Axis distance to bar; distance to point load; lever arm from topping to precast
centroids; axial load factor in biaxial column design; distance to bracing ele-
ment from shear centre; length of bearing ledge in corbels; vertical deflection
due to elongation of catenary tie
aʹ Distance to point load in cantilever
ab Edge distance or half of centre-to-centre distance between bars
ac Distance to forces from centre line of column; distance to load from column
face in corbels
aC Δcrit Critical value of deflection in catenary action under accidental loading
ae Effective distance to load from main rebars in corbels and connections
aeff Required structural bearing length a in corbels
amean am Mean axis distance of a group of bars
asd asd,m Side axis distance to bars or groups of bars
av Distance to load from face of column in corbels
a1 Net (structural) bearing length
a2 a3 Ineffective bearing lengths or permitted deviations at supports
αI αII Deformation parameters in serviceability design
b b1 b2 Breadth, in stage 1 and 2 loading
bc Total breadth of cores (in hollow core slab)
be Breadth of precast floor unit
beff Breadth of in situ topping
bf
Breadth of flanges in beams or slabs
bi
Interface contact length between beams and slabs or infill
bl Bearing length of localised support (e.g. pad, plate)
bmin Breadth of column and beam (in fire)
bp Breadth of bearing; breadth of localised support (e.g. pad, plate); bearing
breadth of the infill at the top of column pockets
bt
Mean width of section in the tension zone
bv bw Breath of upstand in beam
bw Breath of web(s)
b1 Effective breadth of bearing
b1 b2 Depth of bays in horizontal floor diaphragm
c Cohesion factor in interface shear stress
c cov Cover to bars
cd Edge distance to rebars or gap between rebars
c1 c2 Column depths
d Effective depth to tension bars from compression face; net depth of floor slab in
horizontal floor diaphragm; root depth of shear key; distance to holding down
bolts in tension from compression face
dʹ Effective depth to compression bars; depth to the centre of the bottom bars in
deep beam wall; distance to holding down bolts from compression edge of plate
dʺ Effective depth to links (in beam boot or nibs)
dc Effective depth from top of composite section
dct Net depth to dowel bar in shear
deff Effective height of bottom flange of beam
df
Effective depth from column pocket to the edge of the foundation
dh Effective depth to tension bars in nibs
dn Depth to centroid of concrete in compression
dt
Distance from the top of the insert to the uppermost link in connections
dT Effective depth to tendons in tension (ultimate limit state)
d1 d2 Effective depth in stage 1 and 2 loading
d2 Axis distance to tension bars from tension face in columns; axis distance to
starter bars in base plates
d2 d3 Ineffective bearing lengths (e.g. in nibs and corbels)
e Eccentricity to centre of pressure or load from shear centre; eccentricity due to
ultimate loads = MEd/NEd
eʹ Net eccentricity of upper and floor loads of deep beam wall
eb eh Eccentricity of point loads acting over breadth and depth of section
efi Eccentricity due to fire loads = M0Ed,fi/N0Ed,fi
ei Eccentricity due to imperfection
enet Net eccentricity in column due to eccentric loads
eo Eccentricity due frame or floor effects; minimum eccentricity
etot Total eccentricity eo + ei
ey ez Eccentricity of load due to moments about y- and z-axes in columns
enib Eccentricity of load due to load acting on nib of deep beam wall
eup Eccentricity of load due to upper storey deep beam wall
ew e due to wind pressure alone
e2 e2,mean Eccentricity due to second-order deflections in vertical elements; mean value
for multiple columns
f Horizontal shear force per unit length
fb fm Strength of brick element and mortar
fb General term for final stress in bottom fibre of prestressed section
fb1 ft1 fb2 ft2 Bottom and top fibre stress due to stage 1 and 2 bending moments
ft2ʹ Top of topping stress due to stage 2 bending moment
fbd fb,req Design and required concrete bond strength
fbed Design strength of bedding material
fc Mean cylinder strength of concrete required for lifting
fcd fcdi Design strength of concrete; in situ/mortar bedding
fcd,pl Design strength of plain concrete
fci Design stress in infill beneath base plate
fck Characteristic cylinder strength of concrete
fcki fck of in situ or infill concrete
fck(ti
) fck(ti
) Value of fck at time t and at installation ti
fcm fcm,cube Mean value of fck and fck,cube
fcm(t) Value of fcm after time t
fctd fctdi Design strength of concrete and in situ concrete in tension = fctm/γm
