Design of structural elements

 All reinforced concrete building structures are
 composed of various categories of elements includ
ing slabs, beams, columns, walls and foundations
 (Fig. 3.1). Within each category is a range of ele
ment types. The aim of this chapter is to describe
 the element types and, for selected elements, to
 give guidance on their design. A great deal of emphasis has been placed in the
 text to highlight the similarities in structural beha
viour and, hence, design of the various categoriesof
 elements. Thus, certain slabs can be regarded for
 design purposes as a series of transversely connected
 beams. Columns may support slabs and beams
 but columns may also be supported by (ground
 bearing) slabs and beams, in which case the latter
 are more commonly referred to as foundations.
 Cantilever retaining walls are usually designed as
 if they consist of three cantilever beams as shown
 in Fig. 3.2. Columns are different in that they are
 primarily compression members rather than beams
 and slabs which predominantly resist bending.
 Therefore columns are dealt with separately at the
 end of the chapter.
 Irrespective of the element being designed, the
 designer will need a basic understanding of the fol
lowing aspects which are discussed next:
 1. symbols
 2. basis of design

3.material properties
 4. loading
 5. stress–strain relationships
 6. durability and fire resistance.
 The detailed design of beams, slabs, foundations,
 retaining walls and columns will be discussed in
 sections 3.9, 3.10, 3.11, 3.12 and 3.13,respectively