The simple seat connection consist of an angle with its horizontal leg and its top tp receive the reaction from the beam and transfer it to column and beam.

The seat connection required more spacing vertical direction ad hence difficult to make beam to beam connection but this type of connection is suited for beam to column connection. In this case reaction from the beam is transfer to the column to the seat angle by bearing shear and bending of horizontal leg of angle

The top cleat angle provide to keep the beam stable in verticle direction and to prevent it lateral buckling but it is not design to carry any load

When the beam reaction is large($\lt$100kN) the angle along cannot suport it In such case horizontal leg of an angle is stiffened( strengthened ) by means of 1 or 2 type fitting angle such connection is called stiffened seat angle

clearance =3 to 15 mm

Procedure steps

1. No of bolts required

2. Length of an angle supporting beam=width of beam

3. bearing length required at route line of beam

b=$\frac{R}{tw\times fyb}$

1. length of outstanding edge connection the beam =b+clearance

=b+10

1. bearing length of beam at seat angle

b1=b-(tf-y1)

bending moment to width set angle is subjected

b2=(b1+clearance)=ta-$\gamma$a

seat angle subjected to bending moment

mu$\frac{R}{b1}\times b2\times\frac{b2}{2}$

6 . moment resistance capacity of angle

md=1.2$\times\frac{fy}{\gamma mo}\times z$

z=section modulus

=$\frac{I}{y}=\frac{bd^{3}/1^{2}}{d/2}$

z=$\frac{bd^{2}}{6}$

md=1.2$\times \frac{fy}{\gamma mo}\times \frac{bd^{2}}{6}$

md$\gt$ mu connection is safe

7 . Shera capacity of outstanding leg seat angle

=$\frac{bf\times ta\times fu}{\sqrt{3}\times ymo}$ factored load

8.Shera strength of beam

Vd=$\frac{Aw\times fyw}{\sqrt{3}.y}$