Question

What is the net downward load to be considered for the analysis of the prestressed concrete beam provided with a parabolic cable as shown in the figure below?

• A. 12 kN/m
• B. 13 kN/m
• C. 14 kN/m
• D. 15 kN/m

Answer 1

The correct option is C 14 kN/m

A parabolic tendon carrying a tension $P$ will provide an upward uniformly distributed load or pressure which is given by
$\begin{array}{cc}{w}_c& =\frac{8Pe}{l^2}\\ & =\frac{8\times 1000\times 200\times {10}^{-3}}{(10{)}^2}\\ & =16kN/m\\ \therefore \text{Net downward loading}& =30-w_c\\ & =30-16=14kN/m\end{array}$