The following are the details of an error that has been observed in version 11.3 of RCDC (STAAD Advanced Concrete Design).
1. For columns that are designed using the Auto Design facility, RCDC allows some further redesign operations to be performed on those columns. Examples of these redesign operations are:
a) Level Grouping - which allows all the columns at a given level to have the same reinforcement
b) Level Ungrouping - which is the opposite of what is described in (a) above
c) Grouping of any two or more columns specifically chosen for this task
d) Un-grouping of any two or more previously grouped columns specifically chosen for this task
e) Grouping/un-grouping using the Snapshots facility available in the Reports menu of RCDC
f) An ignore/include operation is performed for some columns
An error is present in the reinforcement that is calculated for ductile columns that are subjected to the afore-mentioned redesign operations if the user performs the following steps in the sequence described
a) Performs Auto-design
b) Closes the file
c) Re-opens the file
d) Performs one or more of the redesign operations described in (a) through (f) above.
The error is in the calculation of the main reinforcement of the column. There are chances that the final reinforcement calculated would be lesser than the required reinforcement.
Method to avoid the error:
The error can be avoided if, immediately after performing the redesign operation described above in (a) through (f), the user
(i) Unlocks the file and thus the previous design is discarded
(ii) Performs a new design through Auto-design
Note that this error does NOT exist in the following cases:
2.Columns of Intermediate frames (ACI), DCM (European - BS EN) and IMRF (Australian)
3.If design is performed with a new RCDC file (first occasion). This is because, as described above, the closing and re-opening the file before performing the above-mentioned redesign operations is a key requirement for this error to manifest.
2.Column design – ACI 318 (FPS unit codes) – Issue in length parameters on redesign Screen for grouped columns/walls.
After the Auto design is performed for the column/wall, RCDC allows providing various parameters on the redesign screen. It also allows modifying the length parameters on the redesign screen. Length parameters include the unsupported length and effective length factor for the selected column/walls. If the column/walls are grouped, RCDC allows providing separate unsupported length and effective length factors for each column/wall.
For the ACI 318-2011, ACI 318-2014, and ACI 318-2019 (FPS unit codes) there is an error in displaying the length parameters on the redesign screen for the grouped column/walls. The values of the unsupported length and effective length factor shown on the redesign screen for grouped columns/walls are not consistent with the values calculated during auto design or values provided by the user.