Roycronos
Structural
- Feb 25, 2011
- 15
Hello!
I'm doing a deck of a Bridge, it's of concrete (slab) with steel girders, in Sap2000 I did the Slab with Shell Elements, and the beams with Frame Elements. But after I put every loads and combinations, I need the Forces for the Design of the elements.
I was trying to compare the Forces with another methods, and I have not similar results.
I want to talk about 2 cases:
1) If I do the model considering that both elements (Shell and Frame) are in the same centroid and later I give "Insertion Points" to the Frame elements (Top Center) in order to have the real situation, then: For example about the Moment 3-3 of the Frame Elements, Looking for more information, I found that the real Moment for this, might be obtained considering the Moment 3-3 of the Frame Element PLUS the Moment that the axial force (in same element) generates about the centroid of the composite element.
It because the design of those elements must be done with the composite section (when i'm analizing the service state), but I dont know if it completly right.
2) Another case is when I do the Shell and the Frames in different points, but I give Constraints to both (Body) to do both work together, maybe it's more real, but I dont know if I need to do something similar to 1) case about get Design Forces for every element.
Can someone give me advices about the modeling and how to get the real forces for design of the different elements?
(It's independent of the combinations that I need to put, because in every case I have same problem about the Design Forces)
Thanks in advance, and Sorry for my English (Is not my natural language) xD!
Bye!
I'm doing a deck of a Bridge, it's of concrete (slab) with steel girders, in Sap2000 I did the Slab with Shell Elements, and the beams with Frame Elements. But after I put every loads and combinations, I need the Forces for the Design of the elements.
I was trying to compare the Forces with another methods, and I have not similar results.
I want to talk about 2 cases:
1) If I do the model considering that both elements (Shell and Frame) are in the same centroid and later I give "Insertion Points" to the Frame elements (Top Center) in order to have the real situation, then: For example about the Moment 3-3 of the Frame Elements, Looking for more information, I found that the real Moment for this, might be obtained considering the Moment 3-3 of the Frame Element PLUS the Moment that the axial force (in same element) generates about the centroid of the composite element.
It because the design of those elements must be done with the composite section (when i'm analizing the service state), but I dont know if it completly right.
2) Another case is when I do the Shell and the Frames in different points, but I give Constraints to both (Body) to do both work together, maybe it's more real, but I dont know if I need to do something similar to 1) case about get Design Forces for every element.
Can someone give me advices about the modeling and how to get the real forces for design of the different elements?
(It's independent of the combinations that I need to put, because in every case I have same problem about the Design Forces)
Thanks in advance, and Sorry for my English (Is not my natural language) xD!
Bye!
