German 
French 
Spanish 
Portuguese 
Italian 
Arabic 
Russian 
Japanese 
Turkish In the attached picture; I wonder what my friends think about the structure only the rib directions are different all the dimensions are the same. Also, how does ideStatik look at these projects? In fully rigid diaphragm it does not distinguish the two structures, but in semi-rigid diaphragm (as I expected) it does. I am still waiting for comments from ideYapı. Let's name it for convenience in the comments: 1st structure: Building with horizontal ribs 2nd structure: Building with vertical ribs
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
The Power of the Ribs....
- Thread starter NYILMAZ
- Start date
When the semi-rigid diaphragm option is selected in ideCAD, the program models the rib beams as bar elements and includes them in the system's global stiffness matrix. Although this approach is a much more realistic approach, it is critical in terms of more realistic calculation of static and dynamic parameters of rib and cassette flooring systems. As a result, if the two structures with different rib directions in the figure you specified are handled with the fully rigid diaphragm option, the static and dynamic parameters of the two structures will be the same, since the rib beams are not included in the global stiffness matrix of the system. However, with the semi-rigid diaphragm option, the static loads on beams and columns will change depending on the rib directions, as will many dynamically-related parameters (construction periods, mode shapes and effective modal masses, etc.).
If we assume that there will be no difference in total storey weight due to the rib geometry between the two buildings 1) With the fully rigid diaphragm and the option of concentrating the masses at the storey centre: Dynamic behavior and earthquake effects of the two buildings will be the same. 2) With the option to calculate with fully rigid diaphragms and dispersed masses: Since the dynamic masses of the elements of the two buildings will be calculated from the loads on them (typically G+0.3Q), there will be a difference in mass distribution between the buildings, but no difference in stiffness. This may cause slight differences in the earthquake calculation. 3) With the semi-rigid diaphragm option: -Dynamic stiffness and mass matrices of the two buildings will be calculated differently (the ribs will be included in the system with their own shapes and slab shell elements), and the mass of the building will be modeled as distributed masses in all elements (including shell and bar elements). In the semi-rigid diaphragm option, even if the user selects the distributed mass option, the program will still operate with the distributed mass matrix. In order to model the storey mass as a single point mass, a rigid diaphragm must be assumed in the system, otherwise the nodal point where the single large mass is defined will enter the earthquake motion and cause far-reaching effects. With all 3 methods, vertical loads will be calculated in the same way (by transferring the vertical reactions to the main beams at the ends of the rib beams and adding them to the main system as a load).