ATC-40 - Raw functions

Chapter 8

Capacity Spectrum Method

streng.codes.usa.atc40.raw.ch8.csm.PF1(m, φ)[source]

Modal participation factor for the first natural mode

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 PF1 = csm_atc40.PF1(m=np.array([39.08, 39.08, 39.08]),
                     φ=np.array([0.0483, 0.0920, 0.1217]))
Parameters:
  • m (np.array) – mass assigned to level i
  • φ (np.array) – amplitude of mode 1 al level i
Returns:

Given using the expression:

\[PF_1 = \dfrac{\sum(m_i \cdot φ_i)}{\sum(m_i \cdot φ_i^2)}\]

Return type:

float

streng.codes.usa.atc40.raw.ch8.csm.SRA(βeff, behavior)[source]
streng.codes.usa.atc40.raw.ch8.csm.SRV(βeff, behavior)[source]
streng.codes.usa.atc40.raw.ch8.csm.Sa(V, W, α1)[source]

The spectral acceleration

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 Sa = csm_atc40.Sa(V=bl.y_ini,
                   W=sum(m),
                   α1=α1) # Βάζω όπου W τη μάζα ώστε να βγει το Sa σε m/sec2 και όχι σε g
Parameters:
  • V (float) – base shear
  • W (float) – building weight (dead plus likely live loads…eg g+0.3q)
  • α1 (float) – modal mass coefficient for the first natural mode
Returns:

Given using the expression:

\[S_a = \dfrac{V/W}{α_1}\]

Return type:

float

streng.codes.usa.atc40.raw.ch8.csm.Sd(Δroof, PF1, φroof1)[source]
streng.codes.usa.atc40.raw.ch8.csm.T(Sa, Sd)[source]
streng.codes.usa.atc40.raw.ch8.csm.α1(m, φ)[source]

Modal mass coefficient for the first natural mode

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2
 α1 = csm_atc40.α1(m=np.array([39.08, 39.08, 39.08]),
                   φ=np.array([0.0483, 0.0920, 0.1217]))
Parameters:
  • m (np.array) – mass assigned to level i
  • φ (np.array) – amplitude of mode 1 al level i
Returns:

Given using the expression:

\[α_1 = \dfrac{\sum(m_i \cdot φ_i)^2}{\sum(m_i) \cdot \sum(m_i \cdot φ_i^2)}\]

Return type:

float

streng.codes.usa.atc40.raw.ch8.csm.β0(dy, ay, dpi, api)[source]
streng.codes.usa.atc40.raw.ch8.csm.βeff(β, β0, behavior)[source]
streng.codes.usa.atc40.raw.ch8.csm.κ(β0, behavior)[source]