Stoffgesetz zur Beschreibung des Kriech- und Relaxationsverhaltens junger normal- und hochfester Betone


Book Description

Within this work a material law was developed which correctly describes the creep and relaxation characteristics of young and mature normal strength and high-strength concretes. It is based on an aging thermodynamically sound rheological model and considers the complex nonlinear creep behavior under constant and variable stresses. In case of relaxation the corresponding integral relation is solved by means of a numerical algorithm.




Experimental characterization and modelling of textile reinforced masonry structures with the Equivalent frame method


Book Description

An innovative strengthening technique for the seismic retrofitting of masonry buildings is the fabric-reinforced cementitious matrix (FRCM). The system presented in this work is EQ-GRID, which consists of a multi-axial hybrid grid made of alkali-resistant glass and polypropylene fibres and a natural hydraulic lime mortar (NHL) as matrix. The results of the performed experimental campaign and the numerical modelling with the Equivalent frame method are presented and discussed in this work.




Seismic soil structure interaction of navigation locks


Book Description

This work handles the seismic soil- and water structure interaction of navigation locks in the field of elastodynamics. The investigation is based on numerical analysis with the finite element method. The findings extend the results of available theories and studies and allow for a more precise analysis and design of such structures. Suggestions about the numerical analysis of such problems are also presented. The results can be used also for quay and retaining walls.




Influence of elevated temperatures up to 100 °C on the mechanical properties of concrete


Book Description

Experiments to characterize the effects of moisture content and temperature on the mechanical properties of concrete were conducted. Based on these experiments, a new overall material model capable of predicting the mechanical behaviour of concrete subject to elevated temperatures up to 100 °C was developed. The material model estimates the time, temperature and moisture dependency of the compressive and tensile strength, creep and shrinkage of concrete.




Code-type models for concrete behaviour


Book Description

fib Model Code 2010 represents the state-of-the-art of code-type models for structural behaviour of concrete. It comprises constitutive relations and material models together with the most important explanatory notes. However the underlying normative work, i.e. the fundamental data as well as the considerations and discussions behind the formulas could not be given within the Model Code text. Based on various experiences gained after the publication of Model Code 1990 this lacking background information will lead in the following to numerous questions arising from Model Code users. Consequently the present bulletin claims to conquer this general weakness of codes in a way to guard against any future misunderstandings of the Model Code 2010 related to its chapter 5.1 (Concrete). It discusses the given formulas in connection with experimental data and the most important international literature. The constitutive relations or material models, being included in MC1990 and forming the basis and point of origin of the Task Group’s work, were critically evaluated, if necessary and possible adjusted, or replaced by completely new approaches. Major criteria have been the physical and thermodynamical soundness as well as practical considerations like simplicity and operationality. This state-of-the-art report is intended for practicizing engineers as well as for researchers and represents a comprehensible summary of the relevant knowledge available to the members of the fib Task Group 8.7 at the time of its drafting. Besides the fact that the bulletin is a background document for Chapter 5.1 of MC2010, it will provide an important foundation for the development of future generations of code-type models related to the characteristics and the behaviour of structural concrete. Further it will offer insights into the complexity of the normative work related to concrete modelling, leading to a better understanding and adequate appreciation of MC2010.







Creep and Shrinkage of Concrete


Book Description

Presents the proceedings of the 5th RILEM International Symposium, held in Barcelona in September 1993. The papers discuss creep and shrinkage of concrete, and should be of interest to cement and concrete technologists and researchers, as well as structural engineers.




Time-Dependent Behaviour of Concrete Structures


Book Description

Serviceability failures of concrete structures involving excessive cracking or deflection are relatively common, even in structures that comply with code requirements. This is often as a result of a failure to adequately account for the time-dependent deformations of concrete in the design of the structure. The serviceability provisions embodied in




Creep and Hygrothermal Effects in Concrete Structures


Book Description

This comprehensive treatise covers in detail practical methods of analysis as well as advanced mathematical models for structures highly sensitive to creep and shrinkage. Effective computational algorithms for century-long creep effects in structures, moisture diffusion and high temperature effects are presented. The main design codes and recommendations (including RILEM B3 and B4) are critically compared. Statistical uncertainty of century-long predictions is analyzed and its reduction by extrapolation is discussed, with emphasis on updating based on short-time tests and on long-term measurements on existing structures. Testing methods and the statistics of large randomly collected databases are critically appraised and improvements of predictions of multi-decade relaxation of prestressing steel, cyclic creep in bridges, cracking damage, etc., are demonstrated. Important research directions, such as nanomechanical and probabilistic modeling, are identified, and the need for separating the long-lasting autogenous shrinkage of modern concretes from the creep and drying shrinkage data and introducing it into practical prediction models is emphasized. All the results are derived mathematically and justified as much as possible by extensive test data. The theoretical background in linear viscoelasticity with aging is covered in detail. The didactic style makes the book suitable as a textbook. Everything is properly explained, step by step, with a wealth of application examples as well as simple illustrations of the basic phenomena which could alternate as homeworks or exams. The book is of interest to practicing engineers, researchers, educators and graduate students.




Fibre Reinforced Concrete: Improvements and Innovations


Book Description

This volume highlights the latest advances, innovations, and applications in the field of fibre reinforced concrete (FRC) and discusses a diverse range of topics concerning FRC: rheology and early-age properties, mechanical properties, codes and standards, long-term properties, durability, analytical and numerical models, quality control, structural and Industrial applications, smart FRC’s, nanotechnologies related to FRC, textile reinforced concrete, structural design and UHPFRC. The contributions present improved traditional and new ideas that will open novel research directions and foster multidisciplinary collaboration between different specialists. Although the symposium was postponed, the book gathers peer-reviewed papers selected in 2020 for the RILEM-fib International Symposium on Fibre Reinforced Concrete (BEFIB).