The Single WT is a more unconventional shear connection used due to its requirements when being erected. The WT connection uses a WT shape section as the connection joint between the two members. Using the WT shape greatly increases its bearing and shear strength but will also increase the rigidity of the connection joint. This makes the connection more likely to absorb the moment load which can lead to failure.
This connection can only be welded to the parent member but can be either welded or bolted to the child member. The erection of this connection is considered to be quite expensive, as the connection has to be field welded to the member. The extra rigidity in the connection also makes it more vulnerable to higher moment loads.