us 278 cursory bridge inspection

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Cursory Above Water and UnderwaterInvestigation Of

US 278 East Bound and West Bound

Over

MacKay Creek and Skull Creek

In

Hilton Head, South Carolina

Prepared by:

1180 Sam Rittenberg Blvd, Suite 105Charleston, South Carolina 29407(843) 763-1576 phone(843) 763-1582 faxwww.collinsengr.com Collins Project No. 6336-40

Bridges over MacKay Creek

Bridges over Skull Creek


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Over MacKay Creek and Skull Creek

Collins Project No. 6336-40Page 1

Cursory Above Water and Underwater Investigation of

US 278 West Bound and US 278 East Bound Bridges


Prepared by:Collins Engineers, Inc.1180 Sam Rittenberg Blvd, Suite 105Charleston, South Carolina 29407

SUMMARY OF SIGNIFICANT FINDINGS

Inspection Date: February 11 and 12, 2010

Significant Conditions Observed:

US 278 West Bound over MacKay Creeko Crack up to 3/4 in. wide and 10 ft long located on the bottom of the pile

cap at Bent 2.o Spall measuring 18 in. by 1 ft with 1.5 in. of penetration was located on the

bottom of the pile cap at Bent 2.o The southernmost pile at Bent 2 exhibited 1/8 in. wide cracks with rust

stains around all faces of the pile.

US 278 East Bound over MacKay Creeko Random cracks ranging in width from 1/8 in. up to 1/2 in. wide with rust

stains located on the piles and pile jackets.o Minor cracks and spalls in the superstructure beams.o A spall measuring 3 ft long by 1 ft wide with exposed reinforcing steel was

located on the bottom of Beam 6 at Span 29.

US 278 West Bound over Skull Creeko Approximately 5 ft of vertical undermining of the pier at the east side of the

navigation channel.o Footing and seal exposure of the upstream nose of the pier at the west

side of the navigation channel.

o Missing section of the timber fender system at the west side of thenavigation channel.

o Cracks up to 1/4 in. wide with rust stains located on the bottom of amajority of the pile cap footings for the approach piers.

o Light to moderate corrosion of the cross bracing between the steel plategirders.

o Spall measuring 2 ft long by 10 in. wide with three in. of penetrationlocated on the top of the concrete barrier rail at east end of the bridge.


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SUMMARY OF SIGNIFICANT FINDINGS (Cont.)

US 278 East Bound over Skull Creeko Footing and seal exposure of the pier at the east side of the navigation

channel.o A void between the footing and seal measuring 12 in. vertical with 18 in.

penetration and one exposed H-pile on the pier at the east side of thenavigation channel.

o Cracks up to 1/4 in. wide with rust stains located on the bottom of amajority of the pile cap footings for the approach piers.

o Light to moderate corrosion of the cross bracing between the steel plategirders.

SUMMARY OF BRIDGE RATINGS

Bridge Deck Superstructure Substructure

MacKay Creek WBL 7 6 6

MacKay Creek EBL 7 5 5

Skull Creek WBL 7 6 5

Skull Creek EBL 7 6 5


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1.0 INTRODUCTION

SCDOT Bridge Inspection Program

According to the Federal Highway Administration a bridge is defined as A structure

including supports erected over a depression or an obstruction, such as water, highway,

or railway, and having a track or passageway for carrying traffic or other moving loads,

and having an opening measured along the center of the roadway of more that 20 feet

between undercopings of abutments or spring lines of arches, or extreme ends of

openings for multiple boxes; it may also include multiple pipes where the clear distance

between openings is less than half of the smaller contiguous openings.

In accordance with Federal Highway Administration guidelines, the South Carolina

Department of Transportation inspects their bridges at intervals not to exceed 24

months for above water inspections and 60 months for underwater inspections. These

inspections are based on the Recording and Coding Guide for the Structure Inventory

and Appraisal of the Nations Bridges. This publication is governed by the National

Bridge Inspection Standards (NBIS).

The NBIS was created in the early 1970s as a result of the Silver Bridge collapse in

West Virginia. Before this time, there was very little public interest in the inspection and

maintenance of our nations bridges. After 46 people died as a result of this collapse,

the U.S. Congress required the Secretary of Transportation to establish a National

Bridge Inspection Standard and develop a program to train bridge inspectors. These

inspections are necessary for having an effective bridge maintenance program. The

SCDOT performs five main types of inspections.

- Initial Inspections Inspections performed to document the condition of a bridge

after construction has been completed and the inventoried.

- Routine Inspections Inspections used to document the physical and functional

elements of bridges.


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- In-depth Inspections Close up (arms length or hands on) inspections used to

document the condition of the structure. Underwater inspections are typically

considered in-depth inspections.- Scour The channel is inspected below the waterline to determine the level or

extent of scour or channel migration.

- Fracture Critical Inspection of critical tension members on a bridge structure.

Fracture critical members are considered a member in tension that if failure

occurs could result in partial or total failure of the structure.

- Special Inspections These inspections are performed after repair, rehabilitation,

replacement or after significant natural events like flooding, storms or seismic

events.

Typically all of these inspection levels are coordinated through the SCDOT Bridge

Maintenance Office. The responsibility of this office is to coordinate bridge maintenance

and rehabilitation activities, as well as, overseeing the SCDOT Bridge Management

System (BMS). The bridge management system is a means for managing state wide

bridge data throughout their design life. This includes collecting bridge inventory data,

performing inspections, maintenance and rehabilitation.

SCDOT Bridge Inspection Report Forms

The standard SCDOT Inspection Form used by the Office of Bridge Maintenance is

used as the primary means for inventorying and assigning condition and appraisal

ratings to bridges in South Carolina. This form lists several bridge characteristics and

their corresponding codes as listed in the Recording and Coding Guide. Some aspects

of the form will be presented in the following sections. For a complete view of theinformation contained in this form, please refer to Appendix C.

- General Bridge Data: This section lists the Bridge Identification Number, and

general location with respect to route or waterway crossed. It also lists the year


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it was built or reconditioned, the overall length, number of spans, and the type of

structure.

- Geometric Data: This section lists all pertinent bridge geometry such as:waterway navigation clearance, under clearances, vertical clearances, structure

width, horizontal clearances, number of lanes, and sidewalk dimensions.

- Condition Ratings: This section lists the inventory and operating rating, the last

paint application date (if applicable), and the condition ratings of the deck,

superstructure, and substructure.

- Critical Inspection Data: This section lists the last inspection date, the inspection

frequency, and gives an indication if special, fracture critical, or underwater

inspections have been or need to be performed.

- Appraisal Ratings: This section lists the overall appraisal of the structure, the

deck geometry, under clearance, bridge posting, and waterway adequacy. Many

of these ratings are not assigned by the actual inspector but are calculated using

FHWA Edit/Update computer program.

Bridge Element Grout Textual Dataforms are also used by the inspector during routine

bridge inspection. This form evaluates the condition of: bridge abutments, bents, piers,bearings, girders and beams, truss members, expansion joints, decks, curbs, bridge

railings or barriers, paint systems, waterway condition, fender system, alignment of the

roadway, traffic signs, and encroachments. Under these headings in Textual Data form,

the inspector can add general or specific comments about the items listed above and

their corresponding NBIS rating. An example of this form is presented in Appendix C.

NBI ratings typically cover the deck, superstructure, and substructure in the overall

bridge rating. The PONTIS system described in the following paragraph is an element

based inspection that inventories and rates every element on the bridge. This includes

but is not limited to the deck, beams, piles, bearings, railing, joints, etc. The different

elements rated are according to the material used. For instance, a bare concrete deck

and a concrete deck with asphalt overlay are considered different elements.


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The SCDOT PONTIS BMS Element Data Form is a form that lists the Commonly

Recognized (CoRe) Structural Elements for bridges. PONTIS is owned by the

American Association of State Highway and Transportation Officials. The system isused to store bridge inventory and inspection data using the NBIS guidelines and also

assigns condition states to each bridge element. With this system, each element

corresponds to an element number in the PONTIS System. The total quantity of each

element is then calculated. This quantity is then recorded as percentage of distribution

in each corresponding condition state. Condition states are listed from Condition 1 (little

or no deterioration) to Condition 5 (advanced deterioration). Each condition state is

described for each element and any feasible actions are also presented. For example:

If a bridge has 120 reinforced concrete piles this corresponds to Element 205 according

to the CoRe Elements, and 20 of these piles have deterioration, 17 percent of these

piles would be listed under Condition State 4 and the remaining 83 percent would be

listed under Condition State 1. For the Condition State 4 rating, there are three feasible

actions that can be performed on the 20 piles showing deterioration: do nothing,

rehabilitate the piles, or replace the piles. PONTIS BMS give a more quantitative

assessment of every structural element versus the general assessment given for the

deck, superstructure, and substructure given in the NBI. The SCDOT PONTIS BMS

Element Data Form is presented in Appendix C.

Bridge Inspector Certifications

The training and qualifications of an NBIS bridge inspector are presented in the Code of

Federal Regulations 650C. The following excerpt is from the FHWA Bridge Inspectors

Reference Manual:

A program manager must, at a minimum:

- Be a registered professional engineer, or have ten years bridge inspection

experience; and have successfully completed a Federal Highway Administration

(FHWA) approved comprehensive bridge inspection training course.


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A NBIS bridge inspection team leader can qualify in five ways.

- Have the qualifications for program manager as presented above.

-Have five years bridge inspection experience and have successfully completedan FHWA approved comprehensive bridge inspection training course.

- Be certified as a Level III or IV Bridge Safety Inspector under the National

Society of Professional Engineer's program for National Certification in

Engineering Technologies (NICET) and have successfully completed an FHWA

approved comprehensive bridge inspection training course, or:

- Have all of the following:

- A bachelor's degree in engineering from a college or university accredited by or

determined as substantially equivalent by the Accreditation Board for

Engineering and Technology;

- Successfully passed the National Council of Examiners for Engineering and

Surveying Fundamentals of Engineering examination;

- Two years of bridge inspection experience

- Successfully completed an FHWA approved comprehensive bridge inspection

training course.

-Have all of the following:

- An associate's degree in engineering or engineering technology from a college or

university accredited by or determined as substantially equivalent by the

Accreditation Board for Engineering and Technology;

- Four years of bridge inspection experience; and

- Successfully completed an FHWA approved comprehensive bridge inspection

training course.

-

The individual charged with the overall responsibility for load rating bridges mustbe a registered professional engineer.

- An underwater bridge inspection diver must complete an FHWA approved

comprehensive bridge inspection training course or other FHWA approved

underwater diver bridge inspection training course.


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All of the inspectors for this cursory bridge inspection meet or exceed the requirements

as presented above.

Long Term Expectation of Bridge Life and Maintenance

The current AASHTO LRFD code calls for bridges to be designed for a Design

Life of 75 years (Section 1.2). What the actual in-service life of a structure may be is

dependent on the owners desires and expectations coupled with the effects of things

like the bridges exposure to environmental elements, quality of materials, construction

type and practices used and the level of maintenance. The US 278 Bridges were built

in the following years; 1982 for the two structures over Skull Creek, 1983 for the

Westbound lane over MacKay Creek and 1956 for the one Eastbound lane over

MacKay Creek. This means that they were most likely designed using a Design Life of

50 years, which was common at that time. Therefore, the Eastbound lane over MacKay

Creek has already exceeded its intended Design Life and the others are nearing year

30 of their Design Life. This does not mean that they are no longer functional or safe as

the ability of a structure to survive and perform well beyond its Design Life has been

well documented and is mostly dependent on the environment it resides in and the

maintenance attention it has received.

Many modern structures are now being designed with a Design Life of 100 years,

such as the new Ravenel (Cooper River) Bridge in Charleston, SC. The new Oakland

Bay Bridge in San Francisco has been designed for a Design Life of 150 years. Even

though these structures are designed to last longer, whether they do or not will be

greatly dependent on the factors already mentioned.

Of the several factors that play a role in the reduction of a bridges service life.

Two of the harshest and one that is present at the US 278 bridges, are the coastal

environment and heavy traffic use. In this location, these structures are subjected to

high wave and wind forces as well as being constantly inundated in the corrosive salt


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water environment. This applies to the superstructure as well as the substructure

because of the chloride laden air, and our high humidity, transports that corrosive

element to the bridges girders and concrete deck.

The result of this long term exposure to a salt laden air and water environment is

corrosion. Corrosion affects the life of both steel structures and reinforced concrete

bridges. For steel structures, there are very visual signs of coating failure and

accumulation of rust on the structural steel members. With concrete structures, the

deterioration is usually not evident until it has reached advanced stages. This is

because corrosion attacks the reinforcing steel buried within the concrete and only

becomes visible once it has caused cracks and fractures (spalls) in the concrete surface

and rust staining is then seen.

The other factor mentioned was traffic volume. As the main bridges in and out of

Hilton Head, these structures see not only large volumes of traffic, but heavy usage by

truck traffic, which puts additional strain on the structure over time. Again, the

maintenance of the structure plays the biggest role in preventing deterioration due to

increase traffic volumes and loads. According to the Average Daily Traffic (ADT)

volume obtained from the SCDOT for the 2008 period, US 278 traffic volumes within the

area of investigation range from 44,300 to 57,800. A comparison of this ADT with other

locations indicates that this volume is the highest in Beaufort County.

For your reference, some other bridges that were constructed during the 1950s

and are located in similar coastal environments are listed below. These bridges are still

open to traffic although we are not aware of the current condition of the structures.

Little River Intracoastal Waterway Bridge (Horry County, South Carolina), Built

1935; rehabilitated 1980, Warren through truss swing bridge over Intracoastal

Waterway on S-26-20 (formerly US 17) in Little River


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Ben Sawyer Intracoastal Waterway Bridge (Charleston County, South Carolina),

Built 1945, rehabilitated 2010, Swing bridge over Intracoastal Waterway on SC

703 in Charleston

Intracoastal Waterway Bridge (New Hanover County, North Carolina), Built 1956,

Bascule bridge over Intracoastal Waterway on US 74/US 76 in Wrightsville

Beach

Intracoastal Waterway Bridge (Carteret County, North Carolina), Built 1935,

Swing bridge over Intracoastal Waterway on NC 101

Surf City Bridge (Pender County, North Carolina), Built 1955, Swing bridge over

Intracoastal Waterway on NC50/NC210 in Surf City

Intracoastal Waterway Bridge (Palm Beach County, Florida), Built 1938

Bascule bridge over Intracoastal Waterway on FL A1A in Palm Beach

Southern Boulevard Bridge (Palm Beach County, Florida), Built 1950, Bascule

bridge over Intracoastal Waterway on Southern Boulevard in West Palm Beach

Oakland Park Blvd. Bridge (Broward County, Florida), Built 1955, Bascule bridge

over Intracoastal Waterway on Oakland Park Blvd. in Fort Lauderdale

General Description of the Structures

Bridge 0720027840300 carries the west bound lanes of US 278 over MacKay

Creek in Hilton Head, South Carolina. The bridge consists of 54 prestressed concrete

girder spans and one steel girder span supported by prestressed square concrete pile

bents. The deck consists of stay-in-place forms and a reinforced concrete deck.

Bridge 0720027820300 carries the east bound lanes of US 278 over MacKay

Creek in Hilton Head, South Carolina. The bridge consists of 54 reinforced concrete

girder spans and one steel girder span supported by multiple reinforced concrete pile

bents. The structure originally consisted of pile bents with five octagonal concrete piles


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supporting the reinforced concrete girders. Several of the original piles had a reinforced

concrete circular jacket. When the bridge was widened, two prestressed concrete piles

were driven on each side of the bents and support two additional prestressed concretegirders on either side of the bridge. A retrofit cap connected the widened section to the

original cap. The deck consists of reinforced concrete with an asphalt overlay.

Bridge 0720027840400 carries the west bound lanes of US 278 over Skull Creek

in Hilton Head, South Carolina. The bridge consists of 21 approach spans and five

main channel spans. The main channel piers are comprised of a reinforced concrete

hammer head piers supported by a submerged footing/seal combination founded on

multiple steel H-piles. The approach spans are supported by a reinforced concrete

hammer head pier configuration founded on a waterline pile cap footing supported by

multiple prestressed concrete piles or prestressed concrete pile bents. The

substructure units support steel plate girders with transverse steel cross bracing and a

reinforced concrete deck.

Bridge 0720027820400 carries the east bound lanes of US 278 over Skull Creek

in Hilton Head, South Carolina. The bridge is of a similar configuration to the west

bound bridge. A 22 ft research vessel was used to gain access to the superstructure

and substructure elements. Due to heavy traffic the decks were visually inspected from

the inspection vehicle.

Methods of Investigation

An inspection team consisting of engineer-divers led by a South Carolina-

registered Professional Engineer-diver conducted the above water and underwater

investigation of the four bridges leading to Hilton Head Island on February 11 and 12,

2010. Access to the bridge site was obtained from C.C. Haig Boat Landing on Pinckney

Island.


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The investigation consisted of a cursory inspection of the accessible portions of

the substructure and superstructure. The cursory inspection was performed on a

representative sample of the bridge components to detect obvious and gross bridgeconditions. 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.

2.0 OBSERVED CONDITIONS AND ASSESMENT

The following criteria govern the assessment ratings of the structural components of the

inspected bridges: These criteria are established from the Recording and Coding Guide

for the Structure Inventory and Appraisal of the Nations Bridges. Report No. FHWA-

PD-96-001. These codes also follow the SCDOT Bridge Inspection Form Ratings.

- Code 9 - Excellent Condition

- Code 8 - Very Good Condition no problems noted.

- Code 7 - Good Condition some minor problems but functioning as intended.

- Code 6 - Satisfactory Condition structural elements show some minor deterioration

but are still functioning as intended.

- Code 5 - Fair Condition all primary structural elements are sound but may have

minor section loss, cracking, or spalling.

- Code 4 - Poor Condition advanced section loss, deterioration, or spalling.

- Code 3 - Serious Condition loss of section, deterioration, or spalling has seriously

affected primary structural components. Local failures are possible.- Code 2 - Critical Condition advanced deterioration of primary structural elements.

Fatigue cracks in steel or shear cracks in concrete may be present or scour may have

removed substructure support. Unless closely monitored it may be necessary to close

the bridge until corrective action is taken.


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- Code 1 - Imminent Failure Condition major deterioration or section loss is present

in critical structural components or obvious vertical or horizontal movement affecting

structural stability. Bridge is closed to traffic but corrective action may be put back inlight service.

- Code 0 - out of service beyond corrective action.

The following narrative will briefly describe the existing conditions encountered

during the cursory inspections of US 278 WBL and EBL over MacKay and Skull Creek.

The inspections were conducted over the course of two days. The weather wasovercast with light rain and an air temperature of 40 F both days. The water under the

bridge flowed between 0 and 2 ft/s during the inspection. Underwater visibility was

approximately 2 ft.

Item 61 Channel and Channel Protection

The embankments at all four bridges were found to be in very good condition

(Code 8). The banks along the waterways in the vicinity of the bridges were observedto be in stable condition. Embankment protection in the form of riprap was observed on

the east and west banks of MacKay Creek and aquatic vegetation and oyster shells on

the east and west banks of Skull Creek. There was no sign of active erosion. The

channel bottom consisted of silty sand and oyster shells. There were no signs of heavy

accumulation of debris or drift.

US 278 West Bound over MacKay Creek

Item 58 - Deck

The concrete deck was found to be in good condition (Code 7). There were no

noticeable spalls or significant cracks in the deck or the concrete barrier. In isolated

areas, the expansion joint material had come loose along the shoulder of the roadway.


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Item 59 Superstructure

The superstructure was found to be in satisfactory condition (Code 6). Minor cracking

was noted in isolated locations on the prestressed concrete girders. Several areas of

concrete spall repair were noted in isolated locations. The steel girders supporting the

main span showed signs of light to moderate corrosion with no signs of significant

section loss.

Item 60 - Substructure

Overall, the substructure was also found to be in satisfactory condition (Code 6). Minor

isolated cracks were noted on the piles above the high-water mark. Areas of minor

isolated spall repair were noted in random locations. The most significant defects were

located on Bent 2. On the east face of the reinforced concrete pile cap a crack

measured up to 3/4 in. wide with rust stains. The crack measured approximately 10 ft

long. The southernmost pile at Bent 2 had cracks up to 1/8 in. wide with rust stains

around all faces of the pile and extended from the bottom of the pile cap down

approximately 3 ft. A spall was located on the bottom of the pile cap at Bent 2. The

spall measured approximately 1 ft by 18 in. with 1 in. of penetration.

The piles at Bents 40 through 43 were inspected below water and were found to be in

good condition. The piles exhibited a heavy layer of marine growth from the high-water

mark to the channel bottom. No significant conditions were noted on the below water

portions of these piles. Please refer to Photographs 1 to 12 for typical views of the

conditions encountered on this bridge.

US 278 East Bound over MacKay Creek

Item 58 - Deck

The deck was found to be in satisfactory condition (Code 6). The asphalt overlay

showed minor signs of deterioration along the joints. Minor delamination of the asphalt


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overlay up to 18 in. diameter was observed in isolated locations. There were no

significant defects located on the concrete barrier.


Overall, the superstructure was found to be in fair condition (Code 5). This condition

was based on what the inspectors could visually assess from the boat. The bridge

bearings were not accessible. The steel girders supporting the main span showed

signs of light to moderate corrosion.

Random minor cracks were noted on the bottom and sides of the reinforced concrete

beams. Evidence of previous spall repairs were noted in several locations throughout

the superstructure and appeared to be in good condition. One isolated spall measuring

3 ft horizontal by 1 ft vertical was located on the bottom of Beam 6 at Bent 29. The spall

exposed one reinforcing which exhibited some corrosion but any loss of section could

not be verified. Other random superficial spalls due to lack of sufficient cover over the

reinforcing bars were noted on the reinforced concrete diaphragms.


Several bents of different pile arrangements were inspected below water and were

found to be in fair condition (Code 5). The piles exhibited a heavy layer of marine

growth from the high-water mark to the channel bottom. Minor cracking with rust stains

was observed within the tidal zone on several of the piles. Many of the octagonal piles

have been retrofitted with concrete pile jackets. These jackets were typically located

within the tidal zone. Several jackets exhibited minor cracking between 1/8 in. and 1/2

in. wide with rust stains; however, no significant deterioration such as: large spalls or

section loss was noted on the inspected piles. Please refer to Photographs 13 to 26 for

typical views of the conditions encountered on this bridge.


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US 278 West Bound over Skull Creek

Item 58 - Deck

Overall the concrete deck was found to be in good condition (Code 7). There were no

noticeable spalls or significant cracks in the deck. In areas, the expansion joint material

had come loose in isolated locations along the shoulder of the roadway. A spall

measuring approximately 2 ft long by 10 in. wide with no exposed reinforcing steel was

found on the top of the concrete barrier rail at the east end of the bridge.


The superstructure was visually inspected from the ground and the inspection boat and

was found to be in satisfactory condition (Code 6). The steel plate girders exhibited

minor loss of protective coating and showed no appreciable corrosion. Most of the

transverse steel cross bracing had more moderate loss of protective coating with some

minor corrosion. The corrosion was more pronounced where the steel cross bracing

was connected to the steel plate girders. Due to the height of the structure any loss of

section could not be verified.


The inspections of the selected substructure elements revealed the most significant

deterioration and were rated as fair condition (Code 5). The inspected substructure

units exhibited a heavy layer of marine growth from the high-water mark to the channel

bottom. The east channel pier exhibited complete footing and seal exposure with

undermining of the seal at the upstream nose of the pier. The area of underminingmeasured up to 5 ft vertical. The footing of the pier located at the west side of the

navigation channel was completely exposed and had approximately 4 ft of seal

exposure. No undermining of the seal was detected at this pier. Cracks up to 1/4 in.

wide with rust stains were located on the bottom of a majority of the pile cap footings for


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the approach piers. These cracks were typically located 6 to 8 in. above the bottom of

the pile cap footings and were likely caused by corrosion of the internal reinforcing steel

due to chloride interaction from the saltwater environment.

The timber fender system on the west side of the navigation channel beneath the west

bound lane was partially missing.

US 278 East Bound over Skull Creek

Item 58 - Deck

Overall the concrete deck was found to be in good condition (Code 7). There were no

noticeable spalls or significant cracks in the deck. In areas, the expansion joint material

had come loose in isolated locations along the shoulder of the roadway.


The superstructure was visually inspected from the ground and the inspection boat and

was found to be in satisfactory condition (Code 6). The steel plate girders exhibited

minor loss of protective coating and showed no appreciable corrosion. Most of the

transverse steel cross bracing had more moderate loss of protective coating with some

minor corrosion. The corrosion was more pronounced where the steel cross bracing

was connected to the steel plate girders. Due to the height of the structure any loss of

section could not be verified.


The inspections of the selected substructure elements revealed the most deterioration

and were found to be in fair condition (Code 5). The inspected substructure units

exhibited a heavy layer of marine growth from the high-water mark to the channel

bottom. The east channel pier was found to have up to 5 ft of vertical seal exposure

along the upstream nose. In addition, a void was detected at the footing and seal


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interface. The void measured approximately 12 in. vertical with up to 18 in. of

penetration. A steel H-pile was located in this void and exhibited moderate corrosion

with no appreciable loss of section. Cracks up to 1/4 in. wide with rust stains werelocated on the bottom of a majority of the pile cap footings for the approach piers.

These cracks were typically located 6 to 8 in. above the bottom of the pile cap footings

and were likely caused by corrosion of the internal reinforcing steel due to chloride

interaction from the saltwater environment.

3.0 RECOMMENDATIONS

US 278 West Bound over MacKay Creek

Item 58 - Deck

There are no repair recommendations at this time; however, the expansion joint material

should be monitored for future deterioration and may require replacement in the near

future.


It is recommended that the minor cracking of the concrete girders and the condition of

any repairs be closely monitored during future inspections. The steel girders supporting

the main span showed signs of light to moderate corrosion and should be cleaned and

coated with a protective coating suitable for marine environments.


The minor cracks located within the tidal zone should be monitored for continued

deterioration during future inspections. The 3/4 in. wide crack with rust stains located

on Bent 2 should be repaired by routing the crack and filling it with a flexible mastic

sealant. In addition, the southernmost pile at Bent 2 showed more extensive cracking

and should be repaired using a similar method.


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The spall at the bottom of the pile cap at Bent 2 should also be repaired. This would

include removing all unsound concrete and reforming the area to its original dimensions

using a non-shrink grout suitable for marine environments.

US 278 East Bound over MacKay Creek

Item 58 Deck

There are no repair recommendations at this time; however, the expansion joint material

should be monitored for future deterioration and may require replacement in the near

future.


It is recommended that the minor cracking of the concrete girders and the condition of

any repairs be closely monitored during future inspections. The steel girders supporting

the main span showed signs of light to moderate corrosion and should be cleaned and

coated with a protective coating suitable for marine environments.

The spall located on Beam 6 of Bent 29 should be repaired. This would include

removing all unsound concrete, cleaning and coating any reinforcing steel and

reforming the area to its original dimensions using a non-shrink grout suitable for marine

environments.


There are no pile repair recommendations at this time; however, the piles and pile

jackets should be monitored for increased deterioration during subsequent inspections.


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US 278 West Bound over Skull Creek

Item 58 Deck

The expansion joint material should be monitored for future deterioration. The 2 ft long

by 10 in. wide spall at the top of the barrier parapet is primarily cosmetic. It is also

protected from impact from the median crash barrier.


The loss of protective coating is relatively minor and should be monitored for further

deterioration.


The footing/seal exposure and undermining at the channel piers should be monitored

closely during future underwater inspections. In addition, it is recommended to perform

or review a scour analysis of these piers to determine the anticipated depth of scour and

design countermeasures as necessary.

The cracks located at the bottom of the pile cap footings that are larger that 1/4 in. wide

should be routed and sealed with a flexible mastic sealant.

The portion of the missing fender system on the west side of the navigation channel

should be replaced.

US 278 East Bound over Skull Creek

Item 58 - Deck

The expansion joint material should be monitored for future deterioration.


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The loss of protective coating is relatively minor and should be monitored for further

deterioration.


The footing/seal exposure, as well as voids in the seal, at the channel piers should be

monitored closely during future underwater inspections. In addition, it is recommended

to perform or review a scour analysis of these piers to determine the anticipated depth

of scour and design countermeasures as necessary.

The cracks located at the bottom of the pile cap footings that are larger that 1/4 in. wide

should be routed and sealed with a flexible mastic sealant.

Overall, the four bridges are in satisfactory to fair condition. The type and amount of

deterioration observed during the cursory inspection are indicative of structures of this

age. Because the EBL Bridge over MacKay creek is older, (built in 1956), we saw more

deterioration in the superstructure and substructure. This deterioration has potentially

reduced some of the structures capacity but does not pose an immediate risk of failure.

The structure should however be scheduled for significant rehabilitation and/or

replacement in the near future.

Respectfully submitted,

COLLINS ENGINEERS, INC.

James K. OConnor, P.E.Project Manager

Originated by:William Barna, P.E.


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Appendix A

References


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References:

Bridge Inspectors Reference Manual, Publication No. FHWA NHI-03-001, 2006.

Operation and Maintenance of Waterfront Facilities, Publication No. UFC-4-150-07, 2001.

Recording and Coding Guide for the Structure Inventory and Appraisal of theNations Bridges. Publication No. FHWA-PD-96-001, 1995.

SCDOT Bridge Design Manual, 2006.

Underwater Inspection of Bridges, Publication No. FHWA-DP-80-1, 1989.

AASHTO Guide for Commonly Recognized (CoRe) Structural Elements, 1997.


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Appendix B

Photographs


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US 278 WBL and EBL

Over MacKay and Skull Creek

Collins Project No.6336-40Appendix B

Photograph 1. View of Downstream Fascia, US 278 WBL over MacKay Creek.

Photograph 2. View of Upstream Fascia, US 278 WBL over MacKay Creek.


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Photograph 3. View of the Main Steel Girder Span, US 278 WBL over MacKay Creek.

Photograph 4. Typical Underdeck and Prestressed Concrete Girder Condition, US 278WBL over MacKay Creek.


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Photograph 5. View of Crack Located on the East Face of Bent 2, US 278 WBL overMacKay Creek.

Photograph 6. Close Up View of the Crack Located on the East Face of Bent 2, US 278WBL over MacKay Creek.


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Photograph 7. View of Spall Located on the Bottom of Bent 2, US 278 WBL over MacKayCreek.

Photograph 8. View of Cracks with Rust Stains Located on the Southernmost Pileof Bent 2, US 278 WBL over MacKay Creek.


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Photograph 9. View of West Embankment, US 278 WBL over MacKay Creek.

Photograph 10. Typical Above Water Pile and Prestressed Concrete Girder Condition, US278 WBL over MacKay Creek.


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Photograph 11. Typical Prestressed Concrete Girder and Pile Cap Condition,US 278 WBL over MacKay Creek.

Photograph 12. Typical Below Water Pile Condition Showing Heavy Marine Growth, US278 WBL over Skull Creek.


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Photograph 13. View of the Downstream Fascia, US 278 EBL over MacKay Creek.

Photograph 14. Typical View of Superficial Spalls due to Lack of Sufficient ConcreteCover over the Reinforcing Steel in the Diaphragm, US 278 EBL over MacKay Creek.


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Photograph 15. Typical Spall Repair Located on Bottom of Reinforced Concrete Beam, US278 EBL over MacKay Creek.

Photograph 16. Typical Bent with Longitudinally Battered Piles and Concrete PileJacket, US 278 EBL over MacKay Creek.


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Photograph 17. Typical Bent with Transversely Battered Piles and Concrete Pile Jacket,US 278 EBL over MacKay Creek.

Photograph 18. View of the Upstream Fascia, US 278 EBL over MacKay Creek.


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US 278 WBL and EBL



Photograph 19. Typical Above Water Reinforced Concrete Pile Condition, US 278 EBLover MacKay Creek.

Photograph 20. View of a Typical Retrofit Pile Cap, US 278 EBL over McKay Creek.

Prestressed

Concrete

GirderBeam

Saddle

Reinforced

Concrete

Beam


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US 278 WBL and EBL



Photograph 21. Typical Concrete Encasement Condition, US 278 EBL over MacKay Creek.

Photograph 22. Typical Underdeck and Reinforced Concrete Girder Condition, US 278EBL over MacKay Creek.


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Photograph 23. Typical Main Span Steel Girder Condition, US 278 EBL over MacKayCreek.

Photograph 24. Typical Cracks with Rust Stains on Reinforced Concrete Pile, US 278 EBLover MacKay Creek.


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US 278 WBL and EBL



Photograph 25. 3 ft by 1 ft Spall on the Bottom of the Beam 6, Span 29, US 278 EBL overMacKay Creek.

Photograph 26. 3 ft by 1 ft Spall on the Bottom of the Beam 6, Span 29, US 278 EBL overMacKay Creek.


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Photograph 27. View of the Upstream Fascia, US 278 WBL over Skull Creek.

Photograph 28. View of Typical Exterior Girder Condition, US 278 WBL over Skull Creek.


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Photograph 29. View of Typical Interior Girder and Steel Cross Bracing Condition, US 278WBL and EBL over Skull Creek.

Photograph 30. View of Typical Main Channel Pier Configuration, US 278 WBL over SkullCreek.


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Photograph 31. View of 2 ft long by 10 in Wide Spall Located on the East End of theConcrete Barrier, US 278 WBL over Skull Creek.

Photograph 32. Typical Deck Joint Condition, US 278 WBL over Skull Creek.


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Photograph 33. Typical Condition of the Intermediate Piers with Cracks at the Bottom, US278 WBL over Skull Creek.

Photograph 34. View of the Downstream Fascia, US 278 EBL over Skull Creek.


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Photograph 35. Typical Crack With Rust Stains Located on the Bottom of the Pile CapFooting for the Intermediate Piers, US 278 WBL over Skull Creek.

Photograph 36. Typical Interior Girder and Steel Cross Bracing Condition, US 278 EBLover Skull Creek.


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Photograph 37. Typical Deck Condition, US 278 EBL over Skull Creek.

Photograph 38. Typical Deck Joint Condition, US 278 EBL over Skull Creek.


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Photograph 39. Typical View of Intermediate Bents, US 278 EBL over Skull Creek.

Photograph 40. Typical Shoreline Condition, US 278 WBL over Skull Creek.


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Appendix C

SCDOT Reference Forms


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