Torsion Capacity Reporting

See PRODUCT BACKLOG ITEM 1677993

In RAM Concrete Beam and Column, we report 0.75*Tn, which is actually 0.75*Tth (see ACI 318-19 22.7.4.1). I recommend using that notation in Concrete Beam and Column Design reports when ACI 318-14 or ACI318-19 is used. Use of Tn is not appropriate, because ACI assumes that all torsional strength is resisted by closed stirrups. RAM Concrete does not design transverse reinforcement for torsion and does not calculate Tn using ACI 318-19 22.7.6.1. The manual refers to the threshold torsion as Tc, which is not defined in ACI 318. I believe that was used because it was assumed that was torsional strength of concrete, which is not exactly appropriate. ACI codes older than ACI 318-14 do not use Tth. In those codes, I recommend using 0.25Tcr, which is consistent with how RAM Concept reports that value. We may also want to use "Torsion Checks" instead of "Torsion Capacity Checks" for the title of that section in the reports. Note that these changes affect both the RAM Concrete Beam and RAM Concrete Column Manual.

Please refer to the model "20231107_ECPS4_Rev4.rss" in CS0134958:

It appears that phi*Tn is actually phi*Tth. Also it appears that LC 8 and not LC 187 is the governing load combination. To test, uncheck all load combinations except LC 187 and you will see that the design checks. If you uncheck all load combinations except LC 8, you will see that Tu > phi*Tn and torsional reinforcement is required. LC 187 is reported because it produces the lowest phi*Tn.