Question

In the linear arch, an imaginary line that shows the path of compressive forces curving through the arch's center is known as

• A. Line of thrust
• B. Line of arch
• C. Axis of the arch
• D. The springing line

Hint:

For a safe masonry arch, the line of thrust should remain within the middle third of the arch section to avoid tensile stresses and ensure stability.

Answer 1

The Correct Option is A

Concept: The Line of Thrust is the imaginary curve joining the points through which the resultant compressive force passes inside an arch. For an arch to remain stable, the line of thrust should lie within the middle third of the arch section. If it moves outside the section, tensile stresses may develop, leading to failure.

Step 1: Understand the Line of Thrust. The compressive forces acting in an arch do not travel in a straight line. Instead, they follow an imaginary curved path known as the line of thrust. It represents the locus of the resultant internal compressive forces.

Step 2: Compare with the other terms.
• Line of thrust: Path of the resultant compressive forces inside the arch.
• Line of arch: Geometric centerline of the arch.
• Axis of the arch: Central axis used in geometrical description.
• Springing line: Horizontal line joining the springing points of the arch. Hence, the imaginary line showing the path of compressive forces is the Line of Thrust. Therefore, the correct option is \[ \boxed{(A)\;\text{Line of thrust}.} \]