Download - 10.01.03.112
Presented by
Md. Shariful Islam
Student ID: 10.01.03.112
Department of Civil Engineering
AUST, Dhaka
Presentation onsupport system
CE 416 PRE-STRESSED CONCRETE
LAB
Course TeachersLecturer Mr. Galib Muktadir Ratul
Lecturer Ms. Sabreena Nasrin
Department of Civil EngineeringAhsanullah University of science and Technology
EQUILIBRIUM OF NON-CONCURRENT COPLANAR FORCE SYSTEM
When a body is in equilibrium, it has neither translatory nor rotatory motion in any direction. Thus the resultant force R and the resultant couple M are both zero, and we have the equilibrium equations for two dimensional force system
Fx = 0; Fy = 0 M = 0These requirements are both necessary and
sufficient conditions for equilibrium.
Supports: A structure is subjected to external forces and transfers these forces through the supports on to the foundation. Therefore the support reactions and the external forces together keep the structure in equilibrium.
Types of supportsThere are different types of supports. Some of
them are a) Roller Support b) Hinged or pinned support
c) Fixed or built in support Some supports are shown in the figure along
with the reactions that can be mobilised.
Real example of various supports systems
Roller Support
Hinged Support
Fixed Support
Types of Supports Action on body
(a) Flexible cable ,belt ,chain, rope
BODYBODY
T
Force exerted by cable is always a tension away from the body in the direction of cable
(b) Smooth surfaces
Contact forces are normal to the surfaces
FF
Contact force is normal to the surface on which the roller moves. The reaction will always be perpendicular to the plane of the roller . Roller support will offer only one independent reaction component.(Whose direction is known.)
(c) Roller support
RvR
Rh
θ
This support does not allow any translatory movement of the rigid body. There will be two independent reaction components at the support. The resultant reaction can be resolved into two mutually perpendicular components. Or it can be shown as resultant reaction inclined at an angle with respect to a reference direction.
( d )pinned Support / hinged support
Rv
MRH
M
(e) Fixed or Built-in Support
This type of support not only prevents the translatory movement of the rigid body, but also the rotation of the rigid body. Hence there will be 3 independent reaction components of forces. Hence there will be 3 unknown components of forces, two mutually perpendicular reactive force component and a reactive moment as shown in the figure.