RF-CONCRETE Surfaces

RF-CONCRETE Surfaces

Cambiar al modo de pantalla completa Salir del modo de pantalla completa

2.7.10.8 Propiedades de la sección final

Propiedades de la sección final

The curvature for both crack states c (cracked/uncracked) is calculated as follows:

κc,ϕ1 = ksh,c,ϕ1 · mϕ1 - nϕ1 · ec,ϕ1E · Ic,ϕ1 

  • uncracked state:

κl,ϕ1 = 1.158 · 30 · 103 - -100 ·103 · 1.4 · 10-311 · 109 ·6.816 · 10-4 = 4.655 · 10-3 

  • cracked state:

κII,ϕ1 = 1.353 · 30 · 103 - -100 ·103 · -41.5 · 10-311 · 109 ·2.193-4 = 14.499 · 10-3 

The strain for both crack states is determined as follows:

εc,ϕ1 = nϕ1E · Ac,ϕ1 

  • uncracked state:

εl,ϕ1 = -100 · 10311 · 109 · 0.206 = - 4.413 · 10-5 

  • cracked state:

εIl,ϕ1 = -100 · 10311 · 109 · 0.087 = - 10.449 · 10-5 

Thus, it is possible to determine the mean strain.

εϕ1 = ζϕ1 · εII,ϕ1 + 1 - ζϕ1 · εI,ϕ1 =       = 0.835 · -10.449 · 10-5 + 1-0.835 · -4.413 · 10-5 = -9.459 · 10-5 

The mean curvature is determined as follows:

κϕ1 = ζϕ1 · κII,ϕ1 + 1 - ζϕ1 · κI,ϕ1 =       = 0.835 · 14.449 · 10-3 + 1-0.835 · 4.655 · 103 = 12.885 · 10-3 

With the mean curvature and the longitudinal strain, you can calculate the final cross-section properties while taking account of shrinkage, creep, and tension stiffening.

Ideal cross-section area

Aϕ1 = nϕ1E · εϕ1 = -100 · 10311 · 109 · -9.459 · 10-5 = 958.59 cm2 

Ideal moment of inertia to the ideal center of the cross-section

Iϕ1 = II,ϕ1 ·III,ϕ1ζϕ1 · II,ϕ1 · kdh,II,ϕ1 + 1 - ζϕ1 · III,ϕ1 · kdh,I,ϕ1=      = 6.816 · 10-4 · 2.193 · 10-40.836 · 6.816 · 10-4 · 1.353 + 1 - 0.836 · 2.193 · 10-4 · 1.158=18 391.50 cm4 

Eccentricity of centroid

eϕ1 = mϕ1 - κϕ1 · E · Iϕ1nϕ1 =30 · 103 - 12.855 · 10-3 · 11 ·109 · 1.839 ·10-4-100 ·103 = -39 mm 

Ideal moment of inertia to the geometric center of the cross-section

I0,ϕ1 = Iϕ1 + Aϕ1 · eϕ12 = 1.839 · 10-4 + 0.096 · -0.03932 = 33 207 cm4 

Poisson's ratio is determined as follows:

ν = 1 - maxd{1,2} ζd · νinit = (1 - max 0.0836) · 0.2 = 0.0328 

Figura 2.124 Propiedades de la sección final