for Journals by Title or ISSN
for Articles by Keywords
Journal Cover
Challenge Journal of Structural Mechanics
Number of Followers: 6  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2149-8024
Published by TULPAR Academic Publishing Homepage  [2 journals]
  • Optimum design of purlin systems used in steel roofs

    • Authors: İbrahim Aydoğdu, Mukaddes Merve Kubar, Dahi Şen, Osman Tunca, Serdar Çarbaş
      Abstract: In this study, one existing purlin system which is used in steel roof is optimized by taking into account less cost and bearing maximum load via developed software. This software runs with firefly algorithm which is one of the recent stochastic search techniques. One of the metaheuristic techniques, so-called firefly algorithm imitates behaviors of natural phenomena. Behaviors and communications of firefly are inspired by this algorithm. In optimization algorithm, steel sections, distance between purlins, tensional diagonal braces are determined as design variables. Design loads are taken into account by considering TS498-1997(Turkish Code) in point of place where structure will be built, outside factors and used materials. Profile list in TS910 is used in selection stage of cross sections of profile. Constraints of optimization are identified in accordance with bending stress, deformation and shear stress in TS648. Design variables of optimization are selected as discrete variables so as to obtain applicable results. Developed software is tested on existing real sample so; it is evaluated with regard to design and performance of algorithm.
      PubDate: 2018-06-12
      Issue No: Vol. 4, No. 2 (2018)
  • Re-examination of steel frame office buildings in preventing collapse when
           subject to intense fires

    • Authors: Robert Mathews Korol, Ken S. Sivakumaran, Paul Heerema
      Abstract: The purpose of the paper is to investigate the extent to which present-day design of steel framed buildings is susceptible to total collapse when subjected to extreme fire events. We select a 50 storey structure in which 2 and 4 adjacent storeys located at different above-ground heights are, in separate scenarios engulfed in raging fires. A total of 8 scenarios are analyzed, employing Newtonian mechanics and realistic energy dissipating properties of H-shaped columns and normal concrete floor slabs possessing secondary (shrinkage and temperature) reinforcement alone. While the present Canadian building code is the basis for our column designs, other standards provide very similar specifications. Although fire proofing is required in virtually all high rise building construction, we are excluding such materials in order to simplify the analyses, but clearly do not advocate its omission – quite the opposite in fact. As well, attributes such as floor beams, partitions and furnishings of every description, all of which would in practice participate in absorbing the kinetic energy of a crush-down upper block are excluded. Despite such a vast array of conservative assumptions, it is shown that partial collapse may occur during crush-down, however, in no case will total collapse be the consequence. These results should provide some comfort to code writers that their requirements should indeed prevent the most catastrophic of failures due to fires.
      PubDate: 2018-06-11
      Issue No: Vol. 4, No. 2 (2018)
  • Analyzing pre-stressed steel arch beams

    • Authors: Erkan Polat, Barlas Özden Çağlayan
      Abstract: Techniques are being developed day-by-day to make it possible to pass through larger openings using smaller beam-column sections. Parallel to this trend, there is another necessity to produce not only smaller but also more economical and architecturally attractive beams. The aim of this study is to explain the structural behavior of steel arch beams reinforced using post-tension cables. Due to the effect of these, the arch beam load carrying capacity increases and a smaller sized optimized section can be obtained with a better architectural view. Moreover, it also allows better mechanical and applicable solutions for buildings. For a better understanding of the behavior of the reinforced beam, a steel beam and a steel arch beam with post-tensioned cables were modeled and analyzed using the SAP2000 finite element analysis computer program and compared with each other. In addition, full-scale specimens were prepared for testing to determine the structural behavior and compare the results with those from the computer modeling, the outcome of which was very promising. The similarity between the results inferred that no extra engineering knowledge and effort are needed to design such beams. The predicted (and proved by the testing) beam bearing capacity was 35% higher than that of the unreinforced beam. With just three full-scale tests completed, it was evident that the ratio (35%) could be increased by adjusting the cable post-tension force on much smaller sized beams.
      PubDate: 2018-06-11
      Issue No: Vol. 4, No. 2 (2018)
  • Cover & Contents Vol.4 No.2

    • Authors: Journal Management CJSMEC
      PubDate: 2018-06-09
      Issue No: Vol. 4, No. 2 (2018)
  • Cover & Contents Vol.4 No.1

    • Authors: Journal Management CJSMEC
      PubDate: 2018-03-03
      Issue No: Vol. 4, No. 1 (2018)
  • Influencing factors on effective width of compressed zone in joint column
           - cylindrical shell of steel silo

    • Authors: Lyubomir Zdravkov
      Pages: 1 - 8
      Abstract: In order to ensure unloading of whole amount of stored product by gravity, steel silos are often placed on supporting structure. The simplest way to design these complicated facilities is to divide cylindrical shell on two parts in our minds - discretely supported ring beam and continuously supported shell above it. Obviously, to ensure continuously support of shell, bending stiffness of ring beam should be high. In European standard EN 1993-4-1, that concept is recognized but it keeps silence about recommended stiffness of ring beam. Another way to design is to know law of distribution of compressive axial stresses due to discrete column reactions R, by height of shell. Knowing it, we could calculate the effective width leff of distribution of compressive stresses on every level. Where effective width is equal to distance between discrete supports, there critical height of shell ends and above it cylindrical body is continuously supported. Unfortunately the above quoted standard EN 1993-4-1 does not give an information how to calculate leff. The questions here are; should we accept linear distribution of compressive forces by height' In addition, could we use directly the results of Whitmore (1952), where angle of distribution α = 30°' Or, even to accept a far more brave opinion that α = 45°, used by many of the elder designers' Moreover, is value of angle α constant or does it depend on various influencing factors'
      PubDate: 2018-03-03
      DOI: 10.20528/cjsmec.2018.01.001
      Issue No: Vol. 4, No. 1 (2018)
  • Mechanical performance comparison of glass and mono fibers added gypsum

    • Authors: Sadık Alper Yıldızel, Serdar Çarbaş
      Pages: 9 - 12
      Abstract: Gypsum and gypsum based composite are widely preferred in construction industry for various purposes. Mechanical performances of gypsum composite have been enhanced by researchers in order to increase its area of usage. In this research, gypsum composites containing expanded glass were reinforced by glass fibers (GF) and mono polypropylene fibers (MPF). GF and MPF were used up to 1.5 %. The flexural strength, compressive strength, and shrinkage behavior of the composites were examined within the scope of this study. 50 x 50 x 50 mm and 40 x 40 x 160 sized specimens were prepared for the mechanical performance tests. It was obtained that flexural and shrinkage behavior of the composite were enhanced with the addition of MPF compared to GF added mixes; however, compressive strength values were not as high as GF reinforced composites.
      PubDate: 2018-03-03
      DOI: 10.20528/cjsmec.2018.01.002
      Issue No: Vol. 4, No. 1 (2018)
  • Seismic assessment of a curved multi-span simply supported truss steel
           railway bridge

    • Authors: Mehmet Fatih Yılmaz, Barlas Özden Çağlayan, Kadir Özakgül
      Pages: 13 - 17
      Abstract: Fragility curve is an effective method to determine the seismic performance of a structural and nonstructural member. Fragility curves are derived for Highway Bridges for many studies. In Turkish railway lines, there are lots of historic bridges, and it is obvious that in order to sustain the safety of the railway lines, earthquake performance of these bridges needs to be determined. In this study, a multi-span steel truss railway bridge with a span length of 25.7m is considered. Main steel truss girders are supported on the abutments and 6 masonry piers. Also, the bridge has a 300m curve radius. Sap 2000 finite element software is used to model the 3D nonlinear modeling of the bridge. Finite element model is updating according to field test recordings. 60 real earthquake data selected from three different soil conditions are considered to determine the seismic performance of the bridge. Nonlinear time history analysis is conducted, and maximum displacements are recorded. Probabilistic seismic demand model (PSDMs) is used to determine the relationship between the Engineering Demand Parameter (EDP) and Intensity Measure (IMs). Fragility curve of the bridge is derived by considering the serviceability limit state, and results are discussed in detail.
      PubDate: 2018-03-03
      DOI: 10.20528/cjsmec.2018.01.003
      Issue No: Vol. 4, No. 1 (2018)
  • Forced vibration analysis of Mindlin plates resting on Winkler foundation

    • Authors: Yaprak Itır Özdemir
      Pages: 18 - 26
      Abstract: The purpose of this paper is to study shear locking-free parametric earthquake analysis of thick and thin plates resting on Winkler foundation using Mindlin’s theory, to determine the effects of the thickness/span ratio, the aspect ratio and the boundary conditions on the linear responses of thick and thin plates subjected to earthquake excitations. In the analysis, finite element method is used for spatial integration and the Newmark-β method is used for the time integration. Finite element formulation of the equations of the thick plate theory is derived by using higher order displacement shape functions. A computer program using finite element method is coded in C++ to analyze the plates clamped or simply supported along all four edges. In the analysis, 8-noded finite element is used. Graphs are presented that should help engineers in the design of thick plates subjected to earthquake excitations. It is concluded that 8-noded finite element can be effectively used in the earthquake analysis of thick plates. It is also concluded that, in general, the changes in the thickness/span ratio are more effective on the maximum responses considered in this study than the changes in the aspect ratio.
      PubDate: 2018-03-03
      DOI: 10.20528/cjsmec.2018.01.004
      Issue No: Vol. 4, No. 1 (2018)
  • Investigating the effect of infill walls on steel frame structures

    • Authors: Osman Fatih Bayrak, Seda Yedek, Muhammet Musab Erdem, Murat Bikce
      Pages: 27 - 32
      Abstract: Infill walls consisting of materials such as hollow concrete, hollow clay and autoclaved aerated concrete bricks are not only preferred in reinforced concrete buildings but also in steel frame structures. It is a well-known fact that infill walls limit the displacement of frames under horizontal loads. However, they may also bring about certain problems due to being placed randomly in horizontal and discontinuously in vertical directions for some architectural reasons. Moreover, cracks in frame-wall joints are observed in steel frame structures in which ductile behaving steel and brittle behaving infill walls are used together. In this study, the effect of infill walls on steel frames has been investigated. In the steel frame structure chosen for the study, four different situations consisting of different combinations of infill walls have been modeled by using ETABS Software. Later, the pushover analyses have been performed for all the models and their results have been compared. As a result of the analyses done by using the equivalent diagonal strut model, it has been found out that infill walls limit the displacement of steel frames and increase the performance of a structure. However, it has been also determined that in the steel frame structure in which the infill walls have been placed discontinuously in vertical and asymmetrically in horizontal, infill walls may lead to torsional and soft story irregularities. As a result, it is possible to observe cracks in the joints of infill walls and steel frame, the deformation properties of which differ, unless necessary precautions are taken.
      PubDate: 2018-03-03
      DOI: 10.20528/cjsmec.2018.01.005
      Issue No: Vol. 4, No. 1 (2018)
  • Effects of structural irregularities on low and mid-rise RC building

    • Authors: Hüseyin Bilgin, Rezarta Uruçi
      First page: 33
      Abstract: During the recent earthquakes, it has been observed that structural irregularities are one of the main reasons of the building damage. Irregularities are weak points in a building which may cause failure of one element or total collapse of the building during an earthquake. Since Albania is a country with moderate seismicity which has been hit by earthquakes of different magnitudes many times establishes the need to study the effect of irregularities is well-founded. The main structural irregularities encountered in Albanian construction practice consist of short column, large and heavy overhangs and soft story. In this study, these types of irregularities are considered in two different types of buildings, low and mid-rise reinforced concrete frame buildings represented by 3- and 6- story respectively. Pushover analyses are deployed to get the effect of structural irregularities on RC buildings response. A building set is chosen to represent the existing construction practice in the region; regular framed building and buildings with irregularities such as soft stories, short columns, heavy overhangs and the presence of soft story with heavy overhangs. The analyses have been conducted by using ETABS and Seismosoft software. Pushover curves of building set are determined by nonlinear static analysis in two orthogonal directions. Comparative performance evaluations are done by considering EC8 and Albanian Seismic codes (KTP-N2-89). From the obtained results, it is observed that low and mid-rise structures with soft story- two sided overhangs and short column are more vulnerable during earthquakes.
      PubDate: 2018-04-19
      DOI: 10.20528/cjsmec.2018.02.001
      Issue No: Vol. 4, No. 1 (2018)
  • Performance based study on the seismic safety of buildings

    • Authors: Zinnur Çelik, Ahmet Budak
      First page: 45
      Abstract: In the scope of this study, information has been provided on the Static Pushover Analysis which is a nonlinear deformation controlled analysis method and the Capacity Spectrum Method used to determine the performance point. In this study, static pushover analysis was made on a six-storey building with reinforcement concrete frame system by changing the materials, steel rebars and soil characteristics. The building’s capacity curves were drawn and decided according to different concrete and reinforcement groups. Furthermore the performance points of different classes of concrete were studied according to three seismic effect levels. In the case of a decrease in the reinforcement strength, a decrease of approximately 30% occurs in the base shear force. If the concrete strength is increased, an increase of 11% occurred in the base shear force. Consequently, in the comparisons made with five different concrete groups and two different reinforcement groups, rather than the increase in the strength of the concrete, an increase in the reinforcement strength was observed to be more effective on the structural capacity. Furthermore, local soil classifications were observed to be the most significant point regarding peak displacement.
      PubDate: 2018-02-23
      DOI: 10.20528/cjsmec.2018.02.002
      Issue No: Vol. 4, No. 1 (2018)
  • Use of geosynthetics to reduce the required right-of-way for roadways and

    • Authors: Niyazi Özgür Bezgin
      First page: 54
      Abstract: Roadway and railway routes require a right-of-way (ROW) to provide the necessary width for the required travelled way, drainage and earthwork. Correct understanding of ROW along a route is necessary in order to establish a correct width for the intended transportation corridor. Availability of land becomes scarce and cost of land increases in urban zones. Therefore, the costs of establishing a ROW in rural areas and in urban areas are not the same. Earthworks are an important component of route establishment. The required excavations and fills necessitate the use of proper side slopes for the stability of the excavation or the fill. These side slopes directly relate to the mechanical properties of the soil and the depth of the earthwork. This study provides a quantitative and a qualitative understanding of the ROW requirements of roadways and railways and the influence of the earthworks on the determined values of the ROW. The study further investigates the benefits of using geogrids to reduce the necessary ROW for a transportation route through finite element analysis.
      PubDate: 2018-05-25
      DOI: 10.20528/cjsmec.2018.02.003
      Issue No: Vol. 4, No. 1 (2018)
  • Eigenvector and eigenvalue analysis of thick plates resting on elastic
           foundation with first order finite element

    • Authors: Yaprak Itır Özdemir
      First page: 61
      Abstract: The purpose of this paper is to study free vibration analysis of thick plates resting on Winkler foundation using Mindlin’s theory with first order finite element, to determine the effects of the thickness/span ratio, the aspect ratio, subgrade reaction modulus and the boundary conditions on the frequency parameters of thick plates subjected to free vibration. In the analysis, finite element method is used for spatial integration. Finite element formulation of the equations of the thick plate theory is derived by using first order displacement shape functions. A computer program using finite element method is coded in C++ to analyze the plates free, clamped or simply supported along all four edges. In the analysis, 4-noded finite element is used. Graphs are presented that should help engineers in the design of thick plates subjected to earthquake excitations. It is concluded that 4-noded finite element can be effectively used in the free vibration analysis of thick plates. It is also concluded that, in general, the changes in the thickness/span ratio are more effective on the maximum responses considered in this study than the changes in the aspect ratio.
      PubDate: 2018-05-25
      DOI: 10.20528/cjsmec.2018.02.004
      Issue No: Vol. 4, No. 1 (2018)
  • Structural features of cold-formed steel profiles

    • Authors: Osman Tunca, Ferhat Erdal, Arif Emre Sağsöz, Serdar Çarbaş
      First page: 77
      Abstract: Using capacity of cold-formed steel sections increases thanks to the opportunities which are offered by the developing technology. Low production cost and variety of profiles that can be produce easy, fast, high quality provide to improve its popularity as a structural material. In production, Sulphur and Phosphorous accumulation region occurs at intersection region of flanges and web of hot rolled steel profile. This causes to decrease strength of profile. Other difference between cold-formed and hot rolled steel sections is that mechanical properties of steel material homogeneously distributes throughout the profile. Both in frame and truss systems, cold-formed steel profiles develop both as main and secondary bearing element. These present variety options to the designers with pure, galvanized, aluminized applications. As with many building materials, mechanical behavior of cold-formed steel profile is quite complex due to the nature of thin walled steel sections. Design and analysis methods of cold-formed steel profile are rapidly shaped day by day. The general theory of beams investigated in past studies make possible analyses of cold-formed steel profile. Moreover, in structural systems, using of cold-formed steel profile provide height strength besides sustainable, environmentalist, green building because it requires less material and cost. Although these profiles have many advantages, use of cold-formed steel profiles in our country structures is rather limited unfortunately. New steel construction regulations in Turkey also do not mention cold-formed thin walled steel structure. Main purpose of this study reviews structural specifications of cold-formed steel profiles which are applied world-wide.
      PubDate: 2018-06-02
      DOI: 10.20528/cjsmec.2018.02.005
      Issue No: Vol. 4, No. 1 (2018)
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
Home (Search)
Subjects A-Z
Publishers A-Z
Your IP address:
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-