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.
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