N° 158. 1984. CEB Design Manual Cracking and Deformations

The separate verification of strength and serviceabi\ity in structural concrete is be coming more and more important . 

The CEB-FIP Model Code introduces the general concepts and theories related to serviceability, particularly those concerning cracking and deformability. The need for a Manual allowing the practical application of these concepts has been strongly feIt . 

The preparation of this Manual was assigned, first to a Task Group, and thereafter to a Drafting Group, formed by well-known specialists. Professor Renaud Favre, from the Ecole Polytechnique Federale de Lausanne, chaired both these Groups . 

It is my pleasure to thank the· Task and Drafting Groups, particularly Dr . Beeby and Professor Favre, responsible for the initial drafting of the chapters on cracking and deformability, respectively, for the successful and useful work accomplished . 

The fundamentals of the theories of cracking and deformation in structural concrete were established about 20 years ago. These theories involve a large number of parameters, most of them represented by random variables wi th large coefficients of variation. Consequently, theoretical as weIl as experimental results show large dispersions. 

To obtain easy to use design aids, drastic simplifications have to be introduced in the theories. Often the se simplifications have a limited range of validity. Consequently , it is to be expected that the accuracy of the solutions will diminish as the real conditions diverge from those assumed. These divergences may be particularly important e.g. in the case of members subjected to axial load combined with bending and in the superposition of permanent and transient loads . Even so, the guideliness presented in the Manual give useful information in a large range of situations. 

Julio Ferry Borges-President of CEB