In a reinforced concrete beam, what should the spacing of vertical stirrups be in terms of effective depth, to ensure adequate shear reinforcement as per IS 456:2000? 

Explanation:

• According to IS 456:2000, the spacing of vertical stirrups (shear reinforcement) in a reinforced concrete beam should not exceed 0.75 times the effective depth (d) of the beam.
• This ensures that the shear reinforcement is adequate to resist shear forces and prevent shear failure.

Additional Information Key Points from IS 456:2000:

1. Shear Stress: The shear stress in a beam increases near the supports, so the shear reinforcement must be more concentrated at these locations.

2. Stirrup Spacing: The code stipulates that the spacing of vertical stirrups (shear reinforcement) should not exceed 0.75 times the effective depth (d) of the beam to ensure that shear is effectively resisted across the entire length of the beam.

3. Shear Reinforcement Distribution: In general, stirrups should be placed closer together near the supports where shear is higher, and the spacing can increase as you move toward the middle of the beam where shear stress is lower.