Florida DOT efforts toward improving Post Tension Durability

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Laurel Spencer
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2 Post-Tensioning Strategies Enhanced PT Systems Multiple Tendons Paths FDOT PT Strategy Fully Grouted Tendons Watertight Bridges Anchor Protection (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 2 of 73

3 Requirements Florida PT Strategy Enhanced PT Systems Fully Grouted Tendons Anchor Protection Watertight Bridges Multiple Tendon Paths Pre-Approved PT Systems Pre-Bagged Grout Requirements Three-Level Continuous Protection Anchorage Plastic Ducts Accessibility with Improved Cell Class Positively Low Point Sealed Injection Requirements Ducts Semi-Standard Permanent Plastic Requirements Drawings Anchor Caps 4 Certified Pressure Levels Grouters of Testing Protection and Inspectors No Dry Joints Controlled Semi Standard Rates Details of Grouting Pre-formed Tapered Holes Anchorages Flow Rate Testing Sealed of at Ejected all Times Material Drip Notches at Anchorages Inspect Voids and Secondary Grout Bottom Slab Drains Requirements Sealed Surfaces of Secondary Pours Wearing Maximize Surfaces Use of Smaller for Ride Tendons not Protection No Impact Permanent Due Tensile to Loss Stresses of Critical Tendon Compensation for Loss Due to Corrosion (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 3 of 73

4 Critical Nature of Tendons Essential Critical Very High High Moderate ¼ Point Hinge P/C BC Continuity at EJ P/C SBS External EJ Spans P/C SBS External Typical Spans P/C BC Anchor in Blister P/C BC Anchor on Face P/C BC Bottom Continuity CIP Cantilever & Continuity Flat Slab - Transverse P/C BC Top Continuity (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 4 of 73

7 Critical Nature of Tendons Type of Construction CIP on Falsework CIP Balanced Cantilever P/C Balanced Cantilever P/C Span-By-Span P/C Beam w/ CIP Slab Structural Purpose Superstructure Substructure Construction vs. Permanent Bonded vs. Unbonded Tendon Protection System Mat ls Duct, Anchor, Grout Wet vs. Dry Joints Risk of Exposure Maintainability Access to inspect components Applicability of test methods Ability to be replaced Redundancy External # & Distribution of Tendons (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 7 of 73

8 Contents Precast Balanced Cantilever Precast Span-by-Span Spliced I-Girders CIP Balanced Cantilever CIP on Falsework Substructures Transverse Superstructure (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 8 of 73

10 OBJECTIVE TO PROVIDE CONSISTENCY AND UNIFORMITY IN THE DESIGN, DETAILING, AND CONSTRUCTION OF POST-TENSIONED TENSIONED STRUCTURES IN ORDER TO PROVIDE A HIGHER QUALITY PRODUCT WITH A MINIMUM COST INCREASE (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 10 of 73

11 OBJECTIVE MORE SPECIFICALLY, TO IMPROVE THE QUALITY OF PT HARDWARE, GROUTING, AND ANCHOR PROTECTION IN ORDER TO REDUCE THE INCIDENCES OF RECHARGE AND CORROSION IN POST-TENSIONED TENSIONED STRUCTURES (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 11 of 73

12 OBJECTIVE IMPLEMENTATION STRATEGIES IMPLEMENTED STRATEGY 1 ENHANCED POST-TENSIONING TENSIONING SYSTEMS and installations(pti) SEALING OF GROUT PORTS, VENTS AND DRAINS STRATEGY 2 FULLY GROUTED TENDONS(ASBI) ACCESSIBLE ANCHORS GROUTING OF TENDONS / GENERAL PROCEDURES (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 12 of 73

13 OBJECTIVE STRATEGY 3 MULTI-LEVEL LEVEL ANCHOR PROTECTION ANCHORS AT EXPANSION JOINTS / INSIDE BOXES / BLISTERS EMBEDDED ANCHORS STRATEGY 4 WATERTIGHT BRIDGES: Double Face Epoxy ACCESS, LIFTING HOLES DRIP NOTCHES (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 13 of 73

14 DRAWING INDICES INSTRUCTIONAL NOTES POST-TENSIONING TENSIONING VERTICAL PROFILES POST-TENSIONING TENSIONING ANCHORAGE PROTECTION POST-TENSIONING TENSIONING ANCHORAGE AND GROUTING DETAILS (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 14 of 73

15 INSTRUCTIONAL NOTES DESIGNER TO PROVIDE TENDON PROFILE AND ANCHOR PROTECTION TYPE FOR EACH TYPE OF TENDON TENDON PROFILE AND ANCHOR PROTECTION TYPE TO BE INCLUDED IN THE PT SCHEDULE (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 15 of 73

16 INSTRUCTIONAL NOTES TENDON PROFILES MAY BE AMENDED BY THE ENGINEER EOR RESPONSIBLE FOR REVIEWING THE CONTRACTORS GROUTING PLAN (SHOP DRAWINGS) DEVIATIONS FROM THE STANDARDS SHALL BE APPROVED BY THE FDOT (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 16 of 73

17 POST-TENSIONING TENSIONING VERTICAL PROFILES TYPICAL PROFILES FOR POST- TENSIONING TENDONS USED IN SUPERSTRUCTURE - GIRDER - SEGMENTAL SUBSTRUCTURE - HAMMERHEADS - STRADDLE BENTS VERTICAL APPLICATIONS (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 17 of 73

25 SUBSTRUCTURE VERTICAL PROFILES SUBSTRUCTURE ELEVATION OF BASE OF TENDON SHALL BE A MINIMUM OF FOR SUBSTRUCTURES OVER LAND FOR SUBSTRUCTURES OVER OR NEAR WATER (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 25 of 73

55 POST-TENSIONING TENSIONING SYSTEM example items INSPECTABLE ANCHORS BAR COUPLERS PERMANENT GROUT CAPS INLETS AND OUTLETS DUCT SCHEDULE 40 STEEL OR PLASTIC POLYPROPYLENE CORRUGATED DUCT POLYETHYLENE SMOOTH DUCT (DR 17) PRESSURE TESTING COMPONENTS (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 55 of 73 55

56 PLASTIC DUCT AND CONNECTIONS example issues ALL COMPONENTS ASSEMBLED INTO PRESSURE TESTED SYSTEMS POLYPROPYLENE CORRUGATED DUCT FOR INTERNAL TENDONS GREATER STIFFNESS WITH LESS HEAT GAIN POLYETHYLENE DUCT THICK WALL WITH PRESSURE PIPE CHEMISTRY IN-PLACE TESTING FOR LEAKS BEFORE GROUTING 56 (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 56 of 73

Proper Material is Critical Standardized Details with PCI (C)

to determine critical tendons for selective inspection and repair

60 NeXt Generation at Saw Grass FDOT D-4 and C O of FDOT pioneered a project: Watertight Bridge strategy Balanced against analytical exercise to determine critical tendons for selective inspection and repair grouting 60 (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 60 of 73

Sawgrass Developmental Project Bridge Length = 3990 feet Width = 40 feet 200 Days of MOT= $35,000 Epoxy Overlay= $36.30 per Sq. Yd. Joint Sealant =$24.60 per Lin. Ft.

63 Sawgrass Developmental Project Bridge Length = 3990 feet Width = 40 feet 200 Days of MOT= $35,000 Epoxy Overlay= $36.30 per Sq. Yd. Joint Sealant =$24.60 per Lin. Ft. No LL capacity loss due to light weight Stay tuned: 2008 another repair, Hopeful that Future Costs should come down Close monitoring to see if meet 10 year service life 63 (C) COPYRIGHT POST-TENSIONING INSTITUTE, ALL RIGHTS RESERVED Page 63 of 73

new Autopsy Inspection Video from Skyway Pier 133NB (C)

new A tendon with 17 Strands or 119 wires With 65 pitted wires and 50 Broken

Durability of Post-Tensioning: fib Bulletin 33 and FHWA Scan tour Findings. Presented by Brett Pielstick P.E., F.ASCE

Durability of Post-Tensioning: fib Bulletin 33 and FHWA Scan tour Findings Presented by Brett Pielstick P.E., F.ASCE 1 Introduction Early Durability Issues Assessment Concrete Society TR-47 FHWA Scan Tour