water.

  3. UTILIZATION OF AGGREGATE QUARRY WASTE IN CONSTRUCTION INDUSTRY Download Article

    Mary Ann Q. Adajar, Euclid de Guzman, Ryan Ho, Cesar Palma Jr. III and Dennis Sindico
    • Article Type: Research Article
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    • Pages (16-22)
    • No of Download = 428

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    The use of solid wastes as a new ingredient in construction materials is one possible innovative effort to reduce environmental degradation and to facilitate sustainable use of natural resources. The disposal of the huge amount of wastes from aggregate quarry (WAQ) is one adverse environmental effects of quarrying activities. Finding useful application of this solid waste, specifically as a substitute for fine aggregates in concrete mix, alleviates disposal problems and helps the construction industry to come up with concrete products at lesser cost. This study investigates the structural performance of concrete with WAQ as substitute for fine aggregates in a concrete mix following ASTM standards. Concrete with WAQ as fine aggregates achieved almost 78% of its target compressive strength. The reduced compressive strength is due to the finer and less-angular particles of WAQ in comparison to sand. Empirical model was formulated that can be used to predict the compressive strength of concrete with WAQ as substitute for sand. Using the formulated model, the optimum compressive strength can be achieved at 85% substitution for sand. The flexural strength of concrete with WAQ was in the range of 69% to 72% of the flexural strength of concrete without WAQ. The presence of WAQ in the concrete mixture has no significant effect in its unit weight, however, it affects the workability of the mix due to its cohesive property thus requires higher water-cement ratio. Test results proved that concrete with WAQ as substitute for fine aggregates has strength properties adequate for structural application.

  4. DEM MODELLING OF GEOCELL-STABILISED SUB-BALLAST UNDER CYCLIC LOADING Download Article

    Ngoc Trung Ngo, Cholachat Rujikiatkamjorn and Buddhima Indraratna
    • Article Type: Research Article
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    • Pages (23-29)
    • No of Download = 658

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    Upon repeated train loading, sub-ballast aggregates, placed underneath a ballast layer in rail track, become degraded and fouled by the progressive accumulation of external fine particles such as mud-pumping of soft subgrade, seriously decreasing the shear strength and drainage capacity of the track. This paper presents a study of the load-deformation response of geocell-reinforced sub-ballast under cyclic loads using laboratory tests and discrete element method (DEM). A series of large-scale cubical triaxial tests with and without geocell inclusions are conducted in the laboratory and simulated in DEM to investigate the beneficial effect of the geocells in decreasing the lateral and vertical deformations of railway subballast. Irregularly-shaped particles of sub-ballast are modelled by connecting and bonding of many circular balls together at appropriate sizes and positions. The geogcell was simulated by bonding many small spheres together to build a desired geometry and structure. The load-deformation behaviour of the geocell-stabilised sub-ballast specimen at varied load cycles predicted from the DEM modelling agrees well with those measured experimentally, showing that the proposed DEM model in this study is able to capture the deformation behaviour of the sub-ballast stabilised by the geocell. Additionally, the DEM modelling also provides insight into the distribution of contact forces, average contact normal and shear forces, which cannot be determined experimentally. These observations clearly prove the reinforcement effect of the geocell in eliminating the deformation of sub-ballast from a micromechanical perspective.

  5. APPLICATION OF GROUND SPRING MODEL IN EXCAVATION SUPPORTED BY DEEP CEMENT MIXING Download Article

    Siriwan Waichita, Pornkasem Jongpradist and Chanchai Submaneewong
    • Article Type: Research Article
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    • Pages (30-36)
    • No of Download = 529

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    An application of Deep Cement Mixing (DCM) as a retention system in deep excavation becomes gradually popular in very dense population areas because of less noise and environmental impact of the construction process than other systems. In addition, this new kind of retention system has various forms of utilization, which depend on the designer’s experience and considerations. For better understanding of this system, full scaled test, down scaled physical model test, and numerical analysis are required to tackle the interested problem. To effectively discuss the behaviors observed from the full-scale numerical analysis and physical model test, the scaling factor must be seriously considered. However, it is difficult to scale down the properties of soft clay in the physical model test. Therefore, the soil and its lateral pressure transferred to the wall are modeled as a series of springs and lateral forces in the model, respectively. To ensure the effectiveness of this modeling, preliminary evaluation is necessary. In this study, a 2D plane strain Finite Element model of an excavation with the DCM retaining wall had been validated with field monitoring data, then the 2D model was compared to a 3D Finite Element model with a series of ground springs to take the lateral stiffness of the in-situ soil behind the wall into consideration. The results of this numerical investigation reveal that the ground spring model has sufficient accuracy to represent the lateral soil-structure interaction.

  6. OPTIMIZATION OF COMPRESSIVE STRENGTH OF CONCRETE WITH PIG-HAIR FIBERS AS FIBER REINFORCEMENT AND GREEN MUSSEL SHELLS AS PARTIAL CEMENT SUBSTITUTE Download Article

    Bernardo A. Lejano and Jayvee L. Gagan
    • Article Type: Research Article
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    • Pages (37-44)
    • No of Download = 578

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    The feasibility of different waste materials as substitute to the main components of concrete is attracting attention nowadays. In relation to that, this study focuses on determining the effects of combining two waste materials namely, pig-hair fibers (PHF) as fiber reinforcement and crushed green mussel shells (GMS) as partial cement substitute to the properties of concrete. Response Surface Methodology (RSM) was used to model the relationship between the response and the factors considered. Using central composite design (CCD) to establish the design of experiment, the researchers was able to reduce the required number of experimental runs to 20 from a total of 27 runs for 3 level full factorial experimental program that is common for responses with nonlinear behavior. Optimization was conducted to determine the optimum amount of PHF and GMS in concrete that could yield maximum compressive strength while keeping the workability at an acceptable level. As for the results, an increase in compressive strength of concrete was recorded with the incorporation of PHF and GMS to concrete. However, decrease in workability was experienced due to the amount of fiber reinforcement present in the mix. Results of RSM suggested an optimum combination of 0.70% PHF content and 7.81% GMS partial cement substitute at 0.47 water-cement ratio (w/c) to achieve 27.40 MPa and 2.78 MPa compressive and tensile strength respectively with a minimum recommended slump of 25 mm for concrete beams and columns as per ACI. Based on these results, PHF-GMS concrete could be used in structures not requiring compressive strength above 28 MPa. With the use of GMS as a partial cement substitute, it could reduce the overall cement requirement for a project thus incurring savings and most importantly promotes the use of environment friendly materials.

  7. USING FLOATING WETLAND TREATMENT SYSTEMS TO REDUCE STORMWATER POLLUTION FROM URBAN DEVELOPMENTS Download Article

    Peter Schwammberger, Chris Walker and Terry Lucke
    • Article Type: Research Article
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    • Pages (45-50)
    • No of Download = 4197

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    Floating treatment wetland (FTW) systems are an innovative stormwater treatment technology currently being trialled in Australia. FTWs provide support for selected plant species to remove pollutants from stormwater discharged into a storage basin. The plant roots provide large surface areas for biofilm growth, which serves to trap suspended particles and enable the biological uptake of nutrients. FTWs can be installed at the start of the construction phase and can therefore start treating construction runoff almost immediately. FTWs have the potential to provide a full range of stormwater runoff treatment (e.g. sediment and nutrient removal) from the construction phase onwards. A 101 m2 FTWs has been installed within a greenfield development site on the Sunshine Coast, in Australia. The two-year research study investigated the pollution removal performance of the FTW for two different locations, one with low and one with moderate influent pollutant concentrations. This paper presents the research methodology used, and the initial study results of the treatment efficiency of FTWs.

  8. TUNNELING SIMULATION IN SOFT GROUND USING SHELL ELEMENTS AND GROUTING LAYER Download Article

    Prateep Lueprasert, Pornkasem Jongpradist and Suchatvee Suwansawat
    • Article Type: Research Article
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    • Pages (51-57)
    • No of Download = 347

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    With the advancement of computer sciences and researches on tunneling simulation in the past, the 3D finite element analysis of tunnel excavation by Tunnel Boring Machines (TBMs) has been extensively used over the last decade. Due to that the complicated construction sequences and relevant loads can be taken into account, complex interaction problems can then be performed. Many simulation techniques have been proposed depending on the assumptions used in the modeling. For modeling the tunnel lining, solid elements are commonly used due to the ratio between the width and thickness of the lining is not large. In addition, most studies focused on the ground deformation, not the lining forces. In the circumstance that the lining forces are essentially observed, the structural elements that directly provide the values are preferred. Therefore, this research attempts to propose the shell elements as tunnel lining together with the grouting layer in the analysis. The analysis results from the proposed method and the conventional one are compared and discussed in terms of ground deformation and lining forces together with the field measurement data. The results reveal that the simulation by the proposed method is sufficient and can reasonably reproduce the soil and lining responses.

  9. 3D-FEM ANALYSIS OF SHIELD TUNNEL CONSTRUCTION WITH GROUND-SPRING MODEL Download Article

    Pattanasak Chaipanna and Pornkasem Jongpradist
    • Article Type: Research Article
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    • Pages (58-62)
    • No of Download = 598

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    The shield tunneling has been extensively implemented for construction of underground transportation systems in urban areas. Reports on tunnel segment damage during tunnel construction become increasing. The jack thrust force is the essential cause of damage to the segment. The objective of this article is to present the model which analyzes the behavior of tunnel lining during construction. The model consists of five rings and ten segments for each ring connected together with the shear springs which represent the segment joints and ring joints. The zero thickness interface elements are used to model the segment interface behavior and soil stiffness is represented by mean of ground springs. All relevant construction loads are taken into account in the analysis. The ground spring model is implemented into FEM program ABAQUS to analyze the behavior of segmental lining during construction along straight and curve alignments. The analysis results agree with the measurement data and confirm that the stresses of tunnel segments are governed by jack thrust force. The ground-spring model has been proven to be appropriate for analysis of behavior of the tunnel segments.

  10. INVESTIGATION ON TUNNEL RESPONSES DUE TO ADJACENT LOADED PILE BY 3D FINITE ELEMENT ANALYSIS Download Article

    Narunat Heama, Pornkasem Jongpradist, Prateep Lueprasert and Suchatvee Suwansawat
    • Article Type: Research Article
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    • Pages (63-70)
    • No of Download = 521

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    Underground structures are popularly utilized in urban development, especially tunnels for both transportation and utilities. The interaction problem between existing tunnel and piles from new constructed structures thus becomes unavoidable in dense population area. The tunnel loses its stability if the additional forces and changed diameters (due to adjacent piles under loading) of tunnel lining are drastically high. This depends on many factors, such as the clearance and pile tip level with respect to tunnel position. For preliminary assessment during the first stage of design, it is necessary to estimate this impact. The concept of tunnel protection zone is commonly adopted. However, to establish the tunnel protection zone for adjacent loaded pile, the understanding on this interaction problem is essential. This study analyzes the effect of adjacent pile under loading on the existing tunnel by 3D finite element method. The case study is the tunnel of MRTA project subjected to an adjacent 1 m bored pile under loading with various lengths and clearances. The additional forces (bending moment and axial force) and the tunnel deformations are investigated. The results show that the additional forces and the tunnel deformations decrease when the clearance increase and become insignificantly increasing when the clearance is larger than 3.5 m. The distribution patterns of additional forces and tunnel deformation are similar.

  11. EVALUATION OF POROSITY IN BIOGROUTED SAND USING MICROFOCUS X-RAY CT Download Article

    Shumpei Mitsuyama, Kazunori Nakashima and Satoru Kawasaki
    • Article Type: Research Article
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    • Pages (71-76)
    • No of Download = 563

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    Biogrouting is a method employed for ground improvement based on microbially induced calcium carbonate precipitation. It is commonly believed that biogrout has environmental and economic benefits. However, there remains the need to clearly understand the internal structure of biogrouted soil. In this study, we use microfocus X-ray computed tomography (CT) to evaluate the porosity in biogrouted sand. X-ray CT is useful as a non-distractive inspection tool. First, we prepare small specimens using coral sand at different dilution rates of culture solution. After carrying out a solidification test for 2 wks., we perform an unconfined compressive strength (UCS) test and measure the porosity of the specimens. Our aim is to investigate the influence of the dilution rate on the UCS and the porosity of sand specimens. The results show that a lower dilution rate resulted in a lower sand-specimen porosity and an increase in the UCS. We investigate the precipitation that fills a void. Then, we investigate the relationship between UCS and the ratio of porosity. There was a negative correlation between UCS and porosity, which closely agrees with previous research. We confirm the validity of the result, and we determine the UCS from the porosity.

  12. ARTIFICIAL NEURAL NETWORK PERMEABILITY MODELING OF SOIL BLENDED WITH FLY ASH Download Article

    Jonathan R. Dungca and Joenel G. Galupino
    • Article Type: Research Article
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    • Pages (77-82)
    • No of Download = 566

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    The determination of the permeability properties of soil is important in designing civil engineering projects where the flow of water through soil is a concern. ASTM D2434 Standard Test Method for Permeability of Granular Soils (Constant Head & Falling Head) is being followed to determine the vertical permeability, while for horizontal permeability, there are none. In this study, tests such as Atterberg limit, relative density tests, and particle size analyses are done to determine the index properties of soil blended with fly ash. Subsequently, microscopic characterizations tests, elemental composition tests and permeability tests are done to determine the chemical and physical properties of the soil mixes. A new permeability set-up was used in determining the horizontal permeability soil mixes. Data were extracted during the experiment and a relationship between the properties of soil and the permeability was established. An artificial neural network model was used to predict the coefficient of permeability when the percentage of fly ash is available.

  13. UNIAXIAL COMPRESSION TEST OF UNSATURATED MASADO UNDER CONSTANT DEGREE OF SATURATION CONDITION AND ITS MODELING Download Article

    Yuhei Kurimoto, Seiji Kobayashi, Takashi Tsunemoto and Feng Zhang
    • Article Type: Research Article
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    • Pages (83-87)
    • No of Download = 525

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    Soils in surface ground are usually unsaturated. Proper modeling of the characteristics of unsaturated soil is therefore absolutely needed. However, due to its complicated mechanical behavior, establishing a constitutive model for unsaturated soil is far more difficult than that for saturated soil. In this research, uniaxial compression tests were firstly conducted on unsaturated Masado (Decomposed granite) under constant degree of saturation condition to investigate the mechanical behavior of the soil at different degree of saturation. Then, based on the test data, the performances of previously proposed elastoplastic constitutive model for unsaturated soil were checked carefully, taking the Bishop-type skeleton stress and the degree of saturation as the state variables. It is found that the mechanical behavior of the unsaturated Masado can be properly described by the proposed elastoplastic constitutive model that takes the skeleton stress and the degree of saturation as the state variables.

  14. CONSTITUTIVE MODELING OF COAL ASH USING MODIFIED CAM CLAY MODEL Download Article

    Erica Elice Saloma Uy and Jonathan R. Dungca
    • Article Type: Research Article
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    • Pages (88-94)
    • No of Download = 529

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    Coal ash is a by-product from coal-fired power plants that generates electricity. These waste materials most of the time is kept in storage facilities. Due to the growing demand in electricity generation, storage facilities can no longer accommodate the waste materials. Instead of disposing the waste materials, it can be used as a construction material. A promising civil engineering structure that can use coal ash as a construction material is land reclamation. The structure needs huge volume of materials and this can maximize the usage of coal ash. In the Philippines, most land reclamation projects are conducted at the sea. From this, distilled water was replaced with sea water to have a better evaluation of the strength properties of coal ash. Consolidated drained test was performed having three conditions with respect to sea water exposure. First condition is no exposure, second condition is immediate exposure and third condition is prolonged exposure. Results show that coal ash exposed to seawater, immediate and prolonged, has smaller shear strength. On the other hand, it still has reasonable strength suitable for land reclamation projects. Constitutive modeling using Modified Cam Clay model is incorporated in the study to be able to predict its behavior and failure in terms of mean effective stress, deviator stress and specific volume.

  15. ARTIFICIAL SLUDGE BASED ON COMPOSITIONAL INFORMATION OF A NATURAL SEA SLUDGE Download Article

    Hirosuke Hirano, Takeshi Toyama, Nobuyuki Nishimiya, Davin H. E. Setiamarga, Shugo Morita, Yuto Uragaki and Kyoichi Okamoto
    • Article Type: Research Article
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    • Pages (95-99)
    • No of Download = 412

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    The chemical and physical properties of sludge collected from different aquatic areas differ from one another. Such differences have made the universal standardization of early settings difficult. Usage of artificial sludge with stable characteristics has been thus proposed in the present study. First, values of organic matter, sulfide content, and the inorganic content were measured for the sea sludge collected from Funabashi Port in Japan. Using the obtained chemical and physical properties as reference, we then produced artificial sludge by mixing dry yeast made from yeast cultured in liquid sodium sulfide nonahydrate solutions (3.5-4.0%) and zeolite for inorganic material. In the present study, we understood that we couldn’t obtain the desired organic content for the artificial sludge, simply by adding the yeast with the amount similar to the organic content percentage we aimed. We thus calibrated the amount of yeast by measuring the actual organic content of several artificial sludge samples by thermo-gravimetry analysis. We found out that we need only to write a calibration curve of three measurements (zeolite-dry yeast w/w% = 0%, mid-point, and 83.3%) in order to obtain the information about the right amount of dry yeast addition to produce an artificial sludge with desired percentage of organic material. Finally, we mixed 31.4% of dry yeast (zeolite and other inorganic materials = 68.6%), in order to obtain an artificial sludge with 23.6% organic content. This percentage is similar to the organic content of the sludge collected from Funabashi Port.

  16. COLONIZATION AND MORPHOLOGICAL CHANGES OF A SEDGE RESTRICTING REGENERATION AFTER WIND DAMAGE IN A NATURAL FOREST Download Article

    Teruo Arase, Tetsuo Okano and Tetsuoh Shirota
    • Article Type: Research Article
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    • Pages (100-104)
    • No of Download = 463

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    Many old trees were blown down by typhoons in 1959 and 1961 in a natural coniferous forest deep in the mountains of Kiso District, Central Japan, and dense dwarf bamboo subsequently delayed the growth of tree seedlings. Forest engineers have tried to suppress dwarf bamboo to promote the regeneration of arboreal vegetation. However, after suppression of dwarf bamboo, an unknown grass unexpectedly colonized the area and replaced them. Afterward, almost no tree seedlings could be observed in the newly formed community, which seemed to worsen the extent of regeneration. It has been identified that the grass as Carex oxyandra, a native sedge species indigenous to Kiso District. Commonly, Carex oxyandra grows as short as about 10 cm like lawn grass, but it seems to have exceedingly enlarged the size in the community. Thus, investigation on the morphological variation of this sedge in Miure Experimental Forest within the Kiso National Forest was carried out. Leaf blade length, basal tiller length, and number of leaves per tiller were measured in upper and lower stands on three slopes in 2009. Results revealed that leaf blade length and basal tiller length in lower stands were approximately twice as large as those in upper stands on each slope, whereas the number of leaves per tiller was almost the same (8.8-9.4 leaves). Consequently, tussocks of this sedge became large in lower stands on a slope, which made the community overcrowded and damp, restricting tree regeneration.

  17. 3-D NUMERICAL ANALYSIS OF CONSOLIDATION EFFECT ON PILED RAFT FOUNDATION IN BANGKOK SUBSOIL CONDITION Download Article

    Kongpop Watcharasawe, Pastsakorn Kitiyodom and Pornkasem Jongpradist
    • Article Type: Research Article
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    • Pages (105-111)
    • No of Download = 717

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    This study focused on the investigation of influencing factors on behaviour of piled raft foundation in Bangkok subsoil. To evaluate the possibility of implementing this system in Bangkok subsoil condition, this research performed the consolidation analysis of piled raft foundation systems for low-rise (8-storey) and high-rise (25-storey) buildings with basement levels in clay soil, using coupled three-dimensional (3D) mechanical and hydraulic numerical model. The soils are modelled with Hardening Soil model and Mohr-Coulomb model. Evaluations of piled raft foundation, i.e., the load sharing ratio of piles, settlement behaviours in the foundation system are performed. The parametric study on the effect of raft depth, and load carried by piles of piled raft was done. The consolidation had a strong influence on the load carried by piles of the piled raft foundation in Bangkok. The load shared by piles can increase by up to 12% and 6% for low rise and high-rise buildings, respectively due to the consolidation effect. Therefore, the design of the piled raft foundation system in Bangkok subsoil essentially consider the consolidation effect.

  18. ASSESSMENT OF STRESS-STRAIN BEHAVIOR OF ENERGY PILES INSTALLED IN SAND Download Article

    Anant Aishwarya Dubey and Suresh Kumar
    • Article Type: Research Article
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    • Pages (112-120)
    • No of Download = 988

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    The geothermal piles are dual functional geostructures which provide sub-structural support to the building and also fulfill the energy demands in terms of its climate control. For efficient design of geothermal piles, it is necessary to evaluate the thermo-mechanical behavior of geothermal piles. The purpose of this study is to evaluate the behavior of geothermal heat exchanger pile installed in sand, subjected to a coupled thermo-mechanical loading. Initially, in this study a full scale field test is simulated and results are compared. In the second phase, parametric study by varying mechanical and thermal loading on the geothermal pile placed in dense sand, is performed. In this study, the sand and geothermal pile are simulated as axis-symmetrical models, where pile is considered to be thermo-elastic in nature and sand is considered as Mohr-Coulomb elastic-plastic material. Coupled Temperature-Displacement analysis is applied in order to simulate the observed experimental results. It is shown that the simulated model is able to reproduce the major thermo-mechanical effects for the selected full scale model approximately. Stress and strain behavior along with the depth of energy pile induced by thermo-mechanical loading has been reported. It was concluded that when mechanical load value is comparatively low, the thermal variation influences the induced axial stress while at higher mechanical load the stress behaviour is nearly constant at different temperature variation.

  19. FLOW PROPERTIES AND STRENGTH BEHAVIOUR OF MASONRY MORTAR INCORPORATING HIGH VOLUME FLY ASH Download Article

    Balamohan Balakrishnan, A. S. M. Abdul Awal, Abdul Halid B. Abdullah and M. Z. Hossain
    • Article Type: Research Article
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    • Pages (121-126)
    • No of Download = 483

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    Masonry mortar is one of the most widely used building materials in construction as nearly all the walls made with bricks are finished with mortar. Masonry works with mortar are generally made with cement, sand and water. In this study, mortar mixes were made by replacing the masonry cement with up to 50% of fly ash at an incremental rate of 10%. Six mortar mixes with 1:4 volumetric cement-to-aggregate ratios using natural sand were made and tested for flow and strength properties. The results obtained from the tests showed that the masonry mortars manufactured with fly ash are better off as compared to the mix without any ash. In terms of flow, it was found that the addition of fly ash increased the flow, particularly when the replacement levels were above 40%. Mortar with high volume fly ash has also shown to attain a comparable strength with that of the control mix. Considering the better workability and acceptable strength properties, the results have demonstrated that high volume replacement of fly ash is a viable alternative for producing environmental friendly masonry mortar.

  20. EVALUATION THE PERFORMANCE OF LAKE WATER USED AS HEAT SOURCE FOR HEAT PUMP SYSTEM IN A TYPICAL JAPANESE RESIDENT BUILDING Download Article

    Liwei Wen
    • Article Type: Research Article
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    • Pages (127-133)
    • No of Download = 275

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    The surface water, such as lake-water, sea-water, reservoir-water is considered as one kind of unutilized energy because that they own higher temperature in winter and lower temperature in summer than the ambient air. The energy saving is expectable when the surface water is employed as the heat source of heat pump system. This study examines the potential of lake water used as heat source of heat pump system in a residential building. Annual heating and cooling loads of a typical Japanese residential building were calculated using thermal net-work model of SMASH. The load calculation results indicate that the heating load dominates in the residential building. In addition, the heating load tends to decrease and cooling load minimally varies with the rise in insulation level. The air conditioning is generally operated at low load level in exception of the occasional high load level at the starting running stage. In comparison with the air source heat pump and air conditioner, the predicted energy saving effect for lake water heat pump could attain 60-70% and 30-45% during the cooling and heating periods in different locations, respectively.

  21. GEOPHYSICAL AND HYDROCHEMICAL APPROACH FOR SEAWATER INTRUSION IN NORTH SEMARANG, CENTRAL JAVA, INDONESIA Download Article

    Supriyadi, Khumaedi and Andya Satya Purnomo Putro
    • Article Type: Research Article
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    • Pages (134-140)
    • No of Download = 5665

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    Groundwater over exploitation leads to seawater intrusion in coastal area and influence the quality of the groundwater aquifers. Geophysical and Hydrochemical investigations were carried out to determine subsurface geologic formation and assessing seawater intrusion in Tanah Mas Residential area of North Semarang, Indonesia. The seawater intrusion was investigated by 2D geoelectrical resistivity imaging and generated using multi-electrode system with Wenner array configuration. Chemical analyses of groundwater samples of indicated the range of salt concentrations meanwhile correlation of geophysical data in the study area allows for the predictions of seawater-contaminated zones and their influence on in situ salinity in the study area. The 12 geo-electrical sections were obtain up to penetration depth of about 27 m for a total length of 150 m. The results of groundwater chemical testing indicated that there are three groundwater samples with high levels of chloride ions. The three groundwater samples with high levels of chloride ions are from wells F (434455, 9231239), J (434610, 9230204) and M (434117, 9231156). Seawater intrusion in the study area were also detected and confirmed by the resistivity measurement. It can be concluded that the seawater intrusion has reached the north, east and southern parts of the Tanah Mas Residential area.

  22. UTILIZATION OF BANTAK AND MERAPI VOLCANIC ASH FOR POROUS PAVING BLOCK AS DRAINAGE CONTROL IN THE PRAMBANAN TEMPLE YARD Download Article

    Ahmad Rifa’i and Noriyuki Yasufuku
    • Article Type: Research Article
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    • Pages (141-146)
    • No of Download = 333

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    Ponding area occurred in the main yard of Prambanan Temple during rainfall is very bothering visitor activities. Some improvements have ever conducted but no longer effective. This paper shows the application of porous paving blocks to reduce the puddle. This porous paving block was made using waste materials from Mount Merapi eruption, such as bantak and volcanic ash. Volcanic ash was substituted for cement and bantak would replace the aggregate. Aggregate ratio used on this research is 1:5 and 0,4 for water-cement ratio. Characterization testing of porous paving block consists of density, compressive strength, porosity, and coefficient of permeability. The result shows that the optimum mixture of porous paving block is the mixture with 30% volcanic ash, strength capacity 6.05 MPa, porosity 28.4%, and coefficient of permeability 1.93 cm/s or 8 times faster than normal paving block and 18 times faster than the soil of Prambanan Temple yard. The infiltration analysis indicated that runoff level in the main yard of Prambanan Temple is 8.8 cm and ponding time is 3.2 hours. When using normal paving blocks, ponding can be reduced up to 81.6%, however when porous paving blocks was used, the ponding was not occurred because coefficient of permeability of porous paving blocks is faster than intensity rainfall at Prambanan Temple area (1.5×10-3 cm/s). From the evaluation of porous paving blocks strength against forklift load shows that total forklift load allowed to work on porous paving blocks is 9 tons’ load.

  23. ON THE CONSTRUCTION OF THE NODAL EXACT FINITE ELEMENT MODEL FOR AXIALLY LOADED PILE IN ELASTO-PLASTIC SOIL Download Article

    Chinnapat Buachart and Chayanon Hansapinyo
    • Article Type: Research Article
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    • Pages (147-152)
    • No of Download = 554

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    An iterative algorithm to construct a displacement based finite element method for analyzing axially loaded pile embedded in finite depth of elasto-plastic soil is presented. The investigation herein is conducted on the condition of shape function by which exact solutions may be reproduced at the nodal points regarding to a few number of elements. The examined shape functions which satisfy the homogeneous governing equations in elastic and plastic soil through bisection iterative algorithm are introduced to obtain the so-called exact element stiffness matrix via total potential energy principle. Numerical examples of elastostatic pile embedded in elasto-plastic Winkler foundation illustrate the accuracy of proposed element compare with conventional finite element shape functions. Axial force and displacement solutions show very good agreement with data from the available literature i.e. the exact nodal displacement solution is obtained correspond to any point load level even with a single element mesh employed.