Design Of Concrete Structures With Stress Fields

17 2 STRESS FIELDS FOR SIMPLE STRUCTURES 2. 1 INTRODUCTION In this chapter the behavior and strength of simple structures made of rein forced or prestressed concrete is investigated with the aid of stress fields. In particular, the webs and flanges of beams, simple walls, brackets, bracing beams and joints of frames are investigated. By this means, the majority of design cases are already covered. In reality, all structural components are three-dimensional. Here, however, components are considered either directly as two-dimensional plate elements (i. e. the plane stress condition with no variation of stress over the thickness of the element) or they are subdivided into several plates. Since two-dimensional structural elements are statically redundant, it is pOSSible for a particular loading to be in equilibrium with many (theoretically an infinite number of) stress states. If the lower bound method of the theory of plasticity is employed, then an admissible stress field or any combination of such stress fields may be selected. In chapter 4 it is shown that this method is suitable for the design of reinforced concrete structures, and the consequence of the choice of the final structural system on the structural behavior is dealt with in detail. The first cases of the use of this method date back to Ritter [6] and Morsch [4], who already at the beginning of the century investigated the resultants of the internal stresses by means of truss models.

This text presents the most effective analysis for predicting the true stresses and deflections of concrete structures, accounting for creep and shrinkage of concrete and relaxation of prestressed reinforcement. Sustainability has become a major requirement in modern structures, which need to sustain satisfactory service over a longer life. It is not rare to specify a life span of 100 years for infrastructure such as bridges. This complete and wide-ranging study of stresses and deformations of reinforced and prestressed concrete structures focuses on design methods for avoiding the deflections and cracking that diminish serviceability. This fourth edition has a new emphasis on designing for serviceability. It has been comprehensively updated. It now includes 65 solved examples and more than 45 instructive problems with answers given at the end of the book. An accompanying website contains design calculation programs, which allow interactive data input. Independent of codes of practice, the book is universally applicable, and is especially suitable for practising engineers and graduate students.

The second edition of the Structural Concrete Textbook is an extensive revision that reflects advances in knowledge and technology over the past decade. It was prepared in the intermediate period from the CEP-FIP Model Code 1990 (MC90) to fib Model Code for Concrete Structures 2010 (MC2010), and as such incorporates a significant amount of information that has been already finalized for MC2010, while keeping some material from MC90 that was not yet modified considerably. The objective of the textbook is to give detailed information on a wide range of concrete engineering from selection of appropriate structural system and also materials, through design and execution and finally behaviour in use. The revised fib Structural Concrete Textbook covers the following main topics: phases of design process, conceptual design, short and long term properties of conventional concrete (including creep, shrinkage, fatigue and temperature influences), special types of concretes (such as self compacting concrete, architectural concrete, fibre reinforced concrete, high and ultra high performance concrete), properties of reinforcing and prestressing materials, bond, tension stiffening, moment-curvature, confining effect, dowel action, aggregate interlock; structural analysis (with or without time dependent effects), definition of limit states, control of cracking and deformations, design for moment, shear or torsion, buckling, fatigue, anchorages, splices, detailing; design for durability (including service life design aspects, deterioration mechanisms, modelling of deterioration mechanisms, environmental influences, influences of design and execution on durability); fire design (including changes in material and structural properties, spalling, degree of deterioration), member design (linear members and slabs with reinforcement layout, deep beams); management, assessment, maintenance, repair (including, conservation strategies, risk management, types of interventions) as well as aspects of execution (quality assurance), formwork and curing. The updated textbook provides the basics of material and structural behaviour and the fundamental knowledge needed for the design, assessment or retrofitting of concrete structures. It will be essential reading material for graduate students in the field of structural concrete, and also assist designers and consultants in understanding the background to the rules they apply in their practice. Furthermore, it should prove particularly valuable to users of the new editions of Eurocode 2 for concrete buildings, bridges and container structures, which are based only partly on MC90 and partly on more recent knowledge which was not included in the 1999 edition of the textbook.

Concrete structures must be designed not only to be safe against failure but also to perform satisfactorily in use. This book is written for practising engineers and students, and focuses on design methods for checking deflections and cracking which can affect the serviceability of reinforced and prestressed concrete structures. The authors present accurate and easy-to-apply methods of analysing immediate and long-term stresses and deformations. These methods allow designers to account for variations of concrete properties from project to project and from country to country, making the book universally applicable. Comprehensively updated, this third edition of Concrete Structures also includes four new chapters covering such topics as: non-linear analysis of plane frames, design for serviceability of prestressed concrete, serviceability of members reinforced with fibre polymer bars, and the analysis of time-dependent internal forces with linear computer programs that are routinely used by structural designers. A website accompanies the book, featuring three design calculation programs related to stresses in cracked sections, creep coefficients and time-dependent analysis. The book contains numerous examples, some of which are worked out in the SI units and others in the Imperial units. The input data and the main results are given in both SI and Imperial units. The book is not tied to any specific code, although the latest American and European codes of practice are covered in the appendices.

This text presents the most effective analysis for predicting the true stresses and deflections of concrete structures, accounting for creep and shrinkage of concrete and relaxation of prestressed reinforcement. Sustainability has become a major requirement in modern structures, which need to sustain satisfactory service over a longer life. It is not rare to specify a life span of 100 years for infrastructure such as bridges. This complete and wide-ranging study of stresses and deformations of reinforced and prestressed concrete structures focuses on design methods for avoiding the deflections and cracking that diminish serviceability. This fourth edition has a new emphasis on designing for serviceability. It has been comprehensively updated. It now includes 65 solved examples and more than 45 instructive problems with answers given at the end of the book. An accompanying website contains design calculation programs, which allow interactive data input. Independent of codes of practice, the book is universally applicable, and is especially suitable for practising engineers and graduate students.

For over sixty years, the primary source for design of concrete structures--now revised and updated Simplified Design of Concrete Structures, Eighth Edition covers all the latest, commonly used concrete systems, practices, and research in the field, reinforced with examples of practical designs and general building structural systems. Updated to conform to current building codes, design practices, and industry standards. Simplified Design of Concrete Structures, Eighth Edition is a reliable, easy-to-use handbook that examines a wide range of concrete structures, building types, and construction details. It includes a wealth of illustrations, expanded text examples, exercise problems, and a helpful glossary. Highlights of this outstanding tool include: * Its use of the current American Concrete Institute Building Code for 2005 (ACI 318) and the Load and Resistance Factor Design (LRFD) method of structural design * Fundamental and real-world coverage of concrete structures that assumes no previous experience * Valuable study aids such as exercise problems, questions, and word lists enhance usability

fib Bulletin 61 is a continuation of fib Bulletin 16 (2002). Again the bulletin’s main objective is to demonstrate the application of the FIP Recommendations “Practical Design of Structural Concrete”, and especially to illustrate the use of strut-and-tie models to design discontinuity regions (D-regions) in concrete structures. Bulletin 61 presents 14 examples, most of which are existing structures built in recent years. Although some of the presented structures can be considered to be quite important and, in some instances, complex, the chosen examples are not intended to be exceptional. The main aim is to look at specific design aspects, by selecting D-regions of the presented structures that are designed and detailed according to the proposed design principles and specifications for the use of strut-and-tie models. Two papers at the end of the bulletin deal with the role of concrete tension fields in modelling with strut-and-tie models, and summarize the experiences gained by the Working Group in applying strut-and-tie models to the examples in the bulletin. It is hoped that fib Bulletin 61 will be of interest to engineers involved in the design of concrete structures, supporting the use of more consistent design and detailing tools such as strut-and-tie models.