GGU-UNDERPIN: Analysis to DIN 1045 (old)
To verify the unreinforced concrete the following data is required:
beta(r)
designates the nominal strength of the concrete (see also DIN 1045).n-value
DIN 1045 states that a load distribution may be taken into consideration up to an inclination of 1:2 to the direction of the load. Depending on the soil pressure, other n-values can also be used (see DIN 1045; Table 17 for information on this). Together with the load transmission width, this allows calculation of the width to be adopted for the complete height when verifying the unreinforced concrete.
Verification of the unreinforced concrete is performed using the following relationship to DIN 1045:
allow. N = · 1 / 2,1 · b · beta(r) · (1.0 - 2 · e) [kN/m]
b = governing width of concrete
e = eccentricity with regard to governing width = reduction for slenderness of structural element
is a coefficient for considering the slenderness and unintentional eccentricity to DIN 1045 (Equation 20).
is calculated from:
= 1 - /140 · (1 - m/3)
m = e/k (e = M/V und k = b/6) = slenderness (for rectangular sections = sk/b · 12)
sk = buckling length
The buckling length sk in systems without anchors or struts results approximately from twice the separation between the top of the wall and half of the embedment depth. For walls that are horizontally restrained near the top by other engineering means (e.g. adjoining floor slabs), the single separation may be adopted. The horizontal restraint can be specified using the "Wall top kept horizontal" check box. In system which includes anchors or struts, sk is acquired from twice (once) the separation between the top of the wall and the upper row of anchors (struts), or the separation between the individual anchors (struts). The larger of these values is adopted. The slenderness is recalculated for every section using the respective governing concrete width.
The allowable N calculated in this manner is compared to the existing normal force working N. The utilisation factor g is then acquired from the relationship:
g = work. N / allow. N
Verification of unreinforced concrete can also be performed using a partial section.