If shear reinforcement is not provided, shear resistance in reinforced concrete members is developed by a combination of the following mechanisms:

  1. Shear resistance of the uncracked concrete. From 20% to 40%.
  2. Interface shear transfer due to aggregate interlock tangentially along the rough surfaces of the crack. From 35% to 50%.
  3. Arch action.
  4. Dowel action due to the resistance of the longitudinal bars to the transverse shearing force. From 15% to 25%.