Structural Analysis and Design Software
Updated:
08/ 18/ 2015

# FAQ

#### Category

 Purchase Decision (17) Installation (14) Input (65) Calculation (86) Display (63) Printout Report (28) Archive, Backup (7) Import, Export (11)

### Category Calculation

 1 Because I have to design a very irregular structural system for earthquakes, I would like to know if RFEM performs the so-called modal analysis (considering several mode shapes) automatically on the spatial system, or if it needs a special setting. RFEM DYNAM Addition II 2 I have modeled a simple cable structure with prestress where the support forces are smaller than the prestressing force. To check it, I have analyzed two different spatial systems.Example 1 is defined with a straight cable while the cable of example 2 has a rise.Where does the difference come from? RFEM RSTAB 3 When do I apply the different equation solving methods with "direct" and "iterative"? RFEM 4 The calculation of the critical load factor according to second-order analysis in RSTAB results in a value that differs significantly from the one of the RSBUCK calculation. RSTAB RSBUCK 5 Where are the limits for RSTAB concerning the number of structural elements? RSTAB 6 I noticed an inconsistency for the determined result combinations. For example, why is the maximum vertical support reaction of RC4 zero?In my clear system, I can easily see that this cannot be true. The minimum load is alright. RFEM RSTAB 7 Why the program doesn't show any total displacement for result combinations? RFEM RSTAB 8 I have idealized a taper by using a start and end cross-section (calculated with SHAPE-THIN). Then, I have calculated the frame.When I carry out the stress calculation in STEEL, the error message "Tapered member contains incompatible cross-sections" appears.What can be the cause of the error? STEEL SHAPE-THIN 9 When I tried to pick the imperfections in FE-LTB, the message "Diagonal coefficient of matrix < 0" was displayed.What have I done wrong? FE-LTB 10 I have inserted a predeformation in RSTAB.FE-LTB takes over the loads if desired, why not also the pre-deformations? FE-LTB RSTAB