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Case Studies on 2 Weekend Closures for Bridge Replacements

Bala Sivakumar

FIU Virtual Symposium on ABCs of ABC

December 4, 2020

Agenda

ABC Case Studies

❖ PennDOT SR 30 Bridge over Bessemer Avenue: Superstructure Replacement in One Weekend Using PBES

❖Weekend Slide-in Replacement of Two I-84 Bridges in New York State

❖ Q & A

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Time Metrics for ABC – Mobility Impact Time

TRAFFIC IMPACTS WITHIN:

Tier 1 24 hours

Tier 2 3 days (weekend)

Tier 3 2 weeks

Tier 4 3 months

Tier 5 > 3 months but overall project schedulesignificantly reduced

STATE ROUTE 30 OVER

BESSEMER AVE. East Pittsburg PA

SUPERSTRUCTURE REPLACEMENT IN 57 HOURS

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SR 30

Quick Facts

Quick Facts –PennDOT District 11-0

Designer – HNTB (2015)

Contractor – Brayman Construction

Contract Value -- $2.4 M

SR 30 ADT is 21,798 (2015) with 4% trucks

3 mile detour

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Existing Bridge

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• Existing bridge in poor condition with falling debris.

• Substandard under-clearance• Overhead wires

Built 1930

Carries State Route 30 over Bessemer Ave. in East Pittsburgh, PA; high traffic volume

Concrete T-Beam Superstructure

Span = 52’ - 2” on curved alignment

Under-clearance 13’-9”

Existing Bridge

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Project Goals

Replace the superstructure over a weekend using PBES

Utilize as many precast/pre-fab elements as possible, new precast abutment cap, UHPC connections with a latex overlay to provide long service life

Minimize impact to the adjacent property owner

Increase under-clearance

Apply lessons learned from past ABC projects

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Accuracy of As-Built Information to ensure fit

Choice of ABC method that fits site constraints and 57-hour closure period

Urban area; limited ROW; overhead wires

Skew, curvature, super-elevation considerations for ABC design

Removal and replacement of deteriorated portions of abutment walls

Approach slab replacement

ABC connections

ABC Design

Decisions

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LIDAR SURVEY : AS-BUILT BRIDGE MODEL

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As-Built 3D Bridge Model Shows Bridge Elements to be Removed

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ABC Construction Sequence

Pre-Weekend Closure

Precut and brace abutment walls along frontface

Sawcut roadway pavement at ends

Repair abutment spalls and cracks

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ABC Construction Sequence

Weekend Closure (57 Hours) continued

Demolish superstructure, remove approach slabs and excavate backfill

Sawcut abutment along backface and remove sections

Connect abutments caps with dowels

Erect the six superstructure modules with cranes

Erect precast sleeper slabs and approach slabs

Place accelerated cure UHPC closure pours

Reopen to traffic — Monday 6 AM

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ABC Construction Sequence

Post-Weekend Closure

Backfill abutments with flowable fill (approach slabs are designed to support traffic loads)

Place and cure rapid set Latex Modified Concrete (LMC) overlay to 1 ¼” depth and sawcut grooves

Apply epoxy resin protective coating to abutment surfaces

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Engineer’s ABC Schedule

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Activity Duration (hrs)

Superstructure & approach roadway removals, backfill excavation

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Substructure saw-cutting and removal 6

Install precast abutment caps 8

Install superstructure modules 8

Install approach slabs 4

Place UHPC closure pours 5

Cure time for UHPC 12

Total Duration (ABC) 51 Hrs

ABC Replacement Using Prefabricated Bridge Elements

54’-0” Single Span

Composite Steel Modular Superstructure (shop painted)

Straight Steel Beams with Variable Overhangs to Accommodate Curvature

Accelerated Cure UHPC Closure Pours

New Precast Abutment Caps to Address Deterioration and Super-elevation

New Precast Approach Slabs

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New Superstructure Cross Section

Lightweight Concrete (5 ksi) to minimize lifting weights

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Crane sizes limited by overhead high voltage electrical lines (De-energized during ABC weekend).

Lightweight Concrete (117 pcf) to minimize lifting weights

Concrete Stresses During Erection:

Not to Exceed Modulus of Rupture fr = 7.5*Sqrt(f'ci), Divided by a Safety factor of 1.5.

Dead Loads Multiplied by a Factor of 1.25.

Did not control design

Lifting locations shown for each element

Design Checks

for Erection

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AutoCad Revit Software

3D model of existing bridge using Lidar

New elements modeled in 3D and superimposed on existing

Virtual assembly of bridge during design

Check fitup at each stage of assembly

Several dimensional adjustments were made to precast elements to ensure fit

3D renderings shared with Contractor

3D Model

for Design

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New Superstructure Plan

Straight beams / modules. Bridge curvature accommodated using

overhangs with variable widths 20

Removal of Deteriorated Sections

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Precast Abutment CapsStepped to Match Superelevation

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Precast Cap Elevation

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• Steel shims used to achieve proper seat elevations• Gap around shims filled with rapid set grout -- through

grout ports in cap

Replace with Precast Abutment Cap

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Superstructure Interior Module

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Superstructure Exterior ModuleIncludes Sidewalk and Parapet

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Superstructure Modules Assembly

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Approach Slab Section

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Precast Sleeper Slab

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Abutment Spall and Crack Repairs

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Pre ABC Weekend

Construction

Highlights:

Bridge

Demolition

Friday 11:15 PM

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Rain showers begin

Bridge

Demolition

Friday 11:45 PM

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Precast

Abutment

Cap

Saturday 1:00 PM

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Precast

Abutment

Cap

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Precast

Abutment

Cap

Saturday 3:00 PM

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Precast Deck Panel

Sunday 12:00 AM

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Precast

Deck

Panel

Sunday 7:00 AM

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UHPC

Placement

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Sunday 4:00 PM

New

Bridge

after 57

Hours

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Approach

Slab Flow

Fill

Post ABC

Weekend

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Next

Weekend

Profile

Milling and

LMC Prep.

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Friday 9 PM start

LMC

Placement

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Saturday 6:20 AM

New

Structure

and

Roadway

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Sunday 12 Noon

New

Structure

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Time Lapse Video

Slide In Bridge Construction:

20-Hour Weekend Closure

Twin NYSDOT Bridges on I-84

SHRP2 R04 Demonstration Project

• Bridge design: HNTB (2013)

• Highway design: NYSDOT Region8

• Contractor: Yonkers Contracting

• Precaster: Dailey Precast, Vermont

• Slide Contractor: Barnhart / Marino

• Design funding:

• Construction funding: NYSDOT

Quick Facts

Slide-In Bridge Construction

• 20 Hr closure on two weekend nights

• Bridges too narrow for cross-over

Weekend Replacement of NY I-84 Twin Bridges

• Over 75,000 ADT; 16% trucks

• Existing bridges are too narrow for cross-overs

• Elevation differences between EB & WB roadways

• Under-passing road at 16% grade

NYSDOT Original Replacement Plan

•Build new temporary bridge in the median to maintain traffic

•Additional cost of approximately $2.0 M

•One construction season for each bridge

• Significant traffic impact; Environmental impact

ABC Approach

• Build new substructures working below existing bridges

• Build new superstructures adjacent to existing

• Slide in new superstructures using 20 Hr closure for each slide

ABC Design: Slide-In Replacement

• Slide-In replacement over two weekend nights

• Traffic disruption on I-84 reduced from two years to two Saturday nights (20 hr closures).

• Eliminates need for a temporary bridge & cross-overs –over; $2 M savings.

• Incentive/disincentive clause: $10,000 per hour for early or late completion ($50 K max incentive)

BID / ABC Schedule

• Low Bid: Yonkers Contracting, New York

• $10.2 M (Total Cost); (Bridge cost $6.1 M)

• Contract award January 2013

• Replaced Westbound bridge: 9/21/13

• Replaced Eastbound bridge: 10/19/13

• ABC window: 4 PM Saturday to 1 PM Sunday

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10 months

New Superstructures

Prefabricated Elements used to Expedite Construction

Traffic Control During Construction

• Detour during Saturday night -- Sunday morning

• Route 6/202, parallel to I-84, will be used as the detour.

5757

ABC Design & Roadway Tie-in

• Single span 80’; three lanes at 12’

• Bridge width 33’-4” 57’-0”

• Under passing road on 16% grade

• Minimize structure depth with NEXT beams

• Still, the new bridges needed to be two feet higher than the existing to provide 14’-6” under-clearance.

➢ How do you raise the approaches on an Interstate by 2 ft & place approach slabs within the overnight closure period

➢ Roadway tie-in was on the critical path for ABC

Slide-In Replacement Concept

Slide Surface

Temporary end span

Modular walls

During Slide

Superstructure Sections

• Double T beams (NEXT)

• Precast approach slabs

• UHPC closure pour

Double Tee NEXT Beams with UHPC Connections

Falsework

• Temporary Bents on H piles• Contractor designed• Attach the temp support to

the permanent structure for lateral restraint

• Provide for vertical adjustment by jacking

• Provide soil borings

Precast Approach Slabs Temporary End Spans Carrying Traffic

Flowable fill pumped thru holes in the approach slab to make it ground supported later

Raising the Roadway During ABC Closure

Sleeper Slab used as End Dam for Asphalt Paving

Approach Slab Slide Surface

Stainless Steel on PTFE

No Jacks required at approach slab ends

T-Wall Wingwalls

Drilled Shafts Outside Existing Footprint

Abutment Design

Drilled shafts supporting cap beam

T-Wall

Cap Beam

New Abutment

Straddle Bent Abutment

Diaphragm

Cap Beam

Slide Shoe

End Diaphragm & Slide Shoe

Slide Track/ShoeSlide Shoe

End Diaphragm

Movement Systems

Push/Pull hydraulic jacks

Pulling with

strand jacks /

Power winch

Slide Bearings & JacksStainless Steel on Elastomeric Bearings w/PTFE

PTFE bonded to Elastomeric Bearing Push/Pull Jacks

SLIDING FRICTION

• Design of slide system needs a good estimate of static and dynamic friction. Use a trial slide to verify friction, jack capacity

Rapid Demolition – 4 Hrs

• Chop and Drop• Local road below closed for 5 days

Start Saturday 4 PM

Inverted T Sleeper Slabs

Lateral Slide – EB Bridge

7 hours to demolish bridge and slide-in new bridge

Raising The Approaches

• Raised by 2 feet using warm asphalt in 6” lifts• Takes time: On critical path for closure period

Bridge Opened to Traffic 12 Noon Sunday10 Months from NTP

Cost Savings with ABC

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• Over $ 1.2 M in user delay cost savings by using ABC (Source: NYSDOT)

• $ 2 m cost savings from elimination of cross-overs, temporary bridge (Source: NYSDOT)

• Savings in work-zone accidents costs from reduced work zone traffic control

• Reduced contract administration costs

Lessons Learned

• Focus on Roadway Approaches as much as Structure slide-in. Roadway not the slide was on critical path.

• Need for displacement control at each abutment during slide

• Importance of camber control in P/S beams

• Contractor chose to use permanent bearings for the slide. Use of temporary slide bearings is advantageous

Time-Lapse Video

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❖Questions