dave is having a great time!!
Looking at the damage though, it seems it is not so much that the fabric is weak as that the seams are not so well done - a good double seam along the corners, with a sufficient length of fabric on the edge would probably avoid the seams tearing away like that... Maybe sewing some broad tape across the corners would do the trick. Not on yours though as the torn edge is soo badly frayed as it has come away ... interesting ...
