Shore Drive/Lesner Bridge

April 21, 2005

Introduction

• Current Bridge Condition• Current and Future Traffic Demands• Shore Drive Transportation Study• Shore Drive “Requested but not Funded”

Project• Lesner Bridge Replacement (First Cities

Project)• Future Steps• Questions

Lesner Bridge

• Current Bridge Condition• Maintenance History• Bridge Inspections• Posting• Detour Route• Current/Future Maintenance Efforts

Background

• Structure 1814 (EBL) constructed in 1958• Structure 1827 (WBL) constructed in 1965

• 25 spans prestressed concrete beams, 3 spans steel girders

• Built in the “early days” of prestressedconcrete construction

Background

EBL Constructed 1958WBL Constructed 1965

1988 Bridge Safety Inspection -

“moderate crack” along bottom of 2 girders

1992 Bridge Safety Inspection - Heavy spalls w/ significant loss of prestressing

Steel Beams Painted

1990 Bridge Safety

Inspection -Small spalls

at ~5 locations on each bridge.

1994 Bridge Safety Inspections - Rate of

deterioration increased. One girder with 100%

corrosion of prestressing strands. - 100% loss of entire bottom layer of

prestressing and 2 strandssevered in second layer

1994 - Chloride Contamination Testing -

66% of samples at 1st layer of prestressing

& 20% of samples at2nd layer exceeded ACI recommended threshold

for chloride

1995-1996 ~$500,000 spent on major beam repairs made to the

prestressed concrete beamsand diaphragms, concrete piles, and fender system.

Experimental deck overlay and joint replacement

project also performed (not included in cost figure)

2000 - Bridge Safety Inspection -

Areas of delaminationand spalling -EBL - 170 SF WBL - 110 SF

2002 - Bridge Safety Inspection -

Areas of delaminationand spalling -

EBL - ~ 690 SF WBL - ~ 420 SF

Structure placed on AnnualInspection Cycle

~$475,000 spent to paint steel Beams and perform more deck repairs.

2002 - Chloride Contamination Testing -

96% of samples at 1st layer of prestressing

& 63% of samples at2nd layer exceeded ACI recommended threshold

for chloride

66

20

96

63

0

10

20

30

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60

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100

2 1/2" Depth 4 1/2" Depth

% S

amp

les

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ove

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hre

sho

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1994

2002

170110

690

420

1041

422

0

200

400

600

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1000

1200

EBL WBL

Det

erio

rati

on

(SF

)

2000

2002

2003

2004~$678,000 spent on

concrete beam rehabilitation which

included removal and replacement of deteriorated concrete and theapplication of a

migrating corrosioninhibiting agentand a breathable

sealer.

2003 - Bridge Safety Inspection -

~1463 SF of spallsand delamination

identified &200 End of Beamrepairs identified

Background -Inspection Findings

• 1988 - Moderate cracks along bottom of 2 girders

• 1990 - Small spalls at ~5 locations on each bridge

• 1992 - Heavy spalls w/ significant loss of prestressing

• 1994 - Rate of deterioration increased markedly w/ 100% corrosion of prestressing strands– 100% loss of entire bottom

layer of prestressing and 2 strands severed in second layer

1995-1996 Beam Repairs

• Deck joints sealed• Ends of beams

repaired / sealed• Areas of

deteriorated concrete removed

• Exposed prestressing cleaned and corrosion inhibitor applied

• Repairs shotcreted to provide protective cover

Background -Inspection Findings

• 2000– Delamination and spalls

• ~ 170 SF in EBL• ~ 110 SF in WBL

• 2002 – Delamination and spalls

• ~ 690 SF in EBL• ~ 420 SF in WBL(Only a few isolated locations of previous repairs showing signs of further distress)

– ~$475,000 spent on painting of steel beams– Structural condition rating of superstructure

dropped to Poor– Structures placed on annual inspection cycle– Sufficiency rating dropped to 48.5 – EBL & 44.0 -

WBL

170110

690

420

1041

422

0

200

400

600

800

1000

1200

EBL WBL

Det

erio

rati

on

(S

F)

2000

2002

2003

Background - Chloride Contents

• Chloride contamination suspected.• Tests revealed an increase in the percentage of samples

that exceeded ACI recommended threshold for water-soluble chloride content of 0.06%.

66

20

96

63

0

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20

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2 1/2" Depth 4 1/2" Depth

% S

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19942002

Load Rating Analysis• Load Ratings were performed in 2002 taking into

account loss of prestressing.• Steel Girders govern ratings at this time• Prestressed Beam deterioration threshold:

2AllAllAllEBL

0All2AllWBL

2nd

Layer1st

Layer2nd Layer1st Layer

Present LossStrand Loss that

would require posting

Load Ratings

• WESTBOUND STRUCTURE

Load Ratings

• EASTBOUND STRUCTURE

Background

• Posting of structure not currently required.

• Difficult to add strength to prestressed beams.

• Repairs necessary to slow rate of deterioration so that posting not required in the future.

Rehabilitation Study

• To determine necessary long-term maintenance to extend unposted life of bridge for 15 years.

• Proven rehabilitation technology• New and emerging technologies

Rehabilitation Plan• Combination of Mechanical Methods and

Beam Strengthening– Remove deteriorated concrete. Sandblast

exposed steel. Apply corrosion inhibitor and repair mortar

– Apply migrating corrosion inhibitor to surface of beam bottom flanges

– Apply breathable sealer to all surfaces of beams– Monitor beams at more frequent intervals– Externally post-tension beams on a case-by-case

basis over time to regain strength– Actively pursue replacement structures as soon as

possible

Budgetary Cost Study

Required Repair: 2003 2005 2008 2011 2013 2015Mobilization $27,000 $31,300 $36,286Girder Repairs 2 $310,820 $180,163 $313,287Application of Corrosion Inhibitor $173,750 $201,424 $270,697Application of Silane Sealer $114,450 $132,679 $178,309External Post-Tensioned Repairs3 $25,000 $54,636 $59,703 $126,677 $134,392Engineering & Construction Insp. $120,000 $22,000 $80,000 $12,000 $120,000 $30,000

Yearly Total (Rounded): $746,000 $47,000 $680,000 $72,000 $1,045,000 $164,000

Running Total (Rounded): $746,000 $793,000 $1,473,000 $1,545,000 $2,590,000 $2,754,000

Notes:1. Costs assume 3% annual inflation from the present.2. Cost for girder repairs assume that year 2008 repair quantities will be approximately 50% of year 2003 and year 2013 repair quantities will be approximately 75% of year 2003.

Budgetary Costs Per Year1

(For Beam Rehabilitation Only)

Beam Rehabilitation Work

• 2004– ~1450 SF of spalls and delaminations in

beams repaired• Repairs consisted of removal and replacement

of deteriorated concrete with the application of a migrating corrosion inhibiting agent and breathable sealer.

– ~ 200 End of Beam repairs made– Total Construction Cost - $678,000

Future Maintenance Work/ Proactive Measures

• Maintenance Work– On-going beam rehabilitation– Deck joint replacement– Concrete repairs to bents, piers, and pier caps– Pile jacketing– Rail post replacement– Rip-rap replacement around piers– Fender system repairs

• Proactive Measures– Restriction of superloads and heavy truck traffic

Shore Drive

• Current/Future Traffic Demand• HRPDC Congestion Management

System Study

Level of Service

LOSLOS AA BB C C DD E FE F

Free Flow Operations Reasonably Free-Flow Stable Operations

Borderline Unstable Extremely Unstable Breakdown

Shore Drive

LOS A LOS B LOS C

LOS D LOS E LOS F

Pictures provided by the Department of Transportation Bureau of Transportation Statistics and the MIT Center for Transportation Studies @1995

Shore Drive (Cont.)• Shore Drive Transportation Study

– Shore Drive and Lesner Bridge Recommendations

– City Council Direction• Shore Drive “Requested but not Funded”

CIP 2-857– “The following projects were requested by

departments but not funded in the six years of the CIP. Inclusion on this list does not represent a recommendation. The City Manager may review the merit of these requests in the future CIP processes.”

Shore Drive Recommendations

• “The transportation related recommendations have the goal of extending the traffic carrying potential of the current 4-lane section, consistent with safety, the long range perspective reflected in the SDAC report, and bridge replacement requirements.”

Lesner Bridge Recommendations

• “Continue to maintain the existing facility and review economically feasible rehabilitation activities. Plan to replace the current facility with a ‘signature’ bridge. The new bridge will include multi-purpose trail capabilities and will be designed and constructed so as to allow for the provision of 6 lanes.”

Lesner Bridge Replacement(First Cities Project)

• Proposed Schedule• Proposed Scope• Current Budget

Lesner Bridge ReplacementProposed Schedule

• May 10, 2005 - City Council to approve Capital Improvement Program

• Mid May 2005 - Advertise RFP for Lesner Bridge Replacement Project

• July 2005 - Interviews for Consultants• August 2005 - Scope and Fee

Negotiations• October 2005 - Issue Design Notice to

Proceed• Spring 2006 - First Citizens Information

Meeting

Lesner Bridge ReplacementProposed Scope

• Design a bridge to meet the transportation needs of the City for the next 60 – 75 years

• Design a structurally artistic bridge that is a part of the community fabric

• Insure the bridge is economically feasible

Lesner Bridge ReplacementCurrent Budget

• $1.0 M proposed in FY 2005-2006 for Study

• Coordinating with VDOT to include in City’s Urban Program (First Cities Project) and to accrue funding for construction.

Summary

• Current Bridge Condition• Current and Future Traffic Demands• Shore Drive Transportation Study• Shore Drive “Requested but not

Funded”• Lesner Bridge Replacement (First

Cities Project)• Future Steps

Questions