ANALYSIS OF STRUCTURES

Trusses Method of Joints Method of Sections

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

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

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

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

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

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.

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

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.

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.