Attachment 2_Naha_Inspection Report.pdf

United States Department of Agriculture

Remote Dock and Marine Facility Inspections Southeast Alaska/Tongass National Forest

MATOC Agreement No. 1205G219D005 Task Order No. 12010920F0013

Inspection of Naha Remote Dock Revillagigedo Island|Ketchikan‐Misty Ranger District

Inspection October 5, 2020

United States Department of Agriculture

Remote Dock and Marine Facility Inspections Southeast Alaska/Tongass National Forest

Contract No. 12010920F0013

Inspection of Naha Remote Dock Revillagigedo Island | Ketchikan-Misty Ranger District

Inspected: October 5, 2020

Report Date: September 29, 2021

Joshua Steiner, PE Inspection Leader CONSOR Engineers, LLC

Heath Pope, PE Vice President CONSOR Engineers, LLC

Naha Remote Dock Inspected October 5, 2020

TABLE OF CONTENTS

1 Scope of Work and Inspection Procedure

2 Definitions, Rating Criteria, and Terminology

3 Facility Description

4 Inspection Findings

4.1 General Inspection Findings

4.2 Cathodic Protection System

4.3 Abutment

4.4 Pin and Hanger System

4.5 Gangway

4.6 Guide Piles

4.7 Pile Guides

4.8 Docks

4.9 Safety Ladder

5 Repair Recommendations

Appendix A Damage Rating Criteria ..................................................................................................... A-1

Appendix B Facility Sketches ................................................................................................................. B-1

Appendix C Photos ................................................................................................................................ C-1

1 SCOPE OF WORK AND INSPECTION PROCEDURE

In October 2020, CONSOR Engineers, LLC performed inspections of 16 Forest Service dock facilities in

Southeast Alaska. These inspections were performed with the assistance of Mott MacDonald and R&M

Engineering for SCJ Alliance, under contract to the United States Department of Agriculture (USDA).

The purpose of these inspections was to document and assess the dock facility's existing condition, develop rehabilitation/repair recommendations, and provide the documented field information for the future rehabilitation/repair engineering design and contractor bidding phases. The services performed included a Repair Design Inspection of the accessible underwater and above water structural elements composing the facilities and preparation of inspection reports summarizing the findings and repair recommendations. All inspections were performed in accordance with ASCE MOP 130: Waterfront

Facilities Inspection and Assessment.

The dock facilities were inspected by a crew of five inspectors, led by a Professional Engineer familiar with inspection of waterfront facilities. The docks were accessed by boat, and the above water inspection was performed using various hand tools, measuring devices, and cameras. The underwater inspection was performed using tethered SCUBA with hardwire communications equipment, using various hand tools, an ultrasonic thickness measuring gauge, bathycorrometer, and cameras.

2 DEFINITIONS, RATING CRITERIA, AND TERMINOLOGY

The conditions of the dock facility and structural systems are rated in accordance with MOP 130 according to the Condition Assessment Rating below. Additionally, the inspected structural elements are assigned damage ratings from Minor to Severe, shown in Appendix A.

CONDITION ASSESSMENT RATINGS

6 – Good No visible damage or only minor damage noted. Structural elements may show very minor deterioration, but no overstressing observed. No repairs are required.

5 – Satisfactory Limited minor to moderate defects or deterioration observed but no overstressing observed. No repairs are required.

4 – Fair All primary structural elements are sound but minor to moderate defects or deterioration observed. Localized areas of moderate to advanced deterioration may be present but do not significantly reduce the load-bearing capacity of the structure.

Repairs are recommended, but the priority of the recommended repairs is low.

3 – Poor Advanced deterioration or overstressing observed on widespread portions of the structure but does not significantly reduce the load-bearing capacity of the structure.

Repairs may need to be carried out with moderate urgency.

2 – Serious Advanced deterioration, overstressing, or breakage may have significantly affected the load-bearing capacity of primary structural components. Local failures are possible and loading restrictions may be necessary. Repairs may need to be carried out on a high-priority basis with urgency.

1 – Critical Very advanced deterioration, overstressing, or breakage has resulted in localized failure(s) of primary structural components. More widespread failures are possible or likely to occur, and load restrictions should be implemented as necessary. Repairs may need to be carried out on a very high-priority basis with strong urgency.

3 FACILITY DESCRIPTION

The facility at Naha includes a landside abutment supporting the gangway, gangway, a floating main dock, and a floating finger dock.

The floating main dock is a timber frame with uncoated foam floatation secured by two steel pipe guide piles. The perimeter of the dock has a timber curb on timber chocks, with no mooring hardware. The fender system consists of rubber tires nailed to the offshore face of the dock.

The floating finger dock is a timber frame with uncoated foam floatation secured by two steel pipe guide piles. The perimeter of the dock has a timber curb on timber chocks. The dock has no mooring hardware and no fender system.

The general layout of the facility is shown below.

Figure 1: General Layout

Access to the dock is provided by an aluminum gangway that is 65 ft long and 69 in. wide with a 42 in.

high handrail. The walking surface is constructed of metal grating with 30 in. long 3/4 in. square stock treads on the left half and has transition plates at the top and bottom. The gangway is connected to the landside abutment by pin and hanger assemblies and supported by the dock with a skid-style landing consisting of steel L shapes topped with UHMW material. The abutment is a timber abutment constructed of 12 in. x 12 in. and 3 in. x 12 in. timber members.

The water depths at the site vary from 6.6 ft to 39.2 ft relative to Mean Lower Low Water and are referenced to Tide Station 9450460 Ketchikan, AK.

This facility is typically used by recreational boaters for pedestrian access to the shore. There were two motorboats up to 30 ft long present at the time of inspection, which is assumed typical for this facility, although larger boats were observed at some of the other inspected facilities. There were no Forest

Service barges moored at this facility at the time of inspection.

Drawings and photos are presented in Appendix B: Facility Sketches and Appendix C: Photos, respectively.

4 INSPECTION FINDINGS

4.1 GENERAL INSPECTION FINDINGS

Overall, the facility is in fair condition due to moderate corrosion of the steel guide piles and framing system hardware. Detailed inspection findings for the individual structural components are presented below.

4.2 CATHODIC PROTECTION SYSTEM

There was no cathodic protection system observed at the site. Pile thickness and cathodic potential measurements are presented in Section 4.6 Guide Piles.

4.3 ABUTMENT

The timber abutment is in satisfactory condition with no deficiencies observed at the time of inspection.

4.4 PIN AND HANGER SYSTEM

The pin and hanger system is in satisfactory condition with no deficiencies observed at the time of inspection. There is no redundant safety system.

4.5 GANGWAY

The gangway is in satisfactory condition with minor deformation of the non-structural intermediate rails at several locations, and three locations where the deck grating has been deformed up to 1/2 in. in depth.

There is more than 4 in. of clear space between the intermediate rails.

4.6 GUIDE PILES

The guide piles are in fair condition, due to moderate section loss from corrosion from midheight to the mudline. Piles 1, 3, and 4 typically had flaking surface rust on the bottom 10 ft of the piles. Pile 2 had minor spot rust for the full height with no measurable section loss. Steel pile wall thickness measurements are provided in the table below (10% of piles were required to be measured).

davidlicon Highlight

Table 1: Pile Section Loss

Pile ø

(in.)

Material

Steel Thickness (in.) Section Loss (in.2)

Original Waterline Mid-Height Mudline Original

Area Remaining

Area % Section

Loss

1 16.2 Steel 0.380 0.378 0.355 0.366 18.886 17.616 6.7%

2 16.2 Steel 0.500 - - - 24.662 - -

3 12.9 Steel 0.500 - - - 19.478 - -

4 12.9 Steel 0.506 0.502 0.366 0.370 19.702 14.090 28.5%

The cathodic potential readings were normal for bare carbon steel in seawater without cathodic protection. Cathodic potential readings are presented in the table below (10% of piles were required to be measured).

Table 2: Cathodic Potential Readings

Pile ø (in.) Material Cathodic Potential Readings (mV)

Waterline Mid-height Mudline Average

1 16.2 Steel -633 -645 -644 -641

2 16.2 Steel - - - -

3 12.9 Steel - - - -

4 12.9 Steel -675 -680 -680 -678

4.7 PILE GUIDES

The pile guides are in satisfactory condition with no observed deficiencies at the time of inspection. There is no substantial wear on the steel guides or UHMW guide material.

4.8 DOCKS

The floating docks are in fair condition. There are several elements with major deterioration that do not affect the overall load carrying capacity of the floating dock.

The transition gangplank between the main dock and finger dock consists of three timbers connected to two chocks. The gangplank was originally connected to the main dock; however, the connection has failed and the gangplank is unsecured. Additionally, the gangplank is extremely slippery and due to its construction (above-deck placement without transition plates or non-slip surface) presents a tripping hazard.

4.8.1 Main Dock

FLOATS

The float material is uncoated foam. The foam is located in random locations and covers approximately

50% of the float footprint, resulting in a non-level deck surface. The freeboard of the float varies from

10.5 in. to 6 in. and is typically lower at the gangway landing.

FRAMING

The framing system is timber and exhibited minor deterioration. The hardware for the framing system generally exhibits corrosion with moderate section loss up to 20%. The configuration of the framing system is shown in the drawings in Appendix B.

DECKING

The decking consists of 11.5 in. x 1.75 in. timbers and has deterioration due to vegetation and algae concentrated around the corners and edges of the float. The deck is typically very slick and presents a slipping hazard.

CURB

The curb consists of 5.5 in. x 5.5 in. timbers supported on chocks of the same dimensions spaced at 6 ft on center. The curbs have major deterioration, due to heavy weathering, corrosion of the hardware, and one localized broken segment.

MOORING HARDWARE

There is no mooring hardware at this dock.

4.8.2 Finger Dock

FLOATS

The float material is uncoated Styrofoam. The foam is located along the longitudinal wales of the float in random locations, resulting in a non-level deck surface. The freeboard of the float varies from 10.5 in. to

2.5 in.

FRAMING

The framing system is timber and exhibited minor deterioration. The hardware for the framing system is typically corroded with moderate section loss up to 20%. The construction of the framing system is shown in the drawings in Appendix B.

DECKING

The decking consists of 12 in. x 1.75 in. timbers and has deterioration due to vegetation and algae concentrated around the corners and edges of the float. The deck is typically very slick and presents a slipping hazard.

CURB

The curb consists of 3.25 in. x 3.25 in. timbers supported on chocks of the same dimensions spaced at 6 ft on center. The curbs have major deterioration due to heavy weathering, corrosion of the hardware, and three failed connections.

MOORING HARDWARE

There is no mooring hardware at this dock.

4.9 SAFETY LADDER

There is no safety ladder present at the site.

5 REPAIR RECOMMENDATIONS

The following table summarizes the repair recommendations for this facility.

Table 3: Priority Repair Recommendations

Structure Element Location Quantity Defect Repair Priority Comments

Gangway Pin and Hanger

Above Water 2 EA No redundant gangway support system Install redundant safety system 1-High Safety – Provide a redundant anchorage point for the gangway

Main Dock Steel Pipe Guide Piles

Below Water/ Splashzone

1 Pile Moderate corrosion with section loss up to 29%

Replace Pile 1 with new pile 1-High Structural – Restore original capacity

Main/Finger Dock

Framing Below Water/ Splashzone

220 Each Corroded lag bolts Install additional timber lag bolts for framing system on main dock and finger dock.

1-High Structural – Reduce deterioration rate

Main/Finger Dock

Dock Transition Plate

Above Water 1 EA Deteriorated/detached timber transition plate between docks

Replace transition plate with steel transition plate system.

1-High Safety - Mitigate fall hazard

Main/Finger Dock

Floatation Modules

Below Water/ Splashzone

2 LS Missing/deteriorated foam floats resulting in uneven freeboard

Remove uncoated Styrofoam and replace with coated floatation to provide 10 in. freeboard

1-High Safety/Structural – Provide a level walking surface and restore original capacity

Main/Finger Dock

Safety Ladder Above Water 1 EA No safety ladder present Install safety ladder 1-High Safety - Provide safe emergency egress from water

Main/Finger Dock

Curb Above Water 250 LF Deteriorated curbs with heavy weathering, hardware corrosion, one broken segment, and three failed connections

Remove timber curbs and replace with 6x6 composite curb.

2-Med Structural – Reduce deterioration rate

Main/Finger Dock

Pile Corrosion Protection

Above/Below Water

4 Piles No corrosion protection system Provide sacrificial anode cathodic protection system

2-Med Structural – Reduce corrosion rate. Estimated min. mudline depth 17.2 ft

Main/Finger Dock

Mooring Hardware

Above Water 15 EA No mooring hardware Install 10 in. cleats at 10 ft c/c along berthing faces.

2-Med Convenience/Safety - Provide safe mooring and berthing

Main/Finger Dock

Decking Above Water 1700 SF Slick decking with deterioration due to vegetation/algae growth

Remove timber decking and replace with non-slip composite decking.

2-Med Structural/Safety– Reduce deterioration rate and mitigate slip hazard

Gangway Handrails Above Water 1000 LF Rails do not meet IBC/ADA Standards Install intermediate rails to provide a maximum clear spacing of 4 in.

4-Option Safety – Mitigate fall hazard

A-1

Appendix A Damage Rating Criteria

A-2

Source: ASCE MoP 130 Waterfront Facilities Inspection and Assessment.

A-3

A-4

A-5

A-6

A-7

Source: POLATRAK CP Gun Operation Manual

B-1

Appendix B Facility Sketches

Dock: Naha Island: Revillagigedo Ranger District: Ketchikan-Misty Inspection Date: 5 October 2020

UNITED STATES DEPARTMENT OF AGRICULTURE

REMOTE DOCK AND MARINE FACILITY INSPECTIONS

Southeast Alaska/Tongass National Forest Contract No. 12010920F0013

SHORELINE (VARIES)

MAIN DOCK

FINGER DOCK

12"x1.75" DECK

BOARDS (TYP)

11.5"x1.75" DECK

BOARDS (TYP)

36' 21'-4.00"

40'-0.75"

3.25"x3.25" TIMBER CURB

5.5"x5.5" TIMBER CURB

16" Ø x 0.5" W.T. STL PIPE PILE

16" Ø x 0.5" W.T. STL PIPE PILE

12.75" Ø x 0.5" W.T. STL PIPE PILE

12.75" Ø x 0.5" W.T. STL PIPE PILE

DWG 1 General Layout

PILE 1

PILE 2

PILE 3

PILE 4

GANGPLANK

48'-4.80"

30'-6.00"

16'

8'-6.00"

X" = FREEBOARD (INCHES)

X' = DEPTH (FEET)

8" 17.6'

10.5" 17.2'

6" 6.6'

9.5" 10.3'10.5"

20.4'

6.5" 22.9'

3" 27.2'

4" 27.2'

10.5" 31.7'

2.5" 27.2'

10.5" 39.2'

10" 37.3'

Water depth is presented relative to MLLW based on Tide Station 9450460Ketchikan, AK

TIMBER

GANGWAY

ABUTMENT

ALUMINUM

GANGWAY

0 5' 10'

SCALE: 3/32"=1'-0"

Ranger District: Ketchikan-Misty Inspection Date: 5 October 2020

UNITED STATES DEPARTMENT OF AGRICULTURE

REMOTE DOCK AND MARINE FACILITY INSPECTIONS

Southeast Alaska/Tongass National Forest Contract No. 12010920F0013

11.5"x1.75" DECK

BOARDS (TYP)

DWG 2 Cross Sections

MAIN DOCK CROSS SECTION

3' (TYP)

3"x6" TIMBER

STRINGER (TYP)

4"x8" TIMBER (TYP)1.75"x19" TIMBER WALE (TYP)

OFFSHORE INSHORE

6' LONG STYROFOAM

FLOAT (VARIES)

5.5"x5.5" TIMBER CURB (TYP)

3"x6" TIMBER

STRINGER @ 36"

O.C. (TYP)

FINGER DOCK CROSS SECTION

3.25"x3.25" TIMBER CURB (TYP)

1.75"x16" TIMBER WALE (TYP)

12"x1.75" DECK BOARDS (TYP)2' 4'

STYROFOAM FLOAT (VARIES)

STEEL PLATE

7.5"x2" TIMBER STRINGER (TYP)

7.5"x2" TIMBER CROSS

BEAM @ 3' O.C. (TYP)

ABUTMENT ELEVATION

12"x12" TIMBER

3"x12" TIMBER

8.50"

2.50"

6.25"

0.75" THICK STEEL HANGER

8 " BOLT

SOIL

0 2' 4'

SCALE: 1/4"=1'-0"

0 2' 4'

SCALE: 1/4"=1'-0"

0 1/2' 1'

SCALE: 1"=1'-0" OFFSHORE INSHORE

OFFSHORE INSHORE

A

B

GANGWAY GIRDER

2" Ø HSS BRACEL SHAPE GRATING SUPPORT

STEEL GRATING (TYP)

2" Ø HSS HANDRAIL POST

L SHAPE FLOORBEAM PIN AND HANGER (TYP)

30" x 3/4" STOCK TREADS @ 16" O.C.

5'-9"

65' (GIRDER LENGTH)

GANGWAY GIRDER 2" Ø HSS BRACE

2" Ø HSS HANDRAIL POST

L SHAPE FLOORBEAM PIN AND HANGER (TYP)L SHAPE GRATING SUPPORT

2" Ø HSS BRACE

L SHAPE

GRATING

SUPPORT

1" Ø HSS INTERMEDIATE

RAIL (TYP)

3.5" Ø HSS

L SHAPE FLOORBEAM

STEEL GRATE

3'-6.00"

GANGWAY GIRDER

11.00" (TYP)

5'-9"

2" Ø HSS HANDRAIL

POST

3/4" STOCK

STEEL TREAD

2'-6"

Dock: Naha Island: Revillagigedo Ranger District: Ketchikan-Misty Inspection Date: 5 October 2020

UNITED STATES DEPARTMENT OF AGRICULTURE

REMOTE DOCK AND MARINE FACILITY INSPECTIONS

Southeast Alaska/Tongass National Forest Contract No. 12010920F0013

DWG 3 Gangway Sections and Details

GANGWAY PLAN VIEW

OFFSHORE INSHORE

NOTES:

1. DIMENSIONS ARE APPROXIMATE

NOT TO SCALE

GANGWAY CROSS SECTION A-A

OFFSHORE INSHORENOT TO SCALE

GANGWAY CROSS SECTION B-B

LEFT RIGHTNOT TO SCALE

Ranger District: Ketchikan-Misty Inspection Date: 5 October 2020

UNITED STATES DEPARTMENT OF AGRICULTURE

REMOTE DOCK AND MARINE FACILITY INSPECTIONS

Southeast Alaska/Tongass National Forest Contract No. 12010920F0013

SHORELINE (VARIES)

MAIN DOCK

FINGER DOCK

12"x1.75" DECK

BOARDS (TYP)

DECK BOARDS

(TYP)

3.25"x3.25" TIMBER CURB

5.5"x5.5" TIMBER CURB

PILE WITH MINOR

TO MODERATE

CORROSION

PILE WITH MINOR TO

MODERATE CORROSION

PILE WITH MINOR TO

MODERATE CORROSION

DWG 4 DEFICIENCY PLAN

FRACTURE CRITICAL PIN

AND HANGER WITH NO

REDUNDANT SYSTEM

TIMBER CURB WITH

MAJOR DETERIORATION

TIMBER CURB WITH

MAJOR DETERIORATION

DISCONNECTED GANGPLANK

BROKEN CURB CHOCK

BROKEN CURB

MISSING CURB CHOCK

TYPICAL DEFICIENCIES

1. Inadequate floatation - Freeboard is not uniform across floats

2. Hardware for framing system is deteriorated with up to 20% section loss

3. Timber decking is deteriorated with vegetation and algae growth

4. Several locations of deformed intermediate gangway rails and deformed walking surface up to

2 in. deep

5. Intermediate gangway rails have greater than 4" of clear spacing

6. No safety ladder present

0 5' 10'

SCALE: 3/32"=1'-0"

C-1

Appendix C Photos

C-2

Photo 1: General view of the facility.

Photo 2: General view of the abutment and gangway.

C-3

Photo 3: Profile view of gangway.

Photo 4: Deformed gangway walking surface.

C-4

Photo 5: Deformed intermediate gangway rail.

Photo 6: General view of the pin and hanger assembly.

C-5

Photo 7: General view of the main dock.

Photo 8: Typical pile guide. Note the broken curb and grass growing on the deck.

C-6

Photo 9: Gangplank between main dock and finger dock. Note the detached connection bolts.

Photo 10: General view of the finger dock. Note vegetation growth in deck.

C-7

Photo 11: Failed curb connection due to missing chock on finger dock.

Photo 12: Pile 1 - Typical corrosion on the bottom 10 ft.

C-8

Photo 13: Pile 1 - Typical corrosion with cleaned area on the bottom 10 ft.

Photo 14: Typical condition of the timber framing with no significant damage.