TOC
1.1 Objective
1.1.1 Benefits of Post-Tensioning
1.1.2 Principle of Prestressing
1.1.3 Post-Tensioning Operations
1.1.4 Post-Tensioning Systems
1.2 Permanent Post-Tensioned Applications
1.2.1 Cast-in-Place Bridges on Falsework
1.2.2 Post-Tensioned AASHTO, Bulb-T, and Spliced Girders
1.2.3 Cast-in-Place Segmental Cantilever Bridges
1.2.4 Precast Segmental Balanced Cantilever Bridges
1.2.5 Precast Segmental Span-by-Span Bridges
1.2.6 Transverse Post-Tensioning of Superstructures
1.2.7 Post-Tensioning of Substructures
1.3 Temporary Longitudinal Post-Tensioning (Bars) – Typical Applications
1.3.1 Erection of Precast Cantilever Segments
1.3.2 Closure of Epoxy Joints in Span-by-Span Erection
2.1 Prestressing Steel
2.1.1 Strands and Bars
2.1.2 Shipping, Handling and Storage
2.1.3 Acceptance
2.2 Grout
2.2.1 Purpose
2.2.2 Cement and other Pozzolans for Grout
2.2.3 Pre-bagged Grouts
2.2.4 Thixotropic vs. Non-Thixotropic Grouts
2.2.5 Admixtures
2.2.6 Laboratory Tests
2.2.7 Shipping, Handling, Storage and Shelf life
2.2.8 Acceptance
2.2.9 Field Mock-Up Tests
2.3 Ducts
2.3.1 Duct Size
2.3.2 Ducts for Tendons
2.3.2.1 Corrugated Steel
2.3.2.2 Smooth, Rigid Steel Pipe
2.3.2.3 Corrugated Plastic
2.3.2.4 Smooth, High Density Polyethylene Pipe (HDPE) for External Tendons
2.3.2.5 Plastic Fittings and Connections for Internal Tendons
2.3.2.6 External Tendon Duct Connections
2.3.2.7 Shrink Sleeves
2.3.3 Shipping, Handling and Storage of Ducts
2.3.4 Acceptance of Duct Materials
2.4 Other Post-Tensioning System Hardware
2.4.1 Anchorages
2.4.1.1 Basic Bearing Plates
2.4.1.2 Special Bearing Plates or Anchorage Devices
2.4.1.3 Wedge Plates
2.4.1.4 Wedges and Strand-Wedge Connection
2.4.2 PT Bars, Anchor Nuts and Couplers
2.4.3 Grout Inlets, Outlets, Valves and Plugs
2.4.4 Permanent Grout Caps
2.5 Other PT System Qualification Tests
3.1 Shop Drawings
3.1.1 Drawings and Details
3.1.2 Stressing Calculations
3.1.2.1 Example 1: Four Span Spliced I – Girder
3.1.2.2 Example 2: External Tendon in End Span
3.2 Tendon Testing On Site
3.2.1 Friction
3.2.2 Modulus of Elasticity
3.3 Anchorages and Anchor Components
3.3.1 Standard or Basic Anchor Bearing Plate
3.3.2 Multi-Plane Anchor
3.3.3 Special (Composite) Anchor Plates
3.3.4 Anchor Plates for Bar Tendons
3.3.5 Local Zone Reinforcement
3.4 Duct Installation
3.4.1 Alignment
3.4.2 Duct Supports
3.4.3 Splices and Connections
3.4.4 Grout Inlets and Outlets
3.4.5 Size of Pipes for Grout Inlets, Outlets and Drains
3.4.6 Positive Shut-Offs
3.4.7 Protection of Ducts during Concrete Placement
3.4.7.1 Concrete Pressure
3.4.7.2 Movement of Concrete
3.4.7.3 Vibration of Concrete
3.5 Tendon Installation
3.5.1 Tendon Types
3.5.2 Proving of Internal Post-Tensioning Ducts
3.5.3 Installation Methods
3.5.4 Aggressive Environments
3.5.5 Time to Grouting and Temporary Tendon Protection
3.6 Jacks and Other Stressing Equipment
3.7 Jacking Methods
3.7.1 Single (Mono) Strand Stressing
3.7.2 Multi-Strand
3.7.3 Bar Tendons
3.8 Stressing Operations
3.8.1 Personnel and Safety
3.8.2 Jacking Force
3.8.3 Measuring Elongations on Strand Tendons
3.8.4 Measuring Elongations on PT Bars
3.8.5 Field Variables
3.8.6 Final Force
3.8.7 Strand End Cut-Off
3.8.8 Lift-Off
3.9 Stressing Records
3.10 Stressing Problems and Solutions
3.10.1 Strand Slip
3.10.2 Wire Breaks
3.10.3 Elongation Problems
3.10.4 Breaking Wedges
4.1 Grouting Plan
4.2 Grout Testing
4.3 Grouting Operations
4.3.1 Verification of Post-Tensioning Duct System Prior to Grouting
4.3.2 Grouting Equipment
4.3.2.1 Mixer, Storage Hopper, Screen, Pump, Pressure Gauges, Hoses
4.3.2.2 On-Site Test Equipment for Production Grouting
4.3.2.3 Vacuum Grouting Equipment
4.3.2.4 Stand-by Grouting Equipment
4.3.2.5 Clean Grouting Equipment
4.3.3 Batching and Mixing
4.3.4 On-site Tests for Production Grouting
4.3.4.1 Production Bleed Test – Prior to Injection
4.3.4.2 Normal, Non-Thixotropic, Grout – Prior to Injection at Inlet
4.3.4.3 Thixotropic Grout – Prior to Injection at Inlet
4.3.4.4 Normal, Non-Thixotropic Grout – Discharge at Final Outlet
4.3.4.5 Thixotropic Grout – Discharge at Final Outlet
4.3.5 Injection of Grout
4.3.6 Grout Injection of Superstructure Tendons
4.3.6.1 Locations of Inlets and Outlets
4.3.6.2 Sequence of Using and Closing Outlets
4.3.6.3 Grout Pressure Test for Leaks
4.3.6.4 Release Entrapped Air and Lock-Off
4.3.6.5 Incomplete Grouting
4.3.7 Grout Injection of Vertical Tendons
4.3.8 Post-Grouting Inspection
4.3.8.1 Opening Inlets and Outlets for Inspection
4.3.8.2 Drill Grout to Verify Absence of Voids
4.3.8.3 Frequency of Inspection
4.3.8.4 Filling Drilled Inspection Holes
4.3.8.5 Incomplete Grouting
4.3.9 Filling Voids by Vacuum Grouting
4.3.10 Sealing of Grout Inlets and Outlets
4.3.11 Protection of Post-Tensioning Anchorages
4.3.12 Grouting Report
4.4 Grouting Problems and Solutions
4.4.1 Interruption of Grout Flow
4.4.2 Too High Grouting Pressure
4.4.3 Flushing of Incomplete Grout
4.4.4 Unanticipated Cross-Grouting
4.4.5 Production Grout Fluidity Unacceptable
4.5 Examples of Grouting Procedures
4.5.11 Example 11: Cantilever C-Pier
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