...
This message is given for the basic tie coupling beams.
In TBDY 2018 article 16.8.5.4 , the minimum size of tie coupling beams will be 300 mm × 300 mm, it is stipulated .
...
Give the dimensions of the so-called tie coupling beam at least 300 mm.
Select tie coupling beam, tie beamcoupling beams
Enter the properties.
In the general settings tab, give the width and height at least 300 mm and click the OK button.
...