bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fatigue Failure of runway beams due to wheel loads
Authors: Citarelli Sandro , Feldmann Markus 
Published: September 2019

ABSTRACTThe introduction of the Eurocode 3 led to a significantly stricter fatigue classification, especially for flange to web connections of runway beams of heavy duty cranes compared to former national design rules like DIN 4132. At present, this leads to a doubling of the cross‐sectional thicknesses, which e.g. can result into web plates with extreme thicknesses of 80 mm. Execution as well as monitoring of such flange to web connections using full penetration tee‐butt welds are quite critical and thus no longer to be realized reasonably.On this account new fatigue strengths for the runway beam specific fatigue detail “Top flange to web junction of runway beams” in EC3‐1‐9 Table 8.10 have been established within the FOSTA‐research project “Fatigue failure of runway beams due to wheel loads in heavy smeltery cranes” as recommendations for an eventually modification or even extension of the current codes. In Particular, the detail executed using full penetration tee‐butt welds has been investigated in the framework of this research project.The essential core of the methodical approach is that real existing crane runway girders have been examined, documented and evaluated in regard of fatigue failure of the flange to web connection. In this way, a direct quantitative assessment of safety against fatigue failure for the investigated detail could be derived. In addition, synthetic notch cases have been investigated numerically. The results of both methodologies have been prepared for a proposal of amendment of the current codes. This paper provides an insight into the methodological approaches and the main results achieved.
Temperature distribution of trapezoidal sheeting in fire
Authors: Cábová Kamila , Lišková Nikola , Arha Tesfamariam , Malaska Mikko , Alanen Mika , Mela Kristo , Pajunen Sami , Wald František 
Published: September 2019

ABSTRACTTrapezoidal sheeting has been used for stabilizing steel members for a long time. In recent years several documents which include the comprehensive theoretical background and design guidelines for practice have been published. ECCS published the design recommendations including an example of considerable cost savings in steel constructions when sheeting is used for stabilization. However, these documents did not cover the fire limit state.The study presented in this paper is aimed at stabilization of steel members through the trapezoidal sheeting in fire. The papers describes four full‐scale fire tests carried out on a horizontal furnace for fire resistance testing. The test specimens were assembled from a fire protected steel beam and trapezoidal sheeting. The profile of the steel beam was a HEA 160 (S355) in two of the tests, and a RHS 150×150x8 (S420) in the remaining tests. Two different profiles of the trapezoidal sheeting were used during the tests.Experimental testing was conducted to determine the temperature fields in trapezoidal sheeting and in the supporting structural steel sections as well as in the connectors with special attention given to the temperatures at the joint above the steel beam section.The results of the tests show that at the failure of the specimens the screw temperatures were between 720°C and 780°C. The screw temperatures were lower than the temperature of trapezoidal sheets but higher than the temperatures of the top flanges of fire protected steel beam.The results of the tests provided experimental data for the critical variables related to building stabilization in fire through the cladding systems which is under investigation of RFCS project STABFI.
Repeated loading and unloading of steel material in fire
Authors: Shakil Saani , Lu Wei , Puttonen Jari 
Published: September 2019

ABSTRACTThe effects of permanent strains on the use of a group of stress‐strain curves defined at different temperatures for modelling the steel material under repeated loading and unloading in fire are studied using finite element (FE) method. As a benchmark test for numerical simulations, experimental results received from the literature for a restrained beam exposed to fire including heating and cooling stage are used. The behaviour of both statically determinate and indeterminate steel members are studied using Abaqus/Explicit solver. The mechanical response of the studied members are well predicted based on the assumptions made for the modelling of steel materials in the design‐fire considering the cooling stage. However, the results highlight the need for further studies of modelling the behaviour of steel material subjected to temperature oscillations as in the case of travelling fires.
Experimental study on temperature distribution of sandwich panel joints in fire
Authors: Malaska Mikko , Alanen Mika , Cábová Kamila , Lišková Nikola , Mela Kristo , Pajunen Sami , Wald František 
Published: September 2019

ABSTRACTPrevious research have demonstrated that significant cost savings can be achieved, if cladding panels forming the building envelope are used to provide stability. There is research information and design guidance available for normal temperature design. However, the information available for fire conditions is very limited and it is not known if the panels are able to stabilize steel frame members also at elevated temperatures. The stiffness and resistance of joints, cladding panels and connectors are required for the assessment of interaction between cladding and frame in fire. Temperatures of those components are in important role when evaluating the stabilization effect. This paper presents an experimental research conducted to determine the temperature fields in sandwich panels, supporting structural steel members and screw connectors. Eight full‐scale fire tests were carried out where the structural steel sections supporting sandwich panels were exposed to ISO 834 fire attack on three sides. The test specimen consisted of a fire protected steel beam and load‐bearing sandwich panels with both mineral wool and polyisocyanurate (PIR) core. Two different steel beam sections were used in the tests: HEA 160 (S355) and RHS 150×150x8 (S420). This paper introduces the experimental research and the main observations related to the temperatures. The results show that at failure of the specimens the measured screw temperatures were very different in HEA and RHS tests. The temperatures in HEA tests were much higher than in RHS tests the maximum difference in screw point temperatures being over 400°C. In all the specimens, screw head temperatures were very low throughout the tests, well below 100°C. The tests were part of ongoing RFCS project STABFI.
Experimental Study of Welding Effect on S690Q High Strength Steel Butt Joints
Authors: Chiew S.P. , Cheng C. , Zhao M.S. , Lee C.K. , Fung T.C. 
Published: September 2019

ABSTRACTIn this study, welding effects on grade S690Q high strength steel butt joint are investigated experimentally in terms of microstructure, micro‐hardness, and tensile behaviour. Three butt joints with 16 mm thickness are fabricated with reheated, quenched and tempered S690Q high strength steel (HSS) plates by using Shielded Metal Arc Welding with different welding heat inputs. Post‐welding microstructure transformation is revealed in base material, coarse‐grained heat‐affected zone (CGHAZ), fine‐grained heat‐affected zone (FGHAZ) and tempering zone. It is found that the main microstructure of S690Q high strength steel is tempered martensite. After welding, the microstructure is transformed to granular bainite in CGHAZ and to ferrite & cementite in FGHAZ. While, in tempering zone, some temper martensite decomposed to ferrite. Then, micro‐hardness tests performed for the butt joints confirmed the existence of a soft layer within the HAZ due to the microstructure transformation. The HAZ width increased when higher welding heat input is adopted. Subsequent coupon tensile tests showed that all the welded joint fractured within the HAZ. The tensile strength of the butt joints deteriorated with the increase of the welding heat input since the soft layer became bigger in HAZ.
Prediction of ultimate resistance by application of damage theory with special regard to HSS
Authors: Schaffrath Simon , Feldmann Markus 
Published: September 2019

ABSTRACTIt is a general question as to whether the established rules for predicting ultimate resistance under global tension can also be applied to structures made from HSS, i.e. up to = 960 MPa. Apart from the welding issue, for the base material, this question refers to several items, e.g. the plastic flow curve, the yield stress level, the yield ratio, the upper‐shelf ductility and strainability and the lower‐shelf toughness. It reveals that predicting the ductile fracture of steel components can only be an approximation, and neither allows for a deeper understanding of the real ductile crack development up to ultimate load nor leads to a realistic extrapolation if high‐strength steels are used. The research work presented therefore suggests an innovative extension of the FEM analysis by implementing appropriate damage mechanics based failure criteria. After an introduction to the principles of this methodology, possibilities for its use in structural steel research and design as well as further insights into the structural behaviour of steel components, especially HSS up to S960, are presented – insights that are not possible by traditional testing or simulation.
Shell Structures Made of Curved Sandwich Panels: Assessment of the Load‐Bearing Capacity
Authors: Grimm Sören , Lange Jörg 
Published: September 2019

ABSTRACTLightweight constructions made of sandwich panels became well established for roof and wall claddings of industrial structures. Due to their good heat insulation, their excellent weight to load ratio and high load‐bearing capacity as well as the economical manufacturing and erection process, sandwich structures are build frequently. Besides the mentioned advantages the linear manufacturing process of sandwich panels usually limits the possible building cubature to rectangular shapes. In an interdisciplinary project, architectural, civil engineering and mechanical engineering institutes of Technische Universität Darmstadt are working on a design concept building shell structures with linear manufactured curved sandwich panels.A preliminary study indicates that arched sandwich beams have a high potential regarding the load‐bearing capacity. The comparison between arched and single span sandwich beams shows that, even for asymmetric loads, resulting stresses in the two‐hinged arches are significantly lower than in the related simply supported single span beams.To verify the results of the numeric study full‐scale tests on curved sandwich panels will be performed. Furthermore, an assessment of the load‐bearing behavior of the panels joints loaded with axial forces is planned. Based on the results further numeric studies will be conducted to investigate the behavior of whole shell structures following the developed design principle by taking into account realistic load cases for exemplary building applications, giving special attention to asymmetrical loads.Moreover, further research regarding the requirements for supporting structures as well as for the connection between the shell structure and the supporting structure is necessary to take into account the high axial forces, which are not common in sandwich structures.
Loss of prestress in spiral strand guy ropes in masts
Authors: Koppány Susanna 
Published: September 2019

ABSTRACTIt's known since long that guy ropes in masts lose prestress over time. In many cases this leads to increased utilization of the mast. The problem is usually solved by regularly retightening the guys. The cause of the loss of prestress is not entirely clear, but guys in masts exposed to frequent and large vibrations, seem to be the most affected.Lately at manufacture, the guys undergo a number of large load cycles, thereby enabling the threads to get relocated and tightened in the spiral strand guy rope, in order to reduce the loss of prestress. Certificates describe the load cycles, strains and calculated Young's Modulus during this process. Apparently Young's Modulus doesn't only vary with the load range, but it also differs when loading and unloading. All together this means, when unloading the guy during a large enough load cycle, it will not completely regain its previous length, but instead gain a small remaining elongation.By being exposed to large vibrations in masts, guys can be elongated, something that in this paper is referred to as an explanation for the loss of prestress.This paper presents an analytical model, describing the loss of prestress over time in a guy, exposed to large vibrations in a mast. Prestress measurements from mast inspections also show consistency with the model.Based on three prestress measurements of a guy, carried out with a minimum of a few years interval, the model offers an efficient strategy for choosing when to retighten, or estimating if the expected loss of prestress is small enough not to require adjustment. In addition, the model offers guidelines for choosing guy dimension and initial prestress, in order to actively reduce the loss of prestress and extend the time between retightenings.
Replacement of two 320m masts in Sweden
Authors: Holmstrøm Peter , Nielsen Mogens G. , Lindgren Ola 
Published: September 2019

ABSTRACTThrough the recent three years Teracom in Sweden have replaced two 320m guyed masts to new masts that are designed by Ramboll. Whilst the old mast in both projects was built in the 1960s and primary served as support for FM/TV broadcasting antennas, the background for the replacement is significant different. One mast was exposed from a fatal sabotage, where it was succeeded to have the new mast in service less than one year from this date. The other mast is placed in an area that experience heavy ice formation on a yearly basis and has been replaced due to a lack of fatigue capacity.The new masts have been designed by a full dynamic model, accounting for the local climatic conditions in respect to wind, ice, guy rupture and including maintenance‐free tuned liquid sloshing dampers at the top. For the guy ropes separate foundations have been designed; either gravity based or anchored into the bed rock where applicable. The design has been optimized with respect to the use of materials and particularly in respect to logistics and site work.As the major roll‐out of this type of masts generally went on some years ago, this paper will present some of the issues when designing and building 300m masts to current standards, including some of the specific challenges on the two projects. Topics from installation will also be described. In both project the existing mast (or what was left of it) was kept in service while building the new at less than 20m distance
Numerical and experimental investigation of simply supported steel beams under drop‐weight impact tests
Authors: D'Antimo Marina , Latour Massimo , Jaspart Jean‐Pierre , Demonceau Jean‐François 
Published: September 2019

ABSTRACTDue to the increase in terroristic attack and catastrophic events, the engineering structures are more and more likely to be subjected to abnormal loading conditions. Moreover, exceptional and unpredictable fatalities (extreme wind actions, explosions, car impacts…etc.) could lead to dreadful consequences, such as the partial or total progressive collapse of the structures. In view of this, it is required for engineers and researchers to have a better knowledge of all the phenomena associated to such exceptional loadings on structures.The behaviour of structures under impact, which is the main topic of the present paper, is a complex phenomenon and the response of a structure depends on a large number of variables such as the sensitivity of the materials to high rates of deformation, imperfection of the system, type and velocity of the impacting body among others.The present paper presents the behaviour of simply supported beams under impact loads. In particular, nine drop‐weight impact tests have been performed at different level of impact energy. Within the proposed paper, the experimental impact tests conducted on simply support beams will be first presented. Then, exploiting the power of FEM analyses performed using the commercial software Abaqus/CAE© and validated against experimental evidences, different modelling techniques, along with several material models, are examined and compared. From these results, the ability of a detailed FE modelling to predict the response of impacted beams, when a proper modelling of the material behaviour at high rate of deformation is ensured, is discussed and a first estimation of the dynamic increase factor (DIF) for beam under impact loadings is given.
The influence of joint modelling on the seismic design of steel frames
Authors: Chesoan Adriana , Stratana Aurel , Jakaba Dominiq , Dubina Dan 
Published: September 2019

ABSTRACTJoints play an important role in design and performance of steel structures. Recently, two European projects, EQUALJOINTS (1) and EQUALJOINTS+ (2), addressed seismic prequalification of four types of moment resisting beam‐to‐column joints: extended end‐plate joints with haunches, stiffened and unstiffened extended end‐plate joints and dog‐bone joints. Beam‐to‐column joints with haunches are frequently employed by structural engineers in seismic design of steel moment resisting frames. Their large stiffness and strength allows coping with stringent drift limitation requirements and avoiding experimental validation of partial‐strength/semi‐rigid ones requested by Eurocode 8 (EC8). In current design practice, when modelling steel frames, the finite size of the joints is often neglected for the reasons of simplifying the task. The present paper examines the potential benefits of explicitly modelling beam‐to‐column joints with haunches in structural analysis, and aims at identifying possible simplifications of the structural model, accounting the advantages, but, at the same time, keeping the model as simple as possible. Two types of steel structures are addressed within this study: moment resisting frames and dual frames combining moment resisting frames with eccentrically braced frames. The two configurations are designed and their seismic performance is assessed, using different modelling approaches.
Determination of Effective Breadth Width of Steel Plate‐Stiffener Based on Nonlinear FE Analysis
Authors: Erkmen Bulent , Kilic Burak Talha 
Published: September 2019

ABSTRACTSteel plate‐stiffener systems are widely used in civil engineering applications especially for offshore and onshore oil and gas production facilities as blast walls and blast resistant steel modular structures, and in naval and aerospace engineering applications. Such structures are typically designed based on effective breadth width concept, which enables designer to estimate behaviour of the structure by use of simple beam theory. Although, most of design guidelines for breadth width are based on several idealized steel plate behaviour, the actual behaviour of steel plate is much more complex due to nonlinear 3D stress distribution and stress transfer between the stiffeners and plate. In this study, three prototype blast wall structures were designed with varying plate thickness and stiffener properties. The walls nonlinear behaviour including force‐deflection and longitudinal stress distribution through plate thickness and along plate width were investigated under out‐of‐plane static loading. The longitudinal stress distribution at different stress levels (i.e., elastic and several plastic levels) was used to determine effective breadth width. In addition, computed force‐deflection curves of walls and corresponding simple beams with different breadth widths were compared to verify computed breadth widths. The outcomes of this study indicate that computation of effective breadth width is much more complex and highly depends on stress levels and relative stiffness of plate and stiffeners.
The Use of Box Cross‐Sections for Railway Bridges with Encased Steel Girders
Authors: Odrobiňák Jaroslav , Potančok Matej 
Published: September 2019

ABSTRACTIn the area of railway bridges, the use of the superstructure created by reinforced concrete deck with encased steel beams is often a preferred alternative for small spans. Despite of well‐known disadvantages, this type of bridges is still preferred by railway authorities because of their high stiffness and small construction depth. Research on new bridges of this concept is focused in particular on optimization and saving material. The article presents a follow‐up study focused on the optimization and efficiency of the use of existing database of box girders for bridging small spans. The main dimensions of the bridges in the study were based on the already published study. As box cross‐sections, commercially developed and produced beams were utilized. Because of high combined bending and torsion resistance, and advanced fire resistance, as well, they are primarily applied in the building structures. They have not been able to find use in bridges, especially due to higher prices per unit weight. However, similar beams can be produced routinely, so the study can served to point out the possible benefits of applying similarly shaped build‐up cross‐sections. In addition to the material consumption, the influence on stiffness of the bridge cross‐section is also discussed.
Numerical analyses on welded joints at high‐strength steels
Authors: Stroetmann Richard , Kästner Thoralf 
Published: September 2019

ABSTRACTThe numerical modelling of welds requires profound knowledge due to the material and the geometric heterogeneity. Microstructural changes in the heat‐affected zone lead to local changes in the mechanical properties that can affect the load bearing and deformation behaviour. The necessary material laws can be determined both experimentally and mathematically. For a more precise consideration of the deformation capacity and the softening material behaviour, it may also be necessary to consider damage‐mechanical material models. Numerical calculations of experimental tests to determine the mechanical properties of welds are used to investigate these aspects.
Web Crippling Behaviour of Cold‐formed Stainless Steel Beams with Non‐Circular Web Opening
Authors: Fareed Ishqy , Somadasa Wanniarachchi , Poologanathan Keerthan , Gunalan Shanmuganathan , Beatini Valentina , Sivabalan Sivaram 
Published: September 2019

ABSTRACTIn recent years cold form stainless steels members are becoming the most popular and widely used structural steel member in the construction industry due to their notable corrosion resistance, recycling option, aesthetically pleasing, and the favourable material properties. However, web crippling behavior and the capacity of unlipped channel sections with non‐circular web openings (Square, rectangular and elliptical) has not been investigated sufficiently. Hence, a numerical analyses was undertaken to investigate the web crippling behavior and strength of cold‐form stainless steel unlipped channel beams with non‐circular web openings. Finite element models of cold‐form ferritic stainless steel unlipped channel with offset circular web openings were developed under the interior‐two‐flange (ITF) and external‐two‐flanges (ETF) loading conditions. They were validated with currently available web crippling test results and a detailed parametric study was undertaken to develop an extensive web crippling strength database. Numerical results showed that the currently available reduction factor equations of circular web opening are either conservative or unsafe to use for the non‐circular opening. Hence, numerical results were then used to develop a reduction factor to the web crippling capacities of cold‐formed stainless steel beams with the solid web.