Issue: Resultant of reactions does not match calculation protocol

Issue

For a given seismic load case, the resultant of support reactions exhibits values that are significantly different from expected results.

Typically, the value of the overturning moment is much lower than expected and the vertical resultant is much higher than expected.

The expected magnitude of the main results for seismic action in X direction are Rx = ~1'300 kN, Rz = 0 kN, My = ~24'600 kN

Instead, the obtained values are Rx = 1'585 kN, Rz = 10'312 kN, My = 1'670 kN

The result for Rx is more or less acceptable, but completely off for Rz and My.

Explanation

That type of nonsense result typically happens when using the resultant of reactions service for an unsigned seismic load case (i.e. signed results option disabled in the seismic load case properties).

See detailed explanation in "Seismic modal superposition and resultants in SCIA Engineer".

Solution

• DO NOT use Resultant of reactions for unsigned seismic load cases or load case combinations or result classes that contain such load cases
• Resultant of reactions may be used with signed seismic load cases or load case combinations or result classes that contain such load cases, provided that proper signature is possible (see "Seismic load case settings")
• In general, prefer using other result services to obtain seismic resulting forces, such as
  • summary table of seismic load cases in linear calculation protocol
  • resulting forces per storey from detailed storey results
  • resultant from section on 2D members (in case 1D members are not needed in the resultant)
  • integration strip results (only for single 2D members)
  • integration member results