School of Engineering and Technology, (SET)
 
CE72.9008 : Selected Topic: Prestressed and Post-tensioned Concrete  3(3-0)
 
Course objectives:

Prestressed concrete and post-tensioned concrete structures have became popular in the modern construction industry due to its outstanding advantages. The theory of prestressed concrete is established by employing advantages from notable compressive strength of concrete and the use of high-strength steel reinforcement. The prestressing can be wisely applied so that the structure becomes smaller or thinner while less deflection, longer span, and better crack prevention can be achieved. The content of this course is composed of the principle of prestressed concrete, materials and equipments required for the construction of prestressed concrete member, the design againt internal forces (bending, shear, torsion and anchorage) as well as employment of the concept to the design of post-tensioned slab, prestressed pile, and prestressed tank.
 
Learning Outcomes:
At the end of this course, the students should be able to:
•      Describe mechanisms of prestressed concrete member and recognize the situation where the prestressed concrete is beneficial;
•      Explain about types of prestressing as well as materials and equipment required for the construction of prestressed concrete member;
•      Design prestressed concrete structural element against basic internal forces in structure;
•      Perform calculation regarding to the design of post-tensioned slab, prestressed concrete pile, and prestressed concrete tank;
 
Pre-requisite(s):

None
 
Course Outline:
I.        Concept of Prestressed Concrete
1.     Roles of concrete and steel in prestressed concrete members
2.     Mechanism of prestressed member in stress, internal force, and external load level
3.     “Pre-tensioned system” and “Post-tensioned system”
4.     “Fully prestressed system” and “Partially Prestressed system”
5.     Benefits and limitations of prestressed concrete

II.       Materials and Equipment for Prestressed Concrete Construction
1.     High-strength concrete and high-strength steel
2.     Anchorage and jacking apparatus
3.     “Balanced Cantilever” construction
4.     “Segmental Box Girder” construction
5.     Examples of structures constructed with prestressed concrete

III.       Flexural Analysis and Design
1.   Concept of allowable stress design
2.   Stress and stain Analysis in flexural members
3.   Selection of cross-section and design of prestressing Tendon
4.   Ultimate flexural capacity of flexural prestressed member

IV.       Partial Loss of Prestress
1.     Components of loss of prestress and their influence on the prestressed concrete structure
2.     Immediate loss of prestress
3.     Time-dependent loss of prestressing force
4.     Lump-sum estimation and time-step calculation for loss of prestress

V.        Design for Shear and Torsional Resistance
1.      Effect of prestressing force on shear resistance
2.      Design for shear reinforcement
3.      Behavior of prestressed concrete member under torsion
4.      Design against combined shear and torsion

VI.       Design for End Zone
1.      Stress distribution in end zone of “pre-tensioned member” and “post-tensioned member”
2.      Design for transverse reinforcement in end zone of pre-tensioned member
3.      Design of anchorage zone in post-tensioned member

VII.      Control of Deflection
1.      Deformation at different stages of prestressing
2.      Estimation of instantaneous & long-term deflection

VIII.     Continuous Member
1.        Effect of continuity on stress distribution in prestressed concrete member
2.        Line of thrust and concordant tendon profile
3.        Discussion on effect of continuity on ultimate capacity considering moment redistribution

IX.       Employment of Prestressed Concrete
1.      Design of post-tensioned slab
2.      Design of prestressed concrete piles
3.      Design of prestressed concrete tanks
 
Laboratory Sessions:

None
 
Learning Resources:

Textbook:

No designated text book, but class notes, selected handouts and presentations will be provided.
 
Reference Books:
1.     American Concrete Institute (ACI): Building Code Requirements for Structural Concrete (ACI318-14) and Commentary, 2014
2.     A.H. Nilson: Design of Prestressed Concrete, 2nd Edition, 1987
3.     T.Y. Lin & N.H. Burns: Design of Prestressed Concrete Structures, 3rd Edition, 1981
4.     E.G. Nawy: Prestressed Concrete – Fundamental Approach, 5th Edition, 2009
5.     American Association of State Highway and Transportation Officials (AASHTO): Standard Specifications for Highway Bridges, 2002
 
Journals and Magazines:

Some selected articles from international journal will be used for term project.
 
 
Teaching and Learning Methods:

Major part of the course is lectures. Apart from lectures, there will be tutorial sessions for problem-based learning. There will also be individual/group assignments and term project.
 
Evaluation Scheme:
The final grade will be computed using the following weight distribution: Class participation and performance in tutorial sessions (20%), assignment and term project (20%), Mid-Semester Exam. (30%); Final Exam. (30%).

“A” grade will be awarded if the student is skillfully capable of design prestressed concrete structure with a good understanding.
“B” grade will be awarded if the student has acquired good understanding about the mechanisms of prestressed concrete and shows ability to correctly apply most of the design methods described in the class.
“C” grade will be awarded if the student has acquired acceptable level of understanding on general prestressed concrete construction but fails to show a ability to correctly apply most of the design methods described in the class .
“D” grade will be awarded if a student does not have a basic understanding of the subject and is not capable of applying the methods presented in the course.
 
Instructor(s):
SECTION NAME
A Dr. Raktipong Sahamitmongkol