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Journal Cover Challenge Journal of Structural Mechanics
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  This is an Open Access Journal Open Access journal
   ISSN (Online) 2149-8024
   Published by TULPAR Academic Publishing Homepage  [2 journals]
  • Cover & Contents Vol.3 No.2

    • Authors: Journal Management CJSMEC
      PubDate: 2017-06-13
      Issue No: Vol. 3, No. 2 (2017)
  • Modal response identification of a highway bridge under traffic loads
           using frequency domain decomposition (FDD)

    • Authors: Mehmet Akköse, Hugo C. Gomez, Maria Q. Feng
      Pages: 63 - 71
      Abstract: In this study, a four-span, 224m long, post-tensioned concrete box girder bridge supported on single column piers was subject to a series of controlled vehicle tests. Bridge acceleration response datasets were used to study the effect of truck speed and a sudden stop, on the modal identification of the bridge structure. Natural frequencies and mode shapes of the bridge were determined using the frequency domain decomposition technique for all datasets. The passing of the truck rendered difficult to identify the first bridge frequency. Conversely, the vehicle tests improved the identification of higher vibration modes. This is because the truck preferentially excites the bridge vertical response, which is associated with higher modes of vibrations, especially when a sudden stop of the vehicle occurs. Thus, carefully conducted vehicle-crossing tests provide detailed information about the bridge structure dynamics in the vertical direction. However, to identify lower modes, no vehicle on the bridge is preferred.
      PubDate: 2017-06-13
      DOI: 10.20528/cjsmec.2017.03.009
      Issue No: Vol. 3, No. 2 (2017)
  • Modelling of non-linear seismic ground response using elasto-plastic
           constitutive framework within a finite element soil column model

    • Authors: Azeddine Chehat, Zamila Harichane, Amina Sadouki
      Pages: 72 - 80
      Abstract: The prediction of seismic ground response is conditioned by the knowledge of each material behavior of soil deposits. The recourse to plasticity criterion to simulate cyclic behavior of soils under seismic loading is becoming more realistic. In this study, an elasto-plastic constitutive equation is cast within the framework of one dimensional finite element (FE) soil column model to account for the spatial and material nonlinearity of the secant shear modulus. To account of the spatial non linearity, shear modulus is written in terms of rigid base shear modulus and height of the soil column, while for material nonlinearity, the shear modulus degradation is deducted by the application of the isotropic evolution of the Von Misès criterion. Obtained results proved the efficiency of the proposed methodology and the predictive capability of the elaborated elastoplastic model which captures both small- and large-strain behaviors. They likewise highlight the important roles that play the spatial and material shear modulus variation in the prediction of the seismic soil responses.
      PubDate: 2017-06-13
      DOI: 10.20528/cjsmec.2017.05.011
      Issue No: Vol. 3, No. 2 (2017)
  • Flexural behavior of sustainable reactive powder concrete bubbled slab
           flooring elements

    • Authors: Ashraf Abdulhadi Alfeehan, Hassan Issa Abdulkareem, Shahad Hameed Mutashar
      Pages: 81 - 89
      Abstract: Voided slabs are reinforced concrete slabs in which voids allow to reduce the amount of concrete. The bubbled deck slab is a new and sustainable biaxial floor system to be used as a self-supporting concrete floor. The use of voided slabs leads to decrease the consumption of materials and improve the insulation properties for enhancing the objectives of sustainability. This study presents an investigation into the flexural behavior of sustainable Reactive Powder Concrete RPC bubbled slab flooring elements. Six one-way slabs were cast and tested up to the failure. The adopted variables in this study are: the volumetric ratio of steel fibers, type of slab; bubbled or solid, placing of reinforcement and thickness of slab. The effect of each variable on the ultimate load, deflection and strain has been discussed. The results show that increasing the percent of steel fibers from 1% to 2% in solid and bubbled slabs decreases the deflection by (18.75%) and (50%) respectively. As well as, the deflection increases by (41%) for bubbled slab compared to the solid slab. The slabs reinforced with top and bottom steel meshes show less deflection than slabs reinforced by only bottom steel mesh.
      PubDate: 2017-06-13
      DOI: 10.20528/cjsmec.2017.04.010
      Issue No: Vol. 3, No. 2 (2017)
  • The strain sensitivity of copper powder reinforced concrete

    • Authors: Egemen Teomete, Özkan Ayberk Kolatar, Erman Demircilioğlu, Serap Kahraman
      Pages: 96 - 101
      Abstract: Earthquakes, material deteriorations and other environmental factors challenge the structural safety. In order to protect the lives, structural health monitoring is crucial. The metal foil strain gages have low durability, low sensitivity and can get point wise measurements which are disadvantages. In this study six different concrete mixtures were designed; one without any copper powder, the rest five having different copper powder volume fractions. Three cube samples from each mixture were cast and cured. Simultaneous measurement of electrical resistance and strain were conducted during the compression tests. A strong linear relationship between strain and electrical resistance change was obtained for copper powder reinforced concrete. The results are contribution to the development of “Smart Concrete” which can sense its strain and damage.
      PubDate: 2017-06-13
      DOI: 10.20528/cjsmec.2017.02.007
      Issue No: Vol. 3, No. 2 (2017)
  • Elastic foundation effects on arch dams

    • Authors: Muhammet Karabulut, Murat Emre Kartal, Omer Faruk Capar, Murat Cavusli
      Pages: 102 - 107
      Abstract: Earthquake response of an arch dam should be calculated under ground motion effects. This study presents three-dimensional linear earthquake response of an arch dam. Thereby, we considered different ground motion effects and also foundation conditions in the finite element analyses. For this purpose, the Type 3 double curvature arch dam was selected for application. All numerical analyses are carried out by SAP2000 program for empty reservoir cases. In the scope of this study, linear modal time-history analyses are performed using three dimensional finite element model of the arch dam and arch dam-foundation interaction systems. According to numerical analyses, maximum horizontal displacements and maximum normal stresses are presented by dam height in the largest section. These results are evaluated for rigid and various elastic foundation conditions. Furthermore, near-fault and far-field ground motion effects on the selected arch dam are taken into account by different accelerograms obtained from the Loma Prieta earthquake at various distances.
      PubDate: 2017-06-13
      DOI: 10.20528/cjsmec.2017.02.006
      Issue No: Vol. 3, No. 2 (2017)
  • Cover & Contents Vol.3 No.1

    • Authors: Journal Management CJSMEC
      PubDate: 2017-03-10
      Issue No: Vol. 3, No. 1 (2017)
  • Analytical solution for bending and buckling response of laminated
           non-homogeneous plates using a simplified-higher order theory

    • Authors: Ferruh Turan, Muhammed Fatih Başoğlu, Zihni Zerin
      Pages: 1 - 16
      Abstract: In this study, analytical solutions for the bending and buckling analysis of simply supported laminated non-homogeneous composite plates based on first and simplified-higher order theory are presented. The simplified-higher order theory assumes that the in-plane rotation tensor is constant through the thickness. The constitutive equations of these theories were obtained by using principle of virtual work. Numerical results for the bending response and critical buckling loads of cross-ply laminates are presented. The effect of non-homogeneity, lamination schemes, aspect ratio, side-to-thickness ratio and in-plane orthotropy ratio on the bending and buckling response were analysed. The obtained results are compared with available elasticity and higher order solutions in the literature. The comparison studies show that simplified-higher order theory can achieve the same accuracy of the existing higher order theory for non-homogeneous thin plate.
      PubDate: 2017-03-10
      DOI: 10.20528/cjsmec.2017.02.001
      Issue No: Vol. 3, No. 1 (2017)
  • Research on relation between natural frequency and axial stress of round
           bar with intermediate-supported ends

    • Authors: Tsutomu Yoshida, Takeshi Watanabe, Kunihiko Sakurada
      Pages: 17 - 22
      Abstract: In order to make a method be useful to measure an axial stress of a member by a natural frequency, we investigated a relation between a natural frequency and an axial stress of a round bar with intermediate-supported ends, the boundary condition of which was one between a fix-supported end and a simply-supported end. To define an intermediate-supported end condition, we adopted a parameter, a ratio of a moment of a force to a deflection angle at the end. It was shown theoretically that the parameter of an intermediate-supported end could be evaluated by one at a support on a continuous beam consisted of 3 spans. The 3-spanned beam has same vibration characteristics of a beam with intermediate-supported ends. We manufactured a test device of a 3-spanned beam by which we could simulate a vibration under various intermediate-supported end conditions. The theoretical relation and experimental results between a natural frequency and an axial stress agreed for the most part.
      PubDate: 2017-03-10
      DOI: 10.20528/cjsmec.2017.02.002
      Issue No: Vol. 3, No. 1 (2017)
  • Metaheuristic approaches for optimum design of cantilever reinforced
           concrete retaining walls

    • Authors: Gebrail Bekdaş, Rasim Temür
      Pages: 23 - 30
      Abstract: An approach is presented for optimum design of cantilever reinforced concrete (RC) retaining wall via teaching-learning based optimization (TLBO) algorithm. The objective function of the optimization is to minimize total material cost including concrete and reinforcing steel bars of the cantilever retaining wall by considering overturning, sliding and bearing stabilities, bending moment and shear capacities and requirements for design and construction of reinforced concrete structures (TS 500/2000). TLBO algorithm is a simple algorithm without any special algorithm parameters. This innovative approach is providing an advantage to TLBO in terms of easily applying to the problem. The proposed method has been performed on numerical examples and the results are compared with previous approaches. Results show that, the methodology is feasible for obtaining the optimum design of RC cantilever retaining walls.
      PubDate: 2017-03-10
      DOI: 10.20528/cjsmec.2016.11.031
      Issue No: Vol. 3, No. 1 (2017)
  • Influence of blast-induced ground motion on dynamic response of masonry
           minaret of Yörgüç Paşa Mosque

    • Authors: Olgun Köksal, Kemal Hacıefendioğlu, Emre Alpaslan, Fahri Birinci
      Pages: 31 - 37
      Abstract: This paper focuses on the dynamic response analysis of masonry minaret of Yörgüç Paşa Mosque subjected to artificially generated surface blast-induced ground motion by using a three-dimensional finite element model. The mosque is located in the town of Kavak of Samsun, in Turkey. This study intended to determine the ground motion acceleration values due to blast-induced ground motions (air-induced and direct-induced) calculated by a random method. In order to model blast-induced ground motion, firstly, peak acceleration and the time envelope curve function of ground motion acceleration were obtained from the distance of the explosion center and the explosion charge weight and then blast-induced acceleration time history were established by using these factors. Non-stationary random process is presented as an appropriate method to be produced by the blast-induced ground motion model. As a representative of blast-induced ground motion, the software named BlastGM (Artificial Generation of Blast-induced Ground Motion) was developed by authors to predict ground motion acceleration values. Artificial acceleration values generated from the software depend on the charge weight and distance from the center of the explosion. According to the examination of synthetically generated acceleration values, it can be concluded that the explosions cause significant effective ground movements. In the paper, three-dimensional finite element model of the minaret was designed by ANSYS. Moreover, the maximum stresses and displacements of the minaret were investigated. The results of this study indicate that the masonry minaret has been affected substantially by effects of blast-induced ground motion.
      PubDate: 2017-03-10
      DOI: 10.20528/cjsmec.2016.12.036
      Issue No: Vol. 3, No. 1 (2017)
  • HVAC systems: measurements of airflows in small duct length

    • Authors: Clito Félix Alves Afonso
      Pages: 38 - 46
      Abstract: One of the most feasible ways to measure duct airflows is by tracer gas techniques, especially for complex situations when the duct lengths are short as well as their access, which makes extremely difficult or impossible other methods to be implemented. One problem associated with the implementation of tracer gas technique when the ducts lengths are short is due to the impossibility of achieving complete mixing of the tracer with airflow and its sampling. In this work, the development of a new device for the injection of tracer gas in ducts is discussed as well as a new tracer-sampling device. The developed injection device has a compact tubular shape, with magnetic fixation to be easy to apply in duct walls. An array of sonic micro jets in counter current direction, with the possibility of angular movement according to its main axle ensures a complete mixing of the tracer in very short distances. The tracer-sampling device, with a very effective integration function, feeds the sampling system for analysis. Both devices were tested in a wind tunnel of approximately 21m total length. The tests distances between injection and integration device considered were: X/Dh=22; X/Dh=4; X/Dh=2; and X/Dh=1. For very short distances of X/Dh=2 and X/Dh=1, semi empirical expressions were needed. A good reproducibility of airflow rate values was obtained. These preliminary tests showed that the practical implementation of tracer gas techniques in HVAC systems for measuring airflow rates with a very short mixing distance is possible with the devices developed.
      PubDate: 2017-03-10
      DOI: 10.20528/cjsmec.2016.11.027
      Issue No: Vol. 3, No. 1 (2017)
  • Universal size effect of concrete specimens and effect of notch depth

    • Authors: Sıddık Şener, Kadir Can Şener
      Pages: 47 - 51
      Abstract: The universal size effect law of concrete is a law that describes the dependence of nominal strength of specimens or structure on both its size and the crack (or notch) length, over the entire of interest, and exhibits the correct small and large size asymptotic properties as required. The main difficulty has been the transition of crack length from 0, in which case the size effect mode is Type 1, to deep cracks (or notches), in which case the size effect mode is Type 2 and fundamentally different from Type 1. The current study is based on recently obtained comprehensive fracture test data from three-point bending beams tested under identical conditions. In this test, the experimental program consisted of 80 three-point bend beams with 4 different depths 40, 93, 215 and 500mm, corresponding to a size range of 1:12.5. Five different relative notch lengths, a/D = 0, 0.02, 0.075, 0.15, 0.30 were cut into the beams. A total of 20 different geometries (family of beams) were tested. The present paper will use these data to analyze the effects of size, crack length. This paper presents a studying to improve the existing universal size effect law, named by Bazant, using the experimentally obtained beam strengths for various different specimen sizes and all notch depths. The updated universal size effect law is shown to fit the comprehensive data quite well.
      PubDate: 2017-03-10
      DOI: 10.20528/cjsmec.2017.02.003
      Issue No: Vol. 3, No. 1 (2017)
  • Non-linear behaviour modelling of the reinforced concrete structures by
           multi-layer beam elements

    • Authors: Mourad Khebizi, Hamza Guenfoud, Mohamed Guenfoud
      Pages: 52 - 57
      Abstract: A two-dimensional multi-layered finite elements modeling of reinforced concrete structures at non-linear behaviour under monotonic and cyclical loading is presented. The non-linearity material is characterized by several phenomena such as: the physical non-linearity of the concrete and steels materials, the behaviour of cracked concrete and the interaction effect between materials represented by the post-cracking field. These parameters are taken into consideration in this paper to examine the response of the reinforced concrete structures at the non-linear behaviour. Two examples of application are presented. The numerical results obtained, are in a very good agreement with available experimental data and other numerical models of the literature.
      PubDate: 2017-03-10
      DOI: 10.20528/cjsmec.2016.11.034
      Issue No: Vol. 3, No. 1 (2017)
  • Effect of time step size on stress relaxation

    • Authors: Abdullah Fettahoğlu
      Pages: 58 - 62
      Abstract: Many materials used in industry show time and temperature dependant stress strain relationship. While essentially most of the materials exhibit stress relaxation or in general viscoelastic material properties, some of them are assumed as linear elastic to be able to make their stress calculations simpler. On the contrary, there are some materials showing intense viscoelastic stress strain relationship even at lower temperatures and short time periods. Most of these materials are employed in construction industry as pavements on roads or bridges and needed a better understanding of their viscoelastic material properties and calculation methods for their design. For a better understanding and comparison between several material products in industry, their stress strain behavior shall be evaluated. Stress relaxation of materials, which shows time and temperature dependant properties, is investigated in this paper. For that reason first, relaxation test results existed in the literature are used to verify the numerical stress relaxation calculation of commercial FEM program, ANSYS. Second, the determination of Prony series parameters and the commands to be entered in ANSYS to perform stress relaxation are given. Finally, the amount of error in the numerical calculation depending on time step sizes at different temperatures is presented.
      PubDate: 2017-03-10
      DOI: 10.20528/cjsmec.2016.11.029
      Issue No: Vol. 3, No. 1 (2017)
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
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Fax: +00 44 (0)131 4513327
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