Which risk increases in prestressed concrete beams exposed to sustained high temperatures during a fire?

💡 Explanation

When prestressed concrete is exposed to high temperatures, the steel tendons undergo thermal expansion, then creep, relaxing the tensile force through a process called stress relaxation because steel's modulus weakens at high T. Therefore, accelerated loss of prestress force results, rather than strengthened steel or enhanced bonding, or affects concrete compressive strength in short fire durations

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