bluuebunny/crossref_metadata_2025_split huggingface dataset:
03.29: Behaviour of the short headed anchors with supplementary reinforcement
Authors: Bujnak Jan , Bujnak Jan , Farbak Matus 
Published: September 2017

ABSTRACTPrecast concrete structures are becoming very popular for many construction designers. The appropriate design and performance of structural joints are essential preconditions for durability and effectiveness of this type of structures. Headed fastenings made of rebar steel belong currently to the attractive solution for creating compact structural joints. The resistance of this type of anchors can be increased by using supplementary steel reinforcement. Our actual research and studies focused on headed fastening and supplementary reinforcement are shortly described. Then, the experimental research is discussed in the paper.
03.36: Skewed extended shear tab connections: Behavior, analysis and parametric study
Authors: Mahamid Mustafa , Hijaj Mutaz Al , Rahman Adeeb , Malhas Faris 
Published: September 2017

ABSTRACTThe objective of this study is to investigate the behavior of skewed extended shear tab connections with different support conditions: In which plate (shear tab) is welded to supporting member webs (flexible supports). And with the plate is welded to the supporting member flanges (rigid supports). The finite element analysis software ABAQUS was used to model different configurations for these connections. It was concluded that the connection orientation have significant effect on the connection torsional stability for the case with flexible supports. And there is a need to develop a unique design procedure for these connections. A parametric study was performed to develop a design procedure for skewed extended shear tab connections based on results obtained from finite element analysis for 300 models with different configurations. The variable parameters used for this study are: plate thickness, the a‐distance between the weld line and the bolt line, skewed angle, and number of bolts. These parameters were investigated in terms of the connection vertical displacement, plate twist along the bolt line, plate twist along the weld line, and the connection shear capacity. Modifications to the current connection lateral stability checks in the literature will also be addressed. The proposed design procedure on this study is specific procedure for the skewed extended shear tab connections. This procedure is compared with the current design procedure in the AISC Manual 14th edition.
04.13: Influence of closely spaced ring‐stiffeners on the axial buckling behavior of cylindrical shells
Authors: Jäger‐Cañás Andreas , Pasternak Hartmut 
Published: September 2017

ABSTRACTMaterial efficiency in modern tank constructions often is achieved by combining thin plates with light and heavy ring stiffeners. While the plates are designed to resist hydrostatic pressure, the stiffeners are designed against wind and external pressure. Axial buckling may occur due to high roof loads and wind since very thin plates are prone to a loss of stability.Test results in the 60s and 70s revealed that closely spaced ring‐stiffeners may greatly enhance the axial buckling behavior, allowing for knock‐down factors greater unity. However, until today, no design procedure is available allowing for adopting the beneficial effect of ring stiffeners under axial compression into practical design.In this paper a design procedure is proposed that closes this gap in current design codes. One outcome of the conducted literature study revealed that test results of unstiffened shells may be more closely approximated and is shortly presented. The design procedure for ring‐stiffened shells was then developed from lower bound curves deduced from categorized buckling tests.The results of a parametrical study, that was conducted over a wide range of r/t‐values, is presented. Imperfection depths up to 10t were examined using a stiffener spacing of one buckling half‐wave. Especially highly slender stiffened cylinders benefit from ring‐stiffening, showing up to 380% strength gains.Imperfection depths proposed by the current design code were found to be too conservative.
04.20: Bending of rectangular plates subject to non‐uniform pressure distributions relevant to containment structures
Authors: Brown C.J. , Goodey R.J. , Rotter J. Michael 
Published: September 2017

ABSTRACTRectangular planform silos are often used where there is need for simple construction or space restrictions. The flexibility of the flat plate walls leads to a horizontal variation in wall pressure across each wall, with much reduced pressures at the mid‐side. There is a clear and systematic relationship between the wall flexural stiffness relative to the stiffness of the stored solid and the pressure pattern on the wall which is now well proven. Since the centre of each wall is subject to significantly reduced pressures, it may be expected that the bending moments in the wall will much lower, permitting the use of a thinner wall. In turn, the thinner wall is then more flexible and leads to a further redistribution of the pressures. This paper is the first to examine the structural consequences of these pressure changes.The horizontal variation of the wall pressure is well captured by a hyperbolic form, with much reduced mid‐side pressures and raised corner pressures, characterised by a single parameter “alpha” that determines the strength of this redistribution. This parameter α is naturally dependent on the relative wall and solid stiffness. In this study, the value of α is varied between the uniform pressure condition α = 0 and a high value (α=3). The highest values occur when a stiff solid is stored in a silo with very flexible walls. Wall plates of different aspect ratio are investigated representing conditions in a square or rectangular silo.The finite element predictions show that great savings can be made in the design of these structures by exploiting the reduced deflections and reduced stresses that arise when realistic patterns of pressure are adopted. The results presented here are suitable for transformation into design rules for the Eurocode standards EN 1993‐1‐7 [1] and EN 1993‐4‐1 [2].
05.03: Weld residual stresses effects in the design of welded plate girders: Simulation and Implementation
Authors: Launert Benjamin , Pasternak Hartmut 
Published: September 2017

ABSTRACTEurocode 3 offers different possibilities on a numerically‐aided design of welded plate girders. In this, a geometrically and materially nonlinear analysis of the imperfect structure (GMNIA) provides the theoretically highest possible degree of realism. A correct implementation of “imperfections” is of critical importance in the practical application of this method. The current design rules are based on long term experience in terms of traditional (“old”) welding procedures and regular (“low strength”) steel grades. Thus, they provide very approximate (but safe) rules for these structures. With the introduction of modern shop welding operations and materials, many of these assumptions seem to be over‐conservative. A revision of these rules is being processed in different national and international research projects. This particular study focusses on the weld residual stresses and their effects in conventional steel S355 and high strength steel S690. Metal active gas (MAG) welding under shop welding conditions was used. The measurement of weld residual stresses on component‐like samples (carried out by the BAM Bundesanstalt für Materialforschung und ‐prüfung in Berlin) has been widely published. The hereupon based (simplified) welding simulation as part of a subsequent structural analysis is shown here. A novel numerical approach how to directly incorporate the results into large structural components models is presented. The capacity analysis is performed on a simple example for weak‐axis buckling. The results indicate significant improvements in the utilization of load‐bearing capacity and underline the superior buckling assignment for the S690 compared to conventional S355. The experimental validation of the findings is currently being prepared.
05.11: Local buckling behavior of octagonal hollow cross‐section member under axial compression or bending shear
Authors: Naohiro Wada , Kikuo Ikarashi , Tadayoshi Okada , Yosuke Kawabata 
Published: September 2017

ABSTRACTAn octagonal hollow cross‐section member not only permits the use of thin plate elements, but also suppresses local buckling. The purpose of this study is to clarify how the shape of the cross‐section affects the elastic buckling strength and elastic–plastic behavior under axial compression or bending shear. For this purpose, buckling analysis using the finite element method was performed to examine the shape of a cross‐section, which was changed from a square to an octagon by chamfering the four corners of the square; the chamfer width of the member was also gradually increased. The octagonal cross‐section was compared to a square cross‐section before chamfering, and to a square cross‐section with the same width‐to‐thickness ratio. The conclusions are as follows: (1) when the shape of the cross‐section was changed from a square to an octagon, the elastic buckling strength of the member increased and its plastic deformation capacity improved. (2) Assuming that a square and an octagonal cross‐section have the same width‐to‐thickness ratio by changing the chamfer width, the elastic buckling strength of the octagonal cross‐section did not always change monotonically. (3) The plastic deformation capacity was approximately equal for both octagonal‐ and square‐shaped members when their width‐to‐thickness ratios were equal.
05.16: Stability behavior of graded dented cylindrical steel shells under the action of combined external and axial pressure
Authors: Pourkhorshidi Sara , Abedi Karim 
Published: September 2017

ABSTRACTThin‐walled cylindrical steel shells such as silos, tanks and other containers are used in various applications of engineering. For economic reasons, large fluid storage steel tanks are made with varying thickness in height. Cylindrical steel shells with stepwise variable wall thickness are the most prevalent structural components in petrochemical and oil industry. However, during the construction procedure and service life, these reservoirs may be exposed to some geometrical imperfections in the form of dents. These shells are subjected to peripheral pressure loading and when a large liquid storage is discharged, an internal suction will be applied to its wall and head, causing external pressure on the wall and axial compression on the head. These structures are prone to fail by buckling under external pressure and axial compression. Previous studies show that the stability behavior of cylindrical shells under pressure load is strongly dependent on the nature and magnitude of the imperfections. Despite many studies on the buckling behavior of thin‐walled cylindrical steel shells of constant thickness, so far only a few investigations have been undertaken to examine instability behavior of these structures with thickness variation under the action of combined external pressure and axial compression, considering the dent imperfections. In this study, the effects of vertical and horizontal dents on the buckling and post‐buckling behavior of dented graded cylindrical steel shells with two and three layers under the action of a combination of peripheral and axial pressure are investigated. The models are designed in practical dimensions, with some horizontal and vertical dents in different positions. In the present study, non‐linear buckling and post‐buckling solutions of thin‐walled cylindrical steel shell with varying thickness are obtained by using ABAQUS, which is a general‐purpose finite element program designed specifically for advanced structural analysis.
05.21: Bolted steel angles in compression: Influence of realistic end supports
Authors: Kettler Markus , Unterweger Harald 
Published: September 2017

ABSTRACTFor compression members with primarily axial forces, steel angles with bolted connections are often used. Due to the eccentric connection on only one leg additional bending moments are acting on the member, leading to a complex load carrying behaviour with flexural and/or lateral torsional buckling phenomena. The paper mainly focuses on the presentation of the influence of realistic end support conditions at the gusset plates on the member capacity in compression.The compression capacity of steel angles with bolted connections according to various test results from literature, a large series of sophisticated numerical analyses and common code regulations are presented in a unified form, using the normalized slenderness about the weak axis as basis. Thus, a direct comparison of about 300 laboratory tests with numerical results for bolted angle members is possible, whereby limit cases for the stiffness of the end support of the gusset plate (rigid or hinged) are considered. The systematic conducted numerical calculations show (beside the well‐known influence of one‐bolt or two‐bolt connections) a very high influence of the end support of the gusset plate. The significant difference in the compression member capacity between clamped and hinged support of the gusset plate is even more pronounced than the difference between one‐bolt and two‐bolt connections – a state of affairs that is either not, or only insufficiently, reflected in current design code regulations.Even if the boundary conditions of the compression member are considered by using the corresponding ideal buckling capacity (based on a LBA calculation) for the calculation of, no single buckling curve seems to be appropriate to represent the load carrying capacity of the compressed member.
06.03: Dynamic increase factor for nonlinear static alternate path analysis of steel moment‐resisting frames against progressive collapse
Authors: Ferraioli Massimiliano , Lavino Angelo , Mandara Alberto 
Published: September 2017

ABSTRACTThe paper investigates the dynamic increase factor to be assumed in the nonlinear pushdown analysis of seismically designed steel moment‐resisting frames as a consequence of sudden column removal. The influence of the fundamental parameters, as well as the effect of various design variables, such as the number of stories, the number of bays, the location of the removed column and the level of seismic design load were investigated. The dynamic increase factor was estimated by direct comparison of static analysis with full nonlinear dynamic analysis. Eventually, the values obtained were expressed as a function of the vertical displacement at the location of the removed column and then compared with the GSA formulation based on the ductility factor.
07.16: On the distortional buckling capacity of pallet rack uprights
Authors: Crisan Andrei , Kraus Matthias , Handabut Andreea 
Published: September 2017

ABSTRACTIn nowadays commercial environment, the storage of goods on standardized pallets represent the standard for many companies. As a direct consequence, pallet rack storage systems have become an essential part in their intralogistics. Usual load bearing structures of storage systems consist of longitudinal and transversal frames. In longitudinal direction, along the aisle, the vertical distance between beams is varied function requirements. In transversal direction, usually the frame is a truss structure composed of uprights as chords, diagonals and struts.For the load bearing structure of pallet rack systems, the uprights represent the main elements. Following a long optimization process to increase the load bearing capacity of cold formed elements, the critical load associated with local buckling was increased by introducing folds acting as longitudinal stiffeners. This approach solved local buckling problems but created the premises for another sectional instability, i.e. distortional buckling. The stability issue is further accentuated by arrays of holes along the length of the uprights. These holes enable the user to customize the shelf height, depending on storage requirementsBased on an extensive experimental program developed within the ACTEX laboratory (https://erris.gov.ro/ACTEX), the present paper presents the findings of a numerical study conducted for a heavy load pallet rack upright profile. The aim is the identification of stabilizing stiffness needed to prevent the development of distortional buckling. Based on the numerical results, a series of preliminary solutions are proposed to restrain distortional buckling and improve the cross sectional stability of pallet rack uprights.
07.18: Cold‐formed C‐sections encased in ultra‐lightweight concrete: Development of a Eurocode‐based design method
Authors: Hegyi Péter , Dunai László 
Published: September 2017

ABSTRACTA new direction of development in the field of light‐gauge building systems is when the load bearing elements made of cold‐formed steel (CFS) sections are encased in an ultra‐lightweight material. This material, apart from heat insulation and fire protection effects, can provide bracing effect to the CFS elements, too, therefore can increase the resistance against stability failures. Such lightweight material is the polystyrene aggregate concrete (PAC). Based on previous experimental results this paper develops design method for calculating local, distortional and global resistance of PAC‐encased CFS C‐sections. The proposed design method is based on the specifications of Eurocode, therefore applies the effective width method for calculating local buckling. The proposed procedure considers the effect of continuous bracing of PAC by replacing it with an elastic half‐space, similar to sandwich beam theory. Close form equations are derived to be able to calculate the effective width of plate elements by hand calculation. Distortional buckling is treated as buckling of an equivalent beam resting on elastic foundation, considering the additional stiffness provided by the infill material. The global flexural buckling failure modes of columns are dealt with separately using different mechanical models. Each calculation procedure was compared to existing experimental results in order to evaluate them.
07.19: Geometric imperfection measurements on cold‐formed steel channels: An approach using 3D non‐contact laser scanner
Authors: Selvaraj Sivaganesh , Madhavan Mahendrakumar 
Published: September 2017

ABSTRACTA 3D non‐contact laser scanning method to quantify the deviations in cold‐formed steel (CFS) channel sections (plain and lipped) is presented. The methodologies to segregate the different categories of imperfections from the deviations in the geometry of CFS member are also presented. A total of 13 different C‐sections with varying cross‐sectional parameters totaling to 78 specimens were studied. The nature of imperfections in the CFS members was found to correlate with the geometric properties such as slenderness ratios, torsional constant and plate slenderness. The bow and camber imperfection (global out‐of‐straightness) in the members is presented with respect to the minor and major axis slenderness ratios. A new combined global and cross‐sectional parameter (J/L) was introduced against the deviation due to twist of the CFS member. To predict the imperfection magnitudes based on their geometrical properties, a new set of expressions were suggested.
07.20: Application of the compound strip method in buckling analysis of cold‐formed steel built‐up sections
Authors: Khezri Mani , Abbasi Mandana , Rasmussen Kim J. R. 
Published: September 2017

ABSTRACTIn this paper, the compound strip method is utilised and extended for the stability analysis of cold‐formed steel built‐up sections. The discrete fasteners are incorporated in the analysis such that they can be placed anywhere within the length of the member. A beam element with geometrical and material properties of the fastener is adopted to model the connection between the individual sections. The stiffness matrix terms for the connection element are derived and added directly to the global stiffness matrix of the considered built‐up sections. The proposed numerical technique is verified through various examples and the results are compared with the finite element solutions. The results obtained demonstrate that the developed technique can accurately and efficiently model the behaviour of cold‐formed steel built‐up sections. Furthermore, the influence of the fasteners properties, their longitudinal spacing and also the boundary conditions on the overall buckling behaviour of built‐up sections is examined through numerical examples. The simplicity of the proposed technique facilitates an extensive parametric study of cold‐formed built‐up sections including the search for optimal placement of fasteners and combinations of component sections in built‐up profiles.
08.02: Experimental research of multiple perfobond connectors for composite girders
Authors: Neto C. , Costa‐Neves L. F. , da S. Vellasco P. C. G. , Jordão S. , Ihaddoudene A. N. T. 
Published: September 2017

ABSTRACTExtensive research has been carried out in recent years focusing on the behaviour of innovative connectors for steel and concrete composite girders. Those elements exhibit large resistance and adequate behaviour under different load types, and at the same time are easy to fabricate and to erect on site. Among these types, the Perfobond connector or Perfobond rib, consisting of a perforated steel plate welded to the steel beam flange, has been extensively studied by numerous authors, due to its particularly convenient efficiency, behaviour and ductility characteristics.Although many connector types have been studied in the past, few studies focused on the behaviour of groups of special connectors, a typical arrangement used in conventional headed stud connectors.This paper focuses on the behaviour of multiple Perfobond connectors placed side‐by‐side on a steel girder and immersed in the reinforced concrete slab. This quite innovative arrangement enhances the resistance from a single connector classic layout, but the proximity to other connectors may significantly change the behaviour of individual connectors that interact with each other.Fourteen push‐out tests on groups of Perfobond connectors were carried out at the Civil Engineering Department of the University of Coimbra, Portugal, while this paper reports and discuss the results.The investigated variables were: the number of connectors, ranging from one (the basic arrangement) to three; the spacing between connectors; the transverse reinforcement within the connector's holes; and the concrete strength. The results are presented and discussed concentrating on the connector's structural response for shear transfer capacity, ductility and collapse modes. A comparative assessment of these properties focusing on the number of connectors and its spacing is presented and discussed, aiming at establishing preliminary conclusions about the behaviour of Perfobond groups. In addition, a brief comparison of the experimental results with existing analytical models for Perfobond connectors is also presented to establish the most convenient model for this particular geometry. Finally, some adapted models referred in the literature to cope with Perfobond groups are applied to the tested geometries and the analytical and experimental tests are compared and discussed.