How can I display the code provision that governs the design of program reinforcement?

The code controlling provision can be displayed on screen for all cross sections on any reinforcement plan on the Design Status or Rule Set Design Layer. To view the controlling criteria:

1. Open a reinforcement plan on Layers - Design Status or Layers - Rule Set Designs.
2. Open the Visible Objects dialog. This can be done by clicking on the visible objects dialog or clicking on
   View - Visible Objects or right clicking within the active plan window and choosing
   Visible Objects.
3. In the Visible Objects dialog, check the box for Controlling Criteria.
4. Click OK to close the dialog. The governing code provision will display on screen.

In some cases, "Det" will display before the code provision. This means that the reinforcement is not explicitly required at that cross section but is extended into the section to satisfy another code rule. Typically, this is associated with span detailing requirements.

How do I model user reinforcement?

See Chapter 25 “Drawing Reinforcement Bars” in the RAM Concept Manual for more information. There are two main types of user reinforcement: concentrated reinforcement and distributed reinforcement. Concentrated reinforcement is a fixed number of bars over a parallelogram area. This type of reinforcement is convenient for modeling beam reinforcement. Distributed reinforcement is a bar spacing applied over a polygon area. This type of reinforcement is convenient for modeling layers of reinforcement over a portion or the entire slab area.

There are six tool buttons that can be used to model the reinforcement:

• Concentrated Reinf. (Click at Bar End Points)

• Concentrated Reinf. (Click at Center Point and an End Point)

• Concentrated Reinf.  Cross (Click at Cross Point and an End Point)

• Distributed Reinf. (Click along Region Boundary)

• Distributed Reinf. in Perimeter (Click at Bar End Points)

• Distributed Reinf. Cross in Perimeter (Click at Cross Point and an End Point)

The “Cross” tools are convenient for defining the reinforcement in both directions. The “Distributed Reinf. in Perimeter” tools are convenient for modeling reinforcement over the entire slab area.

The bar elevation is referenced from the center of the reinforcement segment. When defining reinforcement over an area with slab and beams or slabs with drop panels, make sure that this point is in the correct area. For example, if the reinforcement shown in the screenshot below is referenced to the drop panel and not the typical slab as was intended.

I am modeling an existing slab. Can I prevent the program from adding program reinforcement?

Go to Criteria – Calc Options and check the box for “Check capacity of user reinforcement without designing additional program reinforcement.”

When this is done, program reinforcement will not be added, and cross sections that do not satisfy the code requirements are shown as failing. Some users like to plot the bending moment demand and capacity diagrams at this point to see how badly the failure it, though of course there are other possible failures besides bending.

If user reinforcement has been provided and you are confident that it satisfies the code minimum requirements, you can also turn off the Code Minimum design rule completely under Criteria - Design Rules, though we do not generally recommend this practice.

What is the significance of defining the reinforcement “Slab Face”: Top, Bottom, or Both?

Slab face controls on what plan the reinforcement is displayed. By default, reinforcement defined as “Top” and “Both” are displayed on the top reinforcement plans; reinforcement defined as “Bottom” and “Both” are displayed on the bottom reinforcement plans.

The Slab Face also affects the way the reinforcement is used in the Code Minimum Check and Span Detailing. Options for the “Code Minimum Reinforcement Location” include Elevated Slab, Mat Foundation, Top, and Bottom. Each of these options is based on where the reinforcement is placed (top of slab versus bottom of slab). Span detailing extends top and bottom reinforcement to a certain percentage of the span length (see ACI 318-08 Fig 13.3.8 for an example of a span detailing rule). If "Both" is selected for the Slab Face, then the reinforcement will be extended to meet both top and bottom reinforcing requirements.

For mat foundations, the ACI code (R15.10.4) permits the minimum reinforcing steel to be split between the top and bottom faces. If "Both" is selected for the Slab Face, then the program will use both layers in the minimum reinforcement check.

Can I design a slab with one layer of reinforcement?

Program reinforcement is always detailed in two layers: top and bottom. Slabs with one layer of reinforcement can be modeled and designed using user reinforcement as follows:

1. Model user reinforcement in the slab. Set the Elevation Reference and the Elevation so that the reinforcement is in the correct location. Set the Slab Face to “Both.” This will force the program to use the reinforcement in the code minimum check at each cross section.
2. In Criteria – Calc Options, check the box for “Check capacity of user reinforcement without designing additional program reinforcement.” This will prevent the program from adding program reinforcement at the top and bottom face.
3. Run the analysis.
4. Check the Design Status for failures.
5. If needed, make changes to reinforcement size and spacing.
6. Re-run the analysis.
7. Repeat Steps 4 through 7 as needed.

How can I change the format of reinforcement on the Reinforcement Layer?

By default, program reinforcement is displayed showing bar quantity, bar size, length, and bar face. The format can be modified to include other information, like bar spacing, by doing the following:

1. Select the reinforcement on a plan on Layers – Reinforcement.
2. Click on Edit – Selection Properties. A dialog showing the bar information will display.
3. In the dialog, click on the Presentation tab.
4. Change the key value in the “Callout By Quantity Format.” See key and screenshot below:

$Q - Bar quantity       

$F - Bar face

$B - Bar name

$L - Bar length

$U - Bar length units

$u - Bar spacing units

$S - Bar spacing

\n - Start new line

See Also

Product TechNotes and FAQs

Structural Product TechNotes And FAQs

External Links

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

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