phantomlegion86
Structural
- Jan 19, 2010
- 5
Hi Everyone! I want to first start off by saying thank you all for all of the help that you provide on these forums, I have learned quite a bit from the questions and answers here.
Anyway on to my question. I have seen this topic brought up in the past, but I thought I would pose another question in regards to it. I have been given the task of designing the reinforcing for a fairly large tank (120'x150'x22' with 3 intermediate 120' walls within it.) In the past I have used the PCA rectangular concrete tanks manual for this, but unfortunately as can be seen in the other post regarding this, the aspect ratio of the tank does not fall within the values given in the manual.
I have modeled the tank in SAP2000 and have gotten back what I believe to reasonable results.
-I am basing this on the fact that the maximum negative vertical moment that SAP yields for the center of the long wall is just a little less than the max neg vert moment that I calculate if it was treated as a cantilever. 110k-ft and 115 k-ft respectively. This makes sense as there is some stiffness from the outside walls but not much that helps resist the moment. Other values throughout the tank seem reasonable to me as they require reinforcing that is similar to past tanks of this size.
With that being said, I still wanted to go the extra step and try to verify my design methods in SAP with that of the PCA rectangular concrete tank design manual.
So I then modeled a tank that DID fall into the aspect ratio values provided in the manual, but so far I am not having any luck with matching the values this model yields to the values I get with hand calculations from the PCA design method.
Currently I am using Joint Patterns and surface area loads based on the joint patterns to simulate hydrostatic pressure. All joints at the bottom of the tank have been set with fixed restraints. From here I have then done hand calculations to find the PCA design method moments, but like I said I just can't get them to match. Sorry this was a bit rambling, thanks for any help you can provide!
AEM
Go Phantom Regiment!
Anyway on to my question. I have seen this topic brought up in the past, but I thought I would pose another question in regards to it. I have been given the task of designing the reinforcing for a fairly large tank (120'x150'x22' with 3 intermediate 120' walls within it.) In the past I have used the PCA rectangular concrete tanks manual for this, but unfortunately as can be seen in the other post regarding this, the aspect ratio of the tank does not fall within the values given in the manual.
I have modeled the tank in SAP2000 and have gotten back what I believe to reasonable results.
-I am basing this on the fact that the maximum negative vertical moment that SAP yields for the center of the long wall is just a little less than the max neg vert moment that I calculate if it was treated as a cantilever. 110k-ft and 115 k-ft respectively. This makes sense as there is some stiffness from the outside walls but not much that helps resist the moment. Other values throughout the tank seem reasonable to me as they require reinforcing that is similar to past tanks of this size.
With that being said, I still wanted to go the extra step and try to verify my design methods in SAP with that of the PCA rectangular concrete tank design manual.
So I then modeled a tank that DID fall into the aspect ratio values provided in the manual, but so far I am not having any luck with matching the values this model yields to the values I get with hand calculations from the PCA design method.
Currently I am using Joint Patterns and surface area loads based on the joint patterns to simulate hydrostatic pressure. All joints at the bottom of the tank have been set with fixed restraints. From here I have then done hand calculations to find the PCA design method moments, but like I said I just can't get them to match. Sorry this was a bit rambling, thanks for any help you can provide!
AEM
Go Phantom Regiment!
