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Concrete structures: stresses and deformations
C o n c r e t e structures: s t r e s s e s and d e f o r m a t i o n s A. Ghali and R. Favre
Chapman& Hall (1986) xix + 352 pp £35.00 In recent years there have been many books published dealing with the design of concrete structures to resist ultimate loads, and with the strength evaluation of concrete structures. The present book redresses the balance since it is concerned with the evaluation of the stresses and deformations of concrete structures under service load conditions. The authors work in Canada and Switzerland, respectively; consequently a truly international approach has been used in the book. It has been written in completely general terms, but frequent references are made to the CEB-FIP Model Code of I 9 7 8 , and the work of ACI Committee zo 9 on creep, shrinkage and temperature effects in concrete structures. The book includes many useful examples in SI units, with the answers also given in what the authors refer to as British units (ie Imperial units) - although SI units have been used in the British construction industry for two decades! Chapter i discusses the creep and shrinkage properties of concrete and the creep (relaxation) properties of steel in general terms. Equations are presented for determining timedependent stresses and deformations. Two methods of analysis are presented; one uses the concept of an ageing coefficent and is intended for hand calculation whilst the second adopts an incremental approach which requires the use of a computer.
The determination of the timedependent stresses and strains in an uncracked reinforced or prestressed general section is considered in Chapter z. Special cases of uncracked sections (eg rectangular section and/or a single layer of reinforcement) are considered in Chapter 3, together with the calculation of displacements in framed structures. The virtual work and conjugate beam methods are used. Chapters 4 and 5 are concerned with the deformation of timedependent forces in uncracked structures by the force and displacement methods, respectively. Chapter 4 includes some useful examples on prestressed structures made continuous by in situ concrete joints. These examples are particularly relevant to bridge engineers. Instantaneous and time-dependent stresses and strains in cracked reinforced and partially prestressed sections are examined in Chapter 6. Useful graphs and tables for neutral axis depth and second moment of area of cracked T-sections and for the restraining effect of steel on the creep and shrinkage of the concrete are presented. Methods of determining the displacements (axial, curvature, shear and twist) of cracked members are given in Chapter 7. Tension stiffening is discussed in detail. However, one drawback for a UK engineer is that the UK Code approach of an average concrete tensile stress is not covered.
Chapter 8 includes useful simplified methods for the prediction of deflections, including timedependent effects. The final chapter, Chapter 9, deals with the effects of temperature. Both early thermal effects due to the heat of hydration of the cement and the effects of solar radiation are covered. The important stress-relieving effects of creep and cracking are discussed. The book is completed with six appendices. These give basic data on material properties according to the CEB and ACI, and various calculation aids in the form of equations, tables and graphs. One of the appendices is concerned with the prediction of crack spacings and widths. It is unfortunate, from the point of view of a UK reader, that only the CEB approach is presented because the method used in UK Codes is rather different. One minor criticism of the book is that there are relatively few references given, although, as stated by the authors, extensive lists of references can be found in the four references which are cited at the end of the book. In conclusion, this is a well presented book with a well balanced content. It should prove useful to graduate students, research workers and practising engineers, particularly those involved with statically indeterminate prestressed and composite concrete structures.
L.A. Clark
Reprints of all articles in this journal are available in quantities of 100 or more. Reprints are e s s e n t i a l - for the company that wants to distribute impartial comment on its activities to potential customers and clients. for the company that wants to up-date its technical staff on new techniques and new technologies.
For fulldetailsof pricesand availabilityof reprints,pleasewriteto: T h e Reprint Department, Butterworth Scientific Limited, P O B o x 63, Westbury House, Bury Street, Guildford, Surrey, G U 2 5 B H .
242
Int J Fatigue October 1986
Chapman& Hall (1986) xix + 352 pp £35.00 In recent years there have been many books published dealing with the design of concrete structures to resist ultimate loads, and with the strength evaluation of concrete structures. The present book redresses the balance since it is concerned with the evaluation of the stresses and deformations of concrete structures under service load conditions. The authors work in Canada and Switzerland, respectively; consequently a truly international approach has been used in the book. It has been written in completely general terms, but frequent references are made to the CEB-FIP Model Code of I 9 7 8 , and the work of ACI Committee zo 9 on creep, shrinkage and temperature effects in concrete structures. The book includes many useful examples in SI units, with the answers also given in what the authors refer to as British units (ie Imperial units) - although SI units have been used in the British construction industry for two decades! Chapter i discusses the creep and shrinkage properties of concrete and the creep (relaxation) properties of steel in general terms. Equations are presented for determining timedependent stresses and deformations. Two methods of analysis are presented; one uses the concept of an ageing coefficent and is intended for hand calculation whilst the second adopts an incremental approach which requires the use of a computer.
The determination of the timedependent stresses and strains in an uncracked reinforced or prestressed general section is considered in Chapter z. Special cases of uncracked sections (eg rectangular section and/or a single layer of reinforcement) are considered in Chapter 3, together with the calculation of displacements in framed structures. The virtual work and conjugate beam methods are used. Chapters 4 and 5 are concerned with the deformation of timedependent forces in uncracked structures by the force and displacement methods, respectively. Chapter 4 includes some useful examples on prestressed structures made continuous by in situ concrete joints. These examples are particularly relevant to bridge engineers. Instantaneous and time-dependent stresses and strains in cracked reinforced and partially prestressed sections are examined in Chapter 6. Useful graphs and tables for neutral axis depth and second moment of area of cracked T-sections and for the restraining effect of steel on the creep and shrinkage of the concrete are presented. Methods of determining the displacements (axial, curvature, shear and twist) of cracked members are given in Chapter 7. Tension stiffening is discussed in detail. However, one drawback for a UK engineer is that the UK Code approach of an average concrete tensile stress is not covered.
Chapter 8 includes useful simplified methods for the prediction of deflections, including timedependent effects. The final chapter, Chapter 9, deals with the effects of temperature. Both early thermal effects due to the heat of hydration of the cement and the effects of solar radiation are covered. The important stress-relieving effects of creep and cracking are discussed. The book is completed with six appendices. These give basic data on material properties according to the CEB and ACI, and various calculation aids in the form of equations, tables and graphs. One of the appendices is concerned with the prediction of crack spacings and widths. It is unfortunate, from the point of view of a UK reader, that only the CEB approach is presented because the method used in UK Codes is rather different. One minor criticism of the book is that there are relatively few references given, although, as stated by the authors, extensive lists of references can be found in the four references which are cited at the end of the book. In conclusion, this is a well presented book with a well balanced content. It should prove useful to graduate students, research workers and practising engineers, particularly those involved with statically indeterminate prestressed and composite concrete structures.
L.A. Clark
Reprints of all articles in this journal are available in quantities of 100 or more. Reprints are e s s e n t i a l - for the company that wants to distribute impartial comment on its activities to potential customers and clients. for the company that wants to up-date its technical staff on new techniques and new technologies.
For fulldetailsof pricesand availabilityof reprints,pleasewriteto: T h e Reprint Department, Butterworth Scientific Limited, P O B o x 63, Westbury House, Bury Street, Guildford, Surrey, G U 2 5 B H .
242
Int J Fatigue October 1986