Shear cracks form near the supports of members and are inclined at between about 30o and 45o to the axis of the beam, from the tension face of the member back towards the support. As with flexural cracks, they will be widest at the tension face, reducing in width with distance from the face.
When the member has been correctly designed, shear cracks will be controlled by the provision of shear reinforcement in the form of links. Appropriate guidance is given in the design Eurocodes 2; Part 1-1 covers buildings, Part 2 covers bridges and Part 3 covers Liquid retaining and containing structures. These parts of Eurocode 2 have replaced BS 8110, BS 5400 Part 4 and BS 8007.