Hello guys:
Remember you have to provide at least d/2 clearance off the column so it can check shear. If you fail to provide this off the face of the column you will get a n/c at that joint.
For example if you have an 80 cm mat you ought to give a clearance of 40 cms at least from the face of the load size specified in the software. If you specified a 30 cms size load you need to provide a clearance of 55 cms at least.
Hope this help
Juan