GGU-RETAIN: Design

When you start an analysis, the program requires the stiffnesses of the retaining wall and any anchors and struts present. This data can be specified before going ahead with the analysis. The GGU-RETAIN program also provides an additional option for determining the optimum section for the computed action effects, using a list of sections loaded with the program. This list can also be edited and expanded. To do this, the program also requires you to enter the maximum allowable stress. If the newly determined section does not coincide with the section on which the analysis was based, GGU-RETAIN alters the calculated displacements as a function of the moments of inertia of the two sections.

However, a new analysis would normally be performed, as the stiffness conditions have changed, because the axial rigidity of the anchors and struts, and any subgrade reaction moduli, do not alter. In most cases, nevertheless, renewed analysis is unnecessary, because the axial rigidity of the anchors/struts is generally so great that appreciable support displacements do not occur. In the appropriate program situations, you will still be warned.

Stress determination can be by one of three different means:

• working σ = N/A + (N · w + M)/W;

• working σ = N/A + M/W;

• working σ = M/W.

where

N = greatest normal force (absolute)
A = cross-sectional area
w = greatest displacement (absolute)
M = greatest moment (absolute)
W = section modulus.

Shear design is also performed.

In-situ concrete walls can be designed to EC 2. Shear design is also possible here.