At solution, the program creates a finite element mesh for the wall to compute the stiffness. From this mesh the program can also calculate the stresses and forces in the individual plates. In the area that defines the region above the opening, the program uses a summation tool to calculate the forces for the region. This summation is done many times over the horizontal distance of the region and the results are then used to create axial, shear and moment diagrams for the lintel.

These diagrams (both In-Plane and Out of Plane) are presented in the opening detail report and can be used to perform concrete design for the lintel.

For more information see How to Model Concrete Walls with Openings in RISAFloor and RISA-3D.

For wind loads the Occupancy Category is no longer an input option. ASCE now publishes different wind speeds depending on the newly renamed Risk Category of the structure, which incorporate the Importance Factor previously used.

For seismic loads the Occupancy Category has been renamed to Risk Category, although the category options remain the same. Also, for structures which fall under Seismic Design Category A the program no longer generates seismic loads. Per new code provisions, such structures no longer need to be designed for seismic forces.

The new code requires notional loads to be applied to all structures as a minimum lateral force. The Notional Load Generator has been improved to include the default value (1% of g) as the notional load in each direction. This can be accessed through the Insert Menu, under Notional Loads.

The latest ASD and Strength level load combinations are now incorporated into the Load Combination Generator.

At solution the program will take regions above and below openings and “transfer” those loads to the adjacent full story height regions to be designed. Note that the stiffness of the wall considers the entire area of the wall (excluding openings), so it is only the design that is altered.

The regions above and below the openings will have their designs then excluded from the results.

For more information see How to Model Concrete Walls with Openings in RISA-3D.

The Retaining Wall Definitions spreadsheet on the Soil tab is where these properties are defined.

There are inputs for the Heel, Saturated Heel, and Toe. If there is no water table then the Saturated Heel properties can be ignored. These can also be defined from the Retaining Wall Definition Editor.

Note that if you do not input the K values, then the program will use the coefficient of internal friction (φ) and the backfill angle (θ) to calculate K. For a propped wall, only the at rest K is used.

For a cantilevered wall, the active pressure equation will be used on the heel side and the passive pressure equation will be used on the toe side.

The detail report for the wall will give the resulting pressure calculations.

The Retaining Wall Editor has three tabs and allows you to input your retaining wall information in a graphical dialog. The program will then update the Retaining Wall Definitions spreadsheet automatically. Here’s a quick look at the three dialogs:

When you click in a dialog, the status bar at the bottom of the dialog will give information about that entry.

When finished then click OK and you will be brought back to either the dialog or spreadsheet that you came from.

To model a retaining wall, click the Draw Retaining Walls button. Choose the Material and choose or create a Retaining Wall Definition. The Retaining Wall Definition defines all of the parameters for the wall, footing and soil.

In the graphic view click two points to define the centerline of your retaining wall.

After you’ve modeled the wall you can apply loading to the wall and solve the model. Make sure that the HL load category is referenced in the Load Combinations spreadsheet if you want the hydrostatic soil loading to be considered.

After solving the model, the Retaining Wall Results output spreadsheet and the Detail Report will give soil pressure calculations, reinforcement design, and shear and stability (overturning, soil bearing, sliding) checks.

Once the connection has been created, use the Connection Properties inputs on the right side of the screen to set things such as member sizes, plate material, and specify whether various connections are bolted or welded. Use the 2D Views and click on dimensions to type in the necessary values.

Look at the Reports tab to see a Pass/Fail summary of the connection. Click on the tabs along the top to view more specific connection details for each portion of the gusset plate. Once all of the individual checks are listed as passing, the connection will be reported as passing.

Draw Wall Panel

From the editor you can add openings, draw design regions, apply continuous boundary conditions, update the Material and update the Wall Design Rule.

At solution the program will then analyze the wall and design reinforcement for each region separately, as well as provide a lintel analysis for wall regions above openings.

In Booth Seminars

(Located at Booth 721)

Workshops

(Located in Grapevine Rm 1-2)

Can’t Make It to NASCC?

Join us for a live webinar. RISA Technologies offers a variety of topics each month. Earn Professional Development Hours while learning to use RISA more efficiently. Learn More >