April 29, 2025

RISA Customer Portal for Educational Users

RISA Educational Program

RISA is proud to continue supporting the next generation of structural engineers by offering free access to our software through the RISA Educational Grant Program. For 2025, participating universities can access RISA software for $0 with a streamlined renewal and purchase process.

How to Enroll Users

There are two roles: Admin and Engineer. See the roles and permissions explain below.

Instructors or University Admins should be assigned to the Adming role in the RISA Customer Portal
Students should be assigned to the Engineer role in the RISA Customer Portal.

To learn more about the RISA Educational Program, visit the page below.

RISA Educational Program

Already a practicing engineer? Try RISA and see the difference for yourself.

Tags: New, Educational

July 21, 2020 | Seismic, Dynamics, RISA-3D, New

Improving Mass Participation in RISA-3D

In structural engineering, a modal analysis uses the overall mass and stiffness of a structure to find the various periods at which the structure will naturally resonate, along with the frequencies of vibration of the structure. In RISA-3D, the modal analysis is a prerequisite to the response spectra analysis, which uses these frequencies to calculate forces, stresses and deflections in the model. When conducting a modal response spectrum analysis, building codes (including ASCE 7) require that a sufficient number of modes be used to understand the overall response of the structure. While it is not always possible to achieve full participation (a case where 100% of the modal mass is accounted for) the code does at minimum require that a modal analysis shall include a minimum number of modes in order to obtain a combined mass participation of at least 90% of the actual mass in each orthogonal horizontal direction (X & Z directions in RISA-3D). In order to determine the appropriate number of modes for a given structure (while also achieving the 90% mass participation required by code), RISA-3D users must first pick an arbitrary number of modes (5 to 10 is usually a good starting point) and solve…

December 16, 2010 | RISA-3D, New, Instability

How Should I Model Boundary Conditions for a Truss in RISA-3D?

When it comes to trusses in RISA-3D, boundary condition definitions (pin vs. roller) can make a huge difference. Let’s take an example of a typical roof truss. Note that a pin-pin boundary condition has been applied to the ends. First we must make sure to give the truss out of plane stability by setting this up as a 2D Model within RISA-3D. Then, after solving, you will find that this is not at all behaving like a truss. There are huge axial compression forces in the top chords, and there is no tension in the bottom chord. The reason is that the pin-pin boundary condition prevents the bottom chord from elongating. If it cannot elongate then there cannot be axial strain in the member. You will recall from your Mechanics of Materials class that if there is no strain there cannot be stress, and therefore there can be no axial tension in the bottom chord. The program works out statics the only way it knows how by using arching action with the top chords instead of looking at truss behavior. Now instead try a roller boundary condition on one end of the truss: Now the bottom chord is experiencing a…

December 21, 2010 | RISA-3D, Loads, New, Wood, Wind

How Can I Account For Continuous Tie Rods in RISA-3D Wood Walls?

Continuous tiedown systems are used to help resist overturning forces generated by lateral loads, and can be estimated in RISA-3D using the hold-down database and the strap forces. The Holddown Excel database is located in the RISA>Wood Schedules>HoldDowns folder and contains the parameters for the deflection calculations from the NDS 2015 Special Design Provisions for Wind and Seismic, Equation 4.3-1: In order to account for the uplift effects of the tiedown (rod elongation, bearing deformation, fastener slip, etc.) you need to change the change Δa. A good estimate of this value is listed below: P= Allowable Tension L= Length of the rod A= Area of the rod E= Stiffness of the rod It is important to note that this assumes a tied-off system which distributes loads at each level rather than a skipped story system. The manufacturers of the tiedowns require the tension forces at each floor level, and you can find the Strap Forces from Wall Detail Report. This can also be used to select the appropriate tiedown for the wall from the manufacturer’s charts listed under Allowable Tension Capacity based on the wood material…