Shear Force Capacity of Existing Concrete Slabs

This study aims to analyze shear force capacity in reinforced concrete slabs,
comparing different design codes and identifying key parameters influencing
shear capacity. Results show variations in shear capacity predictions across codes,
highlighting the reasons for the observed relatively low shear capacities in existing
concrete slabs.

Specific attention to shear in slabs is not given to a greater extent than that it should be
avoided. The specific shear design in reinforced slabs before BBK became the acting
regulation was a rare occurrence. SBN offers very limited design methods other than a
simple method for checking the shear resistance and providing general advice to avoid
situations where shear becomes the designing failure mode. A comparison between
BBK04 and EC2 shows that BBK04 with safety class 3 has a good margin of 20%, while
with safety class 1 you have similar results as with EC2 for concrete with a compressive
strength less than 18 MPa. SBN80 shows an overestimation of 60% compared to EC2.
For the punching shear capacity, the results show that BBK79 have good safety margin
compared to EC2, due to its shorter effective perimeter calculation. B7 demonstrates
alignment with EC2 for thicker slabs, but slightly overestimates capacity for thinner slabs.
BHB aligns well with EC2 across most slab thicknesses, but deviations occur at greater
depths, where BHB becomes more conservative.