waffle slab

[struengineer]

We have a four floor parking garage with concrete waffle slab (pan size: 5’x5’x 3’ (high)) supported by concrete columns (30’x30’). There are many diagonal vertical cracks are noticed in the waffle beam near the top of column at the second floor only. Is there any body here happens to have experience on this kind of structure and can give me any idea such as what could cause this crack? How to repair?

I am also looking for some textbooks about how to calculate this kind of structure. Is anyone here can recommend any books?

Thank you.

 

[JAE]

struengineer,

Diagonal cracks in the beam....usually vertical diagonal cracks in a horizontally spanning beam should be considered a serious concern. These would be shear cracks representing an shear overload in the beam. Abrupt failure is usually found with shear failures and thus the lower [φ] factor in design for shear.

I have a hard time suggesting a text book to refer you to as this sounds serious enough that you should seek some experienced engineers who can investigate this.

No offense as I don't know your personal qualifications, but asking for that sort of introductory information doesn't sound consistent with what you've described.