Final answer:
A fixed beam experiences less shear near the supports compared to a simply supported beam due to its constraints against rotation and translation. The shear modulus is a measure of a material's ability to resist shear, with steel-reinforced concrete performing significantly better than concrete or brick alone in resisting shear forces.
Step-by-step explanation:
When comparing a fixed beam with fixed supports on both sides to a simply supported beam, the fixed beam is typically designed to experience less shear near the supports. This is because the fixed beam is restrained against rotation and translation, which allows it to distribute loads more evenly along its length. In contrast, the shear force in a simply supported beam will generally be higher, especially near the supports where the bending moment is highest, because it is only supported at its ends and not fixed against rotation.
The shear modulus (S) is a measurement of a material's ability to withstand shear stress. It reflects the material's rigidity when subjected to shear forces. The higher the shear modulus, the more resistant the material is to shearing action. According to the provided reference, materials such as concrete and brick have very small shear moduli and therefore are poor in resisting shear. On the other hand, steel-reinforced concrete can handle both compression and shear better, making it ideal for construction where beams are prevalent.