improving operational and structural performance of the burlington-bristol bridge design team 25:...
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Improving Operational and Structural Performance of the Burlington-Bristol Bridge
Design Team 25:Dan
KramerNate
DubbsTom
GoleckiJim
GardnerKyle
Kessler
Faculty Advisor:Dr. Frank Moon
Industry Sponsor:Pennoni Associates Inc.
December 5, 2007
Project Objective
Investigate means to improve the operational and structural
performance of the Burlington-Bristol Bridge
(including, but not limited to increasing sufficiency rating)
December 5, 2007
Location
December 5, 2007
Background and Description of Structure
• Location, connects Burlington, NJ with Bristol, PA
• Constructed 1930-31• Steel truss bridge• Consists of two tower spans (200’ each) and
a lift span (540’)• Use of counter weights to raise lift span• Built based on traffic of the time
• Current traffic is wider, faster, heavier
• Bridge services 25,000 vehicles per day (AADT)
• (2) 10’ Lanes, below AASHTO minimum for Interstates, 12’
• Current AASHTO standard states 10’ lanes may stay “where alignment and safety record are satisfactory”
December 5, 2007
Pictures
December 5, 2007
During Opening
December 5, 2007
Definition of Terms
• Functionally Obsolete:– Having deck geometry (e.g., lane
width), load carrying capacity, clearance, or approach roadway alignment that no longer meet the criteria for the system of which the bridge is a part.
• Structurally Deficient:– Those that are restricted to light
vehicles, require immediate rehabilitation to remain open, or are closed.
– Categorized by a rating of 4 (poor) or less in any category
• Sufficiency Rating:– Sufficiency rating is a label given
to a bridge as an attempt to quantify its condition
– Factors such as serviceability, functional obsolescence, structural adequacy, safety, and essentiality for public use are used to compute a sufficiency rating.
December 5, 2007
Sufficiency Rating
December 5, 2007
Existing Conditions
• Current sufficiency rating 31.1 - why?
• Functionally Obsolete• Structural Condition
Rating:– Substructure– Deck– Superstructure– Lifting Assembly
NJDOT - 2007
December 5, 2007
Role within Transportation Network
Turnpike BridgeADT = 42,600(9 mile detour)
Burlington-BristolBridge
ADT = 25,000
Tacony Palmyra Bridge
ADT = 50,000(24 mile detour)
December 5, 2007
Internal Criteria
• Maintain operational capacity
• No total replacement
• No restriction of river traffic (maintain clearance)
• No new structures on PA side
• Budget funded from tolls
• Keep toll plaza location
December 5, 2007
External Criteria
• Jurisdictions and Codes
• Maintain operational capacity
• Maintain minimum river clearance
• Limited space on NJ side
• Must maintain lift span
December 5, 2007
Overview of Phased Solutions
• Option I – Operational Safety– Utilize inexpensive actions to enable the near-term mitigation of
operational safety concerns
• Option II – Structural Safety and Serviceability– Identify appropriate intervention strategies to improve the structural
safety and serviceability of the bridge (including the sufficiency rating)
• Option III – Operational Capacity – Identify approaches to improving the operational capacity and
bringing the entire structure up to current standards
December 5, 2007
Option 1 – Operational Safety
• Do Nothing– Existing conditions– 10’ lanes– No barrier
December 5, 2007
Option 1 – Operational Safety
• Remove sidewalk– 12’ lanes– No barrier– Low cost and impact
to traffic
December 5, 2007
Option 1 – Operational Safety
• Remove sidewalk, add barrier
– 10’-6” lanes– Protected lanes– Low cost and impact
to traffic
December 5, 2007
Option II – Structural Safety and Serviceability
• Superstructure– Identify significant deterioration of truss members– Analyze structure for capacity– Design new members to assist or replace existing members as needed– Clean and paint superstructure to inhibit future deterioration
• Substructure– Design bearings– Design retrofit for areas with significant section loss– Inspect foundations for scour and design new scour resistant
foundation systems as needed
December 5, 2007
Option III – Operational Capacity
• Total Replacement– New structure could be designed without need for a lift – Standard lanes and shoulders would be incorporated into
design – Structural sufficiency would score a near perfect– However, replacement was attempted in the past
– Proved difficult for political reasons– Loss of tolls due to diverted traffic
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Option III – Operational Capacity
• Superstructure Replacement– Utilize existing piers– Additional capacity– 12’ lanes & median– Requires closure
December 5, 2007
Option III – Operational Capacity
• Cantilevered Lanes– Maintain traffic flow– Increased lane width– High quantity of new material– Added weight to lift
December 5, 2007
Option III – Operation Capacity
• Additional Deck on Top Chord– Added stiffening of truss “flange”– Minimal amount of new material– Significant approach work– Through towers– Counterbalance
December 5, 2007
Decision Criteria
• Quantitative Considerations: Criteria were chosen based on objective means of quantifying options
– Construction – Time of lost revenue, traffic routing– Operational Capacity – Number and width of lanes– Environmental Impact – Amount of new materials– Sufficiency Rating – Based on Condition, geometry– Cost – Materials, labor
• Qualitative Considerations (not adding to Sufficiency Rating): – Barriers would increase safety– Traffic Directions, safer with opposing traffic
• By constructing a decision matrix we were able to compare options and eliminate those with the lowest scores. For example:
– Total replacement– Deck hung beneath the existing truss– Widening of the existing truss.
December 5, 2007
Decision Matrix
These influence coefficients represent each option's performance in each category on a scale from 0 to 1. The better an option is for a specific category, the higher its influence should be.
Option 3 - Operational CapacityOption 2 - Sufficiency Option 1 - Safety
Rating CategoryWeight Factor
Total Duplication of Bridge
Superstructure Replacement
Additional Deck on top Chord
Additional Lanes Cantilevered
Evaluate and Repair Structural Problems
Add Barrier
Widen Lanes
Operational Capacity 0.25 0.75 0.50 0.50 0.50 0.25 0.00 0.25
Environmental Impact 0.20 0.22 0.50 0.68 0.63 0.83 0.87 0.85
Sufficiency 1.00 0.57 0.82 0.65 0.65 0.65 0.48 0.48
Construction 0.60 1.00 0.00 0.40 0.60 0.60 0.80 0.80
Cost 0.75 0.45 0.25 0.71 0.66 0.87 0.90 0.92
Results - 0.62 0.44 0.60 0.63 0.68 0.65 0.67
Input from sponsor about relative importanceof each criteria.
December 5, 2007
Decision Matrix
0 10 20 30 40 50 60 70 80 90 100
Percentage Score
Total Duplication of Bridge
Superstructure Replacement
Additional Deck on top Chord
Additional Lanes Cantilevered
Evaluate and Repair Structural Problems
Add Barrier
Widen Lanes
Results of Decision Matrix
OperationalCapacity
EnvironmentalImpact
Sufficiency
Construction
Cost
Option 1
Option 2
Option 3
December 5, 2007
Design Tools
• 3D CAD Model– Visualization of Options– Traffic Planning
• Finite Element Model– Locate Structural Inefficiencies– Develop Retrofits
December 5, 2007
Path Forward
• Make final decision on improvement option• Gather technical information
• Construction drawings, traffic counts, soil profiles, inspection reports
• Assess current conditions and determine necessary rehabilitation to facilitate improvements
• Preliminary designs• Progress presentation (March 2008)
December 5, 2007
Schedule
Burlington-Bristol Bridge - Performance / Capacity Improvement Schedule
Identify ExistingConditions
Choose an Option
Traffic Design
Structural Design
Geotech Design
December 5, 2007
Budget
• Method of Developing Design Costs• Assumed pay rate x 100% overhead x 50% markup• Assume 10hr/week/team member for Winter term• Assume 8 hr/week/team member for Spring term
Design Team 25 Engineers RateHours
Total CostWinter Spring
Structural Engineers 3 $120/hr 300 144 444 $53,280
Geotechnical Engineer 1 $120/hr 100 48 148 $17,760
Transportation Engineer 1 $120/hr 100 48 148 $17,760
Technical Consultant: Dr. Moon 1 $200/hr 10 8 18 $3,600
Total = $92,400
December 5, 2007
Questions/Suggestions?
December 5, 2007
References
• (1) U.S. Department of Transportation, Federal Highway Administration, Office of Engineering, Bridge Division, National Bridge Inventory database, available at http://www.fhwa.dot.gov/bridge/britab.htm/\ulnone , as of December 2002.
• (2) NJDOT Bridge Report 10/20/07• (3) National Bridge Inspection Standards (NBIS). (1996). Code of
federal regulations, No. 23CFR650, \i0 U.S. Government Printing Office, Washington, D.C., 238-240.
• (4) Discussion with Mr. David Lowdermilk P.E. and Mr. Lawrence Egan P.E. 11/29/07
• (5) http://www.phillyroads.com • (6) http://en.wikipedia.org/wiki/Tacony-Palmyra_Bridge• (7) http://en.wikipedia.org/wiki/Burlington_Bristol_Bridge• (8) http://www.bcbridges.org/bridge_info/toll.asp
December 5, 2007
Burlington Bristol Bridge - Performance / Capacity Improvement Schedule
9/25/07 10/26/07 11/26/07 12/27/07 1/27/08 2/27/08 3/29/08 4/29/08 5/30/08
Identify Existing Conditions
Structural Identification
Site Data
Traffic Data
Consider Solutions
Option I - Safety
Option II - Sufficiency
Option III - Capacity
Cost Estimate
Economic Analysis
Establish Solution Criteria
Choose an Option
CAD Site Plan
Traffic Design
Traffic Forcasting
Geometry
Approach Design
Road Surfaces / Decking
Report Preperation
Structural Design
demand envelope
FE Modeling
Model Verification
Member sizing
Connections
Final Design
Geotech Design
Ground Modification
Final Soil Profile
Report Preperation
December 5, 2007
Case Studies
• Armour-Swift Burlington Bridge– Missouri River, Kansas City MO– Double deck, lift structure – Roadway above, Rail below
• Steel Bridge– Williamette River, Portland OR– Double deck, lift structure– Rail and pedestrian below, roadway
and streetcar above– Independent lifts
• Tamar Bridge– Tamar River, England– Widened from 3 to 5 lanes while
maintainingtraffic during construction
December 5, 2007
Information Requests
• Survey Information– Existing topography, roadway, ROW, utilities and drainage
• Traffic Information– Traffic counts, CBR values, Truck volume, Traffic forecasting, Accident
Data
• Site Information– Sub-surface profiles, Cross-section and profile of Delaware River,
Aerial photographs
• Structure and Foundation Information– Design plans, construction plans, retrofit design plans, governing
design specifications