February 15, 2022

Seismic Design of Masonry Walls (TMS 402-16) in RISA-3D

RISA-3D is expanding its industry leading support for the analysis and design of various materials with the implementation of Seismic Design of Masonry Wall Panels according to the provisions of TMS 402-16 (as well as ACI 530-13).

When creating a model in RISA-3D, users now have the ability to easily define a "seismic design rule" for masonry walls with one of three options:

Ordinary
Intermediate
Special

When the seismic design rule is established, various provisions from TMS 402-16 are evaluated including checks for:

Boundary Zone Reinforcement
Minimum Spacing of Horizontal Reinforcement (Out-of-Plane)
Maximum In-Plane Shear Reinforcement
Mortar Type

When the analysis is complete, users can evaluate the design either in spreadsheet results or using the detailed reports similar to what has previously been available for concrete shear walls.

For additional details on the calculations, visit the Masonry Walls – Seismic Design topic found in the RISA-3D Online Help file:

RISA Help File

For additional information, check out the video below:

Tags: Seismic, RISA-3D, Walls, New, Masonry

March 10, 2015 | RISA-3D, Walls, New

The Internal Force Summation Tool for Walls

You may be familiar with the Internal Force Summation Tool (IFST) that is currently present in RISA-3D. However, a new tool has been added which allows you to click point to point within a wall and will only sum forces between these two points. Previously when using the IFST, forces were summed across all elements within the plane of a cut. The previous IFST is still available, but the new IFST Wall tool is located on the left side of the screen as well. A few rules to keep in mind when using this tool: A batch solution or single load combination must be run. The wall or walls in question need to be selected in the model view. The IFST Wall can be used along multiple walls. However the walls must be in the same plane. Let’s take a look at an example using the IFST Wall. Below is a model where we are interested in the forces within a section of the wall: 1. Run a single load combination solution of the model. 2. For ease of viewing the wall panel, we will only select that element in the model. This is not necessary though unlike with the…

May 4, 2015 | Dynamics, RISA-3D, RISA-2D, New

Ritz Vector Solver (Dynamics) now Available

RISA-3D v13 includes a new Ritz Vector Solver for the Dynamic analysis. When running a Response Spectrum analysis for seismic design, some structures experience large numbers of local modes that don’t contribute to the lateral response of the structure. The use of load-dependent Ritz vectors (rather than true mode shapes) can greatly improve the speed and accuracy of a Response Spectra analysis for these types of models. There is a new option added to the Dynamic solution options as shown to the right. This dialog can be found by clicking on the Advanced button from the Solution tab of the Model Settings. RISA-3D Output In general, the Ritz vectors will be very similar in shape and frequency to the true dynamic results, though they are not expected to be identical. For that reason, the RISA-3D results will identify them as Ritz Vectors (rather than Mode Shapes) and Ritz Frequencies in the title bar of the dynamic results spreadsheets. Simplified Overview The general concept is that a static solution in the direction of the seismic loading will form a good basis for the approximate mode shapes of the structure which then leads to natural frequency calculations. This concept is nothing new…

February 19, 2018 | RISA-3D, New, Masonry

Masonry Cover Flexibility in RISA-3D

In RISA-3D we now have the ability to: Define a cover other than the minimum from the ACI 530 code provisions Define a single reinforcing bar that is non-centered in a grouted masonry cell From the Wall Design Rules in RISA-3D: We can see here that a new option is available in the Bar Placement column called Non-Center that allows you to place a single non-centered bar in a cell. The Cover then allows you to specify the distance from the exterior of the masonry block to the extreme fiber of the reinforcement. The default cover value is defined as Min. The Min input will use whichever governs between these two sections of the specification (ACI 530-13): Section 6.1.3.5 states a minimum distance between the inside of the face shell and the reinforcement is required. RISA is conservative and always assumes this to be 1/2″. Thus, the cover calculated in this fashion = t_faceshell + 1/2″ Section 6.1.4 requires a cover dimension = 1-1/2″ or 2″ depending on bar size and whether the masonry is exposed to weather. In the program this is always assumed to be 1-1/2″. Thus, the Min term will create a cover equal to the maximum…