1. ANALYSIS OF STRUCTURES

2. Trusses
Method of Joints
Method
of Sections

3. The Method of Sections Used to determine the loadings within a body
If a body is in equilibrium, any part of the body is in equilibrium
To find forces within members, an imaginary section is used to cut each member into 2 and expose each internal force as external

4. The Method of Sections Consider the truss and section a-a as shown
Member forces are equal and opposite to those acting on the other part – Newton’s Law

5. The Method of Sections Free-Body Diagram
Procedure for Analysis
Free-Body Diagram
Choose the section that at least cut almost if not all the required internal forces.
Determine the truss’s external reactions
Use equilibrium equations to solve member forces at the cut session
Draw FBD of the sectioned truss which has the least number of forces acting on it
Find the sense of an unknown member force

6. Question 1
Determine the force members HC,CG and DF of the truss. State if the members are in tension or compression. Use joint method of analysis

7. Question 2
Determine the force members GB,AB of the truss. State if the members are in tension or compression. Use joint method of analysis

8. Question 3
Determine the force in members GE, GC, and BC of the truss using sectional method of analysis. Indicate whether the members are in tension or compression.

10. Question 4
Determine the force in members DE, EB, and AB of the truss using sectional method of analysis. Indicate whether the members are in tension or compression

12. Question 5
The Howe Bridge truss is subjected to the loading shown. Determine the force in members HD, CD and GD. State if the members are in tension or compression. Use section method of analysis.

13. Question 6
Determine the force in members CD,LD and KL of the truss, and state if the members are in tension or compression. Use section method of analysis.