bluuebunny/crossref_metadata_2025 huggingface dataset:
12.21: Cyclic loading in stainless steel links under lateral loads
Authors: Chacón Rolando , Arrayago Itsaso , Mirambell Enrique , Real Esther
Published: September 2017

Link elements are dissipative devices in form of beam segments that are typically included in eccentrically braced frames (EBF) subjected to lateral loads and seismic hazard. Studies related to short links, energy dissipation and plastic hinge formation have been presented for carbon steel elements with several conclusions at material, member and structural levels.

Stainless steel is a nonlinear metallic material with particular appeal for its structural use due to a considerable amount of capabilities such as corrosion resistance, circular life‐cycle, sustainability, strength, ductility and aesthetics. Despite the increase of the use of stainless steel for structural elements in construction, the behaviour of this material for structural purposes is not defined accurately as the carbon steel in all applications. The most important difference between these types of steel is the shape of the stress‐strain curve. Whereas carbon steel typically exhibits linear elastic behaviour up to the yield stress and a plateau before strain hardening is encountered, stainless steel has a more rounded response with no well‐defined yield stress, leading to a non‐linear material behaviour.

The elastic stiffness, maximum load, shear deformation capacity as well as the energy dissipation in short links are generally affected by the defined geometrical parameters such as link length, web stiffening and connectivity. Due to the material nonlinearity of stainless steel, this influence may be considerably affected by the stress‐strain curve and its corresponding energy dissipation since a nonlinear kinematic hardening branch must be adequately provided in numerical simulations for the sake of accurately reproducing the cyclic behaviour.

In this paper, a numerical model aimed at studying the cyclic behaviour of short stainless steel links subjected to seismic lateral loads is presented. The model accounts for the material and the geometrical nonlinearities. Several geometrical as well as material configurations (length, web stiffening and constitutive equations) are studied. The results and conclusions obtained in this research are used for a subsequent definition of a research program related to stainless steel frames subjected to seismic loading including several structural configurations in both concentrically (CBF) and eccentrically (EBF) braced frames assembled with plastic or slender members.
12.22: Seismic performance of high capacity hybrid beam‐columns: Comprising of high strength steel tubes subjected to lateral cyclic loading
Authors: Javidan Fatemeh , Heidarpour Amin , Zhao Xiao‐Ling , Al‐Mahaidi Riadh
Published: September 2017

High strength and ultra‐high strength materials are widely used in industrial applications significantly increasing the load bearing capacity and reducing the overall weight and cost. The present study continues a series of experimental investigations on innovative fabricated hybrid sections consisting of high strength steel tubes welded to mild steel plates. This type of innovative section is proposed with the aim of promoting the application of high and ultra‐high tensile steel in construction, taking advantage of the load‐bearing capacity of these materials along with the coupled effect of ductile mild steel plates. Large‐scale hybrid columns are tested under a combination of axial load and lateral cyclic load using a multi‐axis substructure testing (MAST) facility. Lateral cyclic loadings are applied along with constant axial loads of which the hysteretic curves are obtained for various grades of steel tubes, namely, mild steel tube (grade 300), high strength steel tube (grade 800) and ultra‐high strength steel tube (grade1200). Test results are analysed to examine the seismic performance of these proposed innovative sections and obtain the combined axial and lateral cyclic capacities, drifts, strains and plastic hinge distributions along the beam‐columns. The effect of tube material is considered and the axial shortening observations are compared to constant compression. The experimental outcomes of this paper can be incorporated in nonlinear modelling of structures consisting of ultra‐high strength steel tubes.
13.02: Safety assessment across modes driven by plasticity, stability and fracture
Authors: da Silva Luís Simões , Tankova Trayana , Marques Liliana , Kuhlmann Ulrike , Kleiner Andreas , Spiegler Jennifer , Snijder H.H. , Dekker Rianne , Taras Andreas , Popa Nicoleta
Published: September 2017

The European design rules for steel structures in EN1993 cover various failure modes that were developed using different methodologies in terms of accuracy and safety. Consequently, the safety level of these design rules is not homogeneous throughout their own field of application, as well as in comparison between different rules. Safety is regulated by partial factors for the various loads and resistances, respectively. EN 1990 – Annex D offers a procedure for the reliability assessment of resistance functions, based on a semi‐probabilistic approach. However, its application is not straightforward in many cases concerning steel design rules and several additional assumptions are necessary to ensure that a target probability failure is achieved. Moreover, the design rules are calibrated using certain variability values for the relevant parameters, such as material properties, geometric properties and imperfections. It is therefore required to appropriately characterize the statistical distributions of these basic variables in order to comply with the safety assessment procedure. The present research work, carried out in the context of the European research project SAFEBRICTILE, had as a main objective the harmonization of the reliability level of design rules for steel structures covering modes driven by ductility, stability and fracture.

This paper gives an overview of the reliability assessment of the Eurocode design rules carried out within the project for the studied failure modes; presents the adjustments in these design rules proposed whenever it was necessary; it also transmits the project recommendation on the statistical distributions of the relevant basic variables for steel structures, summarized in the “European database of steel properties” that was also developed within the project framework.
13.04: The next generation of Eurocode 4
Authors: Banfi Mike
Published: September 2017

Work is under way on the next generation of Eurocodes. These will build on the work done by the original authors and seek to enhance the ease of use of the code as well as include revisions requested by users and resulting from research work over the last ten to twenty years. In addition there is an ambition to reduce the number of Nationally Determined Parameters as some relate to the lack of a consensus at the time of the initial drafting of the codes rather than aspects of the code e.g. safety factors that remain the prerogative of the Member States. Eurocode 4 has been well received but improvements can always be made. The systematic review process has highlighted areas where users want clarification or change. Project teams have also been set up to look at three specific aspects of the code. In addition as Eurocode 4 relies on Eurocode 2 and Eurocode 3 an improvement in the harmonisation between the three codes has been requested. This paper sets out the main areas which are being considered during the revision process. Throughout the process the need to balance the benefit of any changes against the disruption that this will make to existing users has been considered.
15.09: High‐resolution modelling and design of steel structures
Authors: Surampudi Bala A.V. , Butler Martin A , Swanson James A , Rassati Gian Andrea
Published: September 2017

The art and science of structural engineering has always required a balance between predicting the demands on a structure and making sure that those demands can be met with the structure's strength and stiffness. Historically, analytical models have been used to predict demands and codified design equations have been used to predict strength. Over the past approximately 50 to 60 years, finite element analytical models have evolved from crude first‐order linear representations made up of dozens of degrees of freedom to sophisticated second‐order nonlinear models made up of hundreds of thousands of elements. With the ever increasing capability of personal computing and the ability to construct more and more sophisticated finite element models, new approaches to the design of steel structures that were once thought impossible are becoming realistic.

State of the art a decade ago was to employ models constructed from discrete one‐dimensional elements based on nominal geometry and linear material behaviour. Influences and behaviours such as residual stresses, initial imperfections, buckling, fracture, and second‐order effects were addressed by codified design specifications, often in the form of tedious hand calculations. Exponential increases in computing power now permit entire structures to be represented using shell or solid elements and explicit modelling of influences such as residual stresses and initial imperfections. As a result, the balance between analysis and design can change. With modern sophisticated computer analyses, the balance can be shifted towards the analysis side of the equation leaving less work in the strength determination. With a model like the one described above, strength could be defined simply as yielding or as the development of a numerical singularity resulting from a loss of stiffness representing buckling or fracture.

This paper outlines ongoing work towards developing guidelines for high‐resolution computer modelling of steel structures and rebalancing the treatment of phenomena between the analysis side and the design side of the equation.
16.13: Queensferry crossing cable‐stayed composite bridge
Authors: Kærn Jens Christian , Hansen John Elnegaard
Published: September 2017

The Queensferry Crossing near Edinburgh is a road bridge which is constructed as a composite cable‐stayed bridge with two main spans of 650 m and two approach bridges. The main bridge has a width of 40 m and has two skew cable planes with spacing of 16.4 m. The composite deck comprises a single open steel box with a concrete slab on the top.

The bridge is designed in accordance with the Eurocodes design standards. The general design approach for the steel deck is based on the Reduced Stress Method in accordance with Eurocode 3 together with finite element (FE) shell method calculations for individual plates and for whole plate panels. The FE shell methods are in accordance with [7] Annex C model 5, which means that the calculation is based on nonlinear material properties and non‐linear geometric behaviour and finally includes plate imperfections.

The typical steel deck box is stiffened with longitudinal trough stiffeners and cross bracing frames at a spacing of 4.05 m. Special details are made around the three Towers and the Transition zone between the single steel box in the cable‐stayed span and separated twin boxes on the approach viaducts.

The steel structure for the cable‐stayed bridge was fabricated in China and steel segments with a length of 16.2 m were transported to Scotland, where the concrete deck was cast. Afterwards the segments were transported by sea to the bridge site, lifted to their final position and the two segment cables were installed and anchored to the deck and the towers.

The Queensferry Crossing is the UK's tallest bridge and has been recognised in the 2016 Guinness World Records for the world's largest freestanding balanced cantilever. The north and south approach bridges were launched with a maximum cantilever span of 104 m.
16.22: Remarks on the material testing of historical railway bridges: Steelworks built from 1873 to 1950
Authors: Hołowaty Janusz , Wichtowski Bernard
Published: September 2017

A decisive role regarding the durability of historical railway bridges is played by degradation processes, which can only be resisted to a limited extent. Since the structural resistance of old bridges decreases naturally, devising design criteria for the assessment of their residual resistance would appear to be unnecessary. In many cases, existing steel bridges which do not obey design code requirements may safely carry current service loads. New methods for the structural capacity assessment of historic bridges have been designed in many countries, which take into account existing loads as well as those expected during the residual working life, along with the material properties of the bridges.

The testing of material samples from 21 historic railway bridges allowed information on the mechanical properties of the steel along with the structures’ response to hitherto existing loads to be gathered. The chemical composition, steel static tension, hardness and toughness, and weldability assessment by factors are verified. All the tested bridges were built from early structural steels. In some bridges, early structural steel of higher strength has also been found in steel manufactured in 1875. The results of the old railway bridge steel tests given in this paper may be utilised in forecasting the further durability of similar structures.
17.03: Dynamic properties of unanchored circular ground‐based steel tanks
Authors: Maheri Mahmoud R. , Karbaschi M. E.
Published: September 2017

This article is not available for publication.
17.04: Design of offshore wind turbine jacket foundations: On the influence of subsequent modifications on fatigue performance
Authors: Augustyn Dawid , Nielsen Martin Bjerre , Pedersen Ronnie Refstrup
Published: September 2017

The design of jacket foundations for offshore wind turbine typically relies on design loads from an integrated aero‐elastic model of the full turbine structure and a reduced (superelement) representation of the foundation. In this paper the influence of introducing subsequent design changes to the foundation that potentially invalidate the design loads is studied based on a generic jacket foundation subject to combined wind and wave loading. The fatigue performance is considered for the reference case as well as a number of structurally modified configurations covering changes in braces, legs, soil conditions and footprint. The modified jackets are examined for both inconsistent design loads based on the reference geometry and updated loads associated with a consistent, aero‐elastic load iteration with the updated geometry and/or soil conditions. Ratios between the fatigue lives based on the inconsistent and the updated forces are presented, indicating whether an additional load iteration is essential or not. By having an overall understanding of allowable structural modifications a foundation designer is able to provide a more efficient jacket design by independently optimizing the structure in the post‐processing stage.

It is shown that the subsequent jacket modifications may significantly affect the quality of the fatigue results. Some modifications, especially the ones associated with the boundary conditions, e.g. soil modifications significantly modify the global dynamic behaviour, thus indisputably require an additional aero‐elastic load iteration. On the other hand, modifications resulting solely in local changes such as minor brace or leg size modifications, especially when increasing the stiffness, may be allowed in the post‐processing phase without committing a significant error.
17.06: Characterization of accidental scenarios for offshore structures
Authors: Čekerevac Damjan , Rigueiro Constança , Pereira Eduardo
Published: September 2017

Offshore structures are complex facilities whose malfunction can lead to serious impacts and losses, such as human lives, environmental disasters and the complete loss of the structure. Additionally, the cost associated to their construction and maintenance is very high, so it is crucial to keep them fully operational throughout their entire service life. Standby periods in offshore platforms generate large financial losses for their owners. The most devastating effects on offshore platforms are often the result of incidents which eventually lead to accidental actions. Hence it is very important to develop measures which limit the effects of accidental actions on the overall performance of these facilities.

In this paper the most likely accidental scenarios and the strategies currently used to mitigate their devastating effects were analysed. Accidental scenarios were discussed based on the available historical data of incidents on offshore platforms, and classified according to the type of offshore platform or the type of structural elements affected. Furthermore, the most frequent hazards were used to introduce specific accidental actions which will then be the subject of a study for comparing the approaches proposed by different technical standards. The strategies currently used for mitigating the effect of accidental actions, both non‐structural and structural, were classified according to the materials used and the structural typology adopted.

The objective of this study was to identify new opportunities for the development of innovative mitigation strategies for the devastating effects associated to accidental actions in offshore platforms, considering the most recent developments in terms of innovative materials and of structural analysis approaches. In this context, this paper discusses the current trends in research and the future challenges related to this issue. This will serve to identify the possible methods for improvement of the existing structural mitigation measures.
01.05: Experimental and theoretical study of large capacity extended end‐plate moment connection
Authors: Samaan Rimon A. , El‐Serwi Ahmed A. I. , El‐Hadary Riham A.
Published: September 2017

Over the years, bolted end‐plate moment connections have been very popular due to the ease of fabrication and erection. The need for large capacity connections with four bolts in one row had become mandatory as a reason of recent complicated structures with large spans and limited available depths. The current research includes an extensive parametric study for the extended large capacity bolted moment connections. For this purpose, three‐dimensional finite element models are prepared using the non‐linear, multi‐purpose, finite element compute package, ANSYS‐11.0. In order to validate the developed finite element model, an experimental program containing five full‐scale flushed and extended, end‐plate connections subjected to bending moment and shear force is performed. The finite element model used throughout the parametric study is verified by comparing its results with the results of the performed experimental study in addition to experimental results recorded by other researchers showing good agreement. The effect of end‐plate thickness, bolt diameter as well as adding horizontal stiffener at two different positions on the connection moment capacity and tension bolt force distribution is studied. Several curves are plotted to show the relation between connection ultimate moments and end plate thickness for different connection configurations. Regression analysis is performed for results and design equations were proposed for each connection configuration.
21.04: Vibration characteristics of an existing high‐rise building in Montreal and the effects of retrofit
Authors: Manolache Laura , Wang Yudong , Tirca Lucia , Bagchi Ashutosh
Published: September 2017

The study described in this paper refers to seismic assessment and retrofit of an existing 10‐storey reinforced concrete office building designed and built at the beginning of the 20 century. When this building with a height of 38.95 m was completed it was the highest in downtown Montreal. According to FEMA 547 classification, the typology of this building structure is associated to model building type “C3”. Consequently, this type of non‐ductile frame building with an insignificant amount of masonry walls is relatively weak and unable to carry the seismic forces when subjected to ground motions from a potential earthquake magnitude. The main deficiencies of this structural system are: poor lateral confinement and shear resistance of columns, the location of lap splices and the number of reinforcing bars often inadequate, the lack of confinement and shear reinforcement in joints, poor anchorage of longitudinal reinforcement of beams into joints and shear resistance of beams. Due to lack of seismic detailing, the common retrofit measure recommended in ASCE/SEI 41–13 for this building is to add new lateral force‐resisting systems designed according to current code and standard provisions. Hence, in this case, the most cost‐effective retrofit solution is to add a steel structure designed to withstand seismic forces while responding to serviceability criteria required to preserve the non‐reinforced masonry facades facing the main streets and the facades ornaments.
21.12: Behaviour of CFS strengthened hot‐rolled structural steel beams under flexure
Authors: Selvaraj Sivaganesh , Madhavan Mahendrakumar , Gopalan Anadh Gopal Venu , Jayabalan Aswin Kumar , Arumugam Pavan Kumar
Published: September 2017

A strengthening system using cold‐formed steel (CFS) channel as an encase to inhibit the lateral‐torsional buckling (LTB) of hot rolled steel (HRS) channel is experimentally examined by conducting a four‐point bending test. An advantage of this technique is that this retrofitting method can be applied in‐situ by minimal manpower. The retrofit technique involves encasing the CFS channel to the HRS channel followed by interconnecting the two with spot welding. In general, the test results of the HRS channel retrofitted with CFS channel indicate that in addition to preventing the LTB mode of failure the moment capacity of the section increases by 60% compared to the control specimen. It was also found that the effectiveness of the retrofitting technique increases with an increase in the slenderness of the HRS channel along with an increase in the number of interconnecting spot welds. In addition, the test results indicate that the current specification for both HRS and CFS are not suitable for an HRS‐CFS built‐up section. Based on the test results a new interconnection spacing limitations to avoid the local buckling of the CFS channel is suggested.
21.15: Resource efficiency in the building sector: Application to steel buildings
Authors: Gervásio Helena , Dimova Silvia , Pinto Artur
Published: September 2017

In light of current European guidelines towards resource efficiency in the construction sector, a performance based approach is herein introduced taking into account environmental criteria, namely the sustainable use of resources. The proposed approach for sustainable design is in line with the safety assessment criteria of the European standards for structural design. Moreover, the approach, which is based on a standardised procedure for life cycle assessment, aims to harmonize the assessment of the sustainability of buildings in Europe and to enable an easier integration of sustainability and structural criteria into the design process of buildings, following the basic requirements for construction works of the Construction Products Regulation.

It is considered that resource efficient building design and construction comprehends the reduction and/or minimization of the use of resources and corresponding environmental impacts, while improving the lifetime performance of buildings through technical and functional achievements. Thus, not only the reduced use of raw materials and other natural resources but also technical and functional aspects such as building adaptability, ease disassembly and deconstruction contribute towards this goal. These are all aspects from which steel structures may benefit.

Hence, the first part of this paper focusses on the presentation of the general framework for sustainable assessment of buildings. Then, in the second part, the life cycle performance of steel buildings is discussed, in light of the proposed approach, and potential aspects leading to improvements are identified. Conclusions are drawn in the end of the paper.
P05.02: Different cross‐section in lateral‐torsional buckling
Authors: Bajer Miroslav , Barnat Jan , Vild Martin , Melcher Jindřich , Karmazínová Marcela , Piják Jiri
Published: September 2017

The goal of the research presented in this paper is the experimental and theoretical analysis of cross‐section which can be asymmetric. Particularly, there are experimental tests of several beams of selected cross‐section shapes described and analysed. The main idea of those experiments was to observe the differences in behaviour between monosymmetric cross‐section and the asymmetric one. Currently used design methods for a solution of lateral‐torsional buckling are based on critical moment approach. This solution is also implemented in design codes but it is limited for use of double and monosymmetric cross‐sections.

Another part of the paper is focused on the numerical evaluation of transversally loaded beam of one monosymmetric and four asymmetric cross‐section shapes susceptible to lateral‐torsional buckling. Several analytic methods used for evaluation of the beam bending resistance in design software were evaluated.

This paper presents the comparison of numerical and experimental results of transversally loaded beams with monosymmetric and asymmetric cross‐sections. Stresses in selected parts of the cross‐section are evaluated and compared together. This comparison shows that the normal stress on both (monosymmetric and asymmetric) cross sections is the subject of the same rules – a combination of stresses inflicted by bending and torsion caused by an eccentricity between the point of load application and the centre of shear.
01.09: Transient state tests of cold‐formed stainless steel bolted connections
Authors: CAI Yancheng , YOUNG Ben
Published: September 2017

This article is not available for publication.
01.14: Tests of alternately loaded single‐cut joints with blind bolts
Authors: Swierczyna Szymon , Wuwer Walter
Published: September 2017

Joints in the frames designed with the cold‐formed profiles with a thickness 4÷5 mm, formed by a lap connection of their members by means of mechanical fasteners, are characterised by a considerable degree of flexibility. In static calculations of exemplary bearing structures resistance of the joints was included on the basis of experimentally established relations: force‐deformation and moment‐rotation, that vary nonlinearly under the influence of loads. Some of this loads, e.g. wind, may change their direction. Then, the effects of the next variable load are superimposed on action of the permanent load and effects of previously existing cycles of the variable actions. In a given joint of a bar structure the directions of resultant forces acting on the individual fasteners are changing, and its behaviour is described by defined hysteresis loops. Calculations of such a structure requires i.a. incremental load‐deformation analysis. Then, internal forces in particular members and deformations in the joints may be significantly different from the case, when horizontal wind load acts only in one direction.

To describe the behaviour of a bar structure with the flexible joints loaded alternately, it is necessary to develop an experimentally verified method for prediction of hysteresis loops for the joints loaded by shearing force and bending moment. Appropriate design procedures of such joints, including proper criteria of their strength and limit deformation are needed.

The paper presents the preliminary results of the tests of the specimens with the alternately loaded joints, in which the cold‐formed profiles are connected by means of proper number of the blind fasteners BOM type. The alternating load of the joint in the test specimen – simultaneously by the shearing force and bending moment – change the direction of the resultant forces, acting on the individual fasteners. Values of the load and its history have been selected to correspond the situation, which may occur in the actual structure of the frame loaded simultaneously by the permanent load, snow and wind.

Results of tests are presented on the diagrams of relation: force‐deformation in the axis of the individual fastener and moment‐rotation in the joint. The preliminary conclusions are formulated and program of further investigations is presented. The aim of the research is to develop the structural system of lightweight steel buildings with latticed bearing structures.
01.17: Photogrammetric analysis of thin end‐plate deformations in steel and composite joints
Authors: Barcewicz Wioleta
Published: September 2017

The subject of the paper concerns the issues related to the deformability of the semi‐rigid beam‐to‐column joints with bolted end‐plate connections. Deformations of the relatively thin end‐plates of different thickness (ranging from 40 to 60% of the bolt diameter) and height (flush and extended) are analysed in steel and composite steel‐concrete joints with varying reinforcement ratio of the composite slab. The joints were originally subjected to hogging bending in the destructive experimental tests, carried out at the Warsaw University of Technology a few years ago. The obtained results, based on the moment‐rotation relationships, were investigated and reported elsewhere.

The aim of the research presented here is a determination of the distribution and the values of the maximum plastic curvatures of the deformed end‐plates by means of the photogrammetric analysis. Application of the digital photogrammetry, called stereophotogrammetry, enabled reconstruction and 3D‐modelling of deformed plate surfaces as well as a presentation of the results in graphic and numerical formats. The results of the photogrammetric analysis allow for determining the yield line patterns, which are the basis for defining the effective lengths of particular end‐plate parts, modelled as equivalent T‐stubs. Such models are used for identification of failure modes as well as a calculation of the basic joint properties by means of the component method, adopted in EN 1993‐1‐8. The examined semi‐rigid joints with the end‐plates of the thickness approximately twice smaller than the bolt diameter, demonstrated the mechanism of complete yielding of the T‐stub flange, representing the end‐plate (related to Mode 1 according to EN 1993‐1‐8). However, the intensiveness of the yield line patterns differs visibly when the same types of end‐plates were used in case of steel and composite joints. The influence of the end‐plate deformations was smaller in the composite ones and decreased with increasing reinforcement ratio.

Comparison of results based on the approach used in Eurocodes and those reported on the basis of photogrammetric analysis is presented.
01.18: Optimization of the pre‐loading procedure for high‐strength bolts of FREEDAM connections
Authors: Cavallaro Giovanni Ferrante , Francavilla Antonella Bianca , Latour Massimo , Piluso Vincenzo , Rizzano Gianvittorio
Published: September 2017

A FREE from DAMage (FREEDAM) friction connection is a particular type of sliding hinge joint where in correspondence of the lower beam flange is realized a friction damper with steel angles and coated plates, pre‐stressed with high strength bolts. In order to master the resistance of a FREEDAM connection it is crucial to know accurately the value of the friction coefficient of the materials employed to realize the damper and to control the preload applied to the friction interface by means of high strength bolts.

Dealing with this last topic, according to Eurocode 3 and EN 1090‐2, High Strength bolts (both of HR or HV type), when installed in friction bearing connections, must be installed based on one of four proposed procedures. The methods currently recommended are torque, combined, HRC and DTI and each of them, as already partially reported in technical literature, can lead to a different level of accuracy. Additionally, once the bolt is tightened it is well known that it undergoes to an “instantaneous” (short‐term relaxation) and to a “long‐term” loosening that, obviously, may affect the response of the FREEDAM connection which has to be designed not to slip under service loading conditions. Within this framework, the goals of the paper are multiple. First of all, by means of experimental analysis, it is wanted to assess the accuracy of some of the codified tightening methods, namely torque and combined, when applied to FREEDAM connections. Additionally, the possible bolts’ loosening occurring in short/medium periods of time (up to one month) are evaluated performing specific tightening tests. Finally, the effectiveness of Belleville spring washers in keeping the pre‐loading constant during the life‐time of the FREEDAM connection is assessed. In order to analyse all these aspects, an experimental analysis carried out at the STRENGTH laboratory of the University of Salerno, regarding 84 tightening tests performed on specimens of friction dampers is presented. All the specimens have been tested measuring with annular load cells the initial force applied to the bolts in order to evaluate the achievement of the target preload. Additionally, in some cases, the loss of pre‐load over a period of time has been monitored.
01.29: Experimental prequalification of bolted extended end plate beam to column connections with haunches
Authors: Stratan Aurel , Maris Cosmin , Dubina Dan , Neagu Calin
Published: September 2017

Modern seismic design codes require that the seismic performance of beam‐to‐column connections in steel moment resisting frames be demonstrated through experimental investigations, which are expensive and time‐consuming. A solution to this problem is the prequalification of typical connections for the design practice, which is common in U.S. and Japan. Recently concluded European research project entitled EQUALJOINTS (European pre‐QUALified steel JOINTS) addressed the seismic prequalification of several beam‐to‐column connection typologies common in the European practice. The current paper outlines the experimental program performed on 24 bolted extended end‐plate connections with haunches investigated at the Politehnica University of Timisoara in the framework of this project. The parameters of the experimental program consist of beam/column size, haunch geometry, joint configuration (single‐sided and double‐sided), panel zone strength, loading protocol (monotonic and cyclic) and beam over strength. The performance of the specimens is quantified in terms of deformation capacity, stiffness, and strength. Tests showed a satisfactory cyclic response, with plastic deformations occurring in the beam, at the end of the haunch. Consequently, extended end plate beam to column connections with haunches prove to be a suitable solution for seismic applications with large plastic deformation demands.
01.30: Evaluation on clamping load of high strength bolts under ambient environment
Authors: Nah Hwan‐Seon , Choi Sung‐Mo
Published: September 2017

The torque shear type high strength bolt is clamped in general when pin‐tail of shank is cut off. However the clamping loads of high strength bolt did not often meet the required tension due to variation of torque coefficient. This is why the viscosity of lubricant on bolt shank affects the torque coefficient by temperature, dust and debris. In this study, the clamping tests of various high strength bolts were performed independently both at indoor condition and at construction sites for six years. The temperature of construction sites was recorded with the range from −11°C to 34°C‥ The temperature at indoor condition was set up to compose from −10°C to 50°C at each 10°C interval. At construction sites, the clamping load of high strength bolt was varied from 159 to 210 kN and the torque value was varied from 405 to 556 Nm. The torque coefficients at construction sites were analyzed from 0.126 to 0.158 whereas tensions were measured from 179 to 192 kN by using tension meter. The torque coefficients at construction sites were analyzed to range from 0.118 to 0.152. From these tests, the diverse equations on torque coefficient, tension subjected to temperature were taken by statistic regressive analysis.
03.06: A study on the behaviour of steel beam‐column connections to deep wide flange columns for seismic applications
Authors: Pettersson Frida , Rassati Gian A. , Swanson James A. , Burns Thomas M.
Published: September 2017

The use of deep column profiles in lateral force resisting systems is becoming increasingly commonplace for the purpose of providing sufficient stiffness to meet lateral drift limits. Existing research on the behaviour of connections to deep column profiles is limited, and consequently this study aims to explore potential issues with these configurations. A parametric analytical investigation was performed focusing on the behaviour of one‐sided reduced beam section connections to columns of variable depths. A total of forty assemblies were designed according to the 2010 AISC Specification. Four column sizes were considered, namely W14×426, W24×192, W27×194, and W30×191 (in metric designations, W360×634, W610×285, W690×289, and W760×284). Columns were subjected to five levels of axial load and were configured with either medium or weak panel zone strength. A common size beam was used for all configurations, namely a W36×150 (W920×223), so that the shear and bending moments transferred to the column were not a variable. Imperfections and second‐order geometric effects were considered as part of the parametric investigation which used geometry and material characteristics from a previous experimental study. The results of this study suggest that the use of doubler plates to strengthen column webs causes a larger twist of the column when the connection is loaded, leading to the recommendation of using heavier profiles instead of reinforcement plates when strength limit states govern. Finally, this study shows that the use of deeper columns does not have a negative impact on the behaviour of the connection as long as the axial loads in the column are relatively low. When column axial loads approach the stability limit of the member, the connection detail used does not perform as intended, as local buckling phenomena reduce the connection capacity before a plastic hinge can fully form in the connected beam.
03.10: Seismic design and performance of extended stiffened end‐plate joints
Authors: Tartaglia Roberto , D'Aniello Mario , Costanzo Silvia , Landolfo Raffaele , De Martino Attilio
Published: September 2017

Bolted extended stiffened end‐plate beam‐to‐column joints are commonly used for steel moment resisting frames in seismic areas. In the framework of European codes, EN 1993:1‐8 provides the design rules and the analytical models to predict the mechanical behaviour of the joints. On the other hand, EN 1998‐1 specifies the required performance for seismic resistant joints. In this paper the criticisms of current versions of both EN 1993:1‐8 and EN 1998‐1 are discussed and design criteria for seismic resistant extended stiffened end‐plate beam‐to‐column joints are proposed based on both experimental tests and parametric finite element simulations.
03.12: Global structural modelling of space frame structures with consideration of joint behaviour: An integral analysis approach
Authors: Mähr Tobias , Espinha Miguel , Ziegler René
Published: September 2017

The effects of the behaviour of joints on the distribution of internal forces and moments within a structure and on the overall deformations of the structure are generally neglected [1]. However, where such effects are significant, they should be taken into account. Provisions are given in Eurocode 3, Part 1‐8 [2] for analysis, classification and modelling of joints with respect to rotational degrees of freedom. Provisions for translational degrees of freedom are missing.

In shear connections slip may occur in case slip resistance is smaller than design load. This holds true for shear connections category A and B according to Eurocode 3, Part 1‐8 [2]. In structures with predominant normal forces such slip effects may accumulate and considerably affect the internal forces as well as the deflections. Structural modelling and calculation of slip effects is a complicated task in structural mechanics. In this paper, concepts are presented how to consider slip effects in joints when dealing with large space frame structures. Stick‐slip‐models are outlined and implemented in 3d structural models. Calculation techniques are discussed relating to the additional degrees of freedom (statically over‐determined systems) and the non‐linear behaviour.

The importance and benefit of this integral analysis approach, where the effects of the joints are considered in the global modelling, are illustrated by the example of the Louvre Abu Dhabi Dome. The dome measures 185m in diameter and consists of approx. 11'000 steel members, most of which having shear connections. The results show that slip in joints must not be neglected in the global structural analysis. The quality and accuracy of the calculated results are verified by deflection measurements on site.
Fine and Clean Photothermally Controlled NIR Drug Delivery from Biocompatible Nickel‐bis(dithiolene)‐Containing Liposomes
Authors: Mebrouk Kenny , Ciancone Mathieu , Vives Thomas , Cammas‐Marion Sandrine , Benvegnu Thierry , Le Goff‐Gaillard Catherine , Arlot‐Bonnemains Yannick , Fourmigué Marc , Camerel Franck
Published: September 2017

This work demonstrates that metal‐bis(dithiolene) complexes can be efficiently incorporated inside organic nanocarriers and, that under near‐infrared (NIR) irradiation, their high photothermal activity can be finely used to release encapsulated drugs on demand. In contrast to gold nanoparticles and other organic NIR dyes, nickel‐bis(dithiolene) complexes do not produce singlet oxygen under irradiation, a highly desirable characteristic to preserve the chemical integrity and activity of the loaded drug during the NIR‐triggered release from the nanocarriers. Finally, cytotoxicity experiments performed on various cell lines have shown that the incorporation of such metal complexes do not increase the toxicity of the final liposomal formulation. These results offer great promise for the development of innovative biocompatible drug nanocargos that are able to safely deliver their content on demand under NIR laser irradiation. Moreover, this work demonstrates that metal‐bis(dithiolene) complexes, owing to their versatility of functionalization and metal complexation, are attractive photothermal agents for the development of original NIR‐responsive materials for application not only in biotechnology but also in materials science.
Quality of life after surgery for intracranial meningioma
Authors: Benz Luke S. , Wrensch Margaret R. , Schildkraut Joellen M. , Bondy Melissa L. , Warren Joshua L. , Wiemels Joseph L. , Claus Elizabeth B.
Published: September 2017

BACKGROUND

To the authors' knowledge, limited data exist regarding long‐term quality of life (QOL) for patients diagnosed with intracranial meningioma.

METHODS

The data in the current study concerned 1722 meningioma cases diagnosed among residents of Connecticut, Massachusetts, California, Texas, and North Carolina from May 1, 2006 through March 14, 2013, and 1622 controls who were frequency matched to the cases by age, sex, and geography. These individuals were participants in a large, population‐based, case‐control study. Telephone interviews were used to collect data regarding QOL at the time of initial diagnosis or contact, using the Medical Outcomes Study Short‐Form 36 Health Survey. QOL outcomes were compared by case/control status.

RESULTS

Patients diagnosed with meningioma reported levels of physical, emotional, and mental health functioning below those reported in a general healthy population. Case participants and controls differed most significantly with regard to the domains of Physical and Social Functioning, Role‐Physical, Role‐Emotional, and Vitality.

CONCLUSIONS

In the current study, patients with meningioma experienced statistically significant decreases in QOL compared with healthy controls of a similar demographic breakdown, although these differences were found to vary in clinical significance. Cancer 2018;124:161‐6. © 2017 American Cancer Society.
Variation in the use of active surveillance for low‐risk prostate cancer
Authors: Löppenberg Björn , Friedlander David F. , Krasnova Anna , Tam Andrew , Leow Jeffrey J. , Nguyen Paul L. , Barry Hawa , Lipsitz Stuart R. , Menon Mani , Abdollah Firas , Sammon Jesse D. , Sun Maxine , Choueiri Toni K. , Kibel Adam S. , Trinh Quoc‐Dien
Published: September 2017

BACKGROUND

This study assessed the use of active surveillance in men with low‐risk prostate cancer and evaluated institutional factors associated with the receipt of active surveillance.

METHODS

A retrospective, hospital‐based cohort of 115,208 men with low‐risk prostate cancer diagnosed between 2010 and 2014 was used. Multivariate and mixed effects models were used to examine variation and factors associated with active surveillance.

RESULTS

During the study period, the use of active surveillance increased from 6.8% in 2010 to 19.9% in 2014 (estimated annual percentage change, +28.8%; 95% confidence interval [CI], + 19.6% to + 38.7%; P = .002). The adjusted probability of active‐surveillance receipt by institution was highly variable. Compared with patients treated at comprehensive community cancer centers, patients treated at community cancer programs (odds ratio [OR], 2.00; 95% CI, 1.50‐2.67; P < .001) and academic institutions (OR, 2.47; 95%, CI, 1.81‐3.37; P < .001) had higher odds of receiving active surveillance. Compared with patients treated at very low‐volume facilities, patients treated at very high‐volume facilities had higher odds of receiving active surveillance (OR, 3.57; 95% CI, 1.94‐6.55; P < .001). Patient and hospital characteristics accounted for 60.2% of the overall variation, whereas the treating institution accounted for 91.5% of the unexplained variability.

CONCLUSIONS

Within this hospital‐based cohort, the use of active surveillance for low‐risk prostate cancer increased significantly over time. Significant variation was found in the use of active surveillance. Most of the variation was attributable to facility‐related factors such as the facility type, facility volume, and institution. Policies to achieve consistent and higher rates of active surveillance, when appropriate, should be a priority of professional societies and patient advocacy groups. Cancer 2018;124:55‐64. © 2017 American Cancer Society.