bluuebunny/crossref_metadata_2025_split huggingface dataset:
08.09: Design of cold‐formed steel composite flooring systems with partial shear connection
Authors: Kyvelou Pinelopi , Gardner Leroy , Nethercot David A. 
Published: September 2017

ABSTRACTRecently conducted research has shown that the development of composite action within systems comprising cold‐formed steel beams and wood‐based floorboards is feasible, leading to substantial improvements in structural performance. Based on the findings from a numerical investigation into the degree of interaction that may be achieved and the resulting benefits that may be obtained by treating the floor as a composite system, proposals for the design of such systems have been devised. At the core of the proposals is the calculation of the attained degree of shear connection and the shear bond coefficient of the system − as a function of the properties of its components and connectors – leading to accurate predictions of moment capacity and flexural stiffness. The method, which has been developed based on the fundamental concepts of current design methods employed in Eurocode 3, Eurocode 4 and Eurocode 5, provides practical and accurate design rules for cold‐formed steel composite floors, which are suitable for incorporation into future revisions of the Eurocodes.
08.31: Analysis of the load transfer between materials in composite concrete encased steel columns loaded axially
Authors: Grzeszykowski Bartosz , Szmigiera Elżbieta Danuta 
Published: September 2017

ABSTRACTThe analysis of the load distribution between steel and concrete parts of the composite concrete encased I‐shaped steel columns subjected to short‐term axial load is presented. The variable parameters were: two loading conditions − load scheme I (specimens loaded through the entire cross‐section simultaneously), load scheme II (specimens loaded only through the steel profiles protruded from the top end) and concrete class (C25/30 and C40/50). Obtained in the experiment longitudinal strains of both steel and concrete were used to compute the force transferred through the steel and concrete parts of the columns. To provide a reference level for the discussion on the results the analytical solution assuming the perfect bond between steel and concrete, Hooke's law for steel and the Rüsch formula for unconfined concrete were used. The force for which the stress in steel and concrete computed using the strain readings obtained from the experiment starts to deviate from the full bond analytical model predictions can be interpreted as the force for which the loss of adhesive bond occurs. Furthermore on the basis of the equilibrium of the infinitesimal cross section of a column, method for estimating the shear stress at which the debonding occurs is shown. The analysis showed that for columns under the load scheme I composite action of steel and concrete is in effect for the entire load range regardless of the concrete class. For elements under the load scheme II the composite action of both materials is in effect only up to a specific value of the force that changes along the height of the column. Presented method can be applied to composite steel‐concrete columns under any configuration of boundary conditions subjected to axial compression. Moreover it can be used to specify the area for which the shear connectors should be provided, to validate constitutive models of shear stress – slip behaviour that can be used is FEM analysis and to analyse adhesive bond properties also in columns made of another materials, for example reinforced concrete members strengthened with FRP sheets.
08.43: Composite effect of binding frames installed inside composite mega column (more than 1m in width)
Authors: Kang Ji‐Su , Ju Jeong‐Su , Hwang Seul‐Ki , Park Yong‐Pil , Yom Kyong‐Soo , Choi Sung‐Mo 
Published: September 2017

ABSTRACTComposite columns are increasingly used due to the construction of super‐tall buildings and large‐scale buildings. Studies on the shapes of and construction technologies for structural members using steel tubes are being conducted actively. Welded built‐up CFT columns previously developed and commercialized by the authors of this study (ACT‐1 columns) are structurally stable and economically efficient. However, the 1m limit in the width of the columns and their small interior spaces impose a difficulty in installing reinforcing materials and thus deteriorate the ease and efficiency with which they are constructed. This study suggests placing thick plates at the centers of the surfaces of the existing ACT‐1 column and installing a binding frame (binding frames) at the central thick plates to enhance the integrity and resist lateral pressure caused by concrete casting. Finite element analysis was conducted with the variables of the number and cross‐sectional size of the binding frame and the cross‐sectional size of the steel tube to estimate the structural behavior of the steel tubes. Hydraulic tests were conducted to analyze load‐displacement relations and identify the influence of the binding frames on the relations. The variables in the tests were the number and cross‐sectional size of the binding frame, welding details, column joint and the cross‐sectional size of the steel tube.
08.47: Experimental study of cross‐section shape and infill influence on CFST stub columns subjected to axial load
Authors: Hernández‐Figueirido David , Ibañez Carmen , Piquer Ana , Martínez‐Ramos Óscar 
Published: September 2017

ABSTRACTIn this paper, the results of an experimental campaign on 12 concrete‐filled steel tubular (CFST) stub columns subjected to concentric load are presented. Different cross‐section shapes are considered in this campaign, i.e. oval, circular, square and rectangular as well as different types of concrete infill, i.e. normal, high strength or ultra‐high strength concrete, in order to study their effect on the ultimate capacity of the columns. Besides, the influence of the steel tube wall thickness is also analysed by including in the tests specimens with thin‐wall tubes, whose behaviour needs to be studied in depth.The experimental program is designed so as all the tested specimens have equivalent cross‐sectional area in order to extract consistent conclusions. The ultimate capacity of each specimen is registered during the tests and a comparison of the shape effect based on this parameter is accomplished. Finally, the dependency of the failure modes on the cross‐sectional shape and type of infill of the specimens is carried out.
09.03: Size effect of as‐welded and post‐weld treated construction details under fatigue loading
Authors: Dürr André , Bucak Ömer , Roth Jakob 
Published: September 2017

ABSTRACTFor the typical construction detail of the transverse stiffener is only given a geometric influence for the length of the welded stiffeners for fatigue design in the as‐welded state in the current version of Eurocode 3 part 1–9. A size effect for the plate thickness is not considered, although numerical calculations with the notch stress concept have shown that an influence of wall thickness is given. For the post‐weld treatment method “High Frequency Mechanical Impact Treatment” (HFMI) the known design recommendations are based only on experimental research programs with maximum plate thicknesses of 30mm. Hence, due to missing fatigue tests it is unknown if in addition a size effect for thick‐walled profiles should be considered for this typical construction detail in the fatigue design.Therefore an extensive research program analyzing the size effect of thick‐walled profiles subjected to fatigue loadings for typical welded construction details was performed at the University of Applied Sciences Munich [1]. In the framework of the experimental research program fatigue tests on specimens with plate thicknesses up to 100mm on the construction detail of the transverse stiffener especially for high strength steel grades (HSS) were conducted. Besides investigations on specimens in the as‐welded state, the effect of the post‐weld treatment method HFMI was examined. Within this paper the results of this research program on the construction detail transverse stiffener is summarized and a conclusion regarding the size effect for thick‐walled profiles in the fatigue design for this detail is given.
09.04: Fatigue behaviour of the closed rib to deck and crossbeam joint in a newly designed orthotropic bridge deck
Authors: Wu Weijian , Kolstein Henk , Veljković Milan , Pijpers Richard , Vorstenbosch‐Krabbe Jos 
Published: September 2017

ABSTRACTOrthotropic decks are widely used in large span and movable steel bridges and the design is dominated by fatigue resistance. Closed rib to deck welded joints in the orthotropic decks are sensitive to fatigue loads and a number of fatigue cracks are reported in bridge inspections. For the design of new bridge decks, thicker deck plates are proposed for reducing stresses in fatigue sensitive locations like the conjunction of the deck plate, rib and crossbeam. Compared to the joints in span, the variation of stress at the crossbeam is larger due to the high stress concentration near the weld root. In this study, fatigue tests are carried out on a full‐scale orthotropic deck segment to study the initiation and propagation of fatigue cracks in the deck plate. Trapezoidal stiffeners are welded to a 20 mm thick deck plate and different welding methods are used in manufacturing the specimen. Various load levels are applied on the deck plate by hydraulic jacks. The strain gauges are attached both at the top and bottom of the deck plate in the vicinity of the expected crack paths. The strain history and distribution of strain ranges at the characteristic sections are analysed. An ultrasonic method, time‐of‐flight diffraction, is used to inspect the sizes of the cracks after testing. Comparison of the number of cycles that corresponds to a crack propagation is given in the hot spot S‐N curve figure. With a failure criterion of 10% strain range deviation, the fatigue strength scatter of the 20 mm thick deck plate is similar to that of the 12 mm deck.
09.05: Remaining fatigue life of steel railway bridges: Improved models for considering realistic behaviour
Authors: Kugler Paul , Unterweger Harald 
Published: September 2017

ABSTRACTMany steel railway bridges will reach the end of their scheduled design service life within the next years. One can also observe some bridges, considerably younger than their scheduled design service life, with insufficient remaining fatigue life and rarely cracks in structural elements. Mostly because of the early applications of the welding technology and sometimes insufficient consideration of fatigue effects, e.g. neglecting of high local secondary stresses. It is a great challenge and very expensive, if a couple of bridges have to be replaced in a short period. Therefore, it is important to have models for realistic fatigue verification to extend the service life.The focus of this paper is to show different approaches – both on the load and the resistance side – to verify an extended service life of steel railway bridges. For example, the big potential of the use of real, measured stress spectra is presented, instead of the common approach according to the Eurocode. In addition, the application of the consequent Miner's rule results in another significant reduction of equivalent stress ranges for application of the fatigue strength curves of the Eurocode.Furthermore, the simplified and conservative assumptions regarding the fatigue resistance in conventional assessment procedures according to the Eurocode (nominal stress approach) are compared with alternative concepts for typical welded joints. For example, the geometric (hot spot) stress concept, the effective notch stress concept and fracture mechanics. The Eurocode already allows the use of the geometric stress concept, but gives little guidance. The practical implementation of these concepts is shown for a representative detail of a steel bridge, considering a variety of geometries.Fracture mechanics approaches are state of the art in mechanical engineering, but still relatively uncommon in civil engineering. These concepts allow for the explicit consideration of real or assumed “non‐detected” flaws or cracks in the component, thereby eliminating the need of an exact knowledge of the past load history, up to the considered defect size. It is shown that the fracture mechanics concept is suitable for steel bridges to determine the remaining fatigue life of critical details.Finally, a multilevel framework is presented to give guidance for engineers to evaluate the service life of a specific steel railway bridge.
09.10: Shear damage evaluation of bolted steel joints
Authors: Ribeiro João , Santiago Aldina , Rigueiro Constança 
Published: September 2017

ABSTRACTThe purpose of this study is to address a way of predicting the ductility capacity of steel joints. Recent research studies show that a joints’ ability to perform under elevated deformations, without fracturing, is a key factor in enabling mechanisms preventing collapse to be developed, and thus, improve the overall robustness of steel framed structures. This theme is becoming rather timely as building owners and insurers try to assess the collapse risk of their buildings, and the probability of a wide spread collapse if subjected to extreme events, either due to natural or terrorist causes. However, regarding this matter, current design code guidelines are limited to a prescriptive approach, by recommending a nominal tying force to be met, or quantifying a force that reproduces accidental scenarios, such as an impact of a vehicle, ships or helicopters, which do not address the overall behavior and performance of the structure.This paper presents an evaluation of the shear damage state of a bolted steel joint. For that, it is necessary to establish the shear damage parameters that are required to numerically obtain the rupture of steel elements, allowing the prediction of the ductility of steel joints. Previous authors’ research has showed that a ductile damage model may be insufficient to capture its end‐plate fracture and to establish a joints’ rupture. Hence, this study looks forward to improve the damage threshold for smaller triaxial stress states, within the shear and compression zones.In order to achieve this objective, a finite element model is developed and compared with real scale test results of a bolted steel joint under bending. The numerical model takes into account the strain softening of the material by means of a continuum damage mechanics approach and making use of the “element deletion” technique to approximate the fracture pattern of the studied joint. The analyses are carried out using the finite element software ABAQUS.
09.12: Assessment of old mild steel structures related to brittle fracture
Authors: Sieber Lars , Stroetmann Richard 
Published: September 2017

ABSTRACTIn the safety assessment of old mild steel structures the verification of sufficient material toughness is important for the decision on necessary repair and reinforcement measures. Based on extensive fracture mechanics investigations the assessment methods in DIN EN 1993‐1‐10 [1] were developed. The determination of permissible element thickness for certain steel grades was derived and tabulated for welded structures made of steels according to DIN EN 10025 with predominantly high toughness's. This simplified method is not suitable for mild steel structures with holes for riveted or bolted joints. In this article, experimental and analytical studies of the brittle fracture behaviour of structures with holes made of old mild steel are presented. The results were carried out through various research projects at the Institute of Steel and Timber Construction of the Technische Universität Dresden and its cooperation partners (see, e.g. [2]).The main topics are extensive material analyses to determine the fracture toughness in the brittle‐ductile transition region according to the Master Curve concept. The evaluations confirm that different grades of steel can be defined depending on the manufacturing process. Additionally, the newly obtained results will be compared to those from previous studies and existing correlations of impact and fracture toughness are checked for their suitability for old mild steels. Furthermore, the analysis of mechanical properties and metallography on components with punched holes to analyse the crack initiation of quasi‐static stressed components made of old mild steel are described.
09.16: Edge clamping effect on the fatigue resistance of an orthotropic steel bridge deck
Authors: Van Bogaert Philippe 
Published: September 2017

ABSTRACTOrthotropic steel decks are an excellent solution for long span bridges, except if the spreading of wheel loads through the pavement is poor. In the latter case they are heavily sensitive to fatigue cracking. The most critical locations of fatigue cracks are the connection of longitudinal stiffeners to the deck plate and the cutouts and cope‐holes in the webs of the transverse stiffeners. OSD with variable depth are seldom used, since the idea contradicts with one of the main assets to limit the bridge deck depth. However, in few cases variable depth may be meaningful as in the case of a railway bridge across river Dyle, recently built in Mechelen (Belgium). This 50 m span bridge consists of 2 lateral stubs of 1.55 m diameter connected by the OSD. The tubes are slightly bent to foster arch thrust action and rotated towards the bridge axis. In addition, the arch springs are encased in the concrete abutment. Due to this arrangement, the crossbeams are partially clamped in the lateral tubes of high torsion stiffness. The effect of the end clamping of crossbeams reduces the tension in the lower part of the crossbeam web, also near the outer cope holes, where the largest stress concentrations occur and fatigue resistance is the lowest. The reduction of the magnitude of these stress concentrations is significant and depends on the crossbeam span. However, the effect disappears if the crossbeam web is higher, thus confirming it is due to bending tension of the crossbeams. In addition, the influence length of crossbeams has been verified in the case of river Dyle bridge and complies well with Eurocode.
10.05: Experimental investigation on ferritic stainless steel post‐fire mechanical properties
Authors: Ho Wing Kei , Huang Yuner 
Published: September 2017

ABSTRACTStainless steel has been increasingly applied in construction applications due to its mechanical, aesthetic and environmental advantages. Strength and stiffness reduce significantly when steel members are exposed to fire. However, previous researches have shown that part of strength and stiffness can be recovered after steel material is cooled down to room temperature. Understanding the post‐fire behaviour of stainless steel is necessary before its application to construction. Ferritic stainless steel, embedded with the advantages of high strength, good corrosion resistance and relatively low cost, has a great potential to be widely utilized as a construction material. Hence, an experimental investigation has been conducted to investigate the post‐fire mechanical properties and effects of cooling rates for ferritic stainless steel of type EN 1.4003. The experimental program consists of 34 coupon specimens, including 4 non‐fire‐exposed coupons and 30 heat‐treated coupons. The designed temperature of heat treatment is ranged from 24°C to 1000°C with the chosen cooling methods as cool‐in‐air, cool‐in‐air‐with‐fan and cool‐in‐water. A heat soak time of 20 minutes is selected for every round of heating. The influence of elevated temperatures and cooling methods on the post‐fire mechanical properties is presented in this paper. Mechanical properties of Young's modulus, yield strength, ultimate strength, strain at ultimate strength and Ramberg‐Osgood parameter obtained from test program are reported.
10.14: Fire design method for eccentrically loaded concrete‐filled steel tubular columns based on interaction diagrams
Authors: Espinós Ana , Albero Vicente , Ibáñez Carmen , Romero Manuel L. , Hospitaler Antonio 
Published: September 2017

ABSTRACTIn this paper, a simplified design method for evaluating the fire resistance of eccentrically loaded concrete filled steel tubular (CFST) columns is presented. The developed method is based on the results of an extensive parametric analysis conducted in the framework of the RFCS European Project FRISCC (Fire resistance of innovative and slender concrete filled tubular composite columns) and is currently being evaluated by the Working Group SC4.T4 for its approval as the method to replace the current Annex H in EN1994‐1‐2, which was proved in previous investigations to be unsafe for slender columns.The method presented in this paper is based on the provisions of Clause 6.7.3.6 of EN 1994‐1‐1 for room temperature design, using bending moment – axial force interaction curves specially built up for the fire situation. These interaction curves are obtained by considering several possible positions of the plastic neutral axis within the cross‐section, and determining the internal forces and moments from the plastic stress blocks, which results particularly challenging for CFST sections subjected to elevated temperatures, given the thermal gradient that occurs within the cross‐section. For simplifying this process, equivalent temperatures are proposed, which allow using a single uniform temperature for representing each part of the composite section. Appropriate coefficients are also proposed for evaluating the effective flexural stiffness for second‐order analysis at elevated temperatures. The influence of the cross‐section shape, load eccentricity and percentage of reinforcement is accounted for in the proposal.
10.28: Fire performance of concrete filled steel tubular columns with built‐in stirrups
Authors: WU Bo , ZANG Jian‐bo , Zhang Qiang 
Published: September 2017

ABSTRACTTwo concrete filled steel tubular columns with built‐in stirrups (i.e., Specimens 1 and 2) and one control column (i.e., concrete filled steel tubular column without built‐in stirrups, Specimen 3) were exposed to the ISO834 standard fire, and fire behaviors of the three columns were investigated and compared with each other. The steel usage of Specimen 1 (2) (i.e., total weight of the steel tube and stirrups) was the same as that of Specimen 3 (i.e., weight of the steel tube). The distance between the stirrup's centerline and inner surface of the steel tube was 20mm for Specimen 1, and 50mm for Specimen 2. The height and outer diameter of all the three columns were, respectively, 3800mm and 320mm. The axial load applied to Specimens 1 and 2 was identical with that applied to Specimen 3. Test results show that when the steel usage keeps unchanged, the fire endurance of the concrete filled steel tubular column with built‐in stirrups is much longer than that of the column without built‐in stirrups. Finally, a finite element analysis (FEA) model was developed and verified against the experimental results, and a parametric study has been preliminarily performed to reveal the fire performance of the concrete filled steel tubular columns with built‐in stirrups.
10.31: Simplified analytical determination of the temperature distribution and the load bearing resistance of slim‐floor beams
Authors: Braun Matthias , Zaganelli Dario , Hanus Francois , Obiala Renata , Cajot Louis‐Guy , Peirce Anthony 
Published: September 2017

ABSTRACTThis contribution presents an analytical method to determine the distribution of temperature within a steel section integrated into a concrete slab, which is subjected to a time‐dependent heat flux. The method developed is based on an analytical solution of the general heat equation for transient conduction simplified to be usable for the calculation of the load bearing resistance of the slim‐floor beam. This simplified analytical solution is validated by comparison against results obtained from numerical simulations. A possible extension of the developed method to fire protected sections is given.