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

December 5, 2007

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