How do you calculate MUTS?
Allowable Initial Force = (Jacking Force) minus (Short-Term Losses) = 70% of MUTS = MUTS x 0.70 (per ACI-318)
- Angular Profile of Tendon.
- Horizontal sweeps in Tendon.
- Wedge-Seating (typically 0.25 inch)
What is prestress transfer length?
The transfer length (Lt) of a prestressing strand is defined as the length from the end of the strand to the point where the effective stress (fse) is developed (see Figure 2-2). After releasing or cutting pretensioned strands, stress is gradually transferred to the surrounding concrete through direct bond.
What is a group of strands or wires used in prestressed concrete?
Tendon
Tendon A group of strands or wires are wound to form a prestressing tendon. Cable A group of tendons form a prestressing cable. Bars A tendon can be made up of a single steel bar.
Is code for HT strands?
Properties of HT Strand (IS: 14268 – 1995)
| Class of HT Strand | Nominal Dia (mm) | Minimum Tensile Strength (N/mm2) |
|---|---|---|
| I | 15.2 | 1860 |
| II | 9.5 | 1860 |
| 11.1 | ||
| 12.7 |
What is ASTM A416?
ASTM A416/A416M-16. March 1, 2016. Standard Specification for Low-Relaxation, Seven-Wire Steel Strand for Prestressed Concrete. 1.1 This specification covers two grades of low-relaxation, seven-wire steel strand for use in prestressed concrete construction.
How do you find the elongation of strands?
a) Elongation Calculation :
- a) Elongation Calculation :
- Design load in N — P.
- Length of Tendon in mm — L.
- Area of Strand in mm2— A.
- Young’s Modulus in N/ mm2— E.
- Elongation (e) = P x L / A x E in “mm”
- b) Modified Elongation Calculation :
- Area of Strand in mm2— A.
What is prestress transfer?
The prestress transfer is the same physical phenomenon as the force transfer of a reinforcing bar. In both cases, the steel force is transferred to the concrete by bond stresses which are activated by the slips at the interactional surface.
What is axial prestressing?
8. Define Axial prestressing. Members in which the entire cross-section of concrete has a uniform compressive p r e s t r e s s . In this type of prestressing, the centroid, of the tendons coincides with that of the concrete section.
What is tendon and strand in prestressed concrete?
A tendon for prestressed concrete structure comprises a core member such as a steel wire for prestressed concrete structures, a steel strand for prestressed concrete structures or a steel bar for prestressed concrete structures, and an unset bonding material coating the core structure in a predetermined thickness.
What is P line and C line in prestressed concrete?
Line of action of P-force is called the P-line. The P-line is nothing but the tendon line itself. The line of action of the C-force is called the C-line or Pressure line. Hence in the absence of any external bending moment the P-line and the C-line coincide.
How do you find the HT Strand area?
Calculating the Area of a Cable
- As an example, let’s assume we want to know the area for a copper conductor cable having 41 strands of 0.20mm wire.
- 0.20 × 0.20 = 0.04.
- 41 × 0.0314 = 1.2874.
What is ASTM A 615?
ASTM A615 covers deformed and plain carbon steel bars for concrete reinforcement. This specification covers bars and coils in four grades, Grade 40, Grade 60, Grade 75, and Grade 80. The grade designates the yield strength of the material, i.e. Grade 60 has a 60ksi minimum yield.
What is ASTM a722?
This specification covers uncoated high-strength steel bars intended for use in pretensioned and post-tensioned prestressed concrete construction or in prestressed ground anchors. Two types of bars are considered: Type I bar, which has a plain surface and Type II bar, which has surface deformations.
How do you calculate modified elongation?
What is FCI concrete?
Note: fci. ‘ = design compressive strength of concrete at transfer of pre- stress. for pretensioned members and at time of application of tendon force for post-tensioned members.
What is vertical prestressing?
Vertical prestress is widely used in the webs of large-span concrete box girder bridges but has lost efficacy since it was first applied. To solve this widespread problem, a dynamic model for the exposed segment of the vertical prestress system is built to help detect effective tension retained in the bar.
What are tendons and Anchorage?
Prestressed concrete contains tendons which are typically stressed to about 1000 MPa. These tendons need to be anchored at their ends in order to transfer (compressive) force to the concrete. In pretensioned concrete, the anchorage consists of a bonded length of tendon, in direct contact with the concrete.
What is the anchorage zone?
An anchorage zone refers to the region of the structure in which the prestress force is transferred from the prestressing steel to the concrete and distributed more widely to the member. In post-tensioned structures the anchorage zone is subdivided into the local zone and general zone.
What is C line or pressure line?
The pressure line (also called thrust line or C-linel•2) is the line of ac- tion of the concrete compressive stress resultant at each section along the beam. Note that in a statically determinate. beam the pressure line departs from the. centroid of the tendons by a distance. MIF, where M is the external moment.