Exam Details
| Subject | Prestressed Concrete | |
| Paper | ||
| Exam / Course | Diploma In Civil Engineering (DCLEVI) / Advanced Level Certificate In Civil Engineering (ACCLEVI) | |
| Department | School of Engineering & Technology (SOET) | |
| Organization | indira gandhi national open university | |
| Position | ||
| Exam Date | December, 2015 | |
| City, State | new delhi, |
Question Paper
Explain the essential requirements of steel and concrete for prestressed concrete. What are the advantages of prestressed concrete over reinforCed concrete?
What are the different types of tensioning devices ?Explain in brief.
How can the loss of stress due to shrinkage of concrete be accounted for in prestressed members?
A pretensioned beam of size 225 mm x 300 mm deep is prestressed by 12 wires, 5 mm diameter initially stressed at 1100, MPa. The centroid of the prestressing wires is located at 100 mm from bottom. Estimate the loss of prestress due to
elastic deformation
creep
shrinkage
relaxation
Grade of concrete M40, relaxation of steel Es=2 x 10^5 MPa, creep coefficient 1.6, residual shrinkage
strain x 10^-4.
Explain the concept of load balancing.
Enlist the factors influencing deflection of prestressed concrete members.
4. A prestressed concrete beam 400 mm wide and 600 mm deep has a span of 6 m. The beam is prestressed with a tendon bent as shown in Figure 1. There is a central concentrated load of 180 kN acting on the beam. Effective prestressing force is 1200 kN. Calculate the extreme fibre stresses at mid span taking into account the self weight of beam also.
<img src='./qimages/13139-4.jpg'>
5. The prestressed concrete beam shown in Figure provided with 9 wires of 4 mm diameter, is subjected to a prestress of 800 N/mm^2. Determine the sagging moment that can be applied to the section, so that the . maximum compressive stress in concrete shall not exceed 14 N/mm^2 and the maximum tensile stress in concrete shall not exceed 1·4 N/mm^2. Neglect the losses in prestress.
<img src='./qimages/13139-5.jpg'>
6. Explain the bearing stresses and bursting tensile stresses in end blocks. Discuss the steps for design of bearing and bursting tensile stresses in end block.
7. Write short notes on any four of the following:
Concordant cable profile
Strength concept of analysis of prestressed concrete
Freyssinet system of post-tensioning
Tendon splices
Advantages and disadvantages of pretensioning systems
What are the different types of tensioning devices ?Explain in brief.
How can the loss of stress due to shrinkage of concrete be accounted for in prestressed members?
A pretensioned beam of size 225 mm x 300 mm deep is prestressed by 12 wires, 5 mm diameter initially stressed at 1100, MPa. The centroid of the prestressing wires is located at 100 mm from bottom. Estimate the loss of prestress due to
elastic deformation
creep
shrinkage
relaxation
Grade of concrete M40, relaxation of steel Es=2 x 10^5 MPa, creep coefficient 1.6, residual shrinkage
strain x 10^-4.
Explain the concept of load balancing.
Enlist the factors influencing deflection of prestressed concrete members.
4. A prestressed concrete beam 400 mm wide and 600 mm deep has a span of 6 m. The beam is prestressed with a tendon bent as shown in Figure 1. There is a central concentrated load of 180 kN acting on the beam. Effective prestressing force is 1200 kN. Calculate the extreme fibre stresses at mid span taking into account the self weight of beam also.
<img src='./qimages/13139-4.jpg'>
5. The prestressed concrete beam shown in Figure provided with 9 wires of 4 mm diameter, is subjected to a prestress of 800 N/mm^2. Determine the sagging moment that can be applied to the section, so that the . maximum compressive stress in concrete shall not exceed 14 N/mm^2 and the maximum tensile stress in concrete shall not exceed 1·4 N/mm^2. Neglect the losses in prestress.
<img src='./qimages/13139-5.jpg'>
6. Explain the bearing stresses and bursting tensile stresses in end blocks. Discuss the steps for design of bearing and bursting tensile stresses in end block.
7. Write short notes on any four of the following:
Concordant cable profile
Strength concept of analysis of prestressed concrete
Freyssinet system of post-tensioning
Tendon splices
Advantages and disadvantages of pretensioning systems
Other Question Papers
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Subjects
- Advanced Steel Design
- Air Quality Monitoring And Control
- Analysis And Design Of Bridges
- Construction Supervision And Building Maintenance
- Earthquake Engineering
- Earthquake Resistant Design Of Structure
- Elements Of Soil Dynamics And Machine Foundation
- Environment Impact Analysis Of Civil Engineering Projects
- Irrigation Engineering
- Prestressed Concrete
- Remote Sensing In Civil Engineering
- Solid And Hazardous Waste Management
- Structural Optimization
- Water Power Engineering