Effective depth is the distance between the centroid of the tension reinforcement and the maximum compressive fiber in a reinforced concrete beam design.

Explanation:
When designing a reinforced concrete beam, it is important to consider the depth at which the tension reinforcement is located. This depth is known as the effective depth.

Centroid of tension reinforcement:
The centroid of the tension reinforcement is the point at which the resultant force of the tension reinforcement is considered to act. It is important to locate the centroid accurately to determine the effective depth.

Maximum compressive fiber:
The maximum compressive fiber refers to the point in the beam where the compressive stress is the highest. It is usually located at the extreme fiber of the concrete section.

Significance of effective depth:
The effective depth plays a crucial role in determining the strength and behavior of a reinforced concrete beam. It affects the capacity of the beam to resist bending moments and shear forces. The location of the tension reinforcement relative to the maximum compressive fiber is a critical factor in ensuring the beam's structural integrity.

Overall depth:
The overall depth of a reinforced concrete beam refers to the total distance between the top and bottom surfaces of the beam. It includes the depth of the concrete slab as well as the depth of any reinforcement.

Lever arm:
The lever arm is the perpendicular distance between the applied force and the axis about which the moment is being calculated. In the context of beam design, it is the distance between the centroid of the tension reinforcement and the point where the bending moment is being calculated.

Depth of neutral axis:
The depth of the neutral axis refers to the location within the beam where the bending stress is zero. It divides the beam into two regions: the compression zone and the tension zone. The depth of the neutral axis depends on the applied loads and the properties of the concrete and reinforcement.

Conclusion:
In conclusion, the distance between the centroid of the tension reinforcement and the maximum compressive fiber in a reinforced concrete beam design is known as the effective depth. It is a critical parameter that influences the strength and behavior of the beam. The effective depth determines the lever arm and the location of the neutral axis, which are essential in calculating the bending moment and determining the required reinforcement.