Thermal Stresses in Reinforced Concrete Tank

[EDub24]

Hi all. I'm currently pre-designing a 1.8MG reinforced concrete tank (not prestressed). The tank is a thermophilic digester meaning the normal operating temperature for the sludge will be on the order of 135 deg F. Because this is a pre-design I decided to run some preliminary calcs using the PCA document "Circular Concrete Tanks w/o Prestressing" circa 1993 in lieu of setting up a 3D model. Everything was going fine until I started looking at the thermal stresses across the wall due to the high differential temperature (design ambient air is 35 deg F). Using the PCA document equations for thermal stresses I'm getting tensile stresses on the order of 3 times the stresses I'm getting for hydrostatic loading. That does not make sense to me at all. I'm using the hinged base-free top equations for hoop stress and circumferential moment in the PCA doc (no equations for hinged top/bottom). The equations in the PCA document come from an old ACI Tech Paper titled "Serviceability of Circular Prestressed Concrete Tanks" by Amin Ghali and Eleanor Elliot (title no. 89-S34). Does anyone have any insight into what I could be doing wrong? I'm wondering if the 24" wall thickness I currently have is too big to adequately use the given equations as both examples I've seen (one in the PCA doc and the other in the ACI Tech Paper) assume a ~10" wall thickness. Are there any other tools I can use to estimate the thermal stresses across a reinforced concrete wall?

Here are some tank parameters:
ID = 90'
Side wall height = 37-9"
Wall thickness = 24"
wall will be hinged at the top/bottom
internal liquid temperature = 135 deg F
design ambient air temperature = 35 deg F

Thanks for the help!