Foundations: the limiting ground pressure q2 and the minimum diameter of reinforcement bars Φmin for column footing on rock
Eurocode 2 part 1-1: Design of concrete structures 9.8.4 (1)
Adequate transverse reinforcement should be provided to resist the splitting forces in the footing, when the ground pressure in the ultimate states exceeds q2. This reinforcement may be distributed uniformly in the direction of the splitting force over the height h. A minimum bar diameter, Φmin, should be provided.
The recommended value for the ground pressure q2 is 5 MPa, that for the minimum diameter Φmin is 8 mm.