Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad ENGINEERS MECHANICS STATICS CHAPTER 5 Lecture Notes: Professor A. Salam Al-Ammri Suhad Ibraheem Mohammed Al-Khwarizmi College of Engineering University of Baghdad asalaam.kecbu@uobaghdad.edu.iq Analysis of Structures Trusses Method of Joint 2/17/2012 Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad

Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad Contents Introduction Analysis of Trusses by the Method of Joints Joints Under Special Loading Conditions Sample Problem 5.2.1 Sample Problem 5.2.2 Sample Problem 5.2.3 2/17/2012 Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad

Analysis of Trusses by the Method of Joints 2/17/2012 Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad

Joints Under Special Loading Conditions Forces in opposite members intersecting in two straight lines at a joint are equal. The forces in two opposite members are equal when a load is aligned with a third member. The third member force is equal to the load (including zero load). The forces in two members connected at a joint are equal if the members are aligned and zero otherwise. 2/17/2012 Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad

Joints Under Special Loading Conditions 2/17/2012 Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad

Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad Sample Problem 5.2.1 Using the method of joints, determine the force in each member of the truss. Joint A is subjected to only two unknown member forces. 2/17/2012 Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad

Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad Sample Problem 5.2.1 Joint D Joint B joint E 2/17/2012 Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad

Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad Sample Problem 5.2.1 All member forces and support reactions are known at joint C. However, the joint equilibrium requirements may be applied to check the results. 2/17/2012 Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad

Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad Sample Problem 5.2.2 Determine the loads in each of the members by using the method of joints. Draw the free-body diagram. Joint B 2/17/2012 Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad

Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad Sample Problem 5.2.2 Look at Joint D and find the angle Joint C 2/17/2012 Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad

Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad Sample Problem 5.2.3 Determine the force in members DB , DC and BC (mention whether they are in T or C), if P1 = 240 lb and P2 = 100 lb . 2/17/2012 Professor Dr. A.Salam Al-Ammri & Suhad Ibraheem Mohammad