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Prestressed Concrete – Erection

2018 Bridge Construction Inspection School

Chuck Snyder

VDOT Staunton District

Bridge Maintenance Specialist

Road and Bridge Specifications

2007 & 2016 Specifications:

• 405.05 (g) – Waterproofing PS Members

• 405.05 (h) – Handling, Storing, and Erecting PS Members

• 405.06 – Tolerances PS Members

• 408.03 12.(g) Placement – Elastomeric Bearing Pads

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Bearing Pad & Expanded Rubber Joint Material Location

Direction Setting Members

Begin Setting Members at High Point of Bridge Seat Crown.

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Setting Prestressed Members

Step 1 – Bearing Pad Layout

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Setting Prestressed MembersStep 2 - Mark initial pad location.

Step 3 – Dust with dry cement, replace pad.

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Setting Prestressed Members

Step 4 - Member Setting Sequence

Step 5 - Setting prestressed member.

Setting Prestressed Members

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Step 6 - Check for bearing with feeler gauge.

Setting Prestressed Members

Step 7 – Pick-up P.S. MemberStep 8 – Lift pad determine non-bearing area

Setting Prestressed Members

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Setting Prestressed Memebers

Step 9 – Outline non-bearing.

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Step 10 - Apply a stiff epoxy mortar to non-bearing areas. Repeat process as necessary.

Setting Prestressed Members

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Setting Prestressed Members

Step 10a - Epoxy mortar mix (finer sand preferred)

Setting Prestressed Members

Step – 11 – Reposition Pads

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Setting Prestressed Memberes

Step 12 – Repeat Steps 5 & 6.

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Setting Prestressed Members

Shims may be added if epoxy build-ups become excessive (> ½”). Shims should always be inserted Under the pad, during the initial setting.

After initial setting and bearing pad has been built-up with epoxy and does not have full bearing than shims may be added on top of the pad. (Once epoxy build-up sets, almost impossible to shim at bottom of pad).

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Setting Prestressed Members

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Bearing checked after epoxy mortar had set beneath the pad. Shim with copper or stainless steel shims on top of pad.

Setting Prestressed MembersShims on top of Bearing Pads – WrongShims to be placed on bottom of pad if not previously built up with epoxy.

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Setting Prestressed Members

Pad racked laterally (transverse)

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Stainless Steel Shims

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Mortar Seepage Thru Joint

Non-Bearing Pad

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Questions?

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Prestressed Concrete – Shear Keys, Post-tension & Epoxy Overlays

2018 Bridge Construction Inspection School

Chuck Snyder

VDOT Staunton District

Bridge Maintenance Specialist

Handling, Storing & Erecting Prestressed Members

2016 Road and Bridge Specifications Section 405.05 (h):

• Shear keys and recesses shown on plans shall be filled with mortar conforming to Section 218. Mortar shall be applied in one continuous operation for each span.

• The following types of “mortar” will be used as shown on the Plans:1. Engineered Cementitious Composite (ECC)

2. Very High Performance Concrete (VHPC)

• Waterproofing material applied to top of units in the field, longitudinal joints shall be sufficiently smoothed to prevent damage to material.

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Epoxy Bridge Deck Overlays

2016 Road and Bridge Specifications Section 431:

• Epoxy overlay shall NOT be placed on hydraulic cement concrete (prestressed members) that is less than 28 days old.

• Epoxy overlay MAY be placed on shear key mortar that has been cured a minimum of 7 days.

• Bridge deck cleaning and testing of trial patches shall be in accordance with VTM-92.

• Test patches for tensile strength must be obtained for each span or 300 square yards, whichever is the smaller area.

• Epoxy overlay shall be applied in 2 separate courses. Total of the 2 applications shall not be less than 7.5 gallons per 100 square feet.

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Shear Key Detail

Grout used for shear keys shall beEngineered Cementitious Composite (ECC)

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Shear Key Detail

Manual of Structure and Bridge Division.

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Shear Key Detail with VAMC Blockouts

Very High Performance Concrete (VHPC) shall be used to fill shear keys and blockouts for Virginia Adjacent Member Connections (VAMC).

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Shear Key Detail with VAMC Blockouts

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Longitudinal Shear Key Being Prepared For Grout

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Shear Key Backer Rod

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Grouted Longitudinal Shear Key

Mortar to be applied in one continuous operation for each span.

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Example of Kevlar Material11

Waterproof Pier Joint

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Longitudinal Shear Key & Transverse Pier Joint Waterproofing

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Skewed Prestressed Members Post Tension – Two Members

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Post-tensioning Transverse Tendons (Rod)

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Post-tensioning Transverse Tendons (Cable)16

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Transverse Tie Rod Too Long

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Proposed Correction For Vertical Offset Between Adjacent Slabs After Setting

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Epoxy Overlay Test Patch & Test Equipment (2016 R & B Spec. Section 431.03)

Epoxy Test Patch

Epoxy Pull Test Equipment

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Vertical Offset Between Adjacent Members

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Bridge Deck Epoxy Overlay Application

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Bridge Deck Epoxy Overlay - First Coat Application After Shear Keys Waterproofed

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Bridge Deck Epoxy Overlay - Applying Second Coat

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Slab End Waterproofing 4” Kevlar Overlap Lifting Strands Cut Off, Cover with 1/8” Thick Epoxy Mortar

Lifting Strands

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Waterproof Outside Vertical Edge& Transverse Tie Blockout

Grout & waterproof blockout after transverse tie rods are tensioned.

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EP-3 Waterproofing Vertical Side of Exterior Members - Applied at Plant

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Waterproofing Slab Ends @ Abutments

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Waterproofing Slab Ends@ AbutmentsExample 1 (Correct?)

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Waterproofing Slab Ends(Example 2 – Correct?)

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Waterproofing Abutment Slab EndsExample 3 – (Correct?)

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End of Prestress Members Offset

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Example #1: Leaking Joint& Damaged Bridge Seat

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Example #2: Leaking Longitudinal Joint & Damaged Prestressed Slab/Box

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Example #3: Leaking longitudinal Joint& Damaged Prestressed Slab/Box

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Prestressed Member Reinforcing Steel –ST0404

4”

2” Max. Clearance

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Questions?

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