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Festkolloquium zum 80. Geburtstag von Prof. Dr. Kurt Schetelig
Weihnachtskolloquium 2016 “Geotechnik” an der TH Georg Agricola

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41. Geomechanik-Kolloquium in Freiberg. (Prof. H. Konietzky, Dr. A. Hausdorf)
8. Hans Lorenz Symposium: Gründung von Offshore-Bauwerken. (Univ.-Prof. Dr.-Ing. habil. Christian Moormann)

32. Baugrundtagung der DGGT (Dipl.-Ing. Steffen Leppla)
22. European Young Geotechnical Engineers Conference (Christian Thienert, Bozhana Stefanova)
Baltic Piling Days 2012 (G. Heerten)
2. Symposium “Baugrundverbesserung in der Geotechnik” (Prof. Dr.-Ing. Ralf Thiele)
11th ISM 2012 “International Workshop on Micropiles” in Mailand, Italien (Dipl.-Ing. E. F. Ischebeck)

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1. Wiener U-Bahn-Tagung
2. RuhrGeo Tag: Eurocode 7

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• 36. Geomechanik-Kolloquium, Freiberg
• Messen im Bauwesen 2011
• 18. Darmstädter Geotechnik-Kolloquium am 17. März 2011

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Concrete is the most widely used construction material. Worldwide consumption of cement, the strength-giving component in concrete, is now estimated to be 4.10 Gt per year, having risen from 2.22 Gt just 10 years ago. This rate of consumption means that cement manufacture alone is estimated to account for 5.2 % of global carbon dioxide emissions.
Concrete offers the opportunity to create structures with almost any geometry economically. Yet its unique fluidity is seldom capitalized upon, with concrete instead being cast in rigid, flat moulds to create non-optimized geometries that result in structures with a high material usage and large carbon footprints. This paper will explore flexible formwork construction technologies that embrace the fluidity of concrete to facilitate the practical construction of concrete structures with complex and efficient geometries.
This paper presents the current state of the art in flexible formwork technology, highlighting practical uses, research challenges and new opportunities.

The impact of heavy trucks on a bridge substructure can lead to progressive collapse of the bridge superstructure, and to disastrous accidents. This type of load should therefore be taken into consideration, especially in the design of motorway bridges. For some structural arrangements, vehicle impact is the decisive loading for the design of the bridge substructure. This paper presents verification of the detailed procedures given by European standard EN 1991-1-7 for bridge pier impact load - dynamic analysis, which is compared with the outcomes from a detailed finite-element model (FEM) of a truck impact prepared using AUTODYN software. A nonlinear material model of concrete with damage and strain-rate effect is used to assess the impact performance of a bridge pier. The paper further presents the results of a numerical study focused on the influence of different types of bridge pier reinforcement arrangement on their resistance to vehicle impact. The performance of various types of reinforcement is analysed and compared. Practical recommendations are drawn for the design of bridge piers which can be subjected to vehicle impacts in an urban environment.

Lateral impact damage from over-height vehicle collisions with bridge superstructures is of increasing concern in the United States. However this issue is not fully addressed in current bridge specifications. Previous researchers have conducted a number of small-scale tests to study the impact process. Also, the finite element method has largely been used to analyze the complicated collision mechanism. This paper provides an opportunity for full-scale lateral impact testing of a prestressed concrete girder, which leads to a realistic level of damage and mechanism analysis. A full-scale lateral impact testing facility was designed and built on a construction site in Knoxville, Tennessee. The over-height vehicle impact was simulated by impacting the bottom of an AASHTO Type I prestressed concrete girder with an impact cart. This paper describes the details of the impact testing facility as well as the response of the prestressed concrete girder during lateral impact. The collected test data were calibrated by using finite element software ABAQUS.

In this article, the cyclic performance of an innovative precast beam-to-column connection is evaluated experimentally and numerically. Two full-scale beam-column cross-shape interior connection specimens named PF-1 and PF-2 are tested. By adding extra nuts to the connecting bolts, specimen PF-2 behaves in a more shear-dominant pattern and shows less pinching. Comparison of performance of these specimens with the numerical monolithic model in terms of stiffness, strength, ductility and energy dissipation capacity indicates the proposed system can provide conditions close to the monolithic connection. However, to reduce the pinching drawback, a minor modification was made leading to performance improvements in strength and equivalent viscous damping ratio up to 51 % and 29 % respectively. The results of this study have direct industrial relevance and may be used for the development of reliable seismic guidelines for precast concrete structures.

The precast shear wall structure has outstanding features for green buildings due to its construction convenience, safety, high quality and low pollution. In general, precast concrete shear walls are connected by multiple joints. The joint between precast walls has very strong influence on the whole structure, which calls for more detailed investigation. A new kind of connection - the joint connecting beam - was developed to connect the vertical reinforcement in precast concrete shear wall structures. This innovative connecting method has the advantages of convenient operation and saving steel. To evaluate the performance and for better application of the joint connecting beam, an experiment on seven full-scale specimens was conducted under cyclic loading, including two cast-in-situ walls and five precast walls with varying reinforcement and sectional heights of the joint connecting beam. A comparison was performed between cast-in-situ walls and precast walls with joint connecting beam, focusing on failure mode, hysteretic curve, skeleton curve, bearing capacity, ductility and energy-dissipating capacity. The results show that the joint connecting beam can effectively transfer the load of precast walls, especially for squat precast walls. Moreover, finite element models were developed to simulate the performance of the specimens. The simulation results agree well with experimental results.

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In this paper, the behaviour of RC slab strips subjected to transverse loads and axial tensile forces is investigated by means of analytical and numerical simulations. The results obtained are compared to the experimental results from tests performed at the Swiss Federal Institute of Technology (ETH). The prediction of the structural response was part of an international benchmark study [1]. The aim of the paper is to investigate the capability of the adopted models and their main influencing parameters, especially from the perspective of a reliable structural robustness assessment. It is known that in some cases axial tensile forces have a beneficial effect on the bearing capacity of slab strips, thanks to the development of catenary actions. Such hidden strength resources are usually not taken into account in the current design process. For this reason, validation of suitable numerical tools, able to properly predict the structural response, is useful for a reliable structural robustness assessment. The paper underlines the importance of benchmark development, especially for specimens, in which both mechanical and geometrical nonlinearities play an important role.

A simplified mechanical model is presented for the shear strength prediction of reinforced and prestressed concrete members with and without transverse reinforcement, with I, T or rectangular cross-section. The model, derived with further simplifications from a previous one developed by the authors, incorporates the contributions of the concrete compression chord, the cracked web, the dowel action and the shear reinforcement in a compact formulation. The mechanical character of the model provides valuable information about the physics of the problem and incorporates the most relevant parameters governing the shear strength of structural concrete members. The predictions of the model fit very well the experimental results collected in the ACI-DAfStb databases of shear tests on slender reinforced and prestressed concrete beams with and without stirrups. Due to this fact and the simplicity of the derived equations it may become a very useful tool for structural design and assessment in engineering practice.