فهرست مطالب

Asian journal of civil engineering - Volume:14 Issue:3, 2013
  • Volume:14 Issue:3, 2013
  • تاریخ انتشار: 1391/10/25
  • تعداد عناوین: 10
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  • D. Tavakoli, A. Heidari M. Karimian Page 369
    A large bulk of ceramic tiles change into wastage, these waste materials are not reusable and recyclable due to their physical and chemical structure. Given the high amount of concrete production and the possibility of wastage materials in them, using ceramic wastage could be an effective measure in maintaining the environment and improving the properties of concrete. The present experimental study deal with the investigation of possibility of using waste ceramic tile in concrete. To do so, first, the characteristics of ceramic aggregate are measured and then being grind they are used in concrete as the substitute for coarse aggregates with 0 to 40 percent of substitution and also for sand with 0 to 100 percent of substation. Besides, all other parameters are constant. Finally the slump value, compressive strength, water absorption, and the unit weight of concrete for the samples were calculated. The findings revealed that generally using waste ceramic tile lead to enhancing the properties of concrete.
    Keywords: Waste ceramic tile, aggregate, concrete, compressive strength, water absorption, sustainable development
  • S.M. Zahrai, A. Zare, M.K. Khalili, A. Asnafi Page 383
    A fuzzy controller is designed in this paper for semi-active tuned mass damper to decrease seismic vibration of buildings. To reach a more desirable performance, the upper stories of an 11-story structure are used as mass damper, i.e. in the first stage the top story, and in the next stage the upper two stories are used as mass damper. The structure analyses are performed for uncontrolled, passive control and semi-active control cases and in each case, maximum displacement, RMS displacement of the stories and RMS base shear are compared. Moreover, applied damping coefficient and damping force are investigated in each case. The results show that the proposed semi-active tuned mass damper decreases the structural displacements where more desirable results can be obtained with smaller structural damping. By adopting top story as mass damper, the reduction of peak displacements is more than 35% and by designating the two last stories as mass damper, this reduction will exceed 55%.
    Keywords: Semi, active control, tuned mass damper, multi–story building, seismic response, fuzzy controller
  • V. Bhikshma, G. Annie Florence Page 397
    In the present paper, an investigation is made to study the effect of maximum size of aggregate in higher grade concrete using high volume fly ash. Three different mixes of M50 grade concrete were designed using graded coarse aggregate of three maximum sizes of10mm, 12.5mm and 20mm. And for each mix, cement was replaced with fly ash at 0%, 10%, 20%, 30%, 40% and 50% (%replacements). All the mixes were cured for 56 days and tested for compressive strength, flexural strength and splitting tensile strength. The test results obtained have suggested that the maximum size of coarse aggregate in M50 grade concrete at various replacement levels of fly ash was 12.5 mm aggregate and optimum replacement of fly ash was 30%. The percentage increase was 20% for compressive strength, 20% for splitting tensile strength and 5% for flexural strength when comparedto the design strength.
    Keywords: Maximum size of aggregate, high volume fly ash, replacement, high
  • B. Kondraivendhan Page 405
    In this study, compressive strength and flow behavior for rice husk ash incorporated cement paste and mortar are investigated. The workability is ensured through Marsh cone and flow table tests for rice husk ash blended cement paste and mortar respectively. The test result shows that compressive strength increases with age as expected in all cases and an empirical relationship for compressive strength of blended cement paste and mortar with mix factors such as w/(c+rha) ratio, rha/c ratio and age is also proposed. The estimated compressive strength versus w/(c+rha) ratio curves follows the similar nature of Abrams’ strength versus w/c ratio curves.
    Keywords: Paste, mortar, RHA, workability, strength
  • Zs. RÉmai Page 417
    The experiences of embankment settlement measurements and the correlation of CPT resistance and deformation properties of soft Holocene clays are discussed in this paper. Embankment settlement measurement results of nine different sites have been studied, the significant parameters have been defined, and the deformation properties have been back calculated. The correlation between the determined deformation properties (Eoed, E50) and the obtained CPT results are evaluated and an empirical coefficient α is determined for each test. The scatter of this coefficient is determined and a formula is proposed to obtain more reliable α values for the studied Holocene clays.
    Keywords: Deformation properties, oedometer modulus, embankment settlement, CPTu, empirical correlation
  • M. Grigorian Page 429
    Performance control (PC) is a new design philosophy that aims at rational and efficient selection of structural members rather than probing their usefulness through iterative proceses. The basic notion behind PC is that structural response is mainly a function of design and detailing, rather than numerical analysis. PC is a design approach in which the properties of the structural elements are selected in accordance with predetermined performance related objectives, such as limiting displacements at first yield and/or at incipient collapse, rather than compared against arbitrary criteria. PC procedures result in highly predictable structural behavior and economically efficient designs for the class of regular, space frames considered in this paper. Neither irregular boundary conditions nor non-uniform loading have been addressed in this paper. The proposed methodology is suitable for both manual as well as spreadsheet computations. The applications of the proposed solutions have been illustrated through a number of generic examples.
    Keywords: Space structures, regular grids, performance control, plastic design, displacements at failure, load sharing
  • S. Rajagopal, S. Prabavathy Page 445
    Generally reinforced concrete exterior beam-column connections joint core are detailed with conventional standard 900 bent hooks for longitudinal beam reinforcement anchorages as per ACI 318, IS 456. Joint are detailed without confinement in seismic zone-II, with confinement in seismic zones-III to V as per IS 13920. This results in congestion of reinforcement in the joint core, concrete placement difficult at site. A potential solution for these problems with significant improvement in the seismic performance, strength, ductility,stiffness and lesser cracks ware observed by using mechanical anchorage as per ACI 35 in combination with additional X- cross bars plus hair clip joint reinforcement for zone-III to V and in combination with X-cross bars for zone-II. To evaluate the performances of these types of anchorages and joint details, the specimens assembled into four groups, each group having three specimens were tested under reversal loading.
    Keywords: Beam, column connection, ductility, stiffness, crack, mechanical anchorage, reversal loading
  • S. Esmaeili Niari, B. Rafezy, K. Abedi Page 461
    Shear wall panel as one of the primary lateral load resisting components, has been extensively used in lightweight framing of low and mid-rise residential constructions. In this paper, the shear resistance of cold formed steel stud walls with single sided steel sheathing has been investigated under monotonic loading by finite element analysis. The numerical modelling of shear wall taking into account geometric large deformation and material nonlinearity has been conducted using finite element method. The results obtained from FEM have been verified against the available experimental results. Using finite element analysis, parametric study is carried out considering height-width ratio of wall, stud and sheathing thickness and screw spacing in order to obtain the shear carrying capacity of the wall. The numerical results have shown the good seismic performance of cold formed steel stud walls with steel sheathing.
    Keywords: Shear resistance, cold formed steel, shear wall, steel sheathing, finite element analysis
  • A. Thirumurugan, M. Sivaraja Page 477
    This paper investigates the workability and mechanical strength properties of the high strength concrete reinforced with two different industrial waste fibres. Locally available steel lathe waste and nylon waste were used at different volume fractions as fibre cocktails in concrete. Steel lathe wastes were used in as received lengths and nylon fibres were chopped in to 40 mm lengths. In total, 12 hybrid mixes were cast and tested at four different volume fractions i.e., 0.5%, 1.0%, 1.5% and 2.0%. The experimental programme used the slump test and the air content test on the fresh concrete. The hardened concrete was tested for its compressive strength, split tensile strength and modulus of rupture. All the mechanical properties of the different mixes were enhanced due to the hybrid nature of the fibre cocktails. Out of all the mixes, the hybrid mix at 2% volume fraction with a combination of steel ½ + nylon ½ gives the best performance.
    Keywords: Fibre reinforcement, mechanical properties, industrial waste
  • H. Mirzaei Alavijeh, E. Farzanegan, F. Sinaeian, P. Karimi, M. Mirsanjari Page 487
    During this year, 329 accelerograms were recorded by 196 accelerographs, which were triggered by 176 earthquakes with different magnitudes. The Reygan earthquake of 2 th December 2010 in Kerman province was the greatest earthquake in this year that triggered 24 accelerographs. The maximum PGA of about 0.61g was recorded in Koohezar station on August 27, 2010 earthquake.
    Keywords: Accelerogram, accelerograph, earthquake, strong motion, peak ground acceleration