Design Mode:
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In Design Mode only the reinforcement type can be changed, this is to allow the program to properly fill the internal reinforcement schedule.
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The most common configuration is a 2-sheet layout with wall laps for the interior sheets, and a 2-sheet layout with slab laps for the exterior sheets. In general, you should not put laps in tension zones, although this is not a code requirement.
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Analysis Mode:
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When operating in Analysis Mode only the reinforcement can be edited. The user can edit the bar or wire size and spacing for each group of bars as defined by location within the culvert. If using mesh reinforcement then you can set the number of levels to one or two for many of the mesh locations. To switch reinforcement types you must first change the program mode to Design Mode.
For mesh users operating in analysis mode, you have a range of inputs available. Note that the A and B marks are always line wires, while the C marks are cross wires. In addition, the base wires extend the full length of the sheets, while the nested zones and adder sheets are only present in specific locations. See the graphic below.
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The nesting zones are treated in Eriksson Culvert as additional line wires spaced between the base line wires, while adder sheets are separate small sheets that are in addition to the base sheets, and are connected with only a few cross wires.
User Defined Longitudinal Steel
Check this to be able to edit the bar or wire size and spacing for longitudinal steel. If this box is checked then the analysis will not design the longitudinal steel but will instead use the values defined in the grid. If not checked, then the program will calculate the longitudinal steel based on the options previously discussed under Design Mode.