Structure I

1. STRUCTURAL ANALYSIS ONE (0670311)
Dr. Ala’Taleb Obaidat
Faculty of Engineering and Technology
Department of Civil Engineering
Jordan-Amman
Chapter one
Introduction
First Semester
Philadelphia University

2. Dept. of Civil Engineering
Dr. Ala’ Taleb Obaidat Chapter One
Introduction
The following Courses are Prerequisites for Structural Analysis course:
 Statics
1. Equilibrium (State of balance)
2. Drawing of free body diagram of the structures.
3. External and internal forces.
4. Determination of reactions at supports.
Structure did not deform
 Mechanics of Materials
Study the following when the loads are applied:
1. Displacement and Deformation of the structure.
2. Stress equations.
3. Changing in shape.

3. Dept. of Civil Engineering
Dr. Ala’ Taleb Obaidat Chapter One
Statics
Equilibrium:
The structure is considered in equilibrium if:
σ 𝑓𝑥 = 0 , σ 𝑓𝑦 = 0 , σ 𝑀 = 0
Warning: The most important thing in this course is to apply equilibrium
equation correctly.
Free Body Diagrams (F.B.D):
 F.B.D is the drawings showing all the
forces acting on the structure including
reactions.
 Draw the reactive forces that are supplied by the supports.
 FBD can be drawn only for a portion of the structure
by taking a section at one or more points.
 Internal forces acting on the section must be included When a FBD
drawn for a section
A
B
Ay
Bx
By
Reactions Reactions
F.B.D
Ay
NC
MC
VC
Internal Forces

4. Dept. of Civil Engineering
Dr. Ala’ Taleb Obaidat Chapter One
The are tow basic types of forces:
 External Forces: Forces act on the
FBD like loads and reactions.
 Internal Forces: Forces are necessary to hold
the structure together and already exist within
the structure.
• These forces are:
Axial forces, shear forces and bending moments
• Taking a section in structures means
have two FBD’s, since each
segment has FBD showing the forces
including internal forces act on it..
A
B
Ay
Bx
By
Reactions Reactions
F.B.D
Loads
Ay
NC
MC
VC
Internal Forces
Ay
Bx
NC
MC
VC
NC
MC
VC
B
By
Internal Forces
Statics

5. Dept. of Civil Engineering
Dr. Ala’ Taleb Obaidat Chapter One
There are different types pf supports, however, there are basically three
popular supports used in 2D structure depending on the number of
reactions (1, 2, or 3) they exert on the structures.
These supports are grouped into three categories,
 Roller: One force reaction acts
perpendicular to the surface
The reaction act up or down
Allows some freedom for slight rotation
 Pin or External hinge:
Provides Two force reactions acts
Perpendicular to each other.
Prevent translation in 2 directions.
 Fixed: Provides Three force reactions
Allows no relative rotation between the connected members
by supplying a moment reaction and is consequently more
expensive to fabricate.
Statics
Reactions at supports
A
B
L
RB
A
B
L
Ay
Ax
Fixed
Ay
Ax
MA

6. Dept. of Civil Engineering
Dr. Ala’ Taleb Obaidat Chapter One
Statics
Reactions at supports

7. Dept. of Civil Engineering
Dr. Ala’ Taleb Obaidat Chapter One
Actual Beam and Idealized Beam
Statics

8. Dept. of Civil Engineering
Dr. Ala’ Taleb Obaidat Chapter One
Statics
Category Type of
support
Symbolic
representation
Reactions Number of unknowns
I
Roller 1
The reaction force R acts perpendicular to the supporting
Surface and may be directed either into or away from the
structure. The magnitude of R is the unknown.
Rocker
Link
1
The reaction force R acts in the direction of the link and may
be directed either into or away from the structure. The
magnitude of R is the unknown.
II Hinge
2
The reaction force R may act in any direction. It is usually
convenient to represent R by its rectangular components, Rx
and Ry. The magnitudes of Rx and Ry are the two unknowns.
III Fixed
3
The reactions consist of two force components Rx and Ry and
a couple of moment M. The magnitudes of Rx, Ry, and M are
the three unknowns.
Fig. 2.1 Types of Supports for Plane Structures

9. Dept. of Civil Engineering
Dr. Ala’ Taleb Obaidat Chapter One
Mechanics of Materials
 The shape of the element will change (deform)
 The deformation is measured by strain (unit less)
 Stress is related to strain through Hooke’s law.
 In this course, we learned to calculate strains, stresses, and
displacements of structures
Displacement and Deformation
 Displacement: is a movement from one location
to another.
 Deformation: change in shape.
 It is not necessary to have both of them
 Usually occur together
 Example of occurring separately
 Example of occurring together
Stress
Equations
from
Mechanics