Analysis of Statically Determinate Trusses

What is a truss?

What are the two primary assumptions made to idealize a truss for the purpose of design analysis?

In truss analysis, what is the term for the stress developed in members due to the rigidity of the joints, which is typically ignored in an idealized analysis?

For a coplanar truss, what is the equation that determines if it is statically determinate?

A coplanar truss has 19 members (b), 3 external support reactions (r), and 11 joints (j). How would this truss be classified?

A coplanar truss has 15 members (b), 4 external support reactions (r), and 9 joints (j). What is its classification?

A coplanar truss with stable external supports has 12 members (b), 3 external reactions (r), and 8 joints (j). What is its classification?

How is a simple truss constructed?

What is a compound truss?

What defines a complex truss?

According to the principles of truss stability, what condition of the support reactions will cause a truss to be externally unstable?

What is the fundamental principle of the Method of Joints for truss analysis?

When using the Method of Joints, the analysis should start at a joint having what characteristics?

For the symmetric roof truss shown in Fig. 3-20a, a vertical support reaction at joint A is 4 kN. The angle of member AG with the horizontal is 30 degrees. What is the force in member AG?

For the symmetric roof truss in Fig. 3-20a, the force in member AG is 8 kN (Compression) and its angle with the horizontal is 30 degrees. What is the force in member AB?

What is the rule for identifying a zero-force member when a joint is formed by only two non-collinear members?

What is the rule for identifying a zero-force member when a joint is formed by three members, two of which are collinear?

In the truss shown in Fig. 3-24a, joint D consists of three members: DC, DE, and DH, where DE and DH are collinear. An external load P is applied at joint E. Based on the rules for zero-force members, what can be concluded about the members at joint D?

In the truss shown in Fig. 3-24a, there is a rocker support at joint G that can only exert a horizontal force, Gx. The members meeting at G are GA and GF. What can be concluded about the force in member GA?

What is the fundamental principle of the Method of Sections for truss analysis?

When using the Method of Sections, a section should generally be chosen that passes through how many members with unknown forces?

In the roof truss shown in Fig. 3-26a, a section 'aa' is cut through members KJ, GJ, and GH. The right portion of the truss has a 300 lb load at J, a 150 lb load at I, and an upward reaction of 1159.3 lb at H. The distance from I to H is 6 ft and the vertical distance from G to the line IH is 3.464 ft. Member GJ is at a 30-degree angle to IH. What is the force in member GJ?

In the roof truss shown in Fig. 3-26a, a section 'bb' is cut. For the left portion, the upward reaction at A is 1159.3 lb. There is a 300 lb downward load at B and a 500 lb load at P. The vertical distance from P to the line AC is 3.464 ft and the horizontal distance from A to C is 6 ft. What is the force in member CO?

In the truss shown in Fig. 3-27, a vertical section is made through GF, GD, and CD. A 7 kN upward reaction is at E, and a 2 kN downward load is at D. The distance from D to E is 3 m. Member GF makes an angle of 26.6 degrees with the horizontal, and its line of action passes through point O, which is 6 m to the left of D. What is the force in member GF?

What is the typical analysis strategy for a compound truss?

What is the simplest stable three-dimensional structural element from which a simple space truss is built?

For a space truss with b members, r reactions, and j joints, what is the equation for statical determinacy?

How many scalar equilibrium equations are available for each joint in the analysis of a space truss?

A space truss has 9 members and 5 joints. It is supported by a ball-and-socket joint (3 reactions), a slotted roller (2 reactions), and a cable (1 reaction), for a total of 6 reactions. How is this truss classified?

In a space truss, if all but one of the members connected to a joint lie in the same plane and no external load acts on the joint, what can be concluded?

What is the primary way that idealized truss members carry load?

For what span length are Pratt, Howe, and Warren bridge trusses normally used?

What is a distinguishing feature of a Parker truss, often used for larger spans?

Why were subdivided trusses, such as the Baltimore truss, developed?

What is the necessary first step in constructing a simple truss framework to ensure it is rigid?

In the determinacy equation for a coplanar truss, b + r = 2j, what does the variable 'j' represent?

In the determinacy equation for a coplanar truss, b + r = 2j, what does the variable 'b' represent?

What does it mean if a truss is said to have a 'critical form'?

At an unloaded joint in a truss, four members meet. Two members, A and B, are collinear. A third member, C, is perpendicular to A and B. A fourth member, D, lies at an angle. What can be determined by inspection?

When using the method of joints, if you assume an unknown member force is in tension and the numerical solution yields a negative scalar, what does this result indicate?

What is the common plate used to connect the ends of truss members by bolting or welding?

A coplanar truss shown in Fig. 3-18c has 9 members, 3 reactions, and 6 joints. What is its classification?

In the analysis of the K-truss in Example 3.7, which method provided a direct solution for the force in member BC?

In the analysis of the complex truss in Example 3.11, what was the first step in the 'Reduction to Stable Simple Truss' procedure?

In the method of substitute members for complex trusses, what equation is used to combine the effects of the external loading and the unit loading to find the final force (Si) in a member?

In the space truss analysis in Example 3.12, the force F_BE is determined at joint B. The vertical component of the force must balance a 600 lb downward force (the vertical reaction at B). The length of member BE is 12, and its vertical projection is 8. What is the total force F_BE?

Which of the following best describes the loads and connections in an idealized truss model?

One way to form a compound truss is by connecting two simple trusses, ABC and CDE, using a common joint C and a connecting bar. Which figure in the text illustrates this specific type of connection?

For the roof truss in Fig. 3-20a, which is symmetric in loading and geometry, the total downward vertical load is 8 kN (2 kN + 3 kN + 3 kN). If the vertical reaction at A (Ay) is 4 kN, what must be the vertical reaction at D (Dy)?

Why must compression members in a truss often be made thicker than tension members?