RAM Concrete Column Tutorial

To design all of your concrete columns you need to be in the Concrete Column Design Mode.

Before you can enter the concrete column design mode the concrete gravity analysis must have been performed. If you have lateral concrete columns you will also want to make sure your model has been analyzed in RAM Frame. Finally, if you are using Special Moment resisting frames, all of the concrete beams must be designed before designing the columns.

To switch to the concrete column mode:

• Select Mode – Concrete Column.

The mode drop-down on the toolbar will indicate you are in column design mode.

Column Design Criteria

The program has an extensive set of design defaults to customize the way concrete columns are designed and detailed. To set up the column design defaults which will be used for all columns in the model:

• Select Criteria – Column Design.
• Select the Code for each of the options under the Reinforcement tab.

• Click on the Bar Selection Tab to set more column design defaults.

• For Transverse Design Spacing,
  • Type 12 for Segment Spacing Increment.
  • Type 1 for Transverse Bar Spacing Increment (the special moment frame columns may require tie spacing other than 3’, 6” etc.)
• For Shear Legs, Type 3 for the Number of Shear Bar Legs for both the Major and Minor directions.
• Click on the Design Checks/Forces tab.
  
• Uncheck the option to Include the Max Column Axial Load Limit.
• For Gravity Forces on Lateral Columns, select Use RAM Concrete Analysis Forces.
• Click [OK].

The other design criteria for Reinforced Concrete Columns is the Lap Spacing which can be customized.

• Select Criteria – Column Lap Splice.
  
• Use the Lap Splice options shown above.

Assign Bar Patterns

Before the Columns can be designed we must specify a bar patterns that we wish to use. You can define any number of bar patterns or layout and the program can consider up to three of these layout for each column that it designs. To define the bar patterns:

• Select Assign – Edit Bar Patterns.
  

For this example we will define three bar patterns.

• Select 3 for Top/Bottom Face Bars (B).
• Select 1 for Additional Bars Each Side (H).
• Select #5 (T08) for Min. Longitudinal Bar Size.
• Select #9 (T12) for Max Longitudinal Bar Size.
• Select #3 (T06) for Transverse Bar Size.
• Click [Add].

A new line of data will appear in the Bar Pattern Groups Created list box.

• Increase the Min Longitudinal Bar size to #8(T10).
• Increase the Max Longitudinal Bar size to #11(T32).
• Increase the Transverse Bar Size to #5(t08).
• Click [Add] to create the second pattern.
• Increase the Additional Bars Each Side to 2.
• Select #5(T08) for Min. Longitudinal Bar Size.
• Select #9 (T12) for Max Longitudinal Bar Size.
• Select #3 (T06) for Transverse Bar Size.
• Click [Add] to create the last pattern of 10 total bars.
• Click [OK].

Now the bar patterns we just defined must be assigned to the concrete columns in the model. To do this:

• Select Assign – Bar Patterns.
  
• Check the box next to each of the patterns that we defined. The graphic on the side indicates the pattern information for the highlighted pattern.

NOTE: As you click on each bar pattern the graphic and data to the right are updated to provide a description of that bar pattern.

• Click [All] to assign those two pattern options for design to all of the concrete columns.

NOTE: You can access the Edit Bar Patterns dialog box directly from this window as well.

At this point you could generate the Load Combinations for design, but the combinations used in the Concrete Beam Module are already defined so we can skip ahead to designing the columns.

Design All and View/Update

With the design criteria set and the load combinations defined, we are ready to design the concrete columns. At this point, the columns should have changed from a light blue color to yellow, indicating that they are ready to be designed. To design the concrete columns:

• Select Process – Design All.

The design process requires numerous code checks for all of the Load Combinations and may take some time to run on large concrete models. The status indicator again displays the progress of the design and indicates when the design is complete.

• Click [Close] to dismiss this window.

The Model graphics will be updated to display the interaction colors similar to Steel Column. Design colors are either Green or Red columns. To see the design colors: View-Colors-Design Colors.

Green– Indicates that the column was designed successfully with no design warnings.

Red– Indicates some aspect of the Concrete Column design is insufficient or incomplete. Complete design warnings can be seen in View/Update.

Blue– Indicates a successful design that is Frozen or Updated. (Columns that have failed will always appear red even if they are frozen.)

• Select Process – View/Update.
• With the Target cursor select one of the interior gravity columns (this can be done from any plan view, elevation view or directly from the 3D view).

The View/Update dialog box will open. There are many options available to in this dialog. For a complete explanation of the View/Update window see the RAM Concrete manual.

The Column View/Update dialog box is separated into three tabs for Longitudinal Reinforcement which is initially displayed, Transverse Reinforcement and Material Properties.

The program determined bar pattern is listed in the upper left corner. This reflects the optimum working design from the assigned bar pattern groups. The design can be changed by simply clicking in the cell with the design and picking another set of bars.

On the right side is an interaction surface for the currently selected level of the column. The program creates an interaction surface for each 2-degree increment around the column. When designing the column, the program investigates each data point (a set of axial forces and moments from a particular load combination or pattern). The data point that is closest to the interaction surface is the point initially shown in the diagram.

At the bottom of the widow is an area for design warnings related to longitudinal reinforcement. There is a separate area for transverse design warnings on the second tab.

• Click in the Final Design Pattern cell for the 1st level
• From the drop down list, select 8-#11 (3x1), #5.
  
• Click [Analyze] to check the validity for the modified design.
  The display will update to provide feedback on the success of the design.
• Notice that the program optimized to the 10 bar pattern since none of the 8 bar patterns worked. The 8 bar pattern selected issues a design warning. Feel free to create new bar patterns or edit the existing ones to get a feeling of the design process.
• Click [Close] to return to the main graphic.

The lateral columns in this model have many more design requirements, not only because of the additional loads, but also because they were designated as Special Moment Frames.

• While in View/Update mode, select one of the moment frame columns.

In this case, the program selects one of the bar sets with #5 ties. To review the transverse reinforcement click on the Transverse Reinforcement Tab.

Notice that the shear reinforcement has to be quite concentrated near the ends of the column in order to meet the special detailing requirements of the code.

To review the complete design results.

• Click [View Results].

The Concrete Column Design Report will open. Review the report. For more information on the designs performed in this check refer to the technical portion of the RAM Concrete Manual. Note; with multi-level columns, the report will start from the top level and work down to the base.

• Close the report to return to the View/Update dialog box.
• Click [Close] to return to the main graphics window.

Copy Design

As with concrete beams, it is often desired to use an identical bar layout for typical columns. To apply the same design to another column:

• Select View – Elevation.
• Click on any beam on Grid 3 to see the interior columns.
• Select Process – Copy Column Line – Single to Fence.

A target cursor with an arrow will appear with the arrow pointing up indicating that the program is expecting you to select the column to copy the design from.

• Click on the gravity column previously modified.
• The fence cursor will then be ready for you to select all other columns that you wish to use this same design. Fence all the interior gravity columns from B-3 to E-3.

An analysis of the new design for the columns will be performed. The log window will open to provide feedback while this is happening.

• Click [Close] to close the pop-up window.

If the design is acceptable, the color of that column will change to Blue indicating the design is frozen.

The new design can be cleared from the beam by using the Process – Clear Column Line command. The columns selected will then be colored Yellow to indicate they are no longer frozen and are ready to be designed. The optimum design will be restored during the next Design-All or View/Update.

Unlike the copy beam design command, the copy column design command transfers not only the reinforcement, but the column size as well. Do not copy to columns that need to retain their size. It should also be noted that the entire column line is copied with this command so you will not be able to copy column of different height or number of stories.

Reports

Many different reports can be generated from the Concrete Column Module. The printed output is mostly generated using the Reports menu.

To print a summary of the concrete column designs:

• Select Reports – Column Design Summary.
• Click  to exit the report.

A similar output is available for a single member through the View/Update dialog box by clicking View Summary. The complete column design results are also available from the report menu.

Take time now to review the various reports available in the Reports menu.

• Continue to RAM Concrete Shear Wall Tutorial
• Go back to RAM Concrete Beam Tutorial
• Up to the RAM Structural System Tutorial