This section (based on ACI 318-14 provisions) defines notation and terminology used in this design example:
a | = | depth of equivalent rectangular stress block, in. |
Ab | = | area of an individual bar or wire, in.2 |
Ag | = | gross area of concrete section, in.2 For a hollow section, Ag is the area of the concrete only and does not include the area of the void(s) |
As | = | area of nonprestressed longitudinal tension reinforcement, in.2 |
As,min | = | minimum area of flexural reinforcement, in.2 |
b | = | width of compression face of member, in. |
bo | = | perimeter of critical section for two-way shear in slabs and footings, in. |
bv | = | width of cross section at contact surface being investigated for horizontal shear, in. |
bw | = | web width or diameter of circular section, in. |
b1 | = | dimension of the critical section bo measured in the direction of the span for which moments are determined, in. |
b2 | = | dimension of the critical section bo measured in the direction perpendicular to b1, in. |
c | = | distance from extreme compression fiber to neutral axis, in. |
cc | = | clear cover of reinforcement, in. |
c1 | = | dimension of rectangular or equivalent rectangular column, capital, or bracket measured in the direction of the span for which moments are being determined, in. |
c2 | = | dimension of rectangular or equivalent rectangular column, capital, or bracket measured in the direction perpendicular to c1, in. |
C | = | cross-sectional constant to define torsional properties of slab and beam |
d | = | distance from extreme compression fiber to centroid of longitudinal tension reinforcement, in. |
db | = | nominal diameter of bar, wire, or prestressing strand, in. |
Ec | = | modulus of elasticity of concrete, psi |
Ecs | = | modulus of elasticity of slab concrete, psi |
Es | = | modulus of elasticity of reinforcement and structural steel, excluding prestressing reinforcement, psi |
fc' | = | specified compressive strength of concrete, psi |
fr | = | modulus of rupture of concrete, psi |
fy | = | specified yield strength for nonprestressed reinforcement, psi |
h | = | overall thickness, height, or depth of member, in. |
hw | = | height of entire wall from base to top, or clear height of wall segment or wall pier considered, in. |
Ib | = | moment of inertia of gross section of beam about centroidal axis, in.4 |
Icr | = | moment of inertia of cracked section transformed to concrete, in.4 |
Ie | = | effective moment of inertia for calculation of deflection, in.4 |
Ig | = | moment of inertia of gross concrete section about centroidal axis, neglecting reinforcement, in.4 |
Is | = | moment of inertia of gross section of slab about centroidal axis, in.4 |
Kt | = | torsional stiffness of member; moment per unit rotation |
l | = | span length of beam or one-way slab; clear projection of cantilever, in. |
ln | = | length of clear span measured face-to-face of supports, in. |
l1 | = | length of span in direction that moments are being determined, measured center-to-center of supports, in. |
l2 | = | length of span in direction perpendicular to l1, measured center-to-center of supports, in. |
Ma | = | maximum moment in member due to service loads at stage deflection is calculated, in.-lb |
Mcr | = | cracking moment, in.-lb |
Msc | = | factored slab moment that is resisted by the column at a joint, in.-lb |
Mu | = | factored moment at section, in.-lb |
Mo | = | total factored static moment, in.-lb |
n | = | number of items, such as, bars, wires, monostrand anchorage devices, anchors, or shearhead arms |
Pn | = | nominal axial compressive strength of member, lb |
Po | = | nominal axial strength at zero eccentricity, lb |
Pu | = | factored axial force; to be taken as positive for compression and negative for tension, lb |
qDu | = | factored dead load per unit area, lb/ft2 |
qLu | = | factored live load per unit area, lb/ft2 |
qu | = | factored load per unit area, lb/ft2 |
vc | = | stress corresponding to nominal two-way shear strength provided by concrete, psi |
vu | = | maximum factored two-way shear stress calculated around the perimeter of a given critical section, psi |
Vc | = | nominal shear strength provided by concrete, lb |
Vn | = | nominal shear strength, lb |
Vs | = | nominal shear strength provided by shear reinforcement, lb |
Vu | = | factored shear force at section, lb |
wc | = | density, unit weight, of normalweight concrete or equilibrium density of lightweight concrete, lb/ft3 |
yt | = | distance from centroidal axis of gross section, neglecting reinforcement, to tension face, in. |
β | = | ratio of long to short dimensions: clear spans for two-way slabs, sides of column, concentrated load or reaction area; or sides of a footing |
βt | = | ratio of torsional stiffness of edge beam section to flexural stiffness of a width of slab equal to span length of beam, center-to-center of supports |
β1 | = | factor relating depth of equivalent rectangular compressive stress block to depth of neutral axis |
γf | = | factor used to determine the fraction of Msc transferred by slab flexure at slab-column connections |
γv | = | factor used to determine the fraction of Msc transferred by eccentricity of shear at slab-column connections |
εt | = | net tensile strain in extreme layer of longitudinal tension reinforcement at nominal strength, excluding strains due to effective prestress, creep, shrinkage, and temperature |
λ | = | modification factor to reflect the reduced mechanical properties of lightweight concrete relative to normal weight concrete of the same compressive strength |
λΔ | = | multiplier used for additional deflection due to long-term effects |
ξ | = | time-dependent factor for sustained load |
ρ' | = | ratio of As' to bd |
ϕ | = | strength reduction factor |