TRUSS & FRAMECourse no-CE 416

course title- Prestress Concrete Design Sessinonal

Presented byMD. Mohotasimur RahmanID 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

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

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

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.

ROOF TRUSS TERMINOLOGY

ROOF TRUSS TYPE

BRIDGE TRUSS TERMINOLOGY

BRIDGE TRUSS TYPE

METHOD OF TRUSS ANALYSIS

Joint Method

Determine the Support 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.

METHOD OF TRUSS ANALYSIS

Section method

Determine the Support 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 FBD.

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.

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.