The structural analysis software RFEM 6 is the basis of a modular software system. The main program RFEM 6 is used to define structures, materials, and loads of planar and spatial structural systems consisting of plates, walls, shells, and members. The program also allows you to create combined structures as well as to model solid and contact elements.
RSTAB 9 is a powerful analysis and design software for 3D beam, frame, or truss structure calculations, reflecting the current state of the art and helping structural engineers meet requirements in modern civil engineering.
Do you often spend too long calculating cross-sections? Dlubal Software and the RSECTION stand-alone program facilitate your work by determining section properties of various cross-sections and performing a subsequent stress analysis.
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The ASCE 7-22 standard provides several types of design spectra. In this FAQ, we would like to focus on the following two design spectra:
The two-period spectrum is implemented in the program as usual. However, based on the data available from the standard, only the horizontal design spectrum / MCER spectrum as well as the modification related to the force and displacement can be offered.
For the multi-period design spectrum, discrete numerical values are specified. ASCE 7‑22 states that these values can be queried on the USGS Seismic Design Geodatabase page. In the current state of development, you have the option to create a user-defined response spectrum with a g‑factor (depending on the mass conversion constant) to use the data from the ASCE 7 Hazard Tool [1], for example.
Please proceed as follows:
The Masonry Design add-on allows you to automatically determine the stiffness of your wall-slab hinge. The diagrams were determined as part of the research project DDmaS - "Digitizing the design of masonry structures" and are derived from the standard.
Define a line hinge on the connection line of both surfaces and activate the slab-wall connection.
You can now enter your parameters in the Slab-Wall Connection tab. Then, click the Regenerate [...] button.
The determined diagrams are displayed subsequently.
All members when using the Design Add-ons for serviceability checks are considered supported at the end nodes by default. If the member is instead a cantilever or includes an internal support for a combination of both a cantilever and supported at both ends member type, a new Design Support should be defined under the member details.
The Design Support option can be found under the member dialog box under Design Supports & Deflection tab. Supports can be added to any nodes detected along the member length such as the member start, member end, or internal nodes.
Under the New Design Support dialog box, you can set the type of support from the drop-down including general, concrete, or timber. The "general" will give the program guidance on the deflection member type and which limiting deflection ratio to reference from the Serviceability Configurations whether cantilever (e.g., L/180) or supported on both ends (e.g., L/360). The alternative types "concrete" and "timber" will also influence the deflection design, but have additional strength design options incorporated such as moment and shear internal force modification for concrete design and a stress perpendicular to grain check for timber design.
For additional detailed information on this new setting in RFEM 6 including a "timber" type design support, refer to the webinar listed below under Links at time 51:05.
Some materials have multiple limit stress limits for compression, tension, and so on. For these materials, the limiting stress must be input manually by the user.
The limit stress values are listed under the Material Values tab.
These values can be added in the Member/Surface Configurations under the User limit stress type.
By default, the Shear plane in thread option is activated and the lower strength according to the selected design standard is considered for the bolt shear check.
In AISC, the bolt nominal shear strengths are listed in Table J3.2. As an example, Group A (for example, A325) bolt has a nominal shear strength of 54 ksi (372 MPa) when the threads are not excluded from the shear planes. To use the higher strength of 68 ksi (469 MPa), the option can be unchecked to exclude threads from the shear planes.
A splice connection using end plates can be easily created using the “Plate to Plate” template from the Components library (Image 01).
For a splice joint without end plates, the configuration can be created manually by adding individual components (Image 02).
The configuration includes the following components. Each component can be easily deleted or copied by right-clicking on the component.
It is required that a small gap is created using “Member Cut” and “Auxiliary Plane”. The gap is divided between the two members (that is, 1/16” gap is applied as 1/32” displacement to each member).
Alternatively, a sample model “AISC Splice Connection” can be downloaded and saved as a user-defined template (Image 03).
In the Effective Length dialog box, you can simply uncheck the "Lateral Torsional Buckling" option to exclude this check in the design add-on.
To perform an earthquake analysis, you need a modal analysis and then a load case of the Response Spectrum Analysis type.
After you have performed your modal analysis, create a new load case. Here you will find the usual settings from the previous program generation.
In the Response Spectrum tab, you can define your response spectrum as usual. If you want to use a response spectrum according to the standard, make sure that the desired standard is selected in the general data of Standards II.
In the Selection of Modes tab, you can select the mode shapes and filter them, if necessary.
After the load case has been calculated, you obtain the results.
Yes, you can also export the response spectra from RFEM 6 and import them into RFEM 5 as a user-defined response spectrum. Please note that export and import via Excel may also have different columns/descriptions due to different versions.
Export your data in RFEM 6 to Excel.
If you want to import this table directly, you will get an error message. RFEM 5 expects a different worksheet description and two columns only.
As soon as you adjust the name in Excel and delete the column with the frequency results, you will be able to edit the response spectrum in RFEM 5.