The model contains 6749 nos. of beam elements, 160 nos. of surface elements. If you model a surface element, by default each edge of the surface gets subdivided into 10 parts at the time of analysis. Thus, when you analyse a model without controlling the edge divisions, the internal elements generated from STAAD.Pro would be huge. In this case, 16,000 nos. of plate elements get generated. The program would take a large time to analyse the model. This is the reason why your model is taking a huge time for analysis. I have controlled the edge division of the surface element by using SET DIV 2 command. The command has been added just before the SURFACE INCIDENCE command. This command instruct the program to subdivide each side of the surface into 2 parts and generate smaller elements accordingly. I have analyse the model with the legacy solver in my computer ( 16 GB RAM, Intel core i7 @2.3 GHz processor) and it took at around 245 Sec. Please find the attachments.
If SET DIV 5 commnad is used, the analysis was complete in my computer in 399 sec.
Regards,
SANJIB DAS
STAAD Technical Support Group