Concrete structures 5
- Department of Concrete and Masonry Structures
Design of prestressed concrete structures, basic principles of structural analysis; structure details
Before taking the examination following this course, it is required to have passed courses design of concrete reinforced structures.
- Syllabus of lectures:
1.Plain, reinforced, prestressed concrete structures. Concrete and steel for prestressed concrete- mechanical and physical characteristic. Prestressing steel with regard to connection with concrete and location in structure.
2.Prestressing techniques - pre-tensioned and post-tensioned prestressed concrete. Principles of production. Advantages and disadvantages of both prestressing techniques. Post-tensioning process - anchorages device and numerous other details, prestressing system of different companies.
3.Prestressing force. Losses of prestressing force - short term (immediate) and long term (service life) losses. Simplifying assumptions for calculation of short term losses.
4.Simplifying assumptions for calculation of long term losses. Value of the prestressing force at the time t.
5.Design of prestressing. Stage of prestressing. Stage of service. Two characteristic values of prestressing force at serviceability limit states. Design of initial prestressing force and its eccentricity.
6.Serviceability control. Stress limitation - stages of prestressing and service. Crack control - full, limited and partially prestressed concrete. Deflection control.
7.Ultimate limit states. Design situations. Effects of loads. Effects of prestressing at ultimate limit states. ULS - normal force and bending moment, shear force.
8.Anchorage zones - transfer of prestressing. Pre-tensioned members - transmission length, dispersion length, anchorage length. Post tensioned members - bearing stresses, bursting stresses, spalling stresses.
9.Detailing and cover of prestressing reinforcement. Arrangement of pre-tensioned tendons and post- tensioned tendons in cross section. Cover of prestressing units. Minimum reinforcement.
10.Pre- tensioned prestressed concrete. Pre-tensioned framing systems. Types of precast concrete. Double and triple T. Double T floor. Hollow core slabs -use, advantages. Other applications.
11. Post- tensioning in buildings. Applications and advantages of post tensioning. Post- tensioning system. Conceptual design and detailing of typical post- tensioned floors Construction of typical post-tensioned floors. Other post tensioned structural elements in buildings.
12.Statically indeterminate prestressed structures. Linear transformation of tendons. Design of prestressing using the load balancing method.
13.Design of prestressed concrete structures with unbonded prestressing reinforcement, difference from design structures with bonded prestressing reinforcement. Partially prestressed concrete with unbonded reinforcement.
14.Concrete liquid retaining structures. Use of prestressing.
- Syllabus of tutorials:
1.Calculations of areas, moments of inertia, and moments of elasticity transformed uncracked and cracked cross section by given cross section with the prestressing steel. Calculation of prestressing force, stresses in the concrete prestressing steel.
For the given simple supported beam calculate the variable load assuming full,
limited and partially prestressed concrete.
2.Design the preliminary value of prestressing force and its eccentricity for post-tensioned double T beam acting as simple supported beam of given span and loading.
3.Design the pre-tensioned roof beam acting as simple supported beam of rectangular cross section. Design the prestressing steel, losses and check the serviceability and ultimate limit states including the anchorage zones.
4.Design of post-tensioned concrete slab with unbonded tendons - partially prestressed structure.
- Study Objective:
Ability of design of basic structures from prestressed concrete elements; understanding and aplication
- Study materials:
Kong, F.K., Evans, R.H.: Reinforced and Prestressed Concrete. Chapman and Hall, 1990,
Holst,H.K.:Brűcken aus Stahlbeton und Spannbeton.EC-Erganzungsband, Ernst&Sohn,Wiley Company,Berlin 2000
Practical design of structural concrete, fip Recommendation, 1999
EN 1992-1-1 Design of Concrete Structures. Part 1-1: Generally rules and rules for building, 2005
- Further information:
- No time-table has been prepared for this course
- The course is a part of the following study plans: