This is a bolted top shear connection. A top and seat connection uses fewer field bolts and has the advantage of having a place to set the beam during erection. This presumes that the seat angle is attached to the column flange prior to setting the beam. In this example it is shown bolted, but it could as easily have been shop-welded. All the shear in this connection is carried by the seat angle; that is why it is heavier than the top angle, which is only there for torsional stability.
Top and seated connections may be used on column flanges, column webs or girder webs. In the case of large shear loads, a stiffener may be used beneath the seat.
