underwater inspection of sr-141 bridge over christina ...gssdocs.deldot.delaware.gov/bids/br 1-501...

Underwater Inspection of

SR-141 Bridge over Christina River

Bridge No. 1-501-006

Soundings - May 26, 2009

Inspection - May 30, 200

Prepared By: Submitted by:

12932 168th Avenue, Suite A Grand Haven, Michigan 49417 Heath K. Pope, P.E. 616/844-9093 Delaware P.E. No. 15479 Fax 616/844-9096 www.collinsengr.com Collins Project No. 5793-70

Bridge No. 1-501-006 Route 141 over the Christina River

Collins Project No. 5793-70 Page 1

TABLE OF CONTENTS

Significant Findings Summary……………………………………………………… 3

1.0 INTRODUCTION………………………………………………………… 3

1.1 Purpose and Scope……………………………………………………… 3

1.2 General Description of the Structure…………………………………… 3

1.3 Method of Investigation………………………………………………….. 4

2.0 EXISTING CONDITIONS……………………………………………….. 5

3.0 CONCLUSIONS AND RECOMMENDATIONS..………………………7

3.1 Evaluation and Assessments…………………………………………… 7

3.2 Recommended NBI Condition Rating………………………………….. 8

3.3 Recommendations……………………………………………………….. 8

APPENDIX A Location Map…………………………………………………….. A-1

APPENDIX B Photographs……………………………………………………... B-1

Photograph 1. Overall View of the East Fascia of Bridge.

Photograph 2. Overall View of the West Fascia of Bridge.

Photograph 3. View of Pier 2, North Face.

Photograph 4. View of Pier 3, South Face.

Photograph 5. View of the North Embankment.

Photograph 6. View of the South Embankment.

Photograph 7. View of Typical Scaling on Vertical Faces of Piers 2

and 3.



Photograph 8. View of the South Side of Pier 2, Typical Pile Cap Scaling.

Photograph 9. View of the West Nose of Pier 2, Typical Map Cracking.

Photograph 10. View of the Upstream Nose of Pier 3.

Photograph 11. View of Scaling, North Face of Pier 2 Pile Cap.

Photograph 12. View of Scaling With Exposed Steel, North Face of

Pier 2 Pile Cap.

Photograph 13. View of Heavy Scaling at the East Nose of Pier 3.

Photograph 14. View of Heavy Scaling at the Southeast Nose of Pier 3.


Photograph 16. View of Heavy Scaling at the West Nose of Pier 3.

Photograph 17. View of Scaling at the Northwest Nose of Pier 3.

Photograph 18. View of Scaling on the North Face of Pier 3.

Photograph 19. View of Scaling on the South Face of Pier 3.

Photograph 20. View Looking Upstream.

Photograph 21. View Looking Downstream.

APPENDIX C Inspection Plan………………………………………………….. C-1

Sounding Plan………………………………………………….. C-2



SIGNIFICANT FINDINGS SUMMARY

Bridge Number 1-501-006 was inspected on May 30, 2009 and the soundings were

performed on May 26, 2009. No structurally significant defects or deficiencies were

observed that could adversely affect the bridge.

1.0 INTRODUCTION

1.1 Purpose and Scope

DelDOT Bridge No. 1-501-006 carries Route 141 over the Christina River in Newport,

DE, New Castle County. On May 30, 2009, Collins Engineers, Inc. performed a routine

underwater investigation at the bridge to evaluate the condition of all substructure units

(SSUs) from the high water mark to the channel bottom which included Pier 2 and Pier

3. This report includes a description of the structure and the method of investigation; a

detailed description of the conditions noted is included on the Inspection Plan in

Appendix C. In addition, this report contains a condition assessment of the bridge

components evaluated and presents recommendations for follow-up actions. Depth

soundings were conducted around the substructure units, along the centerline of the

bridge, along each fascia, and at cross sections of the channel at 50 feet upstream and

downstream of the bridge

1.2 General Description of the Structure

Bridge 1-501-006 is a multi-span bridge spanning over the Christina River, Amtrak

Railroad, and local streets. The superstructure is made up of composite welded box



girders that are supported by reinforced concrete columns resting on a reinforced

concrete pile cap and 10BP57 steel H-piles. Photographs 1 and 2 in Appendix B show

an overall view of the east fascia and west fascia of the bridge. Photographs 3 through

21 show various views of the piers and inspection findings. The Figures in Appendix C

show inspection notes, elevations and soundings taken. Figure 1 in Appendix A depicts

the location of the bridge over the Christina River in New Castle County, Delaware.

1.3 Method of Investigation

A dive team consisting of commercially trained divers, led by a registered Professional

Engineer in the State of Delaware, conducted the underwater investigation. Access to

the bridge site was obtained from a 19 foot boat launched at the boat launch

downstream of the bridge.

The underwater investigation generally consisted of a Level I visual inspection of 100

percent of the accessible SSU surfaces from the high-water mark to the channel

bottom. A Level II visual/tactile inspection, which included cleaning marine growth at the

waterline, mid-depth, and channel bottom, was performed at various locations to

facilitate an evaluation of the underlying surfaces and provide an overall condition of the

structure. Particular attention was given to any observed areas of excessive

deterioration or apparent distress, and the condition of any repairs was noted.

A cursory assessment of the waterway and channel bottom conditions in the vicinity of

the bridge was also made. The type of channel bottom material was noted, as well as

the location and extent of any observed scour, riprap, or debris.



The location of the waterline with respect to a fixed reference on the bridge was noted

at the time of inspection.

2.0 EXISTING CONDITIONS

At the time of inspection, the waterline was located at elevation 0.5 feet at Piers 2 and 3

in reference to the design drawings. At the time the soundings were performed the

waterline was located at elevation 3.6 to 3.9 feet. Bridge soundings indicated that the

maximum water depth was 28.8 feet at the midpoint between Piers 2 and 3 along the

West Fascia of the bridge. During inspection the river current was 1 to 1.5 feet per

second with 0.5 feet visibility.

The embankments in the vicinity of the bridge did not exhibit deficiencies of note. The

North Embankment generally consisted of gravel under the bridge and light vegetation

upstream and downstream of the bridge. The South Embankment consisted of organic

silt in the tidal zone with light vegetation under the bridge and heavy vegetation

upstream and downstream of the bridge. Refer to Photographs 5 and 6 in Appendix B

for a view of the north and south embankments. The channel bottom mainly consisted

of sand and clay with 2 to 3 inches of penetration, 3 to 4 inch diameter river rock

covered 75% of the bottom only from Pier 3 to the North Embankment. Timber debris

was observed at the channel bottom of Pier 2 and Pier 3. Details of the debris can be

found in the Inspection Notes in Appendix C.

Pier 3 had all of the piles exposed from the channel bottom to the pile cap and Pier 2

had all of the piles exposed with exception to Piles 1 and 2 on the east nose of the Pier

2. Pile Bents are numbered from west to east with 1 starting on the west side of the pier



and piles are numbered 1 to 4 with one starting on the south side of the pile moving

north. Generally, the piles exhibited moderate corrosion on 25% of the surface area.

Bents 8-11 on Pier 3 exhibited areas of moderate to heavy corrosion on 100% of the

exposed surface area with areas of 100% section loss on the outer 1/4 inch of the

flanges. Details of the corrosion areas can be found in the Inspection Notes in

Appendix C.

The concrete fender walls on Piers 2 and Pier 3 had random vertical cracks that have

been repaired in the past. The concrete fender walls on both piers had additional,

unrepaired vertical cracks from the pile cap up to the top of the wall in random various

locations up to 1/8 inch wide.

Both of the piers exhibited areas of heaving scaling with exposed steel. The piers had a

horizontal band of heavy scaling on the vertical faces of the pile caps with 6 inches of

penetration. Pier 2 and Pier 3 also exhibited scaling on the top of the pile caps with 1/2

inch typical penetration and 2 inch maximum. Refer to Photographs 7 and 8 in

Appendix B for views of the scaling note. Both noses of Pier 2 and Pier 3 exhibited map

cracking with areas of scaling and vertical cracking on the faces within the tidal zone.

Refer to Photographs 9 and 10 in Appendix B for views of the pier noses along with the

Inspection Notes in Appendix C for more details.

Pier 2 had areas of scaling around the top edges of the pile cap where the vertical and

horizontal faces meet. Steel with light to moderate corrosion was observed within the

scaled areas. Details can be found in the Inspection Notes in Appendix C and views of

the scaling in Photographs 11 and 12 in Appendix B.



Pier 3 had areas of very heavy scaling at the downstream nose of the pile cap with

moderately corroded exposed steel. Sections of the steel were discontinuous. Further

details can be found in the Inspection Notes in Appendix C and views of the scaling in

Photographs 13, 14, and 15 in Appendix B. The upstream nose of Pier 3 had areas of

scaling on the pile cap with moderately corroded exposed steel. Refer to Photographs

16 and 17 in Appendix B for views of the scaling note. Scaling was located at the

upstream 1/4 point of the north face of the pile cap at Pier 3 with moderately corroded

exposed steel. Refer to Photograph 18 in Appendix B for views of the scaling note.

Further details of the scaling can be found in the Inspection Notes in Appendix C.

Heavy scaling was observed on the top south face of the pile cap of Pier 3 where the

horizontal and vertical faces meet. Large areas of section loss have occurred with

adjacent areas of impending section loss. Refer to Photograph 19 in Appendix B for the

view of the section loss note and the Inspection Plan in Appendix C for further details.

The soundings of the channel bottom under Pier 2 varied from 0 feet at the east end to

22 feet at the west end and from 25 feet at the north face to 0 feet at the south face.

Further details of the channel bottom soundings can be found on the Inspection Plan in

Appendix C.

3.0 CONCLUSIONS AND RECOMMENDATIONS

3.1 Evaluation and Assessments

Overall, areas of moderate to severe scaling have occurred on the exterior and edges of

the pile caps. The piles exhibit minor areas of section loss with additional areas of



corrosion. Based on comparison with the previous underwater report, there has

been little or no change in the channel bottom.

3.2 Recommended NBI Condition Ratings

Substructure

Code

(Item 60)

Channel and

Channel

Protection Code

Underwater

Inspection Code

(Item 92B)

5 8 48

3.3 Recommendations

No significant structural concerns were present, however with time, the areas of scaling

may pose a structural problem and should be repaired. Areas of corrosion on the piles

should be cleaned and jacketed to prevent further deterioration. A lateral load rating

analysis should be performed to ensure the length of the pile exposure is acceptable

and the load rating of the bridge is accurate. Also, remove timber debris on channel

bottom around Pier 2 and Pier 3. Underwater inspections of the bridge should continue

at intervals not to exceed 48 months unless a significant high water/high flow event is

experienced, after which, an interim underwater inspection should be conducted if any

damage or other detrimental conditions are suspected.

Bridge No. 1-501-006 SR-141 Bridge over the Christina River/Amtrak

Delaware Department Of Transportation LOCATION MAP

Created by: CH May 2009

Checked by: TWB

12932 168th Avenue, Suite A Project 5793 Grand Haven, MI 49417 Appendix A

1-501-006 Christina River

Bridge No. 1501 050

Northeast Boulevard Over the Christina River

Collins Project No. 5793-70 Appendix B

Photograph 1. Overall View of the East Fascia of Bridge.

Photograph 2. Overall View of the West Fascia of Bridge.

Bridge No. 1501 050



Photograph 3. View of Pier 2, North Face.

Photograph 4. View of Pier 3, South Face.

Bridge No. 1501 050



Photograph 5. View of the North Embankment.

Photograph 6. View of the South Embankment.

Bridge No. 1501 050



Photograph 7. View of Typical Scaling On Vertical Faces of Piers 2 and 3.

Photograph 8. View of the South Side of Pier 2, Typical Pile Cap Scaling.

Bridge No. 1501 050



Photograph 9. View of the West Nose of Pier 2, Typical Map Cracking.

Photograph 10. View of the Upstream Nose of Pier 3.

Bridge No. 1501 050



Photograph 11. View of Scaling, North Face of Pier 2 Pile Cap.

Photograph 12. View of Scaling With Exposed Steel, North Face of Pier 2 Pile Cap.

Bridge No. 1501 050




Photograph 14. View of Heavy Scaling at the Southeast Nose of Pier 3.

Bridge No. 1501 050




Photograph 16. View of Heavy Scaling at the West Nose of Pier 3.

Bridge No. 1501 050



Photograph 17. View of Scaling at the Northwest Nose of Pier 3.

Photograph 18. View of Scaling on the North Face of Pier 3.

Bridge No. 1501 050



Photograph 19. View of Scaling on the South Face of Pier 3.

Photograph 20. View Looking Upstream.

Bridge No. 1501 050



Photograph 21. View Looking Downstream.

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