Transverse and Longitudinal Reinforcement

Design Mode:

In Design Mode only the reinforcement type can be changed, this is to allow the program to properly fill the internal reinforcement schedule.

Longitudinal Steel

For the calculation of longitudinal steel in Design Mode, the user has three options. If they select to follow the specifications for this area, then the program will use a decision tree that is based on the governing specification. If they choose to always use the percentage of the cross section area, then the program will ignore shrinkage and temperature steel and only calculate the area of the longitudinal steel based on a percentage of the cross-section area. Finally, they have the option of always using the shrinkage/temperature steel, which forces the program to calculate and use the shrinkage and temperature steel area for longitudinal steel.

Minimum Reinforcement

For both mesh and rebar, the user has the option of assigning a minimum base reinforcement for both flexural and longitudinal steel. This was added to allow users to follow the provisions of the 7^th Edition of LRFD where a minimum steel provision has been added for both directions and both the interior and exterior faces. In addition, the user also has the option of using the same calculated minimum reinforcement in each face by checking the ‘Maximize’ box. If this option is left unchecked, then the calculated (or assigned) minimum reinforcement is distributed evenly between each face (i.e., ½ of the minimum reinforcement is placed in each face). Finally, the user also has the option of using the individual member thicknesses (or not) to calculate the minimum steel. If this option is checked, the program uses the individual member thicknesses to calculate minimum steel, otherwise the program uses the largest thickness of all members.

Mesh Properties

For designs using mesh reinforcement, there are additional options available that will determine what line wires and cross wires the program selects. The user can select either a 2 sheet or a 4 sheet configuration for both the interior and exterior sheets. The graphic below displays these layouts. Note that for the 4 sheet layout, the user also has the option of no laps for the inner cage (similar to the rebar layout for the inner cage).

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.

Analysis Mode:

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.

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.