You need to add the LOAD LIST ENV 1 2 command to the file as shown next
PERFORM ANALYSIS PRINT ALL
DEFINE ENVELOPE
100 TO 188 ENVELOPE 1 TYPE STRENGTH
200 TO 308 ENVELOPE 2 TYPE SERVICEABILITY
END DEFINE ENVELOPE
LOAD LIST ENV 1 2
PARAMETER 1
CODE AISC UNIFIED 2010
More details on this are available at
communities.bentley.com/.../20793.strengthserviceability-check-in-design
PERFORM ANALYSIS PRINT ALL
DEFINE ENVELOPE
100 TO 188 ENVELOPE 1 TYPE STRENGTH
200 TO 308 ENVELOPE 2 TYPE SERVICEABILITY
END DEFINE ENVELOPE
LOAD LIST ENV 1 2
PARAMETER 1
CODE AISC UNIFIED 2010
More details on this are available at
communities.bentley.com/.../20793.strengthserviceability-check-in-design