Question 1

Which beam type listed below is statistically indeterminate?&#10;A)Simple&#10;B)Complex&#10;C)Continuous&#10;D)Cantilever

Accepted Answer

Beams that are continuous are statistically indeterminate. The internal forces that act on continuous beams cannot be determined through the use of only the laws of statics. There are many formulas that can be used to analyze continuous beams, including the Three Bending Moments Equation (Clapeyron's Equation).

Question 2

What are the three unknowns that must be determined when completely identifying a force?
1. Magnitude
2. Intent
3. Direction
4. Line of action
5. Rotation

A)1, 3, 4
B)1, 2, 3
C)2, 3, 5
D)3, 4, 5

1, 3, 4

Accepted Answer

The three unknowns that must be determined when completely identifying a force are magnitude, direction, and line of action. While the magnitude, direction, and line of action are known for a given external load, the point of application is usually all that is known for a reaction. To figure out if a structure is statically determinate, the total number of unknowns (considering all forces) is compared to the three equations of statics. If there are more unknowns than the number of equations available, the structure is considered statically indeterminate.

Question 3

Which of the following statement regarding hinges that support structural frames is not considered to be true?&#10;A)Also called &#34;pin-type supports&#34;&#10;B)Hinges provide support that is referred to as &#34;inclined force&#34;&#10;C)Forces at hinges have three unknowns&#10;D)All of the above

Accepted Answer

The statement "forces at hinges have three unknowns" is not considered true. Two unknown forces are present at hinge supports: magnitude of the forces that prevents horizontal and vertical movement. Hinge supports do not prevent rotation around the hinge centroid.

Question 4

Which of the following arch design types is the only one that is statically determinate?&#10;A)No hinges&#10;B)One-hinge arch&#10;C)Two-hinged arch&#10;D)Three-hinged arch

Accepted Answer

The only arch design type that is statically determinate is the three-hinged arch. Because horizontal forces are always acting on an arch (including its own weight), an arch must be fixed that its support so that it does not flatten out. Two reaction components are present at each support (horizontal and vertical). Three-hinged arches are commonly used for shorter bridge spans (less than 600 feet long) and for structures that require large interior spaces (for example, airplane hangars and gymnasiums).

Deck 17: Struct Analysis