In this Subsection, Ar = element or component force amplification factor to account for type of attachment, as defined in Sentence 4.1.8.18.(1), Ax = height factor at level x to account for variation of response of an element or component with elevation within the building, as defined in Sentence 4.1.8.18.(1), Bx = ratio at level x used to determine torsional sensitivity, as defined in Sentence 4.1.8.11.(10), B = maximum value of Bx, as defined in Sentence 4.1.8.11.(10), Cp = seismic coefficient for an element or component, as defined in Sentence 4.1.8.18.(1), Dnx = plan dimension of the building at level x perpendicular to the direction of seismic loading being considered, ex = distance measured perpendicular to the direction of earthquake loading between centre of mass and centre of rigidity at the level being considered, (See Note A-4.1.8.2.(1)) Fa = acceleration-based site coefficient for application in standards referenced in Subsection 4.1.8., as defined in Sentence 4.1.8.4.(7), Fs = site coefficient as defined in Sentence 4.1.8.1.(2) for application in Article 4.1.8.1., Ft = portion of V to be concentrated at the top of the structure, as defined in Sentence 4.1.8.11.(7), Fv = velocity-based site coefficient for application in standards referenced in Subsection 4.1.8., as defined in Sentence 4.1.8.4.(7), Fx = lateral force applied to level x, as defined in Sentence 4.1.8.11.(7), hi, hn, hx = height, in m, above the base (i = 0) to level i, n, or x respectively, where the base of the structure is the level at which horizontal earthquake motions are considered to be imparted to the structure, hs = inter storey height (hi − hi−1), IE = earthquake importance factor of the structure, as described in Sentence 4.1.8.5.(1), J = numerical reduction coefficient for base overturning moment, as defined in Sentence 4.1.8.11.(6), Jx = numerical reduction coefficient for overturning moment at level x, as defined in Sentence 4.1.8.11.(8), Level i = any level in the building, i = 1 for first level above the base, Level n = level that is uppermost in the main portion of the structure, Level x = level that is under design consideration, Mv = factor to account for higher mode effects on base shear, as defined in Sentence 4.1.8.11.(6), Mx = overturning moment at level x, as defined in Sentence 4.1.8.11.(8), N = total number of storeys above exterior grade to level n,
= average standard penetration resistance, in blows per 0.3 m, in the top 30 m of *[[a-1.4.1.2.#soil|soil]]*, corrected to a rod energy efficiency of 60% of the theoretical maximum, PGA(X) = peak ground acceleration, expressed as a ratio to gravitational acceleration, for site designation X, as defined in Sentence [[b-4.1.8.4.#^1hplca|4.1.8.4.(1)]], PGV(X) = peak ground velocity, in m/s, for site designation X, as defined in Sentence [[b-4.1.8.4.#^1hplca|4.1.8.4.(1)]], PI = plasticity index for *[[a-1.4.1.2.#soil|soil]]*, Rd = ductility-related force modification factor reflecting the capability of a structure to dissipate energy through reversed cyclic inelastic behaviour, as defined in Article [[b-4.1.8.9.|4.1.8.9.]], Ro = overstrength-related force modification factor accounting for the dependable portion of reserve strength in a structure designed according to these provisions, as defined in Article [[b-4.1.8.9.|4.1.8.9.]], Rp = element or component response modification factor, as defined in Sentence [[b-4.1.8.18.#^1hplca|4.1.8.18.(1)]], Rs = combined overstrength and ductility-related modification factor, as defined in Sentence [[b-4.1.8.1.#^7hplca|4.1.8.1.(7)]], for application in Article [[b-4.1.8.1.|4.1.8.1.]], Sa (T,X) = 5%-damped spectral acceleration, expressed as a ratio to gravitational acceleration, at period T for site designation X, as defined in Sentence [[b-4.1.8.4.#^1hplca|4.1.8.4.(1)]], SC = Seismic Category assigned to a *[[a-1.4.1.2.#building|building]]* based on its Importance Category and the design spectral acceleration values at periods of 0.2 s and 1.0 s, as defined in Article [[b-4.1.8.5.|4.1.8.5.]], SFRS = seismic force resisting system, that part of the structural system that has been considered in the design to provide the required resistance to the earthquake forces and effects defined in Subsection [[b-4.#^418hplca|4.1.8.]], Sp = horizontal force factor for part or portion of a *[[a-1.4.1.2.#building|building]]* and its anchorage, as given in Sentence [[b-4.1.8.18.#^1hplca|4.1.8.18.(1)]], S(T) = design spectral acceleration, expressed as a ratio to gravitational acceleration, at period T, as defined in Sentence [[b-4.1.8.4.#^6hplca|4.1.8.4.(6)]], = average undrained shear strength, in kPa, in the top 30 m of *[[a-1.4.1.2.#soil|soil]]*, T = period, in s, Ta = fundamental lateral period of vibration of the *[[a-1.4.1.2.#building|building]]* or structure, in s, in the direction under consideration, as defined in Sentence [[b-4.1.8.11.#^3hplca|4.1.8.11.(3)]], TDD = total design displacement of any point in a seismically isolated structure, within or above the isolation system, obtained by calculating the mean + (IE × the standard deviation) of the peak horizontal displacements from all sets of ground motion time histories analyzed, but not less than √IE × the mean, where the peak horizontal displacement is based on the vector sum of the two orthogonal horizontal displacements considered for each time step, Ts = fundamental lateral period of vibration of the *[[a-1.4.1.2.#building|building]]* or structure, in s, in the direction under consideration, as defined in Sentence [[b-4.1.8.1.#^7hplca|4.1.8.1.(7)]], Tx = floor torque at level x, as defined in Sentence [[b-4.1.8.11.#^11hplca|4.1.8.11.(11)]], V = specified lateral earthquake force at the base of the structure, as determined in Article [[b-4.1.8.11.|4.1.8.11.]], Vd = specified lateral earthquake force at the base of the structure, as determined in Article [[b-4.1.8.12.|4.1.8.12.]], Ve = lateral earthquake elastic force at the base of the structure, as determined in Article [[b-4.1.8.12.|4.1.8.12.]], Ved = adjusted lateral earthquake elastic force at the base of the structure, as determined in Article [[b-4.1.8.12.|4.1.8.12.]], Vp = specified lateral earthquake force on an element or component, as determined in Article [[b-4.1.8.18.|4.1.8.18.]], Vs = specified lateral earthquake force at the base of the structure, as determined in Sentence [[b-4.1.8.1.#^7hplca|4.1.8.1.(7)]], for application in Article [[b-4.1.8.1.|4.1.8.1.]], Vs30 = average shear wave velocity, in m/s, in the top 30 m of *[[a-1.4.1.2.#soil|soil]]* or *[[a-1.4.1.2.#rock|rock,]]* W = specified *[[a-1.4.1.2.#dead-load|dead load]]*, as defined in Article [[b-4.1.4.1.|4.1.4.1.]], except that the minimum *[[a-1.4.1.2.#partition|partition]]* weight as defined in Sentence [[b-4.1.4.1.#^3hplca|4.1.4.1.(3)]] need not exceed 0.5 kPa, plus 25% of the specified snow load as defined in Subsection [[b-4.#^416hplca|4.1.6.]], plus 60% of the storage load for areas used for storage, except that *[[a-1.4.1.2.#storage-garage|storage garages]]* need not be considered storage areas, and the full contents of any tanks, (See Note [[b-4.1.8.2.(1)-appx|A-4.1.8.2.(1)]]) Wi, Wx = portion of W that is located at or is assigned to level i or x respectively, Wp = weight of a part or portion of a structure, e.g., cladding, *[[a-1.4.1.2.#partition|partitions]]* and appendages, X = site designation, either XV or XS, XS = site designation in terms of Site Class, where S is the Site Class determined in accordance with Sentence [[b-4.1.8.4.#^3hplca|4.1.8.4.(3)]], XV = site designation in terms of Vs30, where V is the Vs30 value calculated from in situ measurements of shear wave velocity, X450 = site designation XV with Vs30 = 450 m/s, δave = average displacement of the structure at level x, as defined in Sentence [[b-4.1.8.11.#^10hplca|4.1.8.11.(10)]], and δmax = maximum displacement of the structure at level x, as defined in Sentence [[b-4.1.8.11.#^10hplca|4.1.8.11.(10)]].
