What kind of crack pattern in beam 1

MyoMaung said:

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

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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.

Myo Maung said:

How can we prevent these cracks?

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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.