July 30, 2020

Introducing Integrated Design: Seamlessly Linking Architecture and…

Learn how Graphisoft and RISA are working together to leverage model information created by the architect to create a more seamless workflow, while minimizing the duplication that is typical of today's design process:

Feature	ADAPT-PT/RC	ADAPT-Builder
Preliminary Sizing	X	X

Tags: RISA, New, BIM, Archicad

December 29, 2010 | RISA-3D, New, Analysis, P-Delta

What is P-Delta Analysis?

When a model is loaded, it deflects. The deflections in the members of the model may induce secondary moments due to the fact that the ends of the member may no longer be vertical in the deflected position. These secondary effects for members can be accurately approximated through the use of P-Delta analysis. This type of analysis is called “P-Delta” because the magnitude of the secondary moment is equal to “P”, the axial force in the member, times “Delta”, the distance one end of the member is offset from the other end. Step 1: The model is loaded with the Applied loads (P shown above) Step 2: The model deflects Δ, and the secondary shear force (V) is calculated for every member; Step 3: The model is re-solved (internally) with the secondary shear forces applied (V shown above). Step 4: The displacements for this new solution are compared to those obtained from the previous solution. If they fall within the convergence tolerance, the solution has converged. If not, return to Step 2 and repeat. The convergence tolerance is found in the Model Settings and is set by default to 05%…

June 21, 2018 | RISA-3D, New, Analysis, Deflection

Beam Deflection Ratio Options

RISA-3D v16.0.4 introduces an enhancement that will allow for more control over the beam deflection ratio through Deflection Ratio Options. As part of the member properties, you can now designate the ends of single and multi-span beams as a cantilever or supported. This will determine whether the beam deflection ratio is calculated as L’/y’ (supported) or 2L’/y’ (cantilever). Modifying Members From the Members spreadsheet, go to the Advanced tab, where you can designate the Defl Ratio Options. Note: These options are only applicable to members designated as beams. By default, the deflection ratio will be calculated automatically, either as a supported member or as a cantilever. An example of when the deflection ratio option can be useful is if the beam deflection ratio of a member is calculated by the program as a cantilever, but you consider it to actually be supported. You can then set the deflection ratio options to explicitly specify that it is supported and the beam deflection ratio will be adjusted accordingly. Single span beams can be designated as supported on both ends, or cantilevered from either end. In addition, multi-span beams have the option to be designated as a double cantilever, where both ends are…

October 8, 2024 | Featured, RISA-3D

How to Troubleshoot Large Deflections in RISA-3D?

Deflection is a key tool for verifying whether your model was built correctly in RISA-3D. After solving, you can view the deflected shape to confirm if the deflections are within the expected range. If you notice abnormal deflections, use the following steps to troubleshoot the issue. Steps for Investigating Large Deflections Check Member Material Properties: Ensure that the correct material properties are assigned to your members. Incorrect materials can result in inaccurate stiffness and deflections. Review Member Sizes: Verify that your members are sized appropriately for the loads they are designed to carry. Oversized or undersized members can affect deflections significantly. Examine Member Connectivity: End Releases: Incorrectly applied end releases can result in overly flexible members. Analysis Offsets: Verify that any analysis offsets are accurate, as these can influence the effective stiffness of the members. Plate Connectivity: Remember that plates only connect to other elements at their corner nodes, not along edges. Verify all plates are supported at their corners. Inspect Boundary Conditions: Ensure that your supports and restraints are correctly defined. Improper boundary conditions can lead to unexpected deflections. Review Applied Loading: Pay close attention to the magnitude and direction of your applied loads. Misapplied loads may cause unexpected…