presentation based on Truss and Frame

1. TRUSS & FRAME Course no-CE 416 course title- Prestress Concrete Design Sessinonal Presented by MD. Mohotasimur Rahman ID NO. 10.01.03.040 Course Teachers Munshi Galib Muktadir & Sabreena Nasrin Lecturer of Civil Engineering Department Ahsanullah University Of Science And Tecnology Dhaka, Bangladesh

2. TRUSS - INTRODUCTION A truss is a structure composed of members fastened together in such a way to resist change in shape and it is rigid structure. A  truss is a structure comprising one or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes . Its purpose is to support a larger load or span a greater distance than any individual member from which the truss may be built Triangular unit

3. TRUSS – INTRODUCTION CONTINUE External forces and reactions to those forces are considered to act only at the nodes. Moments (torques) are explicitly excluded because, and only because, all the joints in a truss are treated as  pin joint or hinge joint . Result in forces in the members which are either tensile or compressive  forces. Node Tie strut

4. PLANE TRUSS VS SPACE TRUSS Plane Truss All member of truss and applied load lie in a same plane. In a simple truss, m = 2n - 3 where m is the total number of members and n is the number of joints . Space Truss An elementary space truss consists of 6 members connected at 4 joints to form a tetrahedron. In a simple space truss, m = 3n - 6 where m is the number of members and n is the number of joints .

5. ROOF TRUSS TERMINOLOGY

6. ROOF TRUSS TYPE

7. B RIDGE TRUSS TERMINOLOGY

8. B RIDGE TRUSS TYPE

9. METHOD OF TRUSS ANALYSIS Joint Method D etermine the S upport Reaction. Apply  Fx = 0 and  Fy = 0 to every node and determine member force Dismember the truss and create a free-body diagram for each member and pin .

10. METHOD OF TRUSS ANALYSIS Section method D etermine the S upport Reaction. To determine the force in member BD, pass a section through the truss as shown and create a free body diagram for the left side . With only three members cut by the section, the equations for static equilibrium may be applied to determine the unknown member forces, including F BD .

11. FRAME (INTRODUCTION) Contain at least one multi-force member, i.e., member acted upon by 3 or more forces . Frames are designed to support loads and are usually stationary.

12. ANALYSIS OF FRAME A free body diagram of the complete frame is used to determine the external forces acting on the frame. Internal forces are determined by dismembering the frame and creating free-body diagrams for each component.