1.1

Chapter 1

Background 1.1 Introduction The purpose of this course is to give the student an introduction to the principles of the structural design of reinforced concrete (the basics of loadbearing masonry or unreinforced masonry forms part of this course but covered in another textbook). This course consist of 13 chapters in pdf format that the student can download form web-ct. The notes are best used when the technical font is used with the word processing software.

The student must have a solid foundation of theory of structures to analyse determinate as well as indeterminate structures. Reinforced concrete elements and structures are analysed to determine forces, reactions, stresses and bending moments that are required for the design of a structure as a whole or in elements to facilitate the design calculations. This background is also essential to calculate the sectional properties of reinforced concrete sections in the design thereof.

Structural concrete is a composite use of concrete and reinforcing steel facilitating an element or structure to support loads for the structures projected and designed life cycle. Loads and stresses unique to the specific materials and form of elements used shall not be exceeded rendering such element or structure unserviceable. The materials used are usually a combination of different unique materials, each one with its own unique characteristics. The composition of the two materials requires a firm understanding by the designer of the characteristics of the materials combined as well as the behaviour of the material at all times during the design life time of the structure under the load application. During the course we will concentrate on the design of reinforced concrete structures. The magnitude and type of loading to be used in the calculation of loading, stresses, shear forces and bending moments on structures are based on SANS 10160 (1). The code also gives permissible values for deflection, as well as values for imposed, dead and wind loading. After the choice of material has been made the analysis of the structure is undertaken in total or in part as set out in the SABS design code of the material. 1.2 Design codes The following codes are relevant for the design of reinforced concrete elements and structures in this course: SANS 10160 1989 (As amende3d 1990, 1991 and 1993): South African Standard Code of

Practice for the General procedures and loadings to be adopted in the design of buildings (1).

1.2

SANS 10100 - 1: 2000: South African Standard Code of Practice - The structural use of concrete, Part 1: Design (2)

The SABS Codes are compiled by the South African Bureau of Standards by utilizing empirical formulae and by using research applications and practical application of material; determined by the studying the behaviour of material and the combination of material subjected to an external load on a structure and monitoring the long term effects of continued long term loading on the material. During the course the student must develop a thorough knowledge of the of the limitations and clauses in the listed Codes with respect to the application of different materials; by using material with a homogenous composition or a combination of different alternative materials. This guide acts only as a guide in the logical application of the design codes as far as the use of reinforced concrete as a structural material. This guide must therefore be used together with the relevant design codes and may not be used as a substitution thereof. The following references may be used for further reading to illustrate the application of the clauses in the design codes. Although these references make specific reference to the British Codes of Practice, i.e. BS8110 it is applicable since the codes have a lot in common. Reinforced Concrete : Design Theory and Examples - TJ MacGinley & Choo (2nd Ed) Reinforced Concrete Design - WH Mosley and JH Bungey (Fourth Ed) Reinforced Concrete Design to BS 8110: Simply Explained - AH Allen Design of Reinforced Concrete Structural Elements to SANS 10100-1:1992 G Parrott. Although due care was taken in compiling tables in the guide, it is the students responsibility to verify the correctness thereof by comparing the values in the Code or by calculating values from first principles, if the tables or figures in the guide are used.