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5.2.1 Provided Longitudinal Reinforcement
Provided Longitudinal Reinforcement
The longitudinal reinforcement to be inserted is arranged by Items (reinforcement sets) and sorted by members and sets of members.
Below the table you can see the reinforcement represented graphically with item members. The current item (row selected in upper part where pointer is placed) is highlighted in red. Modifications to the parameters in the table are immediately displayed in the graphic. The buttons for controlling the reinforcement graphic are described in chapter 6.1.
The reinforcement proposal also considers structural regulations. According to EN 1992-1-1, 184.108.40.206, for example, a minimum reinforcement on supports assumed to be hinged must be arranged in such a way that it covers at least 25 % of the maximum adjacent moment of span and is available over the 0.25-fold of the length of the final span (values for German National Annex).
The results are listed by Items which have the same properties (diameter, length).
The items of all members and sets of members are summarized in the 3.4 Steel Schedule window.
This column indicates the position of the reinforcement in the cross-section:
- basic reinforcement -z (top)
- basic reinforcement +z (bottom)
- -z (top)
- +z (bottom)
- in corners
- all round
RF-CONCRETE Members considers the specifications set in the Reinforcement Layout tab of window 1.6 Reinforcement for the reinforcement's arrangement (see chapter 3.6.4).
The number of rebars of an item can be edited: Click into the table cell to open the edit dialog box with the button.
The Number of rebars can be changed by using the spin buttons or by directly entering a number. In the section below, you can adjust the position of the members in the individual input rows.
The position of a rebar is defined by means of its Bar Coordinates: The coordinates y and z determine the global distance from the cross-section's centroid. The angle β describes the inclination against the longitudinal member axis for the anchorage types "Hook" and "Bend". For example, a Hook Rotation about the angle β = 90° results in a downward rotation (i.e. in direction +z) for the top reinforcement; the angle β = 270° rotates the anchorage end of the bottom reinforcement upwards. For the "Straight" anchorage type, column C is of no importance.
In order to delete the reinforcement of a row, clear the Place rebars evenly check box, which enables the [Delete] button.
The rebar diameters affect the calculation of the inner lever arm of forces as well as the number of rebars per position. Use the list to change the rebar diameter for the current item number.
Column E lists the respective total reinforcement area resulting from the number of rebars and the diameter.
The total length of a representative rebar is shown for each position. The value is composed of the required rebar length and the lengths of anchorage at both member ends. It cannot be edited here.
The values represent the mathematical start and end positions of the rebars. They refer to the member's start node given in RFEM (x = 0). When the program determines the dimensions, it takes the support conditions and the anchorage lengths l1 and l2 into account.
The anchorage lengths of the provided reinforcement can be changed using the list. The Details option opens the following edit dialog box.
The dialog box manages the parameters of the Anchorage on Start and on End of the rebar.
You can adjust the Anchorage type and the Bond type via the lists. The anchorage type is described in chapter 3.6.1. RF-CONCRETE Members automatically recognizes the bond conditions that result from the cross-section geometry and the rebar position. It is also possible to enter user-defined specifications. Figure 8.2 in EN 1992-1-1, 8.4.2 describes good and poor bond conditions.
The Anchorage length l1 is determined with equation (8.4) according to EN 1992-1-1, 8.4.4 (1) considering Table 8.2. It cannot be modified.
The Anchorage length l2 for hooks and bends should be at least 5 dS according to EN 1992-1-1, 8.4.1 (2).
The required Bending diameter dbr is specified according to EN 1992-1-1, Table 8.1.
The entire anchorage length Σ for each rebar end results from the individual portions.
This column shows the total weight of the contained rebars for each position.
If a footer is indicated in the final column, the reason is a special condition. The numbers are explained in the status bar.
To access all [Messages] for the provided reinforcement, use the corresponding button. The Error Messages or Notes to Design Process dialog box appears (see Figure 5.4).
In the graphic zone of the window, the longitudinal reinforcement is represented by item members. The current reinforcement item (row in upper table where pointer is placed) is highlighted in red. Clicking the [Edit Reinforcement] button above the graphic opens the edit dialog box for the selected item.
This dialog box summarizes the reinforcement parameters already described above. Use the dialog box to control or, if necessary, adjust the specifications for Location, Bar Positioning, Reinforcement Diameter, and Anchorages.
After modifying parameters, the designs must be calculated again with the new reinforcement. So, when leaving window 3.1, a query appears that asks if you want to recalculate the safety.
An exception exists for the results of nonlinear analyses: They are generally deleted so that a manual [Calculation] is required.
A modified reinforcement proposal can be stored as a template with the [Save] button. In the following dialog box, the Name of the Reinforcement Template must be entered.
Using these templates, you can reset the user-defined reinforcement when the design specifications have been changed in window 1.6. The changes are not lost if RF-CONCRETE Members creates a new provided reinforcement.