ABC By 2010 1 UTAH Department of Transportation ACCELERATED BRIDGE CONSTRUCTION BY 2010 How have we done? ACCELERATED BRIDGE CONSTRUCTION BY 2010 How have we done? Fred Doehring Fred Doehring UDOT Structures UDOT Structures ABC by 2010 • UDOT goals – Accelerated Bridge Construction • Standard practice by 2010 • What was needed? – Methods of construction – Standard details – Commitment to a program Vision for “Family” of ABC Methods Precast Concrete Elements Prefabricated Prefabricated Components Components Modular Construction Large Prefab. Large Prefab. Components Components Structure Placement Methods SPMT SPMT Sliding Sliding Accelerated Bridge Construction Accelerated Geotech Work Geofoam Geofoam Fast Track Contracting CMGC CMGC Design/Build Design/Build ABC Phase 1 • Early implementation of ABC – Scanning Tours • Looked at what other states were doing – Workshops held • Brought all stakeholders together • Identified what was needed • Prioritized needs • Looked at several specific pilot projects ABC Phase 1 • Results of Phase 1 work – Several key standards were developed • Precast Full Depth Deck Panels • Manual on Self Propelled Modular Transporters (SPMT’s) • Development of specifications and manuals for each • Several pilot projects initiated and built ABC Methods Used • Precast Deck Panels • Voided Slabs • Precast Substructures – Abutments and Bent Caps • Precast Superstructures – Crane, Sliding, and SPMT
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ABC By 2010
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UTAHDepartment of Transportation
ACCELERATED BRIDGE CONSTRUCTION BY 2010
How have we done?
ACCELERATED BRIDGE CONSTRUCTION BY 2010
How have we done?Fred DoehringFred Doehring
UDOT StructuresUDOT Structures
ABC by 2010
• UDOT goals– Accelerated Bridge Construction
• Standard practice by 2010
• What was needed?– Methods of construction– Standard details– Commitment to a program
• Developed Specifications and Manuals• Workshops were held for industry input
ABC Phase 2
• Other work completed in Phase 2– Reviewed computer monitoring data from first
round of SPMT bridge moves– Refined Phase 1 work based on lessons
learned in construction• Deck Panel standards and specifications• SPMT Manuals
• Emulates a reinforcing steel lap splice• Used in precast parking garages and
stadiums and bridges• New seismic research coming
Connections with Grouted Splice Couplers
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Connections with Grouted Splice Couplers
Installation video on Youtube
Search “Georgia Bridge Pier” Column or wall panelto footing connection
Typical Connection Details
Column to capconnection
Typical Connection Details Current Typical Details• Single column hammerhead• Two column bent• Three column bent
Columns• Rectangular are possible,
but not preferred• Round columns are difficult
to precast– Must be cast vertically
• Use Hexagonal or octagonal shape– Can be cast on side (one side open)
Current Typical DetailsFootings• Full Precast
– For smaller footings
Shim and grout under footing through ports in footing
Current Typical Details
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Footings• Partial Precast
– For larger footings– Precast designed to support
DL of bridge– CIP extensions designed for
other loads
CIP Extension
Precast Portion
Shim and grout under footing through ports in footing
Current Typical DetailsPile supported footings
• Use corrugated pipe forms
•Used for integral abutment stems also
Current Typical Details
Pretensioned Bulb Tee Girders Pretensioned Deck Bulb Tee Girders
Post-tensioned Bulb Tee Girders Integral Abutment Details
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Cantilever Abutments and Walls• Use corrugated pipes in stems to reduce weight
– To be filled with concrete in the field– Reduces the number of pieces
1. Drive Piles
Stage 1
1. Place footings over pile and set to grade and alignment (day 1)
2. Cast concrete in voids around piles (day 1)
3. Cast concrete between footings if required (day 2)
Stage 2
1. Install pier wall panels. (day 4)2. Connect to footing via grouted
splice couplers (day 4)3. Fill voids with concrete to within
3 feet of top (day 5)4. Install rebar cage in top of voids
extending 2 feet above (day 5)5. Joints between may be grouted
or left dry
Stage 3
1. Install pier cap, set to grade (day 6)
2. Pour concrete through ports to fill voids and make connection (day 7)
3. Install precast beam seats (day 7)
Stage 4 Final Construction
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Box Culverts• Precast boxes, aprons, and walls
Tolerances
• Tolerance details developed for all critical elements
• Based on PCI Tolerance manual– MNL-135-00
Tolerance DetailsSplice couplers
Tolerance DetailsColumns
Precast Full Depth Deck Panels
• First Generation Standards completed in Phase 1 UDOT ABC Program
• More than 15 project built to date• Costs are coming down• Welded plate details are not desirable
– Time– Leakage issues at joints
• There is new technology in the market
Precast Full Depth Deck Panels• Phase 2 Modifications
– Use Longitudinal Post-Tensioning to Connect Panels• AASHTO Code Recommendation• Better performance over time (no leakage through joints)
– Use multi-strand PT systems• Developed for slabs• More Flexible
– Allow blind pockets for shear stud connection• Based on recent research
– Allow skewed deck panels (up to 15 degrees)
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Precast Full Depth Deck Panels• Recommended Post-tensioning System
– Multi-strand deck PT systems– Developed specifically for decks (thin anchorage)– Used by other states– Recommend the use of less than maximum amount
of PT allowed in the ducts (4-0.5” strand)
Blind Pocket Project – Texas DOT
UDOT Blind Pocket Details
Schematic Construction Details2 Span Bridge using UDOT Standards
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Typical 2 Span Bridge
Excavate and Install Piles
Typical 2 Span Bridge
Install Abutment Stem and Footings
Typical 2 Span Bridge
Install Pier ColumnsFill Voids in Abutment Stems
Typical 2 Span Bridge
Install Pier Cap and WingwallsCast Footing Closure Pour
Typical 2 Span Bridge
Erect Girders
Typical 2 Span Bridge
Install Backwalls and Sleeper Slabs
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Typical 2 Span Bridge
Install Deck Panels and Approach Slabs
Typical 2 Span Bridge
Cast Deck and Approach Slab Closure Pours
Typical 2 Span Bridge
Construction Roadway Approaches Bridge Monitoring (TAC)
• Volunteer group of key stakeholders– UDOT– Design Consultants– Contractors– Industry Representatives
• Charged with review of data and recommendations for future SPMT bridge moves
• Used computer monitoring data from 2008
• Data retrieved– Mostly strain data (deck, girders)– Layouts were similar on each bridge– Used to study the stresses within the bridge during:
• Lifting• Moving• Placement
• Utah State University (USU)– Brought in to analyze and disseminate the data– With input from the TAC
Bridge Monitoring (TAC)
Lifting Strain
Dynamic Strain
Temperature Strain
Typical Data
Bridge Monitoring (TAC)
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• Final Findings and Recommendations– Lifting stresses are very significant
• Supporting the deck at the lift points eliminated most deck cracking• Lift bridge closer to ends (0.2L or less)• Lightweight concrete in the deck helps to reduce deck cracking, and
overall lift weight– Dynamic effects can be approximated by increasing dead load
by 15%• Starting and stopping of SPMT’s• Traversing bumps during the move
– 3d Analysis is needed to estimate lifting stresses if a flexiblecarrying beam is used
– Recommended future gaging locations
Bridge Monitoring (TAC) SPMT Manual Revisions• Build on knowledge gained in 2008• No major changes• Define roles of project participants• Written to fit in with the UDOT Design
Network
SPMT Lifting Methods
• Neg. DL moment on girder• May be a problem with prestressed girders
• Light weight concrete could help
• Little or no deck cracking• Deck is pre-compressed in final condition
• Neg. DL moment on composite section
• Significant deck cracking is possible
• Light weight concrete could help
Lessons Learned• Study of Performance of ABC Bridges• Bridge Types Studied
– Full Depth Deck Panels with welded tie connections (6)
– Full Depth Deck Panels with Post-Tensioning (2)– Precast Parapets integral with deck (5)– SPMT Bridge Moves (9)– Precast Abutments (2)– Precast Piers (2)
• Inspections took place in May, 2009
Lessons LearnedProject locationsMilepost 200 on Route 6 not shown
Lessons Learned• Purpose of the study
– Investigate the performance of each component type
– What is performing well and what is not– Not intended to critique past designs
• Most of these bridges were designed prior to development of standards
• Many were designed as short term fixes prior to full replacement in the near future (10-25 years)
– Goal: Continuous Improvement of Quality
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Lessons Learned• Welded Tie Connections
– Joint Leakage is widespread– Shear transfer is still working– Composite connection is good
Lessons Learned• Welded Tie Connections
Lessons Learned• Welded Tie
Connections
Lessons Learned• Welded Tie Connections
Lessons Learned• Post Tensioned Connections
– 3 span continuous bridge
I-215 at 3900 South
Lessons Learned• Post Tensioned
Connections– No Joint Leakage– Even in negative
moment areas
Underside of deck
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Other Long Term Performance Information
• I-84/Route 8 Interchange –Waterbury, CT
Project Information• Curved structure (straight beams)• 6 Span bridge with continuous spans • Single lane• Prestressed transversely and post tensioned
longitudinally• Details similar to UDOT• 42 Day construction
• No construction problems• Built in 1991
After 18 years of service• Excellent condition• Used membrane waterproofing and Asphalt Wearing
surface• No leakage through joints
After 18 years of service
Route 8 Viaduct, Seymour, CT• 2 Curved structures• Over 50 spans (all simple spans)• Prestressed and post tensioned• Weekend closures only
• Old deck removed on Friday night• New deck erected on Saturday
morning• Post tensioned on Saturday night• Grouting on Sunday morning• Open to traffic Sunday night
– Several have minor leakage around pockets (not all)
• Shrinkage of Grout• Blind pockets should alleviate this
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Lessons Learned Lessons Learned• Recommendations
– Full Depth Deck Panels• Eliminate welded tie detail • Always use post-tensioning• Use blind pocket detail for shear connectors• New Standards address these recommendations
Lessons Learned• Recommendations
– Precast integral parapets• Do not use 2 per panel
– Use a longitudinal closure pour in deck to allow for adjustment in the field
– Cast one or both in the field behind temp. barriers
Lessons Learned• Recommendations
– Precast Abutments and Piers• Use vertical joints in abutment stems and wall
stems– Allows for easier fit-up in the field
• No problems noted with pier construction• New Standards address these recommendations
Lessons Learned• SPMT Moves
– TAC Committee work verifies issues found in the field
• Pick bridges closer to ends• If possible, support girders at lift points during
deck casting• Investigate the use of lightweight concrete to
reduce deck and girder stresses• New SPMT Manual will address these
recommendations
Lessons Learned• Other general recommendations
– Overlays• Consider thicker overlay with a quality
waterproofing membrane– European and East Coast Systems – CME recommendation, not UDOT policy
– Closure Pours• Use a better high early strength concrete mix
– Shrinkage compensating mixes– NY State mix is being investigated
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Where are we going?
• UDOT Themes– Accelerate Delivery
• Design and Construction– Decrease MOT
• Reduce User Costs and impact to society– Encourage Innovation– Get a good price
Where are we going?
• Implementation of Phase 2 Standards– Training
• Designers• Construction Inspectors• Bridge Inspectors• Bridge Maintenance Personnel
– On-call technical support
Where are we going?
• Manuals– Develop a Bridge Design Manual– New SPMT design guide to be issued
• Lightweight Concrete– SPMT Decks (minimize deck cracking)– Substructure Elements (reduce shipping and
handling costs)
Where are we going?
• Continue to monitor progress– Annual inspection of ABC Bridges– Address issues as they arise
• Goal: Continuous Improvement
Questions?This presentation will be posted on the UDOT website