Question

Consider the following statements:
Bars that extend into a simple support must be able to develop their full strength at a designated point L so that their moment capacity is more than the bending moment at that point. The clauses of the code require that $({\sigma }_s=0.85{\sigma }_{sy})$

1. $L_d\le \frac{1.3M_1}{V}+L_0$

2. $\frac{\varphi {\sigma }_s}{4{\tau }_{bd}}\le \frac{1.3M_1}{V}+L_0$

3. $\varphi \le \frac{4{\tau }_{bd}}{{\sigma }_s}(\frac{1.3M_1}{V}+L_0)$

Which of these statements are correct?

• A. 1 and 2
• B. 2 and 3
• C. 1 and 3
• D. 1, 2 and 3

Answer 1

The correct option is D 1, 2 and 3

Development length

$L_d=\frac{\varphi {\sigma }_s}{4{\tau }_{bd}}$

$\therefore$ $\varphi \le \frac{4{\tau }_{bd}}{{\sigma }_s}(\frac{1.3M_1}{V}+L_0)$