Civil Engineering PE Structural Analysis of Trusses 3

Question 1

A roof truss is subjected to a wind uplift load in addition to dead load.
A bottom chord member that was in tension under dead load alone now carries zero force under the combined loading.
This means the wind uplift force magnitude is:

Accepted Answer

Equal to the dead load component causing tension in that member

Answer

Greater than the dead load component causing tension in that member

Answer

Less than the dead load component causing tension in that member

Answer

Equal to the total dead load on the truss

Question 2

The method of joints requires solving joint equilibrium equations. Which order of joint solution is most efficient for a simply supported planar truss?

Accepted Answer

Start at a support joint where only two unknown member forces exist

Answer

Start at the midspan joint where loading is applied

Answer

Start at any joint with the most members

Answer

Start at the joint with the largest applied load

Question 3

A truss has m = 21 members, r = 3 reactions, and j = 12 joints. This truss is:

Accepted Answer

Statically indeterminate to the 3rd degree

Answer

Statically determinate

Answer

A mechanism (unstable)

Answer

Statically indeterminate to the 1st degree

Question 4

Which of the following is NOT an assumption made in the classical analysis of planar trusses?

Accepted Answer

Members can resist bending moments at their ends

Answer

All loads are applied only at joints

Answer

Members are connected by frictionless pins at joints

Answer

Members are straight two-force members

Question 5

A Fink truss is commonly used for which application?

Accepted Answer

Residential and light commercial roof framing

Answer

Long-span bridge construction

Answer

Offshore platform decking

Answer

Heavy industrial floor systems

Question 6

If the top chord of a through-truss bridge is in compression under live and dead loads, lateral bracing of the top chord is required primarily to prevent:

Accepted Answer

Lateral-torsional buckling of the compression chord

Answer

Fatigue cracking at web connections

Answer

Overstress in diagonal tension members

Answer

Settlement of the deck system

Question 7

A truss node has three members connected: one horizontal carrying +50 kips (tension), one vertical carrying -30 kips (compression), and one unknown diagonal at 30° to horizontal. There is no external load at this joint. What is the axial force in the diagonal?

Accepted Answer

57.7 kips compression

Answer

34.6 kips tension

Answer

50.0 kips compression

Answer

60.0 kips tension