accelerated bridge construction university transportation
TRANSCRIPT
1/21/2021
Blackhall Road at Rum Creek Bridge Project • GDOT Project PI 0011691
Modular Decked Beams made with Bulb‐Tee Girders
Accelerated Bridge ConstructionUniversity Transportation Center
January 21, 2021
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Commitment to ABC
• Culture of Innovation and Collaboration
• Solving project time constraints and user cost
• Utilizing Accelerated Bridge Construction
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GDOT Projects utilizing ABC: SR 211 over Beech Creek
• PI 0007159 Barrow County
• 148’‐0” Single span Bulb Tee 72 beams
• Precast Deck Panels with UHPC closure pours
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GDOT Projects utilizing ABC: SR 299 over I‐24
• PI 0011682 Dade County
• 201’‐7” two spans Type III Mod beams
• Prefabricated bridge elements and SPMT
• Construction of proposed substructure underneath existing bridge
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GDOT Projects utilizing ABC: CR 131 (Elliot Rd) over Walnut Creek
• PI 0011690 Henry County
• 145’‐0” Single span Bulb Tee 72 beams
• Precast Deck Panels with UHPC closure pours
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GDOT Projects utilizing ABC: SR 3 over Peachtree Creek
• PI 0007174 Fulton County
• Two 110’‐2” spans, continuous plate girder unit
• Precast Deck Panels with UHPC closure pours
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Project Description
Atlanta
Project Site
• Replacement of a load posted bridge
• Correct substandard roadway geometry• improve sight distances• raise vertical profile • shoulder widths
• Preliminary Design ‐ Conventional construction
• Roadway closure and offsite detour
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Blackhall Road
Existing Bridge
Lake Spivey
Dam
Spillway/Rum Creek
Blackhall RoadADT = 6550
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Preferred Alternative
Offsite detour with a 9 to 12‐month closure
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Plan and Elevation
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Other Alternatives Considered
Permanent roadway realignment
Maintain existing roadway alignment using onsite detour
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ABC Considerations and Alternatives
• Stakeholder Meetingo Home Owner’s Associations and elected officials request for significantly
shortened roadway closure duration
• GDOT Office of Bridge and Structures o recent completion of single‐span ABC replacement project
o seeking multi‐span ABC candidates
o requested project alternatives to achieve maximum 4‐month road closure
• Alternatives Analysis
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Deck Bulb‐tee beams shipped from the fabricator• Deck is integral, only closure pour required • Placement immediately upon shipping• Can be opened to traffic after closure pours and barriers placed
• Local availability; shipping requiring special permitting• Cost• Complications with profile and cross slope
NEXT D & F beams• Placement immediately upon shipping• Stability during shipping and placement• NEXT D beams use to set main span• F‐Beams require deck to be poured• Heavy to ship, pick and set
Contractor Built Modular Decked Bulb‐tee Beams • Availability and shipping • No special equipment or subcontractors
• Requires onsite staging area to pre‐assemble bridge• Final beam is heavy to pick and set
ABC Alternatives Analysis
PROs
CONs
PROs
CONs
PROs
CONs
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Modular Decked Beam Units (DBU)
54”Bulb Tee Beams
Conventional deck cast onsite at laydown yards
Steel DiaphragmsDeck cast with final cross slope
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Letting and Construction…
• Laydown yards and “false bents”
• Superstructure: pre‐cast decked beam units
• Delivery Method: Design, Bid, Build
• 60‐day road closure per special provision
• $4182/day liquidated damages for failure to reopen road
• A+B Bidding
• A = Construction Costs
• B = Total # Calendar Days x LD of $4182/day
AcceleratedBridge Construction
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Project Details
• Two bidders
• Letting in August 2018
• CW Matthews ‐ $5,003,000 bid• Bridge cost = $2,037,000 ($253/sf)• 407‐day schedule
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Construction Sequence
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Laydown Yards
Roadway open to traffic
South Yard
North Yard
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Laydown Yards ‐ South
Buried power at Laydown Yard
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Laydown Yards ‐ North
DamSpillway
Roadway open to traffic
Roadway open to traffic
Ample room for crane/equipment
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Decked Beam Units
Steel H‐Piles
• 54” Bulb‐Tees set on “False Bents”
• Conventional timber formwork & deck construction
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Decked Beam Units
Bearings and Shim Plates
• Utilize steel diaphragm
• Steel diaphragms used 2x at laydown yard & permanent bridge
• Likewise, shim plates and elastomeric bearingsare used at both sites
• Permanent pier caps constructed to match “false bents”
Steel Diaphragms
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Forming Deck Joints
1” Skim Pour over top of foam
Polystyrene foam
Uncoated Reinf. On County Roads
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Forming Deck Joints
Step 4)Surface preparation
Step 2)Remove concrete between saw cuts
Step 1) Shallow Sawcut on both sides of Joint
Step 3) Strip timber forms & remove polystyrene foam
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Pre‐Cast Decked Beam Units
• Block‐out the joints/edge beam/end wall
• ¼” Grinding/wearing thickness
• No overlay
• Deck designed as simple span but constructed to be jointless
• Road is still open to traffic at this point
6’‐0” Block out for Cast in Place Diaphragm (24 hr conc.)
Longitudinal Joints (UHPC)
3’‐0” Block out for Cast in Place End Diaphragm (24 hr conc.)
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Construction: Decked Beam Erection
• Close the road
• Demolish exist. bridge
• Construct substructures
• Move DBU & erect
• 800‐ton crane
• Temp fill at end span
• Center span set in single day
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Construction: Decked Beam Erection
Span 1 Span 1
Span 2
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UHPC: Casting
Longitudinal Joints (UHPC)
6’‐0” Block out for Cast in Place Diaphragm (24 hr conc.)
Block out for Lifting Loops
(UHPC)
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UHPC: Casting
• Start at the lowest point
• Finish ¼” above the surface of bridge deck
• UHPC mixed on site
Exposed aggregate surface 1/8” min amplitude
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UHPC: Casting
Top Forms Installed to prevent UHPC movement downhill
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Construction: Approach Paving
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Construction: COMPLETE – ON TIME! < 60 DAYS
November 2019
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Profile Management with Adjacent Beam Bridges
• Correct roadway profiles vary• flat (level or on a constant grade)• crest vertical curves• sag vertical curves
• Prestressed deck beams are cambered• NEXT beams, Deck Bulb‐tees• the camber does not match the roadway profile
• here are solutions, but it brings complexities
www.pcine.org
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Recommended Approach for Adjacent Beams
Option 1: vary the thickness of the top flange
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Recommended Approach for Adjacent Beams
Option 2: vary the thickness of the overlay (if you have one)
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Effect of Profile Management on the Beam Design
Designer’s Role:
Each solution will have an affect on the design of the beam• variable dead loads• variable beam section properties (flange thickness)• camber tolerance
o can be accounted for in the design if significant
Beam seat detailing• Elevations of beam seats needs to account for:
o the method of profile management choseno camber tolerances
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Benefits of the Blackhall Road Design
The modular decked beams can be built to the exact roadway profile• deck haunch is used to adjust the deck elevations
Best of both worlds• prefabrication• high level of profile accuracy
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Lessons Learned
• No significant problems encountered
• Steel diaphragms performed well – provided immediate stability at both sites
• Utility coordination critical
• Reinforcement fabrication tolerances – additional length cannot be accommodated by splices
• Joint construction with “skim” pour was a success
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Thank you
GDOT, CW Matthews and the CHA team
Responsibly Improving the World We Live In
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Contact Information
Georgia Department of Transportation:• Donn Digamon – [email protected]• Dexter Whaley – [email protected]
CHA:• Jim Aitken – [email protected]• Kevin Kahle – [email protected]• Mike Culmo – [email protected]
CW Matthews Contracting Co.• Mark Dolan – [email protected]• Juan Velasquez – [email protected]
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