Part 6Structural Design

2 TERMINOLOGY

For the purpose of this Subsection, the definitions given in accepted standards [6-5A(2)] shall apply.

3 SYMBOLS

For the purpose of this Subsection, the following letter symbols shall have the meaning indicated against each; where other symbols are used, they are explained at the appropriate place:

A — Area

$b$ — Breadth of beam, or shorter dimension of

a rectangular column

$b_{\mathrm{ef}}$ — Effective width of slab

$b_{\mathrm{f}}$ — Effective width of flange

$b_{\mathrm{w}}$ — Breadth of web or rib

D — Overall depth of beam or slab or diameter of column; dimension of a rectangular column in the direction under consideration

$D_{\mathrm{f}}$ — Thickness of flange

DL — Dead load

$d$ — Effective depth of beam or slab

$d'$ — Depth of compression reinforcement from the highly compressed face

$E_{\mathrm{c}}$ — Modulus of elasticity of concrete

EL — Earthquake load

$E_{\mathrm{s}}$ — Modulus of elasticity of steel

e — Eccentricity

• $f_{\mathrm{ck}}$ — Characteristic cube compressive strength of concrete
• $f_{\mathrm{cr}}$ — Modulus of rupture of concrete (flexural tensile strength)
• $f_{\mathrm{ct}}$ — Splitting tensile strength of concrete
• $f_{\mathrm{d}}$ — Design strength
• $f_{\mathrm{y}}$ — Characteristic strength of steel
• $H_{\mathrm{w}}$ — Unsupported height of wall
• $H_{\mathrm{we}}$ — Effective height of wall
• $I_{\mathrm{ef}}$ — Effective moment of inertia
• $I_{\mathrm{gr}}$ — Moment of inertia of the gross section excluding reinforcement
• $I_{\mathrm{r}}$ — Moment of inertia of cracked section
• $K$ — Stiffness of member
• $k$ — Constant or coefficient or factor
• $L_{\mathrm{d}}$ — Development length
• $L/IL$ — Live load or imposed load
• $l$ — Length of a column or beam between adequate lateral restraints or the unsupported length of a column
• $l_{\mathrm{ef}}$ — Effective span of beam or slab or effective length of column
• $l_{\mathrm{ex}}$ — Effective length about x-x axis
• $l_{\mathrm{ey}}$ — Effective length about y-y axis
• $l_{\mathrm{n}}$ — Clear span, face-to-face of supports
• $l_{\mathrm{n}^{\prime}}$ — $l_{\mathrm{n}}$ for shorter of the two spans at right angles
• $l_{\mathrm{x}}$ — Length of shorter side of slab
• $l_{\mathrm{y}}$ — Length of longer side of slab
• $l_{0}$ — Distance between points of zero moments in a beam
• $l_{1}$ — Span in the direction in which moments are determined, centre-to-centre of supports
• $l_{2}$ — Span transverse to $l_{1}$, centre-to-centre of supports
• $l_{2^{\prime}}$ — $l_{2}$ for the shorter of the continuous spans
• $M$ — Bending moment
• $m$ — Modular ratio
• $n$ — Number of samples
• $P$ — Axial load on a compression member
• $q_{\mathrm{o}}$ — Calculated maximum bearing pressure of soil

PART 6 STRUCTURAL DESIGN — SECTION 5 CONCRETE: 5A PLAIN AND REINFORCED CONCRETE

s — Spacing of stirrups or standard deviation

$w_{\mathrm{d}}$ — Distributed dead load per unit area

$w_{1}$ — Distributed imposed load per unit area

$\delta_{\mathrm{m}}$ — Percentage reduction in moment

$\sigma_{cbc}$ — Permissible stress in concrete in bending compression

$\sigma_{cc}$ — Permissible stress in concrete in direct compression

$\sigma_{mc}$ — Permissible stress in metal in direct compression

$\sigma_{\mathrm{sc}}$ — Permissible stress in steel in compression

$\sigma_{\mathrm{st}}$ — Permissible stress in steel in tension

$\sigma_{\mathrm{sv}}$ — Permissible stress in shear reinforcement

$\tau_{\mathrm{bd}}$ — Design bond stress

$\tau_{\mathrm{c}}$ — Shear stress in concrete

$\tau_{c,\max}$ — Maximum shear stress in concrete with shear reinforcement

$\tau_{\mathrm{v}}$ — Nominal shear stress

$\Phi$ — Diameter of bar

4 MATERIALS