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VisualAnalysis Tutorials: ACI Concrete Wall Design

Project Description:

This example project will illustrate the design of a concrete wall.

Version Note: This tutorial may have been created using a prior version of VisualAnalysis. Minor changes to the software may have occurred including new features and graphics updates. The appearance of dialog boxes and the Project Manager may be altered slightly. ()

The Model and Loading

The purpose of this example is to illustrate the steps involved in designing a concrete wall. With this in mind, a copy of the un-designed model, complete with loading is available in the Examples folder. The file is titled ACI Concrete Panel Design Example.vap. Please open the file and proceed with the design.

The Design Groups

Once you have opened the example project file, move into the Design View. Notice that the structure has been automatically organized into 5 design groups (one for wall and the base). Since the model consists of only plate elements, the only Design Type available should be Concrete Walls and Slabs. We want to design the front wall which is under the design group name "Mesh4."

Design Group Parameters

The design parameters are controlled completely through the Project Manager. After creating the design group, select the member in the design view and click on the Modify tab of the Project Manager to begin editing the design parameters.

Concrete Wall/Slab Parameters:

These general parameters are the first parameters available for editing in the Project Manager. For this example, leave the general parameters unchanged.

Wall/Slab Details:

The "Details" parameters are next in the Modify tab. As their name implies, these parameters are for the reinforcing details of the mesh.

We will leave these unchanged until we have results later on in the tutorial

Reinforcement Parameters:

The "Reinforcement" parameters are next in the Modify tab. 60000 psi reinforcing steel will be used. Choose Top and Bottom for the bar layers. The preliminary wall size is 10". For walls 10" or thicker according to ACI at least two layers of steel are required. It should be noted that the top layer will be located on the inside face of the wall and the bottom layer will be located on the outside face of the wall. Please refer to the "Concrete Wall/Slab Limitations" topic under Concrete\Slab in the User's Guide (Help | Contents).

Enter 1.5 inches for both the top and bottom cover.

In this tutorial, the horizontal and vertical moment values are similar in magnitude. If one or the other was clearly greater in magnitude, it would be beneficial to set the appropriate bars (horizontal or vertical) to be on the outside in order to better resist the moment. Since neither dominates, arbitrarily set the horizontal bars as the outside layer. We will want to check the ACI wall minimum steel provision in this case.

Analyzing the Structure

In order to design the concrete wall, you must first analyze the structure. It should be noted that the model is non-linear because of the compression only spring supports. Before you analyze, go to Analyze | Advanced Analysis Options you will note that the Non-Linear Force and Displacement tolerances are probably set to the default values 0.1 and 0.01, respectively. Change these values to 0.5 and 0.05, so that the model will converge within the allotted number of iterations. For more information on non-linear analyses in VA please consult the VisualAnalysis User's Guide (Help | Contents). Analyze the model.

Designing the Mesh

Once the analysis is complete, you are ready to design the wall. Select a plate element in the design group and choose Details | Top x Bars. The Details dialog is brought up. (This dialog can be brought up by choosing any of the options with the ellipsis button.) This is the dialog you design the wall in. For each reinforcement area there is an associated bar size and bar spacing. The required area of steel per foot is displayed for each area. A red X and green checkmark indicated if the current bar size/spacing meet the requirements for that area. Once the desired bar size/spacing combinations have been selected, hit the OK button to save the reinforcement details. Unity values for the design mesh will be recalculated using the new details. To modify the thickness of the wall/slab use the Details | Thickness area in the project manager.

Synchronizing Design Change

To synchronize the design changes, select Design | Synchronize Design Changes. If the mesh thickness needs to change, you will be warned that some of your results will be lost. Choose "Yes" to continue. You will be prompted to re-analyze, select "Yes", and when it finishes re-analyzing go back to the Design View and review the unity values.

If an element's unity check is great than 1.0, it has failed the Project Settings. The closer the unity value is to one the more efficient, but less conservative the element is. Reiterate the design process as needed.