IdeCad and Sap2000 Raft Results

M

miralay

New Member
You do not have permission to view link Log in or register now.
It actually caught my attention in a few models, but I had to try it. As in the picture above, I am modeling a rectangular coffee table-like structure with a height of 5 meters, 20 cm, and a height of 6 meters, 6 meters, with an 8*8*0.5m raft under both idecad and sap2000. Although the axial loads and deformations given by both programs are very close to each other in the 1.4g+1.6q combination, the stresses at the points where the columns are attached to the foundation are very different in the M11 moment diagrams given for the raft foundation. The stresses in the areas where the columns do not press almost overlap. What might this difference be due to? Sap2000
You do not have permission to view link Log in or register now.
İdeCad
You do not have permission to view link Log in or register now.
 
Hi, ideCAD makes column-finite element connections at the bottom of the columns by spreading them to the nearest finite element nodes. However, in the sap2000 model, the columns seem to be connected from a single node. Therefore, you get different diagrams under the columns. If you make column-finite element rigid connections in Sap2000 as in ideCAD, you will get similar results. (You can try by transferring directly from the program to Sap200)
 
Mr. Hakan, we are having problems with V15 import. Sap2000 cannot fully import the model. I have one more question. As far as I understand, while Idecad is spreading to the nodes, it divides the foundation under the column into meshes according to the dimensions of the column and runs it together. So what is the interoperability logic? So, which degrees of freedom of these node points work together?
 
Hello again, The program models a "rigid body" behavior by connecting the bottom end joint of the column to the raft (shell) nodes that coincide with the bottom of the column area with rigid connections. The degrees of freedom are not equal, since the raft region under the column will behave rigidly, the joint points corresponding to the relevant area also move together, that is, the translations are affected by rotations.
You do not have permission to view link Log in or register now.
The SAP2000 equivalent of similar behavior is the "body constraint" definition.
You do not have permission to view link Log in or register now.
Regarding your second question: ideCAD is importing data to sap2000 in ver 10 format. Sap2000 ver 15 also creates this problem when reading Sap2000 ver 10 files. Sap2000 v15 also gives the same problem when reading files created with sap200 v10. In short, the cause of the reading problem is not ideCAD. As a solution, you can open the file with sap2000 ver 14 and save it. You can contact the place where you purchased the sap2000 to correct the error.
 
Since the raft area under the column will behave rigidly, the joint points corresponding to the relevant area also move together, that is, the translations are affected by rotations.
Click to expand...
Mr. Hakan, thank you very much for your answer. I meant that too. Transferring loads from a single point to the foundation causes incorrect load distributions, especially under large axial loads. Therefore, the method used by IdeCad was quite consistent. I have one more question, Does the program calculate the forces used for raft foundation reinforcement calculation by taking a certain average? Or is it sizing it to accommodate the greatest stress on the foundation?
 
Dimensioning is made according to the maximum values of the M11 and M22 diagrams in the relevant direction on the line through which the reinforcement axis passes. If necessary, additional reinforcements are placed in the area determined by the working distance of the reinforcement axis.
 
You must log in or register to reply here.
Back
Top