Which material is commonly used in bridge elements due to its compressive strength when reinforced?

• A. Timber
• B. Reinforced Concrete
• C. Glass
• D. Plastic

Answer: (B)

Reinforced concrete is used because it combines the best of two materials to handle how bridges carry loads. Concrete has excellent compressive strength, so it resists crushing forces well. But under bending, parts of the member are driven into tension, and concrete alone is weak in tension and would crack. By embedding steel reinforcement, the material becomes capable of carrying those tensile forces too, since steel is strong in tension and bonds well with concrete. This combination—compression-resisting concrete with tension-carrying steel—creates a strong, durable, and economical option for bridge elements like girders, decks, and columns. Timber, glass, and plastic don’t provide the same reliable balance: timber can deteriorate and has variable strength, glass is brittle and unsuitable for bending with reinforcement, and plastic generally lacks the stiffness and long-term durability required for bridges.