Question

For production of structural elements, which of the following system is used?

• A. Freyssinet system
• B. Magnel-Blaton system
• C. Hoyer's system
• D. Lee McCall system

Hint:

Prestressing systems: \[ \boxed{ \begin{aligned} \text{Hoyer} &\rightarrow \text{Pre-tensioning}\\ \text{Freyssinet} &\rightarrow \text{Post-tensioning}\\ \text{Magnel-Blaton} &\rightarrow \text{Post-tensioning} \end{aligned} } \]

Answer 1

The Correct Option is C

Step 1: separate the prestressing systems into two families.
Freyssinet, Magnel Blaton, and Lee McCall systems are all post-tensioning systems, where the tendon is stressed against the already hardened concrete member, usually suited to large in situ members cast one at a time.
Step 2: think about what mass production of structural elements needs instead.
Factory production of standard precast elements like sleepers and small beams needs the tendons stretched first on a long casting bed, with concrete poured around them and the tendons released only after the concrete gains strength, which is a pre-tensioning approach.
Step 3: name the pre-tensioning system used for this.
Hoyer's long line system is exactly this pre-tensioning method, built around fast repetitive factory casting of precast structural elements.
\[ \boxed{\text{Hoyer's system (option C)}} \]