Course detail

Prestressed concrete

FAST-CL01Acad. year: 2019/2020

Principle of prestressing. Basic concept of pretensioning and post-tensioning. Material properties, manufacturing, types. Pretensioning operations, technology. Post-tensioning operations, technology, prestressing systems.
Losses of prestressing of pretensioned and post-tensioned concrete, tendon profiles.
Equivalent load method, statically determinate and indeterminate structures, examples. Response of structures subjected to prestressing, simplifications, decompression state.
Resistance of prestressed members against cracks. Tensile stresses in the concrete after cracking. Control of crack width and deflection of prestressed members.
Ultimate limit state of prestressed members, full stress-strain response, shear resistance.

Language of instruction

Czech

Number of ECTS credits

5

Guarantor

prof. RNDr. Ing. Petr Štěpánek, CSc., dr. h. c.

Department

Institute of Concrete and Masonry Structures (BZK)

Learning outcomes of the course unit

A student gains these knowledge and skills:
• Understanding of the behaviour of prestressed concrete structures.
• Design of prestressed concrete structural members and structural systems, analysis and detailing.

Prerequisites

structural mechanics, theory of elasticity, plasticity, concrete members and concrete structures

Co-requisites

Not applicable.

Planned learning activities and teaching methods

Not applicable.

Assesment methods and criteria linked to learning outcomes

Not applicable.

Course curriculum

1. Introduction, basic concept of prestressing. Behaviour of non-prestressed and prestressed concrete beams. Material properties of concrete.
2. Material properties of prestressing tendons and bars, manufacturing, mechanical properties, types. Prestressing technology, basic terminology. Pretensioned concrete.
3. Post-tensioning operations, technology, prestressing systems.
4. Losses of prestressing. Frictional loss, anchorage set loss.
5. Losses of prestressing due to elastic concrete deformation, relaxation of prestressing reinforcement, creep and shrinkage. Construction and serviceability stages.
6. Effects of prestressing. Equivalent load method, statically determinate and indeterminate structures, concordant tendon, linear transformation of tendon.
7. Design of prestressing - load balanced method. Allowable stresses, allowable zone of prestressed tendon, and line of pressure. Crack resistance.
8. Structural analysis of step-by-step built structures, non-homogeneity of structures. Creep analysis – analytic solution.
9. Ultimate limit state (ULS) of prestressed members loaded by axial force and bending moment, decompression state, initial state of stress. Secondary effects of prestressing at ULS of the structures.
10. Prestressed members loaded in shear and torsion, stress analysis, proportioning.
11. Anchorage zone analysis, calculation model, check of resistance, proportioning.
12. Serviceability limit states (SLS). Crack resistance, tensile stresses in the concrete after cracking.
13. Control of crack width of prestressed members. Control of deflection.

Work placements

Not applicable.

Aims

Understanding of the behaviour of prestressed concrete structures. Design of prestressed concrete structural members and structural systems, analysis and detailing.

Specification of controlled education, way of implementation and compensation for absences

Extent and forms are specified by guarantor’s regulation updated for every academic year.

Recommended optional programme components

Not applicable.

Prerequisites and corequisites

Not applicable.

Basic literature

VOVES, Bohumír: Navrhování konstrukcí z předpjatého betonu v příkladech. Praha: SNTL, 1980. (CS)
LIN, T. Y. a BURNS, Ned H.: Design of Prestressed Concrete Structures. New York: John Wiley & Sons, 1981. ISBN 0471018988. (EN)
COLLINS, Michael P. a MITCHELL, Denis: Prestressed Concrete Structures. New Jersey: Prentice Hall, 1991. ISBN 0-13-691635-X. (EN)
ROMBACH, Günter: Spannbetonbau. Berlin: Ernst und Sohn, 2010. ISBN 978-3-433-02911-4. (DE)

Recommended reading

KLUSÁČEK, Ladislav, PANÁČEK, Josef a ŠTĚPÁNEK, Petr: Betonové konstrukce. Předpjatý beton podle ČSN 73 1201. Brno: VUT, 1991. ISBN 80-214-0267-9. (CS)
GERWICK, Ben C.: Construction of Prestressed Concrete Structures. USA: John Wiley and Sons, 1997. ISBN 978-0-471-18113-2. (EN)
NAVRÁTIL, Jaroslav a ZICH, Miloš.: Předpjatý beton (průvodce předmětem v elektronické podobě). Brno: VUT, 2006. (CS)
NAVRÁTIL, Jaroslav: Předpjaté betonové konstrukce. Brno: CERM, 2008. ISBN 978-80-7204-561-7. (CS)
NAVRÁTIL, Jaroslav a ŠTĚPÁNEK, Petr: Předpjaté stavební konstrukce. Modul M01 (část studijní opory v elektronické podobě). Brno: VUT, 2009. (CS)
PROCHÁZKA, Jaroslav a kol.: Navrhování betonových konstrukcí podle norem ČSN EN 1992 (EUROKÓDU 2). Část 2: Předpjatý beton. Praha: ČBS Servis, 2010. ISBN 978-80-87158-21-0. (CS)

Type of course unit

 

Lecture

26 hours, optionally

Teacher / Lecturer

prof. RNDr. Ing. Petr Štěpánek, CSc., dr. h. c.

Syllabus

1. Introduction, basic concept of prestressing. Behaviour of non-prestressed and prestressed concrete beams. Material properties of concrete. 2. Material properties of prestressing tendons and bars, manufacturing, mechanical properties, types. Prestressing technology, basic terminology. Pretensioned concrete. 3. Post-tensioning operations, technology, prestressing systems. 4. Losses of prestressing. Frictional loss, anchorage set loss. 5. Losses of prestressing due to elastic concrete deformation, relaxation of prestressing reinforcement, creep and shrinkage. Construction and serviceability stages. 6. Effects of prestressing. Equivalent load method, statically determinate and indeterminate structures, concordant tendon, linear transformation of tendon. 7. Design of prestressing - load balanced method. Allowable stresses, allowable zone of prestressed tendon, and line of pressure. Crack resistance. 8. Structural analysis of step-by-step built structures, non-homogeneity of structures. Creep analysis – analytic solution. 9. Ultimate limit state (ULS) of prestressed members loaded by axial force and bending moment, decompression state, initial state of stress. Secondary effects of prestressing at ULS of the structures. 10. Prestressed members loaded in shear and torsion, stress analysis, proportioning. 11. Anchorage zone analysis, calculation model, check of resistance, proportioning. 12. Serviceability limit states (SLS). Crack resistance, tensile stresses in the concrete after cracking. 13. Control of crack width of prestressed members. Control of deflection.

Exercise

13 hours, compulsory

Teacher / Lecturer

prof. RNDr. Ing. Petr Štěpánek, CSc., dr. h. c.

Syllabus

1. Effect of prestressing on statically determinate structures. Students are to solved tasks individually. 2. Effect of prestressing on statically indeterminate structures. Students are to solved tasks individually. 3.- 4. Project: Design and assessment of prestressed roof girder. Action and combination of loads, design of cross-section, characteristics of materials, types of prestressing steels, structural requirements. 5.– 6. Continuation of project. Design of eccentricity and magnitude of prestressing force, design of amount of prestressed strands. 7. Continuation of project. Immediate (short-term) losses of prestress. 8. Continuation of project. Long-term (time dependent) losses of prestress. 9.– 10. Continuation of project. Verification of design by serviceability limit state – stress limitation, crack control. 11. Continuation of project. Verification of design by ultimate limit state – bending moment. 12. Continuation of project. Scheme of girder reinforcement by prestressing strands. 13. Project and tasks submission. Credit.