bluuebunny/crossref_metadata_2025 huggingface dataset:
15.08: Influence of deterioration modelling on local deformation demands in steel moment frames
Authors: Bravo‐Haro M. , Tsitos A. , Elghazouli A.Y.
Published: September 2017

This paper assesses the influence of the cyclic strength and stiffness degradation on the local demands in moment resistant steel frames (MRF), designed according to Eurocode 8. For steel structures, local demand is frequently evaluated by means of plastic rotation of structural members. This local response is relevant both for the design of new structures and particularly for the assessment or safety evaluation of existing structures. Recent studies have illustrated the weaknesses of the local demand prediction methods based on linear analysis. When predictions based on linear analysis were contrasted against nonlinear models, mismatches up to 100% were found. However, those nonlinear analysis approaches have not considered the effect of cyclic strength and stiffness degradation. In this study, degradation models are used and calibrated for assessing structural collapse scenarios. A set of twelve MRF systems, designed according to the provisions of Eurocode 3 and Eurocode 8, are examined using two different modelling approaches: a degrading model and a conventional non‐degrading approach. The frames are subjected to different levels of given inelastic demands by means of a scaling procedure using a suite of ground motion records. Plastic rotations are directly measured during the nonlinear analyses and consequently contrasted to quantify the effect of degradation at different levels of induced inelasticity. It is shown that using degrading models results in local inelastic rotations which can be significantly higher, reaching up to 25% more than without degradation. Finally, the implications of the findings on current European seismic design procedures are outlined.
15.16: Vibration Analysis and Human Comfort Investigation of a Steel‐Concrete Composite Building under Nondeterministic Wind Loadings
Authors: da Silva José Guilherme Santos , Barboza Rafael Rangel
Published: September 2017

Based on a favourable economic scenario combined with a significative technological advance in science materials and also construction processes, it must be emphasized that the Brazilian cities have shown substantial growth, regarding the construction of tall and slender buildings. This architectural trend has conducted the design of these buildings to solutions composed by very flexible structural systems, resulting in slender buildings with very low natural frequencies values and therefore more susceptible to problems of excessive vibrations, undesirable crack openings and even discomfort to the occupants. This way, having in mind the slenderness levels presented more recently, these buildings need to have their structural dynamic behaviour investigated, in order to ensure the human comfort. Thus, this research work aims to investigate the dynamic structural behaviour and also evaluates the human comfort of tall buildings, when subjected to the non‐deterministic action of the wind. This way, the structural behaviour of a forty eight‐storey steel‐concrete composite building with 172.8m high subjected to the nondeterministic wind dynamic actions is investigated. The results obtained along the numerical analysis, in terms of the displacements and accelerations values, in time and frequency domain, are compared with the limits proposed by technical guides and design recommendations, aiming to evaluate the human comfort levels of the analysed building, regarding to the situations of the design practice.
15.17: Progress in the development of production of heavy plates. S355‐S460ML till 100 mm at NLMK DanSteel
Authors: Goli‐Oglu Yevgen , Greisen Zibrandt
Published: September 2017

At the end of 2012 a new 4200 mm rolling mill was put into service in Frederiksvaerk at NLMK DanSteel. Since then the company has focused on production of heavy plates for construction, offshore, shipbuilding and boiler purposes, i.e. steel plates with higher mechanical properties. The company is constantly expanding its product program assortment with regards to sizes and grades. As an example of this, the company in 2015 expanded the range of thermomechanical rolled heavy plates, of structural steel of strength category S355ML, S420ML, S460ML up to 100 mm and received the achieved approval for CE‐marking of these grades.

The article presents slab quality requirements, some features of production technology for specified quality and thickness categories as well as enhanced mechanical test results, including evaluation of the anisotropy of the hardness gradient and toughness downp to −80°C both in longitudinal and transverse directions, showing the actual level of low temperature impact toughness properties in ¼ and ½ of heavy plate thickness.

Some additional investigations of weldability of low carbon heavy plates were done. The micro hardness of the basic sections in the weld joint of micro alloyed low‐carbon steel heavy plates is investigated. Two‐coordinate measurements of the micro hardness in the basic HAZ are described. The influence of post weld heat treatment on the micro hardness of opposite walls of the weld joint is determined.
16.01: Bjørnafjorden suspension bridge TLP concept
Authors: Sørensen Jesper
Published: September 2017

The Bjørnafjorden TLP (Tension Leg Platform), a multi span suspension bridge solution, is one of the possible fjord crossings options considered as part of the ambitious “Ferry‐free Coastal Highway E39” under development in Norway. The original design concept for Bjørnefjorden was very much similar to that of a conventional suspension bridge using central locks between main cable and bridge deck to distribute movements equally to the bridge ends. However since the bridge is of the multi‐span type, the inherent flexibility of the pylons caused a severe of in‐plane stability of the original system leading to large vertical displacement of the deck. To mitigate this effect top cables have been introduced between pylon tops preventing these from excessive longitudinal displacements and thereby also limiting the vertical deck displacement from traffic load. In this paper the different concept challenges for the Bjørnafjorden TLP solution is outlined.

The suspension bridge has a total of four pylons – a northern and southern pylon of concrete located near shore, while two central steel pylons are supported by TLP's at 550m and 450m depth. The TLP's, as well known from off‐shore industry, consist of pre‐tensioned steel pipes anchored in the seabed and at the surface connected to a large steel “floaters” onto which the towers are placed. The main spans are 1300–1400m and the bridge has an overall length from anchorage to anchorage of about 5200m.

Due to the long tethers of the TLP the central pylons are relatively unrestrained to move up to 20m horizontally and thus in order to achieve sufficient stability of the bridge system a special feature in form of top cables are introduced. The top cables connect the tower top of all four pylons and are anchored to the bridge anchor blocks together with the main cable.

The bridge structural system is the outcome of innovative thinking and a fine example on how a few unconventional features can make a very conventional bridge system work in challenging conditions. As the bridge is floating it is essential that the structure is light and therefore the primary structures are in steel.
16.04: High strength steel (HSS) S690 in highway bridges: Comparative design
Authors: Pedro José J. Oliveira , Reis António J. , Baptista Cláudio
Published: September 2017

The use of High Strength Steel (HSS) S690 in highway bridges decks is not yet widespread. A research program investigated the optimal use of HSS S690 within bridges was conducted.

A comparative design is presented for a 21.5 m wide highway bridge, with a typical 80 m long span and a composite steel‐concrete twin plate girder deck. Two designs are compared, using the Eurocodes: Design (A) adopted standard S355 NL steel grade whereas Design (B) uses HSS S690 QL or QL1 on the main girders.

Comparison between the two designs shows that using S690 enables reductions of 25% on the steel weight and about 65% on full penetration welding volume, compared to design with S355. The deck can be slender using HSS and have thinner plates, but it is more susceptible to local buckling phenomena. Brittle fracture is slightly less dimensioning using HSS, but girders are likely to be much more prone to fatigue, which proves to be the main issue of the design together with the local buckling phenomena.

The critical fatigue welded joints are analysed according to EN 1993–1‐9. For plate girders with transverse stiffeners, fatigue presents a major design constraint, namely on span sections, due to allowable plate stresses range near the welded joints.

Standard fatigue load model FLM3 with the damage equivalent factor concept is used for fatigue design of several plate girder details. Fatigue resistance of the welded joint between the transverse stiffeners and the bottom tension flange proved to be the most relevant aspect of the design of the composite steel‐concrete twin plate girder deck designed for HSS S690.
16.06: Realization and launching of the Adda‐Bitto Viaduct in Italy
Authors: Maiorana Emanuele , Sartori Lorenzo , Lazzari Massimiliano , Pellizzer Luca
Published: September 2017

In Valtellina near Sondrio, a large viaduct is to be built which will permit overpassing the town of Morbegno more quickly. Given the impossibility of carrying out installation operations using cranes from the ground and to limit the environmental interferences due to the presence of two rivers, the erection method was by launching, starting from an abutment towards the opposite one. The launching activities covered only the steel part of the deck, 167 m long, overpassing the Bitto stream and the River Adda, while the remaining portions of the deck, located near the abutments, were assembled, after completion of the launch, by crane from the ground.
16.08: The dynamic behaviour of the third Bosporus Bridge
Authors: de Ville de Goyet Vincent , Duchêne Yves , Propson Arnaud
Published: September 2017

With a length of 2240 m, this new hybrid cable cable‐stayed bridge have a main span of 1408 m. Like the Brooklyn bridge (New York), the main span is supported on one side by main cables with hangers and on the other part by stay cables. The concrete pylons reach the height of 320 m, while the deck 58 m wide and 5.50 m high bears twice four bands for international road traffic, two lanes of railway and two lateral sidewalks for pedestrians. The third bridge over the Bosporus, called Yavuz Sultan Selim Bridge is located at the North of Istanbul near the black Sea. Exceptionally bridge leads to exceptional loadings. In an area of high seismicity and in view of its length, the bridge must be checked under differential accelerations time histories in each support. Such a bridge is automatically extensively studied under the wind effects on basic data analysis of weather stations and numerous wind tunnel tests to verify its behaviour under dynamic wind gusts and verify the aerodynamic instabilities that could occur both in service and during the construction phases. For road and railway traffic, the response of the bridge depends on the speed of the train; to limit the longitudinal displacements, pendular bearings have been added. The bearings are also very useful under seism.
16.09: Influence of arch bridge skewness
Authors: De Backer Hans , Outtier Amelie , Van Puymbroeck Evy , Van Bogaert Philippe
Published: September 2017

This article performs a parameter study on a detailed finite element model of a simple arch bridge consisting of a single arch. The objective is to investigate the influence of different hanger arrangements, dimensions and finally a variation of the angle of skewness between the arch axis and longitudinal bridge deck axis. The influence on the stresses, forces and bending moments in the bridge deck girders, hangers and arch is examined. Finally, a buckling analysis is performed on all different models and the change in critical buckling load is discussed.

The displacements in the bridge deck stay the same for small angles of skewness. Starting from an angle of ± 13°, the position of maximum deflection in the bridge deck shifts towards the ends of the bridge deck instead of being situated staying in the middle. This can be explained by the influence of the wind load acting on the arch structure and the direction of the horizontal resultants of the hanger forces. This can cause partial relaxation, thus ensuring a small uplift at the longitudinal girders of the bridge deck. This is also the cause for the higher displacements in the arch. The torsion effect in the arch results in a counter clockwise rotation of the arch. When performing a buckling analysis on the changing angle of skewness, it is found that this initially has only a small impact on the critical load factor.
16.10: Challenges with water ingress in bridge cable systems
Authors: Jensen Jakob Laigaard , Lambertsen Jens , Zinck Morten , Stefansson Einar
Published: September 2017

Experiences over the last 20 years with operation and maintenance of cable borne bridges of various ages shows that water ingress in steel cable systems often occurs and causes a large risk of serious corrosion with may lead to restriction in traffic, extra ordinary inspection and maintenance costs and in worst case bridge closure. Examples of such experiences cover suspension bridges as well as cable stay bridges in USA, UK, Germany, France, Argentina, Sweden, Norway, Denmark and many other countries. The problem with water ingress is particularly critical as inspections for corrosion in cable systems are difficult to carry out and early warnings difficult to obtain.

Water ingress into a cable system means that there is a significant risk of steel corrosion even with precautions by use of galvanization and HDPE coating of cable wires. Although, cable system designs generally comprise multiple barriers against corrosion, there is often a weak link in the design. This combined with an unintended outcome in the construction phase or inadequate maintenance, may allow water to start accumulating and lead to corrosion.

This paper will explain and discuss cases from main cable and cable stay systems and point out the water ingress modes and their causes for main cable systems and different cable stays systems. Based hereupon, the paper discusses the weaknesses of the different steel cable concepts and different mitigations. The discussion also includes the mitigation of the water ingress problem by use of dehumidification. For main cables of suspension bridges, the concept has been in operation for more than 15 years with success. Considering the number of known problems with water in cable stays, the paper also contemplates on the possibility of using dehumidification for cable stay bridges as a way of handling the large amount of existing cable stay bridges.
16.11: Experimental tests on the fatigue behaviour of thick‐plate trough railway bridges
Authors: Breunig Stephanie , Kuhlmann Ulrike
Published: September 2017

One of the basic aspect of sustainability assessment for bridges is the durability namely the fatigue resistance, because bridges are planned for very long lives of more than 100 years and suffer from high cyclic loading which may restrict lifetime of the bridge by fatigue failure. Nowadays final decisions on tenders are usually based on production costs and not on lifetime costs where a high performance in view of durability may pay off.

Within a German FOSTA‐AiF‐research project an evaluation method for a life‐cycle assessment on railway bridges was developed and then applied on three different bridge types, exemplified by real reference bridges. For short spans, as an innovative bridge type, thick‐plate trough bridges were investigated because benefits in terms of sustainability were assumed due to the reduced construction time, simplified fabrication as well as prolonged durability through post‐weld treatment. Especially for the thick‐plate trough bridge, which was compared to different variants and an innovative composite bridge solution the sustainability assessment revealed high potential.

This paper gives an overview on the fatigue investigations on thick‐plate trough bridges in the frame of this research project also in view of the weld improvement through Pneumatic Impact Treatment (PIT). Aims of these investigations were the improvement of single construction details and the characterization of the load‐bearing behaviour in order to identify the most critical fatigue detail for the fatigue assessment of these small span bridges with the help of experimental investigations and analytical methods.
16.17: N‐M‐Q interaction of cross sections in steel‐concrete double composite girder bridges
Authors: Nishioka Bungo , Imagawa Yusuke , Ohyama Osamu
Published: September 2017

Recently, a double composite structure is watched in Japan. This is a structure of composite I girder bridges with lower concrete slab which is one of the major characteristics of double composite structures. That can be considered as an effective cross section, that is, moments of inertia drastically increases in comparison with usual one. Additionally, by adopting the composite action between steel girder and lower concrete slab in the region of the intermediate supports, it is not necessary to take into account of the local buckling. Moreover, the hybrid rigid frame bridge between steel girder and reinforced concrete(RC) pier has some advantages for the seismic design and also maintenance. However, this type of structures hasn't yet been researched so well in Japan. Before applying the limit state design method, for designing this structure, under the action of normal force(N), shear force(Q), bending moment(M) and each combination should be confirmed at which all cross section is in full plastic. So, in this paper, the interaction relationships among bending moment and shear force, normal force and bending moment and normal force, shear force and bending moment are discussed are reported. One of numerical results in case of applying N‐M‐Q is shown that the safety area regarding a verification of the ratio of Q/Qpℓ= 0.7 and Q/Qpℓ= 0.9 decrease about 11% and 24% compared with that of Q/Qpℓ= 0.0, respectively.
16.27: Fabrication activities and quality aspects of the Third Bosphorus Bridge orthotropic steel deck
Authors: Molinaro Carmine , Sorge Roberto , Fiscina Gennaro
Published: September 2017

The Third Bosphorus Bridge is the link of two continents, Asia and Europe, joining the two sides of Istanbul, Turkey. With its “hybrid” cable‐stayed/suspended configuration, its 322m A‐shaped towers and its Orthotropic Steel Deck, the widest (59m, 8 lanes of motorway and 2 lanes of railway) and heaviest in the world (each of the 59 segments weighting about 850 Ton, over 50000 Tons total), this is not a common bridge. And, as a consequence, not common are the technical requirements, the reference Norms and Standards and the problems and challenges encountered and tackled during its construction. This statement has proved to be particularly true with regard to the Orthotropic Steel Deck for two reasons: a) the complexity of the fabrication operations, given the difficulty of the Design and the unusual dimensions and weights involved; b) the exceptionally high quality levels to be met in terms of dimension control, surface preparation and welded joints in particular, arising from the adoption of the UNI EN 1090–2 Execution Class EXC4, requiring the EN ISO 5817 level B and the additional quality requirements specified for quality level B+.

This paper aims to describe the whole process of the Steel Deck fabrication. Raw material procurement and preparation activities are discussed. Prefabrication activities, showing how each 850 Tons segment is broken up into components to satisfy handling and assembling needs are analysed. The automated and manual welding procedures developed to meet quality and productivity requirements are described. Final segment assembly and coating activities are shown. Last but not least, the QA/QC System put in place is described, showing, where relevant, how the implications arising from UNI EN 1090–2 EXC4 come into play and how they are dealt with.
16.30: Safety evaluation of a large‐span double‐deck cable‐stayed steel bridge under fire
Authors: Liu Yushu , Lou Guobiao , Ju Xiaochen , Liu Xiaoguang
Published: September 2017

This paper presents a detailed safety evaluation of a large‐span cable‐stayed steel bridge under fire, which is also the first large‐span double‐deck highway cable‐stayed steel bridge in China. This steel bridge is a crucial part of urban lifeline engineering and is close to an industrial park which might raise the probability of being damaged by oil tank trucks or hazardous chemical vehicles, especially when a truck traveling on the lower deck of the bridge catches fire, it will endanger the safety of major steel bridge components supporting the upper deck and steel trusses on two sides. So, it is very important to conduct the performance evaluation and design of this steel bridge under fire. In this paper, the dangerous fire scenarios are selected and fluid dynamic simulations are conducted and the temperatures of the air and steel components are obtained, based on the component temperatures, structural analysis and capacity checks are made to offer reasonable preventive measures and solutions to protect the bridge subjected to the fire loading. The methodology presented in this paper is an effective approach for fire performance evaluation of bridge structures and has the potential for applications to other types of bridge structures.
18.01: Effective Vibration Dampers: Mast, towers and chimneys
Authors: Christensen Rasmus Magdal , Nielsen Mogens Gunhard , Støttrup‐Andersen Ulrik
Published: September 2017

Slender steel structures such as mast and towers consisting of or supporting cylindrical elements or chimneys can be susceptible vortex shedding. Vortex Introduced Vibrations (VIV) can be induced for slender structures because a fluctuating across wind force is generated from vortices shed alternately from opposite side of the structure. Significant VIV occurs when the frequency of the vortex shedding is the same as the natural frequency of the structure. If the critical wind speed for VIV is often occurring for the structure and the vibration amplitudes caused by the VIV are critical with respect to fatigue it can result in failure of the structure. Here an effective method of damping the vibrations can be the installation of a Tuned Liquid Sloshing Damper (TLSD). This paper focuses on design of a TLSD and compares this to the tuned mass damper (TMD) solution.

Compared to the fabrication and installation of a TMD it is much simpler to make a container and fill it with liquid. The container is often made as a square box or a cylinder that is easily mounted at the top of a mast, tower or chimney providing the most efficient damping of the critical vibration mode. Also with respect to maintenance the TLSD is preferred as it only requires that the liquid level is controlled whereas a TMD needs maintenance and possibly repair or even replacement of damper parts.

The TLSD is designed by calculating the dimensions that will result in a mode shape of the sloshing liquid with a frequency close to the natural frequency of the structure that wish to be dampened. As the liquid moves in the container the sloshing energy of the water reduces the dynamic response of the structure subjected to VIV. Experiments have shown that the TLSD is rather broad‐banded in its efficiency and also that it is effective with sloshing liquid mass down to values below 1% of the effective mass of the mode that it is designed to dampen.

Ramboll has experience with design of both types of dampers TMD and TLSD for broadcast masts and towers and for chimneys. Especially for a broadcast tower in Norway where a TMD has been replaced by a TLSD Ramboll has tested the efficiency of the TLSD for comparison with the replaced TMD. This paper will present these results and give an introduction to TSLD design.
18.05: Second‐order effects of cantilever concrete filled double skin tube (CFDST) transmission towers
Authors: Alhalaby Mahmoud , Wang Yong
Published: September 2017

Concrete Filled Double Skin Tubes (CFSDT) are an alternative to steel lattice transmission towers for supporting overhead transmission lines due to their many advantages including small footprint, fast construction, easy maintenance and elimination of large number of connections. CFDST transmission towers are tapered cantilever structure consisting of a CFDST pole and steel cross‐arms. Due to high slenderness, one key issue for static design of CFDST poles is the effect of second‐order bending (P‐Delta effect). A parametric study was conducted to investigate the second‐order effects exhibited by the CFDST transmission towers. The main parameters investigated include Horizontal to Vertical Load Ratio (HVLR) which reflects the range of environmental loads such as wind and ice, taper ratio (ratio of the bottom to the top outer diameter of the tower), and Hollow Section Ratio (HSR, ratio of the outer diameter of the inner steel tube to the inner diameter of the outer steel tube). The results of the numerical simulations indicate that the second‐order bending moments at failure of CFDST transmission towers are significant, magnifying the total bending moment by 20% or more of the first‐order bending moments. Based on the results of a parametric numerical investigation of second‐order effects of CFDST transmission tower under different conditions, this paper proposes a simplified analytical equation to estimate the second‐order bending moment.
21.10: Upgrading of a riveted railway bridge: Retrofitting of corroded plate girder steelwork
Authors: Hołowaty Janusz
Published: September 2017

The long service of railway bridges results in natural ageing and degradation which weakens the structures if they are not maintained regularly. Poor funding and prolonged service without regular repair may result in severe corrosion damage and lower structural capacity. Older structures also feature some structural solutions which have made them prone to corrosion. However, prolonged service combined with no regular painting and a harsh environment are the major reasons for corrosion resulting in the loss of a section which should be repaired accordingly.

Plate girder spans on a railway bridge were retrofitted when severe corrosion to the steelwork was discovered. The corrosion was more evident in the four oldest spans with the longest lifespan. The top flanges of the spans as well as bracing members and many rivet heads showed damage with different corrosion rates. The corrosion was uniform with local deep pitting. There was also crevice corrosion between the flange plates near the vertical stiffeners. The damaged flange plates were replaced with new thicker plates, along with the corroded bracing elements. Pretension bolts were used for the new connections. The spans were also upgraded and new cantilevers and centring shims were welded on the steelwork. Despite the corrosion losses, the plate girders were retrofitted, giving the bridge further decades of operation.
21.11: Asymmetrical cross sections in historic riveted bridges
Authors: Van Bogaert Philippe
Published: September 2017

The assessment of the load‐carrying capacity of two steel bridges dating from 1907 and 1912, showed that most of the heavily loaded cross‐sections were asymmetrical. The bridges are of the two‐hinged portal frame type. Compared to simple beam bridges, portal frames with clamped or hinged supports allow redistribution of bending moments from the span centre towards the frame nodes. Consequently, the beam height at the span centre can be reduced, which is exactly what is needed for obtaining maximum vertical clearance of the subjacent waterway. Both bridges show heavy corrosion, some parts of the flanges and angle profiles of the end portals being seriously weakened. Full inventory has been made of the corrosion damage, as it appeared mostly in the edge frames of both structures. Reduction or suppressing of flanges has been introduced in the FE‐models of both bridges to assess the remaining load‐carrying capacity for real traffic loading.

A particular characteristic are the asymmetrical cross‐sections of the main portal frames. Because of this, the compression and tensile stresses in both flanges are of unequal magnitude, favouring the latter. The reason for this became evident rather quickly. In tensile parts of the riveted structure, weakening of cross‐sections by holes has been taken into account, whereas it is not considered in compressed areas. Older standards and literature confirm the fact that this was allowed at the time riveted structures were still being built.

As today little is known about riveting, it was felt that this needed further underpinning. Apart from the longitudinal effects, lateral shrinkage of rivets during placing and plastic deformation also exist within the holes. The plastic deformation in the hole introduces a high compression between the rivet and the hole edge. As the heated rivet is cooling down and before further shrinking of the rivet diameter, this pressure must be reversed. Hence, cooling does not reduce the rivet diameter entirely, a portion being used to decompress the connection. Approximations of the process have been worked out and showed that the final reduction of the rivet section is less than the tolerance for fitting bolts. Hence, the assumptions made in the past may be underpinned to a certain extent.

This surely was resourceful during assessment of historic structures, requiring considerably more detailed numerical modelling than new structures, thus having better chances to preserve these valuable bridges for continuing use.
01.07: Numerical investigation on the semi‐rigid behaviour of austenitic stainless steel connections
Authors: Hasan Mohammad Jobaer , Ashraf Mahmud , Uy Brian
Published: September 2017

This article is not available for publication.
21.13: Experimental study on retrofitting method against fatigue cracking at the upper end of vertical stiffeners
Authors: Sakamoto Chihiro , Sakano Masahiro , Konishi Hideyuki , Koyama Masahiro
Published: September 2017

Lots of fatigue crackings were reported at the upper end of vertical stiffeners connected to sway bracings in steel highway girder bridges. In this study, we propose two types of retrofitting methods against fatigue cracking at the upper end of vertical stiffeners under RC slab. They are steel plate reinforcement using a jack‐up jig, and angle steel reinforcement using thread rolling screw (TRS). The effectiveness of those two types of retrofitting methods are experimentally investigated through fatigue tests using a large specimen with three main girders under alternative loading using two actuators. As a result, both retrofitting methods can reduce the local stress concentration at the crack initiation point to about half of that before reinforcement, and can prevent fatigue cracking. Post cracking measure, i.e. angle steel reinforcement using TRS after grinding away crack tips can extend fatigue crack propagation life more than 10 times of that without the reinforcement.
21.14: Life cycle analysis of steel structures: Why the recycling potential must be considered
Authors: Hauke Bernhard , Kuhnhenne Markus , Kreissig Johannes
Published: September 2017

A clearly structured argumentation is presented why considering the recycling potential in life cycle analysis of steel structures is the correct choice. The both prevailing production routes of structural steel, electric arc furnace and blast furnace are looked at as well as end‐of‐life collection scenarios including re‐use or recycling rates. The value of structural steel is differentiated between material value and product value when a product, e.g. a steel beam is rolled out of the steel material. With this the fair evaluation is made based on cradle to gate versus considering additionally the end‐of life scenarios of recycling and reuse. Shortcomings and merits of the methods are pointed out.
22.01: Fire and seismic assessment of an existing steel‐concrete composite structure
Authors: de Silva Donatella , Nuzzo Iolanda , Bilotta Antonio , Losanno Daniele , Nigro Emidio , Serino Giorgio
Published: September 2017

An existing steel‐concrete composite structure is analyzed in order to assess its level of protection against both fire and earthquakes. The building has been designed and built more than thirty years ago, implying that both these hazards may not be adequately verified with respect to the current codes. As concerns the fire protection, intumescent coating (IC) was applied on steel members, while an original passive energy dissipation system was employed against seismic actions. In particular, special devices were introduced to sustain the floors, which are suspended at reticular beams on the top of concrete pillars. A Fire Safety Engineering approach has been adopted to assess the structural resistance to fire. To define the thermal properties of the protective, experimental tests were carried out on the existing IC and a new IC. Moreover, thermomechanical analyses of the existing steel structure were carried out, under different fire scenarios, selected according to the fire risk of the different occupancy class of the structure. Non‐linearities and large displacements effects were taken into account. The seismic structural response has been investigated by implementing a dynamic nonlinear analysis according to the current Italian Code. In particular the seismic passive protection system, consisting in dissipative hysteretic devices combined with isolators, has been modelled as a parallel elastic and elasto‐plastic springs' system. Mechanical parameters adopted for the analyses are the result of a wide bibliography study.
22.02: The music square canopy: An outdoor stage for Amager Kulturpunkt
Authors: Aanhaanen Jaap
Published: September 2017

Musiktorvet, or “The Music Square” is the connecting element for a number of local cultural institutions, like music venues, a scenographic art institution, a children's theater and children's day care institutions. The music square is their collective outdoor stage, marked by a recently completed canopy.

The canopy provides shelter and functional space, setting the stage for concerts, circus, markets, theatre, etc. Provisions are made to allow both spontaneous and planned events, for example by a number of fixed light setups for various stage positions, whilst fixing points are provided in the roof for the attachment of audio and lighting racks.

The 500m2 canopy is formed by a grillage of welded steel box beams, supported by five slender columns, placed around the perimeter of the roof. The 70 tons roof was produced in 8 pieces which were assembled at the production facility, using the final bolted connections, before welding. This was done to ensure that all parts would fit perfectly together for the on‐site assembly. After the roof was assembled on the ground, the whole roof was lifted into place in one lifting operation.

The top of the roof is covered with triangular ETFE foil cushions, whilst a ceiling of reflective, perforated aluminum panels allows a large amount of sunlight to penetrate the roof structure. A special feature of the canopy is the steel mesh curtains that can be drawn around the perimeter of the canopy to create a more sheltered space, to match the type of event taking place. The installation of the mesh curtains required a consideration of the various wind loading conditions for open, closed and semi‐closed conditions.

This paper describes the design process and the chosen solutions with their argumentation, as well as the production and erection process.
P16.02: Sognefjord buoyancy bridge: Feasibility and sensitivity analysis
Authors: Visser Wouter , Amico Fabio , Torsing Rob , Top Reinald , Oosterman Kay , Bhattacharya Anurag , Bijlaard Frans S.K. , Yip Christine
Published: September 2017

This abstract regards the feasibility and sensitivity analysis of the Sognefjord buoyancy bridge. The bridge will be located in Norway, along the coastal highway E39, between Lavik and Oppedal. It is 4.5km long and has an S‐shape which can change depending on the weather and flow conditions. The S‐shape smoothly extends and connects the two part of the coast roads. As an architectural requirements no cable‐stayed bridge or pylons extruding above the deck are allowed. The deck has a width of 24m and an height of about 25m and in its highest point is positioned at 75m above the sea level. It will bear on 22 separate floating pontoons which will be restrained below the sea level by 44 secondary cables linked to two big main cables spanning from coast to coast and having a diameter of around 1.2m. The typical length of the side spans between the pylons is 200m and the simple supported central span has a length of 450m to allow the passing of the ship. There is no other bridge with the dimensions of the Sognefjord bridge which is the most structural challenging buoyancy bridge ever designed. An extensive analysis of the feasibility of the bridge, pontoons and anchoring system has been developed together with a sensitivity analysis of the main parameters which govern and can affect the design. The outcome of the feasibility analysis is positive and the sensitivity analysis shows that the bridge design has quite good margins to compensate for an increase of the loads. Even though future and further analysis need to be run the design and several other evaluations need to be done (connections, second order effects, fatigue, impact loads). our intermediate conclusion is that it is a feasible concept.
01.13: Experimental study of cover‐plate bolted joints with large or slotted holes
Authors: Cavène Edouard , Durif Sébastien , Bouchaïr Abdelhamid , Toussaint Evelyne
Published: September 2017

Connections in steel structures are of main importance in the design process. Cover‐plate connections with circular or slotted holes are of common use in steel structures. The behavior of such connections is characterized by various failure modes. Bearing mode is one of the most complex due to the distribution of stresses and strain around the loaded holes. This paper deals with the characterization of the behavior of cover‐plate bolted joints with slotted holes. Numerical simulations using the Cast3M FE package are performed in association with an original experimental method based on full‐field measurements. The strain fields obtained with these methods (grid method and Digital Image Correlation (DIC)) give the possibility to observe the evolution of the local deformations in the loaded zones of the connections. These evolutions are compared to those given by the Finite Element model for each configuration at different loadings stages. Thus, the experimental results are used to validate the numerical model. The comparisons are based on the load‐displacement curves, the failure modes and the local deformations in the zones around the bolts holes. Six different geometrical parameters of the holes and their positions are considered in the tests. The validated numerical model is used to evaluate the influences of the dimensions of the slotted hole. The results showed that the geometry has a significant influence on the failure mode of the connections such as net section and bearing. Both numerical and experimental results are compared to those given by the analytical approach of Eurocode 3 to evaluate the accuracy of the analytical prediction. The study shows the influence of various geometrical parameters on the resistance and the failure mode of the connections with slotted holes. The strain fields obtained with the grid method and DIC are observed in the plate around the bolt in the elastic and plastic phases. They give the possibility to observe experimentally the evolution of strains in a wide area of the most stressed zones in order to develop more accurate analytical models based on experimental evolutions of strains.
01.27: Numerical analysis E‐stubs with four bolts per row
Authors: Lopez M. , Loureiro A. , Gutierrez R. , Reinosa J. M.
Published: September 2017

The characterization of bolted steel joint behavior and properties have been matter of research for a number of years and all the accumulated knowledge has been compiled to a large extent in the currently available steel design codes like Eurocode 3. This design code uses the component method to evaluate the behavior of the steel joints.

This paper will be focused in the study of E‐stub component with four bolts per row. This component appears in three dimensional joints with additional plates welded to the column flanges to attach beams in the minor axis. The E‐stub component is not covered by the formulation of Eurocode 3. Some works have been done in the component, formulations of stiffness and strength have been proposed in previous works but only for the case of two bolts per row. Because of that a 3D advanced finite element model has been developed in order to evaluate the influence of the 4 bolts per row and to compares the results of stiffness and strength with the case of 2 bolts per row.
02.03: A reliable modelling of thermal, microstructure, and stress in arc stud welding joints and effect on fatigue strength
Authors: Soltanzadeh Hadi , Hildebrand Jörg , Kraus Matthias
Published: September 2017

This paper presents numerical calculations of welding residual stresses and the evolution of microstructure in stud joints embedded in common structural steels S235 and S355. The study deals with a numerical transient thermal modelling of stud welding using the commercial software suite SYSWELD FE. Microstructure phase fraction of Martensite, Bainite and Ferrite‐Pearlite are also calculated by trajectory tracking of the thermal profile on the CCT diagram for the weld region. Thermal loading from welding as non‐moving heat source is further fed into the stress solver and welding residual stresses are computed. The computational stresses are validated by comparison with stresses of XRD experimental measurements. The aim of this paper is to specify the stress distributions regarding residual stresses from the manufacturing and welding processes as well as stress states due to operational loads, which can constitute the basis of fatigue analyses.
02.06: Weldability of old mild steels within the rehabilitation of historical steel structures
Authors: Sieber Lars , Kilian Andrè , Flederer Holger , Göbel Gunther , Steinhauser Marco
Published: September 2017

Welding process causes notch effects and residual stresses. Accordingly, the risk of brittle fracture grows. In comparison with currently used steels, old mild steels have a lower toughness. The weldability of mild steel is limited and only feasible under specific conditions. If for structural reasons welding is preferred instead of the use of bolts, the metallurgical characteristics of the steels have to be considered. These include the concentrations of impurities in the zones of segregation and the tendency to embrittlement by nitrogen‐induced ageing.

In the corresponding paper, experimental and analytical studies of the weldability of old mild steels are presented. Extensive material analyses to determine the mechanical and the technological properties of the material will be an essential part of the investigations. Particularly, the increased impurities of phosphorus, sulfur, nitrogen and also oxygen in the segregation zones as well as the distinctive non‐metallic inclusions complicate to produce load‐bearing butt welds. Welding materials currently available are not designed for welding such materials. Nevertheless, in the context of a research project welding tests on old mild steels has been carried out using current welding electrodes. Supported by involved industrial partners, a stick electrode adapted to the characteristics of old steels will be developed.
03.03: Feasibility of hybrid simulation for testing steel connections of braces with intentional eccentricity
Authors: Skalomenos Konstantinos A. , Shimada Hironari , Kurata Masahiro , Nakashima Masayoshi
Published: September 2017

An online hybrid test environment to examine the seismic performance of the gusset plate connections of steel braces is developed by incorporating sub‐structuring techniques and finite element methods. In the developed test system, the behaviour of the brace member is simulated by the finite element analysis program ABAQUS, while the brace end connection is physically tested. Two hydraulic jacks are used to simulate the physical continuity between the analytical and experimental substructures by controlling axial load and out‐of‐plane rotation. A MATLAB user subroutine is created as the interface between the main control program and ABAQUS to impose the target rotation and axial force to the connection quasi‐statically. A gusset plate connection designed to behave as a pin connection is tested and its efficiency to accommodate inelastic rotations was evaluated up to 4% story drift. The test method is reasonable, with smooth operation and ensures realistic loading and boundary conditions.
03.07: Robustness in fire of a new type of beam‐to‐column connection
Authors: Malendowski Michał , Burgess Ian , Glema Adam
Published: September 2017

In this paper a new type of beam‐to‐column connection is introduced, which is capable of absorbing both very large rotations and axial movements, due firstly to thermal elongation and subsequently to extreme weakening of the connected beam. The main idea is to connect the beam and column using a special connector bolted to the column flange using a face‐plate and to the beam web using a fin‐plate. Between these a highly ductile element, which is in this case a hollow circular tube, is included. This plays the crucial role in absorbing beam‐end movements occurring firstly during the expansion of the beam and secondly during its catenary behaviour at very high temperatures.

This study aims to extend the research on this connection to structural case studies in the context of performance‐based structural fire engineering design. The connection has been modelled using different approaches, starting with 3‐D finite element modelling and proceeding to validated simplifications which feed into a component‐based model. In order to make calculations feasible, the mathematical model of the ductile component is developed and calibrated using the information provided by parametrized numerical FEM computations. The component model is developed to be capable of representing the hysteresis occurring due to deformation‐reversals as temperatures rise, as well as failure corresponding to fracture in tension. Thus, the component model is described as a function of displacement and temperature, including sufficiently realistic plastic deformation and fracture criteria. This model is then implemented into global FEM models and utilized to assemble the stiffness matrix of a special connector element used to join the beam and column nodes. This component‐based connection model is then applied in some comparative studies.