Bearing stiffeners are structural elements that are added to steel beams to provide additional support and strength at specific locations. These stiffeners are typically welded to the web of the beam and help to distribute loads more evenly, reducing the potential for web buckling or failure.

Bearing stiffeners are provided at three key locations:

1. Supports: Bearing stiffeners are commonly provided at the supports of a beam. This is because the maximum bending moment typically occurs at the supports, and the presence of stiffeners helps to prevent excessive deformation and failure. By adding stiffeners at the supports, the beam can better resist the applied loads and maintain its structural integrity.

2. The mid-span: In addition to the supports, bearing stiffeners are also provided at the mid-span of a beam. The mid-span is another critical location where significant bending moments occur. By adding stiffeners at this location, the beam's capacity to resist bending and shear forces is enhanced, ensuring that it can safely carry the applied loads without experiencing excessive deflection or failure.

3. The point of application of concentrated loads: Bearing stiffeners are also required at the point of application of concentrated loads. These loads, which are applied at specific locations along the span of a beam, can cause localized stress concentrations. By adding stiffeners at these points, the load is distributed more evenly, reducing the risk of localized failure and ensuring that the beam can effectively support the concentrated load without buckling or collapsing.

In summary, bearing stiffeners are provided at supports, the mid-span, and the point of application of concentrated loads to enhance the overall strength and load-carrying capacity of steel beams. By adding these stiffeners, the beams can better resist bending moments, shear forces, and concentrated loads, ensuring their structural integrity and safety.