Why we Provide Reinforcement in Beam? Why we called it Placing of Reinforcement!

Reinforcement in Beam

Why we Provide Reinforcement in Beam? Why we called it Placing of Reinforcement!

A structural element that resists loads applied laterally to its axis called beam. Its primary mode of deflection is bending. Reaction forces are generated at the beam's support points by loads applied to it. The sum of all the forces acting on the beam produces shear forces and bending moments within the beams, which cause internal stresses, strains, and deflections.

Compressive, tensile, and shear stresses are created internally in beams that are subjected to loads that do not cause torsion or axial loading. Under gravity loads, a beam's original length is typically slightly compressed at its top to contain a smaller radius arc and placed under tension at its bottom, where the same original beam length is slightly extended to enclose a larger radius arc. Sagging and hogging are two terms used to describe different types of deformation where the top face of the beam is in tension or compression, such as when it is over a support or under a vertical load.

Since the middle of the beam, which is often located midway between the top and bottom, has an identical original length to the radial arc of bending, it is neither under compression nor tension and serves as the neutral axis (dotted line in the beam figure). The beam is subjected to shear stress above the supports.

Placing of Reinforcement is the process of adding steel reinforcement to concrete to strengthen it when it becomes apparent during construction that the concrete's strength is insufficient to sustain the demand (applied loads).

Consider the following loaded Beam example:

When we apply a load to a point, we can see that the upper and lower sides are put under compression and tension, respectively. Because we know that concrete is substantially weaker in tension than it is in compression, we employ reinforcement steel to strengthen the concrete in the lower area (Rebars). These rebars are provided based on the results of analysis and in conformity with building code recommendations.