Question:
In versions 8.0.1.33 and older, in the Load Safety Factor Table, for Primary load cases, one could specify one value as the Serviceability factor, and another value as the Design factor.
In the current version, we are unable to specify two different values, meaning, the program permits a value to be specified to only one of those two, which it then forcibly assigns to the other factor too. Is this an error?
Answer:
It is not an error. It is an intentional change made to the program with effect from the SFA CONNECT Update 2 (build 8.2.0.31). The reason for the change is the following.
Load factors are used as multiplying factors to calculate a modified set of loads for a specific purpose. In past versions, in the load safety factor table, the facility for specifying one value as a serviceability factor and another value as a Design factor was available so that users could instruct the program to internally generate two sets of loads from each Primary load case. Then, one of those sets could be used for situations where service loads are to be used (like base pressure calculations), and the other load case could be used for calculations where strength loads are used (like concrete design).
However, it was discovered that the program is not designed to use these two separate factors. In other words, the analysis as well as design of the foundation was being performed only using one of those factors. The other factor was simply not used at all.
An example of this would be a mat foundation which needs to be analyzed twice for a primary load case: once using the loads generated using the serviceability factor, and a second time using the loads generated using the Design factor. But an inspection of the FEM model of the mat will show that it contains only the loads generated using the serviceability factor.
To prevent this, we had to change the program so that any given load case cannot be allowed to have two factors. In a future version of the program, the feature will be enabled to accept two factors.
Thus, this is not a defect. This is deliberately implemented this way in the current versions of the program to avoid an error.
A workaround for this would be to specify two separate load cases in place of the primary load case - one for the serviceability checks and the other for the strength checks. The program is designed to handle those correctly.