Theory of
Structures 2
Introduction to Theory of Structures
Prepared by: Engr. Trisha D. Faustino
TOPICS
• Definition of Terms
• Phases of a Typical Structural Engineering Project
• Statically Determinate Structure Vs. Statically
Indeterminate Structure
Definition of
Terms
Structure
 A structure refers to a system of connected
parts used to support a load.
 It is defined as an assembly of different
members connected to each other which
transfers and transmits loads to the
ground.
Structural Analysis
 It is the prediction of the
performance of a given structure
under prescribed loads and/or other
external effects, such as support
movements and temperature
changes.(Kassimali 2011)
Structural
Engineering
 It is the science and art of
planning , designing and
constructing safe and
economical structures that will
serve their intended purposes.
Phases of a Typical
Structural
Engineering
Project
Phases of a Typical Structural
Engineering Project
1. Planning Phase
2. Preliminary Structural Design
• Involves the establishment of the
functional requirements of the
proposed project, layout and
dimensions of the structure, choosing
of the intended type of structure for
the specific purpose and
consideration of materials to be used.
• It is in this stage where sizes and dimensions
of components and members are estimated
based on the approximate analysis done in
accordance to code.
Phases of a Typical Structural
Engineering Project
3. Estimation of Loads
4. Structural Analysis
•
• It is in the application of the estimated
loads to determine the stresses on
members and deflection at various
points of the structure.
Determination of all possible
loads that are expected to act
on the structure.
Phases of a Typical Structural
Engineering Project
5. Safety and Serviceability
Checks
•
The results of the analysis are
thoroughly check to determine
whether or not the structure will
comply and satisfy the safety and
serviceability provisions of the
design codes.
6. Revised Structural Design
• If the code are not satisfied, the needs
of revision in the design is mandatory.
The member sizes are re-evaluated and
phases 3 through 5 are repeated until it
complies.
7. Construction Phase
Determinacy of
Structures
Determinacy of Structures
Determinacy of Structures
STATICALLY DETERMINATE
• X-Y Coordinate System (2D/Plane)
• X—Z Coordinate System (3D/Space)
Determinacy of Structures
DETERMINACY and STABILITY of BEAMS and FRAMES
 A stable structure remains stable for
any imaginable system of loads.
 Considered externally determinate if
the total number of reaction is equal to
the equations of equilibrium available.
Determinacy of Structures
DETERMINACY and STABILITY of BEAMS and FRAMES
Determinacy of Structures
DETERMINACY and STABILITY of TRUSSES
 Internal determinacy is a type of
indeterminacy that is associated to
trusses.
 The basic form of the truss is a
triangle. To make the truss, add two
members and one joint , and repeat.
Determinacy of Structures
DETERMINACY and STABILITY of TRUSSES
Any questions?
Thank you!