What kind of crack pattern in beam 1

[Myo Maung]

What kind of crack pattern in beam to column joint due to earthquake? How can we prevent these cracks?

 

[KootK]

What kind of crack pattern in beam to column joint due to earthquake?

This will be greatly influenced by the proportions and detailing of the members coming into the joint. In a well designed and detailed joint following weak beam / strong column principles, you might get something like I've shown below.

How can we prevent these cracks?

In many flexural situations, you don't want to prevent them. the rebar does not get engaged, and therefore does not contribute to ductility, until after the cracks form.