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BaeÃŸler, Matthias; RÃ¼cker, Werner; CuÃ©llar, Pablo; Georgi, Steven; Karabeliov, Krassimire  Largescale testing facility for cyclic axially loaded piles  Steel Construction  3/2013  200206  Articles 
KurzfassungOffshore piles have to withstand predominantly cyclic axial loads when they are installed in multipile configurations, as in jacket foundations. The dimensions of the pile are governed by both the internal capacity and the fatigue behaviour of the steel crosssection as well as by its external capacity in the pilesoil interaction. Owing to the large numbers of piled foundations required for current and future offshore wind farms, there is an urgent need to optimize the dimensions and related costs of single piles. With regard to the pile capacity, two major topics of research are the determination of possible capacity gains due to pile ageing effects and proper consideration of cyclic degradation. In order to investigate both effects, a largescale testing facility has been constructed at the BAM TTS site in Horstwalde near Berlin. This openair facility allows large tubular driven piles to be loaded cyclically in both tension and compression while studying the ageing effects by introducing delays between the testing campaigns. First results already show a moderate increase in pile capacity over time. Concerning the anticipated capacity degradation of cyclically loaded piles, preliminary results show an unexpected behaviour. Additional tests are currently being conducted for further clarification. x


Founding of "Gesellschaft fÃ¼r Bautechnikgeschichte"  Steel Construction  3/2013  206  News  
Schmidt, Michael; Fehling, Ekkehard; Braun, Torsten  Grouted connections for offshore wind turbine structures, Part 1: Individual approval, materials and quality control  Steel Construction  3/2013  207215  Articles 
KurzfassungOn offshore wind turbine structures, grouted connections are widely used to connect the tower structure to the foundation while accommodating the unavoidable geometrical tolerances effectively. The longterm behaviour of high and ultrahighstrength grouts primarily depends on the adequate strength and durability of the material plus the process reliability. The performance of the fresh and the hardened grout is influenced by many factors that have to be evaluated and considered individually with respect to the “rough” offshore conditions. Those factors are: mix performance and consistency, the ambient conditions at the place and time of use, the equipment for and stability of the mixing and casting processes, the length of casting time and the thermal and mechanical loads during the early stages. To ensure adequate longterm behaviour, a meaningful quality assurance system should be set up to cover both the materials and the processes. The article emphasises some fundamental experiences gained by the authors with numerous wind turbine parcs in the North Sea and the Baltic Sea. x


Fehling, Ekkehard; Leutbecher, Torsten; Schmidt, Michael; Ismail, Mohammed  Grouted connections for offshore wind turbine structures, Part 2: Structural modelling and design of grouted connections  Steel Construction  3/2013  216228  Articles 
KurzfassungIn many cases, the design checks of grouted connections follow international standards which contain analytical design equations. In order to also obey mechanical consistency especially for structures with significant bending moment and to satisfy basic requirements according to the Eurocodes, different mechanical models have been used in practice in a number of cases. In this regard, nonlinear finite element models as well as analysis with strut and tie models have been applied. Findings from these calculations as well as from experimental investigations on both the material and the structural level are analysed and compared. In conclusion, an improved design approach based on a strut model which is easy to handle is presented and exemplified. x


Kido, Ewa Maria; Cywinski, Zbigniew  The new steelglass architecture of buildings in Japan  Steel Construction  3/2013  229237  Reports 
KurzfassungPractical examples of modern architecture in the western hemisphere based on structural compositions of steel and glass have been presented several times in recent years. In doing so, their theoretical background has also been discussed. This paper focuses on the relevant architectural manifestations in Japan. Buildings for commercial and public use are the sole interest here  with special emphasis on the ultramodern character of their design. It is planned to consider infrastructure elements such as railway stations and airport structures in a future article. x


Ernst , Claudia; Brunier , Knut  The Design Carport  A selfsupporting folded steel sheet structure  Steel Construction  3/2013  238241  Reports 
KurzfassungIn the design and making of complex architectural systems, sheet metal is still predominantly used as a cladding material. The objective here is to integrate innovative digital and analogue methodologies to develop a design system for a selfsupporting lightweight structure entirely based on the use of sheet metal as a construction material. x


Eilzer, Wolfgang; Jun, Rolf; Angelmaier, Volkhard; Maier, Markus  HansPeter AndrÃ¤ reached 65  Steel Construction  3/2013  242243  People 
Hovering wings of light in Hamburg are completed  Steel Construction  3/2013  243  News  
Announcement: Steel Construction 3/2013  Steel Construction  3/2013  243  Announcement  
ECCS News: Steel Construction 3/2013  Steel Construction  3/2013  244246  ECCS News  
Contents: Structural Concrete 3/2013  Structural Concrete  3/2013  Contents  
Foster, Stephen  Physical understandings and development of mechanical models for the design of concrete structures  Structural Concrete  3/2013  193194  Editorial 
Sigrist, Viktor; Bentz, Evan; Ruiz, Miguel FernÃ¡ndez; Foster, Stephen; Muttoni, Aurelio  Background to the fib Model Code 2010 shear provisions  part I: beams and slabs  Structural Concrete  3/2013  195203  Technical Papers 
KurzfassungThis paper examines the evidence for the oneway shear model developed for the fib Model Code for Concrete Structures 2010 and provides examples of its application. For the design and analysis for shear, for members with and without shear reinforcement, the fib Model Code 2010 procedures have been developed from physicalmechanical models that are based on observed behaviour at the mesoscale level; they represent a significant advance over previous standardized empirical methods. In addition, an approach referred to as “level of approximation” (LoA) is incorporated where advanced models are simplified in a consistent and conservative way such that the designer can select the effort needed to justify their design. To illustrate the practical use of the models and the LoA approach, two examples are presented. The first is a deck slab of a cutandcover tunnel where design and possible refinements are discussed for a given configuration. The second is a prestressed concrete bridge girder, which is considered for the cases of design and for the analysis of an existing structure. x


Muttoni, Aurelio; Ruiz, Miguel FernÃ¡ndez; Bentz, Evan; Foster, Stephen; Sigrist, Viktor  Background to fib Model Code 2010 shear provisions  part II: punching shear  Structural Concrete  3/2013  204214  Technical Papers 
KurzfassungThis paper outlines the theoretical background to the punching shear provisions implemented in the fib Model Code for Concrete Structures 2010 and presents a practical example of their application. The aim is to explain the mechanical model that forms the basis for the punching design equations, to justify the relevance of the provisions and to show their suitability for the design and assessment of structures. x


Fardis, Michael N.  Performance and displacementbased seismic design and assessment of concrete structures in fib Model Code 2010  Structural Concrete  3/2013  215229  Technical Papers 
KurzfassungThe scope of fib Model Code for Concrete Structures 2010 includes the fully fledged performance and displacementbased seismic design of new structures and assessment of existing ones. This part of fib Model Code 2010 covers buildings, bridges or similar concrete structures and aims to provide welldefined performance levels for specific seismic hazard levels. Detailing of members for ductility is not based on opaque prescriptions, as in current codes, but on transparent, explicit verification of inelastic deformation demands against capacity limits. The reference analysis method is nonlinear dynamic, but under certain conditions inelastic deformation demands may be estimated from linear analysis and the 5%damped elastic response spectrum; in that case force demands on forcecontrolled, brittle failure modes are estimated from the plastic mechanism through equilibrium. In order to predict the seismic deformation demands with some confidence, the analysis should use realistic values for the member secant stiffness up to the yield point. The paper explains the background to the expressions given for this property in fib Model Code 2010 as well as of those for the deformation limits used when verifying seismic deformation demands. The modifications to the shear resistance approach of fib Model Code 2010, which takes cyclic loading into account, are also explained and justified. x


Randl, Norbert  Design recommendations for interface shear transfer in fib Model Code 2010  Structural Concrete  3/2013  230241  Technical Papers 
KurzfassungInterface shear transfer between differently aged concretes is a topic that crops up frequently and in different situations in structural design. In the fib Model Code for Concrete Structures 2010 the fundamental basics of concretetoconcrete load transfer are given in section 6.3 and the corresponding design rules in 7.3.3.6. The different potential mechanisms contributing to the shear resistance along the interface, i.e. adhesive bond, aggregate interlock, friction and dowel action, are thus combined and their relationship taken into account by interaction factors. This article summarizes the most important results from past and ongoing studies and presents the background to the theory forming the design basis of fib Model Code 2010, the “extended shear friction theory” (ESF). x


Belletti, Beatrice; Damoni, Cecilia; den Uijl, Joop A.; Hendriks, Max A. N.; Walraven, Joost C.  Shear resistance evaluation of prestressed concrete bridge beams: fib Model Code 2010 guidelines for level IV approximations  Structural Concrete  3/2013  242249  Technical Papers 
KurzfassungThe design shear resistance of an existing structure can be evaluated with analytical design procedures and numerical procedures provided by nonlinear finite element analyses. The new fib Model Code 2010 proposes different calculation methods that fall into four different levels of approximation. As the level of approximation rises, so the complexity and the accuracy of the calculated shear resistance increases. Nonlinear finite element analyses belong to the highest level of approximation, but although they are more and more becoming a customary tool in the daily design process, building codes do not provide guidance on how to perform these analyses. x


Ayoub, Essam; Malek, Charles; Helmy, Gamal  Highlights of the design and construction of a 12 km elevated APM bridge project in Saudi Arabia  Structural Concrete  3/2013  250259  Technical Papers 
KurzfassungThe automated people mover (APM) bridge project constructed at Princess Nora University (PNU) in Saudi Arabia and inaugurated in May 2012 is a major project with many challenges in design and construction due to its strict timeframe compared with the big scale of the project. Therefore, the design had to be such that it ensured simplicity, timesavings, lowest costs, aesthetics and the high quality required for bridge project elements. For aesthetic reasons, a box section was chosen for all the APM bridge sections for the bridge project, including straight, bifurcation and curved parts. This paper highlights the efficiency of the precast concrete techniques used in the design and construction of big projects such as this elevated APM bridge project at PNU in Saudi Arabia. x


Zanuy, Carlos; Curbach, Manfred; Lindorf, Alexander  Finite element study of bond strength between concrete and reinforcement under uneven confinement condition  Structural Concrete  3/2013  260270  Technical Papers 
KurzfassungIt is well known that many factors affect the bond behaviour between concrete and steel reinforcement. Most of them characterize the degree of confinement, which is necessary for an appropriate determination of the bond strength and bondslip relationship according to most extended models. Nevertheless, there are situations where the confinement is not known in advance or it can hardly be defined. That is, for example, the case of reinforced concrete under transverse pressure or tension. Under such conditions the confinement varies both longitudinally and circumferentially. This paper presents a 3D finite element approach to study the bond capacity of cases where the bond strength of the specimen is the result of the different contribution provided along the steelconcrete interface and cannot be described uniquely. A surfacetosurface contact model with frictional behaviour and debonding is used to study the influence of the local stress state at the interface. The model is able to reproduce the different failure modes (splitting or pullout) obtained in experiments and provide a rational explanation of the influence of transverse tension. x


Iskhakov, Iakov; Ribakov, Yuri  Twolayer concrete bridge beams as composite elements  Structural Concrete  3/2013  271277  Technical Papers 
KurzfassungTwolayer highperformance RC beams can be used in the traffic (longitudinal) direction of longspan bridges. The beam section consists of two parts: a bottom part made of normalstrength concrete (NSC), which has a Utype section, and an upper one made of steel fibrereinforced highstrength concrete (HSC), which has a rectangular section. Using twolayer beams is logical because as the beam span becomes longer and the service load increases, so a higher concrete strength is required in the beam's compression zone to withstand rather large bending moments. As concrete in the tension zone of the section contributes little to the beam's loadbearing capacity, this zone is made of NSC. This is an important economical advantage of twolayer beams. Steel fibres are only used in the compression zone made of HSC. The addition of steel fibres results in a higher ductility for the HSC layer, allowing proper design of twolayer bridge beams for dynamic loads. The design parameters for such beams include the HSC class, where the HSC layer depth is known and is equal to the depth of the rectangular section (above the Usection). The bottom NSC part (Usection) of a longspan beam is usually prestressed. Taking into account this circumstance, the total beam section depth should be checked for the serviceability limit state. x


Yamanobe, Shinichi; Saito, Kimio; Ichinomiya, Toshimichi; Kanamitsu, Yoshihisa  Bilateral loading experiment on and analysis of concrete piers using mortarjointed ultrahighstrength fibrereinforced concrete precast formwork  Structural Concrete  3/2013  278290  Technical Papers 
KurzfassungThe seismic performance of a reinforced concrete pier structure depends greatly on the plastic hinge region at the base of the pier. To improve the plastic hinge region of the structure, we propose using ultrahighstrength fibrereinforced concrete (UFC) formwork for the concrete cover at the base of the pier. This study describes the structural characteristics of a pier with a base cast using mortarjointed UFC formwork. x


fibnews: Structural Concrete 3/2013  Structural Concrete  3/2013  291297  fibnews  
KurzfassungFirst International Conference on Concrete Sustainability (ICCS13) in Tokyo, Japan x


Contents: UnternehmerBrief Bauwirtschaft 3/2013  UnternehmerBrief Bauwirtschaft  3/2013  Contents  
Schalk, GÃ¼nther  Von neuen und verhinderten Gesetzen ?  UnternehmerBrief Bauwirtschaft  3/2013  1  Editorial 
Kurz infomiert  UnternehmerBrief Bauwirtschaft  3/2013  2  Kurz informiert  
KurzfassungBau startet mit gemischten Gefühlen ins neue Jahr x
