bluuebunny/crossref_metadata_2025_split huggingface dataset:
11.54: A proposal to improve the seismic behaviour of eccentrically braced structures
Authors: Köber Helmuth , Stoian Marina 
Published: September 2017

ABSTRACTThe present paper is intended to relieve the behaviour under severe seismic actions of some eccentrically bracing systems equipped with additional vertical connection elements (vertical truss elements between the ends of all dissipative members that are not connected directly to columns) compared to the seismic behaviour of traditional eccentrically bracings. Each considered structural type (with and without additional vertical truss elements) was subjected to three dynamic nonlinear analyses using Vrancea earthquakes acceleration records.The values of different parameters recorded during nonlinear analyses were compared: extreme base shear forces, maximum plastic deformations in the dissipative members, greatest member forces in different structural elements, extreme horizontal floor displacements. The amount of dissipated energy and the estimated steel consumption for each considered frame was analyzed.
11.64: Seismic behaviour of steel Chevron bracing systems by non‐linear dynamic analyses
Authors: Faggiano Beatrice , Formisano Antonio , Castaldo Carmine , Canicattì Luca , Landolfo Raffaele , Mazzolani Federico Massimo 
Published: September 2017

ABSTRACTThe paper focuses on steel Chevron concentric bracing systems (CBF‐V) as seismic resistant structures, presenting the evaluation of the structural seismic performance through dynamic analyses, aimed at improving the design methods.A wide numerical study is carried out. Different CBF‐V configurations are designed, for a total number of 12 structures, by varying number of storeys (3, 6, 10), design methods (linear and dynamic analysis) and braces sections (H‐shaped and circular hollow sections). Nonlinear Incremental Dynamic Analyses (IDA) are performed by the SeismoStruct software, considering 7 earthquakes records, in order to investigate the seismic response. The most relevant evaluation parameters are shown and discussed, IDA curves are caught and the behavior factors calculated. Results show that expected collapse modes, involving the braces only, according to the Capacity Design, are not in agreement with the noted mechanisms, in which damage also involves non‐dissipative elements, in particular the beams. Hence, it is needed to deepen such key issue, through further experimental and numerical investigations in order to optimize the design procedure.
11.65: An axial type self‐centering energy dissipation device with shape memory alloy for seismic mitigation
Authors: Li Ran , Shu Ganping , Liu Zhen , Lyu Xiao , Chen Meihe 
Published: September 2017

ABSTRACTServe earthquake often cause large deformation to structures which might deteriorated or degraded seismic performance level. Installing shape memory alloy (SMA) dampers to the structure is one of the most effective approaches to mitigate earthquake disasters. The mechanical behaviour of superelastic Ni‐Ti shape memory alloy wire is tested and a multi‐linear constitutive model which appropriately describes and elucidates the mechanical property and material characteristics is obtained by simplifying the hysteretic response. A new axial type SMA damper with energy dissipation and self‐centering property is proposed. The structure, the design method, the working principle and the model of the recovery force are introduced. The energy dissipation capacity and the self‐centering property are examined by low cyclic loading processes. Both the two properties reach an excellent effect. The result indicate that SMA has a great potential to be used in structures to mitigate seismic displacement response and improve the self‐centering performance of structures.
11.67: Cyclic backbone curves for steel wide‐flange columns: A numerical study
Authors: Ozkula Gulen , Harris John , Uang Chia‐Ming 
Published: September 2017

ABSTRACTExperimental and analytical studies on the cyclic behaviour of deep, slender wide‐flange steel beam‐columns funded by the National Institute of Standards and Technology (NIST) is ongoing at the University of California at San Diego (UCSD). In parallel with full‐scale column tests, numerical simulations of columns under monotonic and cyclic loading conditions were conducted to generate a wide‐ranging database of results. A correlation study using results from the full‐scale tests was conducted to validate the numerical simulation procedure. The simulated columns covered a wide range of cross‐sectional (local) and member (global) slenderness ratios, axial force level, and yield stress. Regression analyses were conducted to construct moment‐rotation responses, ‘backbone curves’, for use in performance‐based evaluations of steel moment frames. The database is divided into three groups based on observed buckling modes. Computational expressions for the key parameters that define the backbone curves are presented.
I.11.61: Full scale tests on moment‐resistant‐frames under cyclic loading
Authors: Avgerinou Stella , Lignos Xenofon , Thanopoulos Pavlos , Vayas Ioannis 
Published: September 2017

ABSTRACTThree large scale tests on two‐story Moment Resistant Frames (MRF) under cyclic loading were conducted in the Laboratory of Steel Structures of NTUA in the frame of the RFCS‐supported project MATCH. Selected joints of the frames were formed with Reduced Beam Sections (RBS), in order to achieve plastic hinge formation away from the welded connections and the heat affected zones. In addition, holes were drilled in the flanges in order to study the crack initiation and crack propagation under large plastic deformations.The experimental set‐up consisted of a rigid test rig frame providing horizontal support to the hydraulic actuator, a base girder on which rested the test frame and a supporting frame, which prevented the out‐of‐plane movement of the test frames. The base girder was attached to the test rig so that no net horizontal force was transferred to the ground. The experimental set‐up was anchored to the Laboratory's strong floor. The test frames were simply supported on the base girder.The test frames were designed with weak beams and strong columns. The beam–to–column joints were realized with all‐around fillet welds. In the two‐bay frames the beams of a selected joint were designed with RBS near the connection regions while the rest of the connection regions were locally reinforced with stiffeners and beam haunches in order to ensure plastic deformation would occur in the selected joint. In the one‐bay frame all beams were designed with RBS sections towards the joints. The distance of the RBS sections from the column faces as well as the geometry of the flange reduction was specified in accordance with the provisions of EN 1998–3.The tests were performed under displacement control using a computer controlled hydraulic actuator. A cyclic load of increasing amplitude was applied according to ECCS provisions while the maximum interstory drift reached was approximately 5%.The actuator's force was applied through a vertical spread beam, which ensured that the load was applied in an inverted triangular pattern, in accordance with the anticipated seismic forces.In the present paper, the design of the test specimens and the experimental set‐up is described in detail, and the preparation and results of the experimental investigations are presented.
12.06: Numerical analysis of stainless steel, concrete encased and carbon steel double skin tubular stub columns
Authors: de Araújo Raphaella Oliveira , de Lima Luciano Rodrigues Ornelas , da Silva Vellasco Pedro Colmar Gonçalves , da Silva André Tenchini 
Published: September 2017

ABSTRACTThe use of stainless steel as formwork for concrete columns provides several benefits for the structure, including the high corrosion resistance, durability, fire resistance, ease of maintenance and high aesthetic value. The use of composite systems in columns has been a major breakthrough in bridges and viaducts. A particular advantage of the composite columns is the reduction of cross sectional area, speed of construction, easy maintenance and material saving when compared to conventional reinforced concrete structures. These advantages are related to the idea that the columns are concrete filled eliminating the use of forms and the need for extra steel reinforcing bars. The investigated system adopts a second carbon steel tube inside the primary stainless steel tube composing the structural system made of concrete‐filled double skin composite tube columns (CFDSCT). This study aims to develop numerical models, using the finite element method and considering geometric imperfections. The structural behaviour was assessed through a nonlinear analysis and was later compared to compressive tests performed in the laboratory. After the completion of the numerical models calibration, a parametric analysis was performed to investigate the influence of parameters like the diameter, thickness and height of the stainless steel tube (outer) while its results were also compared to predictions made by traditional design equations.
12.07: Numerical assessment of stayed austenitic steel columns
Authors: Ribeiro Danielle M. , da S. Vellasco Pedro C. G. , de Araujo Ricardo R. , de Lima Luciano R. O. , da Silva André T. 
Published: September 2017

ABSTRACTThe use of prestressed steel stayed columns systems in construction has numerous advantages related to its light weight, load bearing capacity and assembly process flexibility. A practical application of these structural systems could be recently observed in Brazil for the erection of the Rock in Rio III world stage. In this event the use of prestressed stayed carbon steel columns were used for temporary shoring, optimizing the erection sequence. The main stage had a 82 meters span with a 40 m clear height and a 4500 m2 area. Two stayed column were used, both with a 20 m length. Up to the present the majority of investigations of these stayed systems have been focused on carbon steel columns. In view of these facts the present paper aimed to present an investigation of the structural behaviour of columns made with the austenitic stainless steel. Numerical models were developed in the Ansys software, focusing on the structural system load carrying capacity and the optimal level of prestress to be used. The optimal level of prestress to be used was also determined considering the influence of initial imperfections. The results confirmed that the use of prestress in the cables significantly enhance the ultimate loads and ductility capacity of the columns.
12.09: Weathering steel – 30 years of experience in Banedanmark
Authors: Holmstrøm Peter , Nielsen Mogens G. , Cero Dritan 
Published: September 2017

ABSTRACTBanedanmark has used weathering steel for more than 30 years and has gathered unique information about corrosion of weathering steel during this period. Not only has the corrosion rates been noted – but also the good and poor detailing. The conclusions of this will be given in this paper. Based on the information gathered from the tests, a method for estimating the corrosion lifetime for the specific type of structure is given.Since 1986 weathering steel has been widely used on the Danish rail network for overhead line equipment structures such as masts and frames etc. As these structures now represent a very large investment to the owner of the rail net, it is crucial to follow if the expected lifetime from design is valid.These structures are based on a ‘standard‐design’ developed by Ramboll in the mid 80ti'es. At that time the knowledge on how weathering steel would behave on these specific structures was limited, hence a test‐programme was carried out from 1988 to 1994, in order to verify the corrosion rate in general, along with the suitability of the design philosophy of details. This test‐programme was carried out using designated test‐masts that was located along the rail track at selected locations.After seven years of studying the test‐masts, the test‐programme was stopped, as these results indicated that the required service life would be met. And there was not observed any critical items on the detailing used.Now, after almost 30 years of service, the designated test‐masts are still available, and as results from the first test‐regime indicated some conservatism in design assumptions, it might be the case that the existing structures can be considered safe beyond the original design life of 50 years.To investigate this further a pilot test‐has been carried out, to check if the test‐regime is still suitable for gathering new information after almost 30 years of exposure. This initial test showed that it might be possible to increase the expected service life from 50 to perhaps 80–100 years of existing structures.In addition it was evident that the design philosophies of details are suitable for long time exposure. It even indicated some conservatism in the philosophy of detailing too.The tests have gathered unique knowledge of how mast structures for overhead lines of weathering steel behaves after long time exposure.
12.12: Influence of welding on mechanical properties of high strength steel butt joints
Authors: Chen Cheng , Zhao Ming‐Shan , Fung Tat‐Ching , Chiew Sing‐Ping , Lee Chi‐King 
Published: September 2017

ABSTRACTIn view of the fact that welding thermal cycle could adversely affect the mechanical properties of heat affected zone (HAZ) for quenched and tempered (QT) high strength steel (HSS) due to the transformation of microstructures, experiments were conducted to find out the correlation of welding heat input, hardness, microstructure and the tensile strength of HSS butt joints. Two S690 QT HSS butt joints were welded with 8mm thickness plates by shielded metal arc welding (SMAW), and 3.2mm and 5.0mm diameter electrodes were employed to achieve the conditions of different heat inputs. During welding, the thermal cycles near the weld bead were recorded by thermocouples. After the welding, the test specimens were cut out from the welded joints. Then, coupon tests were carried out to measure the tensile strength of joints. In addition, hardness tests and microstructure observation of HAZ on the well‐polished specimens were conducted. The test results reveal that a soft layer was generated in the fine grain heat affected zone (FGHAZ) with a lower hardness value. Eventually, it affects tensile strength of S690 QT HSS to some extents. Additionally, it was also found that increase of heat input leads to longer cooling time and consequently higher degree of HAZ softening.
13.10: Angles connected by one leg in tension
Authors: Može Primož 
Published: September 2017

ABSTRACTThe paper deals with bolted connections of angles connected by one leg subjected to tension force. These connections are characterized by the eccentricity of the tension force and are dealt with in the EN 1993‐1‐8 standard that provides the design resistance for block tearing, for bolt bearing and for reduced effective net cross‐section that is based on β factors. A closer look on the design resistance of the reduced effective net cross‐section shows that the calculation of β may lead to inconsistencies. An addition of a bolt may lead to decrease of the net cross‐section resistance. Moreover, the formulas for the calculation of the reduced net cross‐section resistances are only a different presentation of the formulas for the block tearing resistance. Analysis of 631 test results from literature shows that the calculation of the block tearing resistance is sufficient and that equations 3.12 and 3.13 of EN 1993‐1‐8 are redundant. The study will also show that a constant distribution of stress on the tension face may be assumed in the formula for the block tearing resistance of the angles connected by one leg in tension (eq. 3.9, EN 1993‐1‐8), similarly to the provisions in American standard AISC 360–05. A modified bolt bearing strength function is also presented and statistically analysed on 631 test results. It is simpler and less conservative than the one in EN 1993‐1‐8.
13.14: Seismic assessment and strengthening of existing steel moment‐resisting frame buildings: the European EC8‐3 and current challenges
Authors: Araújo Miguel , Macedo Luís , Castro José Miguel 
Published: September 2017

ABSTRACTIn Europe, the revision of part 3 of Eurocode 8 (EC8‐3), which is the part of the Eurocodes that specifically addresses the seismic assessment and strengthening of existing structures, has been set as a first priority in the preparation of the new generation of Eurocodes that are expected to be released in 2020. However, and although EC8‐3 has been the focus of extensive research in the case of existing reinforced concrete buildings, very few works focused on the seismic assessment of existing steel buildings. The aim of this paper is hence to provide a discussion on the applicability of EC8‐3 to steel moment‐resisting frame (SMRF) buildings, to highlight the code main limitations and inconsistencies and present new steps taken forward in order to overcome them. Various issues regarding the definition of the performance requirements, the feasibility of using the most common linear methods of analysis, the adequacy of the code deformation capacity limits for steel members, the treatment of uncertainty and the influence of modelling approaches, are herein discussed. In brief, this work intends to present to the scientific and structural engineering community the current limitations of EC8‐3, to identify topics in need of future research and to disseminate new findings achieved by the authors.
14.04: Temporary steel structures: for strengthening of a large excavation for new metro in Sofia
Authors: Partov Doncho , Petkov Milen , Matuski Vladimir , Zhelev Dimo 
Published: September 2017

ABSTRACTThe topic of this paper relates to the projects, forming the conception design and technology of construction of the temporary steel structures used for strengthening of deep excavations for Sofia metro Line – 1 Extension Project from Sveta Nedelya Square to Vassil Levski Stadium. The excavation is supported by R.C. wall and pilot, which are additionally supported to keep vertical position by steel frames. The temporary steel construction is analysed as a frame structure using FEM in the light of robustness structures theory. The steel frames is from hot‐rolled section in the range from HEB 300 to HEB1000, doubled and situated along the whole perimeter of the frame.
14.06: Beam‐to‐column joints, column bases and joint components under impact loading
Authors: Demonceau Jean‐François , Vanvinckenroye Hélène , D'Antimo Marina , Denoel Vincent , Jaspart Jean‐Pierre 
Published: September 2017

ABSTRACTRecent events such as natural catastrophes or terrorist attacks have highlighted the necessity to ensure the structural integrity of buildings under exceptional events. For more than 10 years, the University of Liege is strongly involved in researches on the response of structures further to such exceptional events through participations to national or European research projects.In particular, the University of Liege has contributed very recently to a European research project entitled ROBUSTIMPACT investigating the behaviour of steel or steel‐concrete composite building structures subjected to impact loading and proposing simplified procedures to predict the response of such structures under the considered scenario.As a contribution to this research project, an experimental test campaign was realised in Liège; the objective was to study the behaviour of beam‐to‐column joints, of column bases and of most of their constitutive components under impact loading and, in particular, to highlight the influence of the strain rate effects on the response of the studied joints and components.The proposed paper first describes the conducted test campaign with all the required details about the tested specimens and the testing setup; then the analysis of the so‐obtained experimental results is presented. Finally authors’ views on how to account for the strain rate effects in analytical approaches for joint design is briefly expressed.
15.04: Parametric study on steel beams with fin‐plate joints under falling floor impact
Authors: WANG Hao , TAN Kang Hai , YANG Bo , PENG Jing 
Published: September 2017

ABSTRACTDuring the past decade, many quasi‐static tests were conducted on structures against progressive collapse. As a typical testing method, middle‐column‐removal scenario was used in most studies. It should be noted that another important scenario, i.e. falling floor impact, may also cause progressive collapse. In this paper, a series of numerical analyses was carried out to study the dynamic behaviour of steel beams subjected to falling floor impact. Fin plate connections were used to connect the beam and the columns. 3‐D finite element models (FEM) were established by ANSYS/LS‐DYNA and validated against experimental data. Good consistency was shown between experimental tests and numerical analyses. By using the validated finite element models, four parameters including strength of material, impact load, impact location and inertia effect were studied. High strength materials were beneficial to enhance the impact resistance in the falling floor impact scenario. Higher impact velocity can slightly improve the capacity of energy dissipation. For location of falling impact, it was more critical if the hammer dropped onto the joint region compared to the mid‐span region. The inertial effect should be considered in the impact analyses because it significantly decreased the maximum vertical displacement of specimens.
00.06: Advances and development needs in the structural design of steel box girders for major bridges
Authors: Polk Henrik , Walker Chris 
Published: September 2017

ABSTRACTMajor cable‐supported bridges with a span exceeding 600m would not normally be feasible without a steel box girder to carry the traffic load. These box girders generally comprise a structural steel deck plate stiffened longitudinally by open or closed ribs and transversely by diaphragms. The stiffened deck plate supports the local wheel load and distributes it to the diaphragms from where it is transferred into the box girder. The stiffening ribs also increase the total cross‐sectional steel area and thereby contribute to the overall bending capacity of the box girder and finally, the stiffeners increase the resistance of the plate to buckling.This type of deck structure is generally called an “orthotropic bridge deck” due to the orthogonal nature of the stiffened deck plate and was first developed and utilised in 1950. The orthotropic steel deck is considerably lighter than a concrete slab in a composite girder and therefore makes longer span bridges possible, by reducing the self‐weight forces that would otherwise dominate. The self‐weight of the girder is a key driver in major bridge designs since it must be carried by all other bridge components, such as cables, towers, anchorages and foundations. The orthotropic steel girder is usually a fully closed box girder with all stiffening ribs placed inside the girder giving a smooth outer surface that is easy to paint and maintain. The interior of the closed box is often dehumidified without being painted giving an environmentally‐friendly fabrication that is safe to operate and maintain.However, the orthotropic steel deck is highly prone to fatigue meaning that the number of passing lorries, their axle/wheel configuration and total vehicle weight have a significant impact on the bridge deck design and fatigue life. The orthotropic deck therefore has higher fabrication costs when compared to conventional steel structures due to the high‐quality steel manufacturing and welding procedures that are necessary to achieve the required fatigue performance.The overall layout of an orthotropic bridge deck is basically unchanged since the 1960s, however the detailing has been refined considerably to a level where it is now seems difficult to improve it much further. However, the introduction of new materials e.g. sandwich steel deck structures in combination with new welding or gluing techniques could push box girder designs to new heights.