Design of structural elements

 For the purpose of this book, the following sym
bols have been used. These have largely been taken
 from BS 8110. Note that in one or two cases the
 same symbol is differently defined. Where this
 occurs the reader should use the definition most
 appropriate to the element being designed.
 Geometric properties:
 b width of section
 d effective depth of the tensionreinforcement
 h overall depth of section
 x depth to neutral axis
 z lever arm
 d′ depth to the compression reinforcement
 b effective span
 c nominal cover to reinforcement
 Bending:
 Fk
 characteristic load
 gk
 , Gk
 characteristic dead load
 qk
 , Qk
 characteristic imposed load
 wk
 , Wk
 characteristic wind load
 fk
 characteristic strength
 fcu
 characteristic compressive cube strength
 of concrete
 fy
 characteristic tensile strength of
 reinforcement
 γf
 partial safety factor for load
 γm
 partial safety factor for material
 strengths
 K coefficient given by M/fcu
 bd2
 K′ coefficient given by Mu
 /fcu
 bd2=0.156 when
 redistribution does not exceed 10 per cent
 M design ultimate moment
 Mu
 design ultimate moment of resistance
 As
 area of tension reinforcement
 As
 ′ area of compression reinforcement
 Φ diameter of main steel
 Φ′ diameter of links
 Shear:
 fyv
 characteristic strength of links
 sv
 spacing of links along the member

V
 design shear force due to ultimate
 loads

 v
 vc
 Asv
 design shear stress
 design concrete shear stress
 total cross-sectional area of shear
 reinforcement
 Compression:
 b
 h
 bo
 be
 bex
 bey
 N
 Ac
 Asc
 width of column
 depth of column
 clear height between end restraints
 effective height
 effective height in respect of x-x axis
 effective height in respect of y-y axis
 design ultimate axial load
 net cross-sectional area of concrete in
 a column
 area of longitudinal reinforcement