What can lead to tension cracks in structural beams or slabs?

Tension cracks in structural beams or slabs primarily occur due to bending in the material. When a beam or slab is subjected to loads, it experiences bending moments that create tension forces on the underside of the structural element. If these tensile stresses exceed the material's tensile strength, cracks will form. This phenomenon is especially prevalent in concrete beams or slabs, which have low tensile strength compared to their compressive strength.

Bending introduces a certain amount of deformation, leading to the elongation of the material on the tension side. Once this elongation surpasses the capacity of the material to withstand such stress, cracks will develop, allowing for structural weaknesses and potential failure. Understanding this behavior is critical in assessing the structural integrity of beams and slabs during inspections and in planning for remediation or reinforcement as needed.