Abnormally high Live Load runtime - Australian code


Please find the Composite steel tub grillage model attached. The overall length of bridge modeled is 255m divided into 5 spans.
Live load is defined as per Australian code with 12 lanes and a moving load case incorporating 4 individual load cases.
The model is taking more than 12 hours for analysis (even with the moving load increments of 2m and moving load calculation filters set for main girders alone).

Please provide a solution for the same because we have many such bridges and we can't devote so much time for LL analysis of each bridge.




Actually when concurrent forces are to being calculated, the filters are not considered, since vehicle needs to be placed at all possible locations to check the effect of concurrence.
Hence, when going for such analysis, it is recommended to turn off the concurrent effect.
With that done, it could be noted that the analysis time is quite quick.  If concurrent forces are required, moving load tracer could be used to obtain critical vehicle positions from the above analysis.
Hope this helps.  Kindly let us know if further assistance would be required.

Technical Manager, MIDAS
Creation date: 10/17/2018 9:11 PM (dklee@midasit.com)      Updated: 10/18/2018 6:42 AM (dklee@midasit.com)