abo_gift abo_online abo_print abo_student abo_test angle_left angle_right angle_right_filled arrow_big_down arrow_big_down_filled arrow_big_left arrow_big_left_filled arrow_big_right arrow_big_right_filled arrow_big_up arrow_big_up_filled arrow_dropdown_down arrow_dropdown_up arrow_small_left arrow_small_left_filled arrow_small_right arrow_small_right_filled arrow_stage_left arrow_stage_left_filled arrow_stage_right arrow_stage_right_filled caret_down caret_up close close_thin close_thin_filled contact download_thick download_thick_filled download_thin download_thin_filled ebook edit element_headline element_label element_relatedcontent lock mail minus page page_filled pages pages_filled phone plus print print_filled quotationmarks_left quotationmarks_right search send share share_filled shoppingcart_big shoppingcart_big_filled shoppingcart_header shoppingcart_small shoppingcart_small_filled social_facebook social_googleplus social_linkedin social_pinterest social_twitter social_xing social_youtube user_big user_small

Artikeldatenbank

Filter zurücksetzen
  • Autor(en)

  • Sprache der Veröffentlichung

  • Erschienen

  • Rubrik

Zeitschriften-Selektion

  • Alle auswählen Keine auswählen
Autor(en) Titel Zeitschrift Ausgabe Seite Rubrik
Contents: Structural Concrete 4/2014 Structural Concrete 4/2014 Contents

Kurzfassung

Keine Kurzfassung verfügbar.

x
Glavind, Mette Innovations in concrete for sustainable infrastructure constructions Structural Concrete 4/2014 439-440 Editorial

Kurzfassung

Keine Kurzfassung verfügbar.

x
Dahl, Kaare K. B. Bella Sky Hotel - taking precast concrete to the limit Structural Concrete 4/2014 441-447 Technical Papers

Kurzfassung

The Bella Sky Hotel consists of two towers each leaning away from each other at an angle of 15°. The basic principle is vertical loadbearing walls with precast concrete hollow-core floor slabs.
At the ends of the building, inclined walls are used to carry the vertical walls above where they are undercut. At these junctions the horizontal forces induced by turning the vertical forces are huge, and need to be transferred through the floors into the longitudinal walls. The complexity of the structure comes from the number of openings in these walls for doors and services in conjunction with the enormity of the horizontal loads from the lean of the building.
The use of precast elements meant that the forces had to be transferred through the joints in the elements. Severe reinforcement congestion - plus the fact that most of the geometry throughout the building is unique - led to an enormous design and engineering effort required to produce a solution.
The final result is a simple, elegant hotel structure that with one of the greatest leans of any building worldwide jumps into the record books.

x
Clark, Gordon Challenges for concrete in tall buildings Structural Concrete 4/2014 448-453 Technical Papers

Kurzfassung

Tall buildings present unique challenges in terms of both design and construction. The definition of tall is always a matter for debate and actually is related to the proportions of the building, although the actual physical height does also result in other influences such as extreme lateral loading.
Concrete features prominently in providing the structural material for most cores and framing options, thus ensuring stability of the structure. The core of a tall building is important structurally as well as for forming the spine for vertical transportation and services. There can be a wide choice of size and shape, which is dictated in part by the geometry of the building and the site.
This paper focuses on some of the issues for concrete, which is a key material in tall building construction, and is based on some of the work of an fib task group that has been formed to bring together important guidance based on experience of design and construction.

x
Reinhardt, Hans-Wolf Aspects of imposed deformation in concrete structures - a condensed overview Structural Concrete 4/2014 454-460 Technical Papers

Kurzfassung

Imposed deformation is a special case of loading that gets much less attention than mechanical loading due to external forces. However, imposed deformation can impair the serviceability of structures such as tightness and durability. Imposed deformations are due to shrinkage of concrete and temperature variations. The boundary conditions play an important role when analysing stresses due to imposed deformation. This paper provides an overview.

x
Theiner, Yvonne; Andreatta, Andreas; Hofstetter, Günter Evaluation of models for estimating concrete strains due to drying shrinkage Structural Concrete 4/2014 461-468 Technical Papers

Kurzfassung

The present contribution focuses on a comparative study of shrinkage prediction models according to the European Standard Eurocode 2 (EC2), the recommendation by ACI committee 209 and fib Model Code for Concrete Structures 2010. The estimated ultimate drying shrinkage strains and the predicted evolution of drying shrinkage strains are compared with respective shrinkage strains measured on normal-strength concrete specimens of different sizes. For all prediction models, the estimated ultimate values are found to agree quite well with the ultimate drying shrinkage strains measured on thin concrete slices. Whereas the evolution of drying shrinkage strains measured on small concrete prisms agree quite well with the predicted values, substantial differences between code values and experimental data are encountered for larger specimen sizes.

x
Scott, Richard Serviceability uncertainties in flat slabs Structural Concrete 4/2014 469-483 Technical Papers

Kurzfassung

Service load tests on the 6th floor of the full-scale reinforced concrete building at BRE Cardington are described. Both deflections and reinforcement strains were measured. Finite element analyses of the floor slab were then undertaken using the measured material properties and four different models for the behaviour of the concrete in tension, the tension stiffening effect being known to influence slab behaviour significantly. Calculated deflections and reinforcement strains from the four analyses were compared with values measured in the load tests. As a consequence, comments, reservations and recommendations are made concerning the use of FE analyses for predicting deflections and reinforcement strains. Finally, the need to appreciate and accommodate the indeterminate nature of many of the parameters involved is emphasized.

x
Winkler, Karsten; Mark, Peter; Heek, Peter; Rohländer, Sandra; Sommer, Simone Punching shear tests on symmetrically reduced slab quarters Structural Concrete 4/2014 484-496 Technical Papers

Kurzfassung

Experiments on large-scale reinforced concrete members such as beams or slabs with large effective depths are challenging and - not least due to the extensive material and financial input - rarely performed. However, results from such experiments are desperately needed, as critical size effects affect shear and punching shear failure types. At the Institute of Concrete Structures at Ruhr-Universität Bochum (RUB), an innovative test setup was devised following the principle of “upsizing by downsizing”. It transfers symmetry reductions - a standard feature in numerical simulations - to experiments. Thus, test loads and dead loads decrease markedly in proportion to the degree of symmetry, giving rise to larger specimens within given testing facilities. The setup enables tests on symmetrically sectioned concrete members - halved beams or quarters of slabs - concurrently implying the load-deformation behaviours of corresponding, i.e. full-size members, by simply factoring the loads with twice the axial symmetry degree.
This paper presents the single steps in the development to test quartered slabs, including the modular support constructions with sliding planes and anchoring of the bending reinforcement as well as the concrete specimen itself, with interconnections to the symmetry planes, measuring techniques and its specific assembly. Results from a first prototype testing prove the general applicability for failure modes, crack patterns and kinematics. However, ultimate punching loads are still slightly overestimated.

x
Siburg, Carsten; Ricker, Marcus; Hegger, Josef Punching shear design of footings: critical review of different code provisions Structural Concrete 4/2014 497-508 Technical Papers

Kurzfassung

Eurocode 2 and the corresponding National Annex were introduced in Germany in 2012. Most of the design provisions for these new standards were adopted from Model Code 1990 and provide a new design approach for ground slabs and footings. For the fib Model Code for Concrete Structures 2010, the punching shear design concept has been revised and introduced in Swiss standard SIA262:2013. This paper presents in detail the design equations for determining the punching capacity according to Eurocode 2, the German National Annex to Eurocode 2, fib Model Code 2010 and SIA 262:2013.
Parametric studies have been used to examine the influence of the main parameters (shear span-depth ratio, effective depth, longitudinal reinforcement ratio and concrete compressive strength) on the punching shear resistance of footings. To quantify the level of safety and the efficiency, the design provisions are compared with systematic test series.

x
Abdellahi, Majid; Heidari, Javad; Bahmanpour, Maryam A new predictive model for the bond strength of FRP-to-concrete composite joints Structural Concrete 4/2014 509-521 Technical Papers

Kurzfassung

In this work, gene expression programming (GEP), as a new tool, has been used to predict the bond strength of fibre-reinforced polymer-to-concrete composite joints as the performance symbol of this structure. Some 238 datasets were collected from the literature, divided into 192 and 46 sets at random and then trained and tested respectively by means of GEP. The parameters width of prism, concrete cylinder compressive strength, width of fibre-reinforced polymer (FRP), thickness of FRP, modulus of elasticity of FRP and bond length were used as input parameters. Using these input parameters, the bond strength of FRP-to-concrete composite joints in different conditions was predicted in the GEP model. The training and testing results in the GEP model show that GEP is a powerful tool for predicting the bond strength values of the FRP-to-concrete composite joints in the range considered.

x
Hertz, Kristian; Castberg, Andreas; Christensen, Jacob Super-light concrete decks for building floor slabs Structural Concrete 4/2014 522-529 Technical Papers

Kurzfassung

This paper presents investigations carried out at the Technical University of Denmark (DTU) on a prototype series for a super-lightweight prestressed concrete deck element called the SL-Deck.
The intention behind making a new prefabricated deck element is to improve performance with respect to flexibility, sound insulation and fire resistance compared with present-day prefabricated structures.
Full-scale tests and theoretical investigations show that the deck structure performs as intended. Also, that it is possible to assess by calculation the loadbearing capacity in bending and shear, and assess the pull-out strength of prestressing wires, the fire resistance and the acoustic insulation. Based on the results of the investigations, recommendations are given for further development of the structure before fully automated mass production is established.

x
Urban, Susanne; Strauss, Alfred; Schütz, Robert; Bergmeister, Konrad; Dehlinger, Christian Dynamically loaded concrete structures - monitoring-based assessment of the real degree of fatigue deterioration Structural Concrete 4/2014 530-542 Technical Papers

Kurzfassung

When it comes to dynamically loaded concrete structures, determining the real degree of fatigue damage of a structure on site is a very demanding process that has not been explored in depth. Calculation concepts according to current codes and specifications (e.g. fib Model Code for Concrete Structures 2010 [1]) do not offer efficient results for this task. However, the permanent monitoring from the erection of a structure up to the end of its lifetime is seen as a very promising possibility for assessing the degree of damage constantly. This article takes a closer look at the concrete fatigue concept of fib Model Code 2010 [1], shows an FE simulation of a time-dependent fatigue process for an offshore wind turbine foundation and presents a fatigue monitoring concept including laboratory tests, which enables the detection of the real degree of deterioration in a concrete structure. During tests, the use of ultrasound was identified as the most appropriate method. Measuring wave velocity enables the determination of the dynamic E-modulus, which correlates to the degree of damage within the cross-section of the structure considered.

x
Won, Deok Hee; Park, Woo Sun; Jang, In-Sung; Han, Sang-Hun; Han, Taek Hee Fire resistance performance of steel composite hollow RC column with inner tube under ISO 834 standard fire Structural Concrete 4/2014 543-555 Technical Papers

Kurzfassung

An internally confined hollow RC (ICH RC) column offers strong and durable confinement owing to the reinforcement provided by the inner tube. The strength and ductility of the column are enhanced because of the continuous confining stress provided by the inner tube. The excellent structural performance of ICH RC columns makes them particularly suitable for applications in high-rise buildings. However, if a high-rise building is damaged by fire, it will collapse without fire resistance performance. Also, lack of evacuation measures endangers human life. Thus, to predict the status of structures in fires, their behaviour should be evaluated in terms of fire time. In this study, the fire resistance performance of an ICH RC column was analysed during an ISO 834 standard fire and with certain initial conditions. Furthermore, the effects of hollow ratio, thickness of inner tube and thickness of cover concrete on the fire resistance performance were analysed. The results could be used for designing fire-resistant ICH RC columns.

x
Messari-Becker, Lamia; Mettke, Angelika; Knappe, Florian; Storck, Ulrich; Bollinger, Klaus; Grohmann, Manfred Recycling concrete in practice - a chance for sustainable resource management Structural Concrete 4/2014 556-562 Technical Papers

Kurzfassung

Private households consume about 30 % of Germany's total primary energy and cause about 15 % of the total CO2 emissions, and so this sector represents a key sector for climate protection targets. Whereas primary energy consumption in buildings is limited by regulations, the production of carbon emissions-intensive materials is only moving slowly into the focus of legislation, regulations and, ultimately, the perception of society. Considering a thermally conditioned building during its life cycle, most environmental effects are during operation. Nevertheless, the grey energy of a concrete structure can add up to 20 % in individual cases. Owing to the carbon-intensive cement production, concrete as a material causes relatively high environmental impacts. Logical options appear to be substituting cement with so called by-products or using recycled additives. In fact, there are only a few projects that have used a resource-saving concrete. In 2010 in Ludwigshafen, one building in a group of buildings was chosen as the first building in Germany to be built almost completely from recycled concrete without increasing the cement content. It was built as a low-energy construction and in a zero-carbon-emissions area. The project was supported scientifically by the Institute of Energy and Environmental Research in Heidelberg and the Brandenburg University of Technology Cottbus. The buildings won the Construction Prize 2011 with the distinction “best relation between quality and costs”. This paper discusses integral aspects of the use of recycling concrete from the structural design, eco-accounting and materials properties perspectives. It demonstrates the potential and opportunities for the quality-assured use of recycling concrete for sustainable resource management.

x
Randl, Norbert; Kunz, Jakob Post-installed reinforcement connections at ultimate and serviceability limit states Structural Concrete 4/2014 563-574 Technical Papers

Kurzfassung

When reinforcing bars are post-installed in holes drilled in cured concrete, adhesive mortars are used to create a bond between concrete and bars. Appropriate adhesives can develop higher bond strengths than standard ribbed bars cast into concrete. A detailed design concept for the anchorage length of reinforcing bars has been developed by taking into account splitting/spalling of the concrete and pullout. Pullout and splitting tests on reinforcing bars set in concrete were carried out with different adhesive mortars and with varying concrete strengths and concrete covers. When higher bond strengths than those recommended for cast-in reinforcement are taken into account, it is important to check deformations and crack widths at the serviceability limit state (SLS) separately. For this reason, structural tests on slabs and corbels were carried out. Moreover, pullout tests on post-installed reinforcing bars were performed in order to measure displacements at service load level.

x
Korte, Sara; Boel, Veerle; De Corte, Wouter; De Schutter, Geert Behaviour of fatigue loaded self-compacting concrete compared to vibrated concrete Structural Concrete 4/2014 575-589 Technical Papers

Kurzfassung

Fatigue loading and its sometimes inevitable fatigue failure are common in many civil engineering construction projects. The behaviour of vibrated concrete (VC) under this type of loading is well understood. However, the fracture and fatigue resistance of self-compacting concrete (SCC) is poorly documented in literature. Considering the substantially different composition of the two concrete types (VC and SCC), it is uncertain whether their mechanical properties are similar or not. This paper describes the results of a series of destructive static and cyclic four-point bending tests on inverted T-shaped reinforced concrete beams, made from VC and SCC in equal quantities and of equal compressive strength. A comparison of the two concrete types is made, based on deflection, strain, crack width evolution and failure mechanism. The experiments prove that these mechanical properties of VC and SCC, subjected to a fatigue load, in some cases relate differently from a static loading process. Furthermore, the results reveal a faster concrete strain and crack width development for SCC during the fatigue tests. Regarding the number of cycles to failure, the applied load level is crucial.

x
2014 reviewers Structural Concrete 4/2014 590 Reviewers

Kurzfassung

Keine Kurzfassung verfügbar.

x
fib-news: Structural Concrete 4/2014 Structural Concrete 4/2014 591-597 fib-news

Kurzfassung

Structural changes in the fib; 60 years of setting standards; Summer studies in Milan; fib Bulletin 73; New fib Presidium; HPC conference and MC2010 workshop in Beijing; Short notes; Congresses and symposia; Acknowledgement

x
Structural Concrete 1/2015 Structural Concrete 4/2014 598 Preview

Kurzfassung

Keine Kurzfassung verfügbar.

x
Inhalt: UnternehmerBrief Bauwirtschaft 4/2014 UnternehmerBrief Bauwirtschaft 4/2014 Inhalt

Kurzfassung

Keine Kurzfassung verfügbar.

x
Schroeter, Heinrich Wo kommen die Ingenieure her? UnternehmerBrief Bauwirtschaft 4/2014 1 Editorials

Kurzfassung

Keine Kurzfassung verfügbar.

x
Kurz informiert: UnternehmerBrief Bauwirtschaft 4/2014 UnternehmerBrief Bauwirtschaft 4/2014 2 Kurz informiert

Kurzfassung

ÖPP und PPP sind nicht so schlecht wie ihr Ruf
Deutscher Immobilienmarkt als “sicherer Hafen”
Lob für Gesetzentwurf gegen Zahlungsausfälle am Bau

x
Danielzik, Jürgen; Stenger, Stefan Duales Studium schafft ideale Führungskräfte von morgen UnternehmerBrief Bauwirtschaft 4/2014 3-9 Berichte

Kurzfassung

Unsere Gesellschaft und mit ihr die Bauwirtschaft befindet sich im demographischen Wandel. Als direkt spürbare Folge zeigt sich in vielen Unternehmensbereichen der Mangel an gut ausgebildeten Nachwuchs-Führungskräften. Heute und vermehrt in der Zukunft verlieren die Bauunternehmen in allen Hierarchieebenen wichtige Fachkompetenzen durch das altersbedingte Ausscheiden von erfahrenen Führungskräften. Für Baufirmen aller Größenordnungen stellt sich daher seit längerem die gleiche Frage: “Woher bzw. wie bekomme ich meine Führungskräfte von morgen, die sowohl in Theorie als auch der Praxis überzeugen können?” Eine Antwort auf diese Frage ist ein Absolvent eines dualen Studiengangs, der eine qualifizierte Ausbildung in einem Bauberuf des Hoch- oder Tiefbaus mit einem Hochschulstudium zum Bauingenieur kombiniert.

x
BMWi-Markterschließungsprogramm für KMU UnternehmerBrief Bauwirtschaft 4/2014 9 Berichte

Kurzfassung

Keine Kurzfassung verfügbar.

x
Talebitari, Burkhard Feiermarathon: BVMB wird 50 und vollzieht Generationenwechsel UnternehmerBrief Bauwirtschaft 4/2014 10-12 Berichte

Kurzfassung

Der Wechsel des Hauptgeschäftsführers der BVMB von Friedhelm Noss zu Michael Gilka - 50 Jahre Bundesvereinigung Mittelständischer Bauunternehmen e.V. - traditioneller Neujahrsempfang: Anlass zum Feiern, diesmal im Bonner Maritim-Hotel mit über 650 Teilnehmern, aber auch Anlass für deutliche Worte des Präsidenten der BVMB, Thorsten Bode. Denn zum Ausruhen, zumal nach wenig Winter, lässt die aktuelle Situation am Bau der nun 50jährigen, wie eh und je schlagkräftigen Vereinigung, wenig Zeit...

x