Find vertical prestressing force if characteristic strength is 8.2, wires are stressed at 1000n/mm², diameter is 150mm? A)1500kn B)1230kn C)4567kn D)8967kn

Question

Quizplus · Accepted Answer

The vertical prestressing force can be calculated using the formula for the area of a circle (since the diameter is given) and the stress applied to the wires. The area $A$ of the circle is given by $A = \pi r^2$, where $r$ is the radius of the circle. Given the diameter is 150mm, the radius $r$ is half of that, which is 75mm or 0.075m. Therefore, the area $A = \pi (0.075)^2 = 0.0177 m^2$. The stress applied is 1000N/mm$^2$ or 1000 x 10$^6$ N/m$^2$ (since 1m$^2$ = 10$^6$ mm$^2$). The force $F$ is then the product of the area and the stress, $F = A \times \text{stress} = 0.0177 m^2 \times 1000 \times 10^6 N/m^2 = 17700000 N$ or 1770 kN. However, none of the options exactly match this calculation, suggesting a possible mistake in the interpretation of the question or in the provided options. Given the options, 1230kN seems to be the closest, indicating a potential error in the calculation or an assumption made in the question's context.

Find Vertical Prestressing Force If Characteristic Strength Is 8