Structural Engineering — Quiz 2

Questions in this quiz (10)

1. A two-dimensional truss has $$18$$ members, $$10$$ joints, and $$3$$ reaction components. According to the equation for static determinacy of trusses $$m+r=2j$$, this truss is:

   • Statically determinate
   • Statically indeterminate to the 1st degree
   • Statically indeterminate to the 2nd degree
   • Unstable

2. A simply supported beam with a span of $$12$$ m has an influence line constructed for the reaction at the right support. A moving concentrated load of $$60$$ kN traverses the beam. What is the maximum value of the right reaction?

   • 30 kN
   • 45 kN
   • 60 kN
   • 120 kN

3. A steel wide-flange beam is made of Grade $$50$$ steel $$\left(F_y=50\ \mathrm{ksi}\right)$$ and has a plastic section modulus $$Z_x=95\ \mathrm{in^3}$$. Determine the nominal plastic moment capacity $$M_p$$ of the beam.

   • 396 kip-ft
   • 475 kip-ft
   • 525 kip-ft
   • 600 kip-ft

4. A reinforced concrete beam has a width $$b=10$$ in, effective depth $$d=18$$ in, and tension steel area $$A_s=2.6\ \mathrm{in^2}$$. The concrete compressive strength is $$f'_c=4000\ \mathrm{psi}$$ and steel yield strength is $$f_y=60{,}000\ \mathrm{psi}$$. Assuming the beam is tension-controlled, determine the nominal moment capacity $$M_n$$.

   • 188 kip-ft
   • 215 kip-ft
   • 204.2 kip-ft
   • 268 kip-ft

5. A cantilever beam with a length of $$10$$ ft carries a uniformly distributed load of $$3.0$$ kip/ft over its entire length. Determine the maximum bending moment at the fixed support.

   • 75 kip-ft
   • 150 kip-ft
   • 300 kip-ft
   • 225 kip-ft

6. The moment reaction at point $$A$$ due to the applied loads shown in the frame below is most nearly:

   • 165 kip-ft
   • 185 kip-ft
   • 255 kip-ft
   • 305 kip-ft

7. The design moment strength $$\phi M_n$$ for the reinforced concrete beam section shown is most nearly.

   • $$115.7\ \mathrm{kip\text{-}ft}$$
   • $$218.7\ \mathrm{kip\text{-}ft}$$
   • $$314.6\ \mathrm{kip\text{-}ft}$$
   • $$357.8\ \mathrm{kip\text{-}ft}$$

8. A $$10$$-ft-long reinforced concrete beam with the cross-section shown is subjected to a uniformly distributed service dead load of $$5$$ lb/ft and a concentrated service live load at midspan. Taking $$f'_c=3000$$ psi and $$f_y=40000$$ psi, determine the maximum allowable service live load using LRFD.

   • $$23{,}000\ \mathrm{lb}$$
   • $$29{,}000\ \mathrm{lb}$$
   • $$35{,}000\ \mathrm{lb}$$
   • $$50{,}000\ \mathrm{lb}$$

9. The beam shown is a $$W18\times71$$ wide-flange steel section bent about its strong axis and fixed at $$A$$. Determine the magnitude of the maximum deflection due to the applied loads, ignoring self-weight.

   • $$0.02\ \mathrm{in}$$
   • $$0.05\ \mathrm{in}$$
   • $$0.09\ \mathrm{in}$$
   • $$0.12\ \mathrm{in}$$

10. For the singly reinforced concrete beam shown below $$\left(f'_c=4000\ \mathrm{psi},\ f_y=60000\ \mathrm{psi}\right)$$, determine the ultimate shear strength $$\phi V_n$$.

    • $$77.8\ \mathrm{kips}$$
    • $$94.8\ \mathrm{kips}$$
    • $$145.6\ \mathrm{kips}$$
    • $$300.7\ \mathrm{kips}$$