What is the horizontal force I get from the vertical force F (EC2 6.5.3)?

[rte4563]

If you look at figure 6.25 you can see I have a force "F" acting on an area "a" - what horizontal force does this give? I wanna make sure I have enough reinforcement in my concrete foundation to take this horizontal force that "spreads out" in the concrete, say if for example force "F" is 100 kN and "a" is 100mmx100mm.

 

[centondollar]

The figure answers your question. Vertical compression causes transverse tension, and the figure contains transverse links.

You should ask a colleague to teach you this or consult a textbook on basic RC design.