Concrete Wall Design

IES VisualAn alysis 6.0

ACI Concrete Wall Design Project Descrip Descrip tion: This example project will illustrate the design of a concrete wall.

The Model and Loading The purpose of this example is to illustrate the 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 Panel Design Example.vap. Please open the file and proceed with the design.

The Design Groups Once you have opened the example project project file, move into the Design View. View. Notice that the the structure has been automatically broken up into 5 design groups (one for each mesh). Since the ACI Con cr ete Wall Wal l Desig Des ig n

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model consists of only plate elements, the only Design Type available should be Concrete Walls and Slabs. We want to design the rear wall which is under the design group name “Mesh2.”

Design Group Parameters The design parameters are controlled completely through the Project Manager. Manager. After creating the design group, select the select the member in the design view and click on click on the Modify tab of the Project Manager to begin editing the design parameters. General Parameters: The “General” parameters are the first parameters available for editing in the Project Manager. For this example, example, leave the general parameters unchanged. Mesh Parameters: The “Mesh” parameters parameters are next in the the Modify tab. As their name implies, these parameters are mesh specific. Set the Starting Thickness of 10 in (the thickness of the wall plate elements in the model view) and the Thickness Increment to 2 in. These settings let the design software software know that you want it to work through thicknesses two inches at a time (i.e. try 10”; then 12”; then 14”…). Set the Critical Shear Shear Location to “At the support face”. We want it set up this way because in the Water Loads case the supporting members (the other walls) will not provide a confining effect (i.e. the shear failure location will not be pushed away from the face of the support.). Choose one for the number of both horizontal and vertical detail regions. regions. Please refer to the “Concrete “Concrete Slab/Wall Capabilities” topic under Concrete\Slab in the User’s Guide (Help | Contents) Contents ) for more information on when you might want to use detailing regions. Set the Left, Right, and Bottom support widths to 6 in (the widths of the other walls walls and slab). Set the Top support width to 0 in since there is no top support (i.e. the top is open). Visual Design assumes that the plate elements were drawn in from centerline of support to centerline of support. These widths are used to determine the critical location for moment and shear. Concrete Parameters: The “Concrete” parameters parameters are next in the Modify tab. As their name implies, these parameters provide information about the mesh’s concrete. Specify 3500 psi for the f’c valu e. Leave the High Seismic Risk option unchecked. Please refer to the User’s Guide (Help (Help | Contents) Contents) for more information on when you might want to use this option. Since the structure is a water retaining structure, you might want to check the option to enforce the Z-quantity requirements for crack crack control from ACI 318-05. Check the Use z factor option and set both the Top and Bottom face z stress to 175 kips/in.

ACI Con cr ete Wall Wal l Desig Des ig n

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Reinforcement Parameters: The “Reinforcement” parameters 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 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. wall. Please refer to the “Concrete “Concrete Wall/Slab Limitations” topic under Concrete\Slab in the User’s Guide (Help (Help | Contents). Contents ). Enter 1.5 inches for both the top and bottom cover. Enter 3 inches for the bar spacing module. This tells the software that you only want it to look at bar spacings that are multiples of 3 inches. Leave the default maximum bar spacing of 18 inches. Leave the Use Metric Bars option unchecked. Set the minimum bar size to #3’s. The horizontal and vertical moment moment values are similar in magnitude. If one or the other other was clearly greater in magnitude, it would be beneficial to set the appropriate bars (horizontal or vertical) to be on the the outside in order to better resist the moment. moment. Since neither dominates, arbitrarily set the horizontal bars as the the outside layer. We will want to check the ACI wall wall minimum steel provision in this case. Check the Use ACI Wall Minimum box to indicate that we want to perform the minimum steel checks.

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 the compression only spring supports. Before you analyze, go to An aly ze | An alysi aly si s Opt io ns ns 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 within the allotted number of iterations. iterations. For more information on non-linear analyses in VA please consult the VisualAnalysis User’s Guide (Help (Help | Contents). Contents).

Designing the Mesh Once the analysis is complete, you are ready to design the wall. Select a Select a plate element in the design group and choose Design | Design Selected Group. Group . The Mesh Details: Design Design Mesh 1 dialog is brought up. This is the dialog you design the wall in. The “Select a wall/slab thickness” thickness” area contains a list of wall thicknesses to choose from. from. When you select one of these, the rest of the dialog is updated to match match your selection. Also take a look at the reinforcing details in the


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right side of the dialog. The design software prepares prepares the initial reinforcing configurations. Note that you can change these these configurations. Probably the most important area to look at is the Code Checks area at the bottom of the dialog. This area lists whether or not the selected wall with the currently specified reinforcing passes he code checks or not. It also tells you which which specific code checks the wall doesn’t pass if it fails. Note that if you change the reinforcing configuration, the code checks area is automatically updated based on the changes you made. Select a wall from the “Select a wall/slab thickness” area that passes all of the code checks and choose “OK”. After accepting the design, the design view will generate a color-coded plot of the unity values for each element. It should be noted that a red element indicates that the element has failed a unity check. check. Because the design changes changes haven’t been synchronized yet, these unity values are preliminary values based on the analysis results with the original elements in place. To get updated unity values the design changes need to be synchronized.

Synchronizing Design Change To synchronize the design changes, select An aly ze | Synch Syn ch ro ni ze Desi gn Chan ges. ges . If the mesh thickness needs to change, you will be warned that some of your results will be lost. Choose “Yes” Choose “Yes” to continue. You will be prompted prompted to re-analyze, select “Yes”, select “Yes”, and when it finishes re-analyzing go back to the Design View and review the unity values. If an element is red, it has failed failed a unity check and you need to reiterate the the design process. The closer the unity value is to one the more more efficient, but less conservative the the element is. Reiterate the design process as needed.


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Concrete Wall Design

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