B08-Appendix_C_-_Inspection_Guidance_Documents.pdf

Appendix C

EXP ER I ENCE YOUR AMER I CA T M

The National Park Service cares for special places saved by the American people so that all may experience our heritage.

Park Facility Management Division National Park Service U.S. Department of the Interior

1201 Eye Street, NW, 10th Floor Washington, DC 20005

Inspection Guidance: 2100 Trails

Trails (2100) Asset Category Inspection Guidance i

National Park Service U.S. Department of the Interior

Park Facility Management Division National Park Service

1201 Eye Street, NW, 10th Floor Washington, DC 20005

TABLE OF CONTENTS

INTRODUCTION

COMMON COMPONENTS AND CRITICAL SYSTEMS

COMPREHENSIVE CONDITION ASSESSMENTS

Tips for Inspections

Component Inspection Guidance

Barrier & Fencing

Fence/Gate

Generic Barrier

Cattle Guards

Furnishing

Exterior Furnishings

Benches

Signage & Marking

Sign

Structure

Base and Sub‐Base

Stairs

Walkable Structure

Raised Trail Structures

Minor Trail Bridges

Wall

Retaining Walls

Surface

Land Surface

Paved and Unpaved Surfaces – Tread

Rock Excavation & Disposal

Plant or Vegetation

Social Trails

Clearing

Tree Removal

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Stump Removal

Selective Thinning

Water Control

Culvert

Drain/Drainage Systems

Waterbars and Retainer Bars

RESOURCES

REFERENCES

RELATED DOCUMENTS

Trails (2100) Asset Category Inspection Guidance 1

1201 Eye Street, NW, 10th Floor Washington, DC 20005

INTRODUCTION

This document contains the inspection guidance for trails. The asset records associated with a trail should be inspected using the guidelines in this document. In some cases, major electrical systems (e.g., lighting) or storage facilities will be present along a trail. When these assets are present, they should be inspected using the guidelines in the appropriate inspection guidance (e.g., Inspection Guidance – Buildings).

Trails have many different bridge types ranging from footbridges and footlogs to sophisticated, engineered bridges. As a general rule, any “major” trail bridge should be classified as a trail bridge location record (2200 asset category) separate from the trail location record (2100 asset category) in the Facility Management Software System (FMSS). A trail bridge should be considered a location record (2200 asset category) in the FMSS if: (a) it has a span greater than 20 feet or a vertical distance greater than 5 feet in height (excluding footlogs, boardwalks, and similar trail structures); or (b) it is determined to have user safety concerns. Otherwise, a trail bridge should be classified as an asset record of the trail location record (2100 asset category) in the FMSS. Trail bridge assets should be inspected and assessed using the guidelines in the document, “Inspection Guidance –Trail Bridges.” Trail bridges that do not fall into these categories could be considered components of a trail and should be inspected using this document.

Any trail condition inspection should include a complete visual inspection of all constructed architectural, civil/structural, and mechanical components. A field inspection should be performed using both a system and component inspection method to identify all maintenance and repair deficiencies that need correction. The inspector should determine if there is sufficient evidence to warrant complete replacement of a system versus repairing only specific components of that system (e.g., replacing minor bridge decking as opposed to replacing the entire bridge).

A systematic approach to visual inspections must be employed to document all problems with a given trail. Some deficiencies announce themselves, such as washed out trail sections or boulder blockage. However, many deficiencies are more subtle and may require further examination (e.g., sloughing retaining wall).

During an inspection, the inspector should thoroughly document the information that will be needed in the preparation of cost estimates and inspection reports. At a minimum, the following should be recorded for each deficiency:

The trail deficiency should be defined (e.g., trail location, trail grading, drainage, erosion, blowdown, encroaching vegetation).

The corrective action should be specified with the appropriate verb (e.g., build/add, repair, replace, realign, adjust, relocate, remove, reopen, maintain, monitor).

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Location data should be provided with global positioning system (GPS) reading coordinates and/or a wheeled distance from a recognizable trail component, and, if possible, the geographical location should be marked on a map (e.g., 300 feet north, east, south, or west of a sign or crossing).

Data should be quantified in sufficient detail to permit later development of budget-level cost estimates using the appropriate unit of measure (e.g., 3 rock water bars, each 8 linear feet). It may also be useful to note whether on-site or imported materials will be used.

The relative priority of the deficiency should be noted as high, medium, or low.

Additional comments or notes should be included that will help to define the project needs or special circumstances to consider.

Immediate actions should be taken on safety issues found in a remote location during an inspection to mitigate identified safety issues.

While this document lays out universal inspection guidance, it does not establish one standard for all trails. Trails are constructed and maintained to different standards, as defined by a park unit’s trail management plan and/or by the standard Trail Classification Standards. For example, a typical Class II trail will likely have more obstacles and more exposed rock and roots than a typical Class IV trail. These park-level standards must be considered when completing trail assessments and should guide the corrective action (and costs) to address identified deficiencies.

Trails should be assessed to identify the standard industry cost estimates of materials, supplies, and labor required to repair the deferred maintenance (DM) to a sustainable/maintainable standard in accordance with the design and use parameters assigned to that trail asset, such as its functional class. Work on a trail that alters an existing trail or new construction that helps an asset better meet its intended purpose should be classified as capital improvement (CI). Trail assessments should identify those repairs required to preserve a trail to a maintainable standard within its current functional class, move it to a sustainable design to reduce future maintenance, or establish it back to an appropriate identified historical context. Examples of trail issues to consider when conducting an inspection include the following:

Tread that is restored or stabilized to an acceptable level according to local management policies

Drainage systems that are completely working Corridor that is brushed to appropriate standard Cultural and natural resources that are stabilized/protected All constructed components (e.g., walls, steps) are operational and safe Trail that is able to withstand its current level of use

Note: Alterations made to trails to withstand future anticipated levels of use should be captured as CI – Alterations. In addition, alterations may trigger the need to evaluate the trail for accessibility compliance.

Sustainable design and construction methodologies.

Trails (2100) Asset Category Inspection Guidance 3

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Trail assessments should document the work activities and repairs necessary to keep the trail operational within its existing functional class while mitigating the loss of cultural and natural resources and ensuring visitor safety. Major reroutes that significantly alter the trail alignment may be categorized as CI. The addition of features that would alter the level of functional classification should also be categorized as CI, such as adding pavement to an unpaved trail or allowing for new uses (modifications for stock use on former pedestrian-only trails).

Short or minor reroutes that do not significantly alter the trail corridor alignment or trail classification can be considered DM or component renewal (CR). Trail managers should note that it is not mandatory for trail repairs identified during an assessment to require restoration of a trail tread to its original design grade relative to the surrounding landscape. In some circumstances, it is not necessary, practical, or feasible to return tread to its original grade. Repair decisions should be made with consideration to park priorities, trail management plans, local trail management best practices, and identified historic standards. Recommended solutions to trail repairs should also follow a common sense approach, comply with local management policies, and acknowledge the limitations of work solutions in remote or wilderness areas.

When creating work orders based on the output of an assessment, please refer to the Life-Cycle Business Practices, Volume 3 for lumping and splitting guidance.

COMMON COMPONENTS AND CRITICAL SYSTEMS

Table 1 lists typical classifications used for the trail asset category. Any classification in the FMSS can be used to categorize components of a trail, but the table contains those most likely to be used.

Table 1. Trail Component List

Top‐Level Classification Classification Critical System

Barrier/ Fence/Gate No

Barrier/ Railing No

Electrical/ Lighting No

Furnishing/ Exterior Furnishing No

Marking/ Sign No

Marking/ Pavement Marking No

Structure/ Abutment Yes

Structure/ Deck Structure No

Structure/ Piling Yes

Structure/ Platform No

Structure/ Superstructure Yes

Structure/ Wall Yes

Structure/ Walkable Structure Yes

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Top‐Level Classification Classification Critical System

Structure/Access/ Stairs No

Structure/Base & Foundation/ Base and Sub‐Base Yes

Surface/ Land Surface No

Surface/ Traffic Surface Yes

Water Control/ Culvert Yes

Water Control/ Drain Yes

COMPREHENSIVE CONDITION ASSESSMENTS

TIPS FOR INSPECTIONS

For trail assets, an annual and comprehensive condition assessment requires the same diligence, accuracy, and time. Conducting annual assessments is not feasible and so parks should only complete comprehensive condition assessments.

Comprehensive condition assessments must be completed every five years. There are two approaches parks can take to complete these comprehensive assessments:

Conduct assessments on all assets once every five years. This approach requires parks to dedicate many resources during one year to completing the work.

Complete comprehensive assessments on 20 percent of trail assets ever year. By assessing 20 percent of trails each year over a five-year timeframe, all trails in a park will receive a comprehensive assessment every five years.

It is recommended that assessors become familiar with one or more of the resources available (see References below) to understand different trail design, construction, and maintenance techniques. There are many methods for conducting a trail assessment.

This inspection guidance only provides the basic information specific to the FMSS, but does not prescribe a specific methodology to complete the inspection. Assessors can use paper and pen, a Toughbook, or other handheld device to capture assessment information. Contact the FMP Help Desk to ask about available tools for conducting assessments.

Structures that make up the trail asset are integral to the integrity of the overall trail.

Structures should be inspected in relation to how they impact other structures. In other words, structures should not be viewed as standalone, but rather should be inspected with an eye toward how they integrate with all the structures that make up a trail.

Below is a short list of items that may be useful during a field inspection:

Fully charged GPS unit for collecting point and line data Digital camera with a fully charged battery and spares Sufficient storage space on the GPS unit and camera memory cards Paper maps, paper, and a pencil/pen for field notes

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Compass and measuring tape and/or measuring wheel Previous inspection information or a list of current work orders for that section of trail Necessary hiking gear.

COMPONENT INSPECTION GUIDANCE

Barrier & Fencing

Fence/Gate

Fencing and gates commonly found on trails include barbed wire, board, buck and rail, chain link, drift, open rail, picket, post and chain, privacy, riprap, split-rail, split-rail worm, stake and wire, and stockade. A more comprehensive list of fences (e.g., concrete, masonry or metal panels, security fences) is available in the document titled “Inspection Guidance – Roads.”

A fence consists of a line of posts secured to the ground and connected with railings, pickets, planks, braces, and other fence members secured in place. Posts out of plumb may be checked by eyesight, string line, or transit. Wood gates are constructed with wood rails, pickets, planks, braces, and other members securely fastened into a single unit. Metal gates are fabricated with pipe/tube framing covered with metal chain link or other woven wire mesh, preformed panel, or metal laced fabric, and kept in shape with wires, rods, or turn buckles.

Figure 1. Dodgeway (© Appalachian Trail Conservancy)

Checks to be made:

1. Fence panels and railings (wood):

Splits/cracking/broken:

o Surface fibers separated, extending over entire member, less than 25 percent of thickness affected o Surface fibers separated, extending over entire member, greater than 25 percent of thickness affected o Physically damaged and broken

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Rot, fungus, or decay:

o Moist stained area o Discolored, soft, or crushed area

Parasite damage:

o Holes less than ⅛ inch diameter, surface sag, and frass observed o Large holes greater than ⅛ inch diameter, surface channels, punctures, and crushing Out of plumb: more than 3 inches in 8 feet Erosion/vegetation:

o Soil erosion under fence wall o Vines, trees, or shrubs climbing over or growing into fence

2. Fence posts (wood):

Splits/cracking/broken:

o Surface fibers separated, extending over entire member, less than 25 percent of thickness affected o Surface fibers separated, extending over entire member, greater than 25 percent of thickness affected o Physically damaged and broken Rot, fungus, or decay:

o Moist stained area o Discolored, soft, or crushed area

Parasite damage:

o Holes less than ⅛ inch diameter, surface sag, and frass observed o Large holes greater than ⅛ inch diameter, surface channels, punctures, and crushing Out of plumb: more than 3 inches in 8 feet Erosion/vegetation:

o Soil erosion around posts o Vines, trees, or shrubs climbing over or around posts

3. Fence posts (metal):

Loose connections/anchorage:

o Loose bolts or wire fasteners o Loose or bent pipe posts or railing o Missing or broken components

Out of plumb: more than 3 inches in 8 feet Corrosion:

o Missing protective coating-galvanizing/paint, no pitting evident o Corrosion evidenced by pitting or blistering o Rust/corrosion evidenced by loss of base metal

Erosion/vegetation:

o Soil erosion around posts o Vines, trees, or shrubs climbing over or around posts

4. Fence posts (concrete):

Cracking:

o Hairline crack

Trails (2100) Asset Category Inspection Guidance 7

1201 Eye Street, NW, 10th Floor Washington, DC 20005 o Wide cracks more than 1/16 inch wide o Disintegration of concrete surfaces, with loss of surface exceeding depth of 2 inches Spalling:

o Less than 1 inch deep or 6 inches in diameter o More than 1 inch in depth or greater than 6 inches in diameter, or loss of more than 10 percent of surface area of a member o Disintegration of surface area, with corrosion of exposed reinforcing steel

Scaling:

o Loss of surface up to ½ inch deep, with exposure of coarse aggregates o Loss of surface from ½ inch to 1 inch deep with coarse aggregates clearly exposed o Loss of surface exceeds 1 inch, reinforcing steel usually exposed

Reinforcing steel corrosion:

o Rusting/discoloration evident o Cracks occurring parallel to reinforcement

Out of plumb: more than 3 inches in 8 feet Erosion/vegetation:

o Soil erosion around posts o Vines, trees, or shrubs climbing over or around posts

5. Fence piers (masonry/stone):

Deteriorated mortar joint material:

o Cracked mortar joint material o Loose/missing mortar joint material

Out of plumb: more than 3 inches in 8 feet Damaged bricks, stones or concrete masonry unit (CMU):

o Cracked, split, damaged o Loose, missing

Erosion/vegetation:

o Soil erosion around piers o Vines, trees, or shrubs climbing over or around piers

6. Gates (wood):

Defective gate:

o Surface fibers separated, extending over entire member, less than 25 percent of thickness affected o Surface fibers separated, extending over entire member, greater than 25 percent of thickness affected o Damaged or missing wood sections Rot, fungus, or decay:

o Moist stained area o Discolored, soft, or crushed area

Parasite damage:

o Holes less than ⅛ inch diameter, surface sag, and frass observed o Large holes greater than ⅛ inch diameter, surface channels, punctures, and crushing

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Out of plumb: more than 3 inches in 6 feet Connections:

o Loose wood at connection site o Broken, split, or damaged wood at connection site

Missing fasteners or anchorage

7. Gates (metal):

Defective gate fabric:

o Loose or sagging gate fabric o Damaged or missing gate fabric

Defective gate panels:

o Loose gate panels o Damaged or missing gate panels

Loose connections:

o Loose bolts or wire fasteners o Loose or bent pipe post/bracing o Missing or broken hinges, latches or other components

Out of plumb: more than ½ inch in 6 feet Corrosion:

o Missing protective coating-galvanizing/paint, no pitting evident o Corrosion evidenced by pitting or blistering o Corrosion evidenced by loss of base metal

Generic Barrier

Cattle Guards

Trail structures not found in other sections include cattle guards.

Checks to be made:

1. Cattle guards:

Gaps or depressions on approaches to cattle guards that could injure animal or user

Furnishing

Exterior Furnishings

Benches

Typical trail “furnishings” include benches and hitch racks.

Checks to be made:

1. Benches:

Structural soundness of seating surface, backrest (if applicable), and base

Trails (2100) Asset Category Inspection Guidance 9

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Gouges, wood slivers, and protruding fasteners (bolts and spikes) on seating surface and backrest (if applicable)

Signage & Marking

Sign

Signs are displayed to convey information. Four basic types of signs are common to NPS trails: identification signs, directional signs, information/education signs, and regulatory signs. Signs differ in purpose and size (e.g., small directional metal sign versus kiosk/bulletin board with a roof), and signs may be made of acrylic, aluminum, concrete, fiberglass embedment, fiberglass, glass, high-pressure laminate, laminate, masonry/stone, metal, plastic, recycled plastic, steel, timber, and wood.

Figure 2. Timber Sign (© Acadia National Park)

1. Signage:

Missing sign resulting in noticeable damage, such as inappropriate social trails or resource damage Signs contain incorrect information

2. Kiosk/bulletin boards:

Warped, rotting, or loose shingles on kiosk roof Ultraviolet damage to Lexan/Plexiglas case, cracked or checked Kiosk/bulletin board contains incorrect information

3. Signage (wood):

Loose, damaged, illegible, or missing sign face:

Trails (2100) Asset Category Inspection Guidance 10

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Splits/cracks/broken posts:

o Surface fibers separated, less than 25 percent of thickness affected o Surface fibers separated, greater than 25 percent of thickness affected o Physically damaged and broken

Rot, fungus, or decay of posts:

o Moist stained area o Discolored, soft, or crushed area

Parasite damage of posts:

o Holes less than ⅛ inch, surface sag, and frass observed o Large holes greater than ⅛ inch, surface channels, punctures, and crushing Out of level:

o Less than or equal to 3 inches in 4 feet o More than 3 inches in 4 feet

Out of plumb:

o Less than or equal to 3 inches in 8 feet o More than 3 inches in 8 feet

Erosion/vegetation:

o Soil erosion around posts o Vines, trees, or shrubs climbing over or obscuring sign

Decaying or leaning trees (if sign is mounted to tree)

4. Signage (metal):

Loose, damaged, illegible, or missing sign face:

o Loose sign face o Damaged sign face o Illegible sign face o Missing sign face

Out of level:

o Less than or equal to 3 inches in 4 feet o More than 3 inches in 4 feet

Out of plumb:

o Less than or equal to 3 inches in 8 feet o More than 3 inches in 8 feet

Corrosion of posts:

o Surface corrosion, no pitting evident o Corrosion evidenced by pitting or blistering o Rust/corrosion evidenced loss of base metal

Erosion/vegetation:

o Soil erosion around posts o Vines, trees, or shrubs climbing over or obscuring sign

5. Signage (concrete):

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Loose, damaged, illegible, or missing sign face:

o Loose sign face o Damaged sign face o Illegible sign face o Missing sign face

Cracking:

o Hairline crack o Medium cracks 1/16 inch wide o Wide cracks more than 1/16 inch wide o Disintegration of concrete surfaces, with loss of surface exceeding depth of 2 inches Spalling:

o Less than 1 inch deep or 6 inches in diameter o More than 1 inch in depth or greater than 6 inches in diameter, or loss of more than 10 percent of surface area of a member o Disintegration of surface area, with corrosion of exposed reinforcing steel

Scaling:

o Loss of surface up to ½ inch deep, with exposure of coarse aggregates o Loss of surface from ½ inch to 1 inch deep with coarse aggregates clearly exposed o Loss of surface exceeds 1 inch, reinforcing steel usually exposed

Reinforcing steel corrosion: rusting/discoloration evident, cracks occurring parallel to reinforcement

Out of level:

o Less than or equal to 3 inches in 4 feet o More than 3 inches in 4 feet

Out of plumb:

o Less than or equal to 3" inches in 8 feet o More than 3 inches in 8 feet

Erosion/vegetation:

o Soil erosion around posts o Vines, trees, or shrubs climbing over or obscuring sign

6. Signage (masonry/stone):

Loose, damaged, illegible, or missing sign face:

o Loose sign face o Damaged sign face o Illegible sign face o Missing sign face

Deteriorated mortar joint material:

o Cracked mortar joint material o Loose/missing mortar joint material

Out of level:

o Less than or equal to 2 inches in 8 feet o More than 2 inches in 8 feet

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Out of plumb:

o Less than or equal to 3 inches in 8 feet o More than 3 inches in 8 feet

Damaged bricks, stones, or CMU:

o Cracked, split, damaged o Loose, missing

Erosion/vegetation:

o Soil erosion around sign footing o Vines, trees, or shrubs climbing over or obscuring sign

Structure

Base and Sub‐Base

Base and sub-base are the compacted and prepared gravel, soil, or geosynthetic layers that are placed prior to the installation of the final surface (see Figure 3).

Geosynthetics (e.g., geotextile, geonets, sheet drains, geogrids, geocells) are plastic or non-woven fabrics, sheets, nets, grids, or honeycomb-like mats usually made of polypropylene or polyethylene that can help stabilize the treadway. Inspection of base and sub-base applies primarily to unpaved, graded paths with non-native surfaces(e.g., off-road bicycle trails).

Figure 3. Geotextile Base (© ATC)

1. Exposed and/or worn out geosynthetic layer

2. Shoulders:

High shoulders (secondary ditches)

3. Standing water:

Standing water on the surface that seeps into the subgrade, causing a general softening of the entire path

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4. Rutting:

Longitudinal depressions in the paths caused by high moisture content in the subsurface soil or base, inadequate surface course thickness, or heavy traffic loads

5. Depressions:

Localized low areas one or more inches below the surrounding tread surfaces caused by settlement, excessive moisture content, or improper drainage

Stairs

Stair steps may be made from stone, iron rungs, pinned steel, concrete, earth, treated timber, and/or log to armor a steep trail tread or to provide a means of ascension. Iron rungs are inserted into holes drilled in rock and provide a “step ladder” for crossing an exposed ledge.

1. Iron rungs:

Loose rungs Corroded or cracked rungs Missing rungs

Figure 4. Steel Rungs (© ATC)

2. Log:

Loose or missing steps Strength/sturdiness of ladder Visible signs of decay

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Figure 5. Step Ladder (© ATC)

3. Logs pinned to rock:

Loose or missing logs Strength/sturdiness of logs Corroded pins/loose pins Visible signs of decay

4. Rocks pinned to ledge Water has damaged edges of steps Corroded pins Loose or missing steps

5. Treated timber:

Water has damaged edges of steps Loose or missing steps Strength/Sturdiness of steps Visible signs of decay

6. Stone steps Continuous stone steps installed where trail grade exceeds 10 percent in order to harden the trail and prevent erosion No steps are present where they should be Water damage has dislodged steps or made them not level or loose Steps are too small and likely to be dislodged Steps are not keyed into the edge of the trail with rock Steps are too high (greater than 10 inches high or evidence that hikers avoid them) Stones are separated where they are intended to be congruous

Trails (2100) Asset Category Inspection Guidance 15

Figure 6. Rock Step (© Acadia National Park)

Figure 7. Rock Steps

(© AMC)

Walkable Structure

Raised Trail Structures

Raised trails include elevated sections of trail, such as footbridges, turnpikes, and causeways, and different types of boardwalks, such as puncheons, bog bridges, and gadburies.

Turnpikes and causeways are elevated sections of trail, usually through permanently or seasonally wet areas. The terms are used largely interchangeably, although the outer walls of a turnpike are generally log and those of a causeway are rock. Both provide a dry, elevated tread through the muddied area and are constructed to allow drainage through the structure.

Figure 8. Turnpike (© ATC)

A puncheon is an elevated boardwalk used to cross boggy or marshy ground where uneven terrain or lack of trail tread material makes a turnpike or causeway impractical.

Puncheons resemble a short version of the log footbridge. Its main components are sill logs laid perpendicular to the trail, two to three stringers laid on the sill logs parallel to

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Gadburies also span muddy or boggy sections and allow for clear drainage. Gadbury components include sill logs, large deck logs, bull rails, and crowder rails.

Bog bridges (bogwalks) are simplified gadburies without rails of any kind and are also similar to the simplest puncheon. The difference between a bog bridge and a puncheon or gadbury may be in nomenclature only, varying from park to park or region to region.

Check with local subject matter experts to confirm local naming conventions.

Figure 9. Bog Bridge(© Federal Highway Administration [FHWA])

1. Turnpikes (wood):

No turnpike structure where one is needed Cross drainage – see if turnpike dams water, causing water to flow over trail Depressed fill surfaces that may collect water Check for washed-out tread within turnpike walls Exposed fill (rocks) within turnpike walls Loose joints or deteriorating log turnpike walls Treadway crown is deteriorated

2. Causeways (rock):

No causeway structure where one is needed Washed-out tread within causeway walls Exposed fill (rocks) within causeway walls Loose or missing rocks from causeway walls Treadway crown is deteriorated

3. Bog Bridge (one or two stringers resting on sill logs):

No puncheon structure where one is needed Broken bridge planks Sloping planks, either side to side or along length of bridge

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Broken planks Missing sections of bridge Algae growth and slippery bridge surfaces Rusted or missing spikes

4. Puncheon (one or two stringers resting on sill logs):

No puncheon structure where one is needed Broken bridge planks Sloping planks, either side to side or along length of bridge Broken planks Missing sections of bridge Algae growth and slippery bridge surfaces Rusted or missing spikes

Figure 10. Puncheon (© ATC) Figure 11. Puncheon

(© FHWA)

Figure 12. Puncheon

(© FHWA)

5. Gadbury:

No gadbury structure where one is needed Brush and other debris inhibiting proper drainage Sinking, deteriorating, or buried sill logs Splitting or decay in stringers Missing, damaged, or loose decking logs Missing, damaged, or loose bull rails

Figure 13. Gadbury (© FHWA)

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6. Boardwalk:

No boardwalk structure where one is needed Splitting or decay in stringers Missing, damaged, or loose decking logs Missing, damaged, or loose bull rails Missing or damaged railing

Figure 14. Boardwalk (© FHWA)

Minor Trail Bridges

This section includes trail footbridges that are not “substantial” in size. Bridges included in this category typically are small, do not carry vehicular traffic, span small bodies of water, and do not require inspection by a civil engineer. A trail bridge should be considered a location record in the FMSS (2200 asset category) if: (a) it has a span greater than 20 feet or a vertical distance greater than 5 feet in height (excluding footlogs, boardwalks, and similar trail structures); or (b) it is determined to have user safety concerns. Substantial trail bridges and those listed with the FHWA need to be classified as individual location records (Trail Bridge – 2200 asset category) in the

FMSS.

Most of the non-substantial bridges to be assessed using the guidelines in this document can be broken down into the following components: substructure (e.g., abutment, footer, piling) and superstructure (e.g., girders, stringers, decking, railing, parapets).

Figure 15. Log Stringer Bridge(© FHWA)

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An abutment is a substructure unit located at the end of a bridge. Its function is to provide end support for the bridge and to retain the approach embankment. The primary materials used in the construction of abutments for footbridges are stone masonry, timber, or a combination of these materials. A piling is a center structure designed to support the bridge at one or multiple midpoints.

Figure 16. Abutment (© Acadia National Park)

The superstructure is designed to carry dead and live loads associated with the structural deck to the substructure (abutments/pilings). The superstructure includes primary members, a floor system with two or more main supporting members, secondary members, connections, and bearings. The main supporting members for footbridges are timber beams or timber trusses. Beams are considered single elements, while trusses have several identifiable parts: the chords (longitudinal members at the top and bottom of a truss) and the verticals and diagonals called web members. Bearings transmit and distribute the superstructure loads to the abutment and pilings, if present.

The primary function of a footbridge deck is to provide a surface over or through which pedestrian traffic can move and distribute the live and dead loads to the superstructure.

Footbridges generally have noncomposite decks, which do not contribute to the structural capacity of the supporting members. A noncomposite deck only functions to span between supporting members and to provide a wearing surface for traffic.

The bridge railing is a fence-like construction built at the outer most edge of the bridge.

The primary function of the bridge railing is safety—to guard and guide the movement of pedestrian and stock traffic.

Checks to be made:

1. Rock abutment or piling:

Cracks o Signs of water stain around cracks on the face of abutment o Visible signs of water seeping through cracks or joints in the abutment

Erosion or scouring at abutment or wingwalls, voids, undermining of abutment Joints o Joint deteriorated with voids

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Stone deterioration:

o Minor spalling and hairline cracks in stone o Spalling with cracks and chipping and loose stones o Masonry stone spalling with large cracks and chipping, section loss greater than 15 percent Rotational movement (some abutments are constructed with battered or slope front face):

o Abutment walls rotated inward or outward o Wingwalls rotated inward or outward

Breast wall bearing seat (critical where beam bears directly on the abutment wall):

o Light spalling and chipping of concrete o Dirt and debris accumulated on bearing seat o Spalling and cracking of concrete at edge of seat o Severe spalling and cracking with crushing of concrete and exposed reinforcing bars Collision damage: member out of alignment; member cracked, crushed, or missing

2. Timber abutment or piling:

Erosion or scouring at abutment or wingwalls, voids, undermining of abutment Breast/wingwall decay (decay from rot/fungus is most likely to occur at connections, splices, and support points or around bolt holes – this may be due either to the tendency of such areas to collect and retain moisture or to bolt holes or cuts being made in the surface after the preservative treatment has been applied):

o Moist and stain or discolored area with signs of fungi although surface is solid o Surface spongy and member may show signs of crushing o Brown and white discolored area and member may show section loss and crushing Parasites in breast/wingwalls and pile lagging (termites, carpenter ants, powder post beetles):

o Pinholes with dark stain area around the holes o Holes with surface sag and sawdust observed o Surface channels and crushing of the member

Weathering:

o Surface of wood is rough and corrugated and member may be warped o Surface of wood is rough and corrugated with cracks partially through the wood member, may have minor section loss o Member may be warped

Trails (2100) Asset Category Inspection Guidance 21

1201 Eye Street, NW, 10th Floor Washington, DC 20005 o Large cracks extend deeply or completely through the wood o Wood is crumbly and seriously deteriorated

Rotational movement (some abutments are constructed with battered or slope front face):

o Abutment walls rotated inward or outward o Wingwalls rotated inward or outward

Bearing seat:

o Moist and stained, surface solid o Dirt and debris accumulated on bearing seat o Moist and stained, surface soft, slight crushing o Area soft and crumbly and seriously deteriorated

Collision damage: member out of alignment; member cracked, crushed, or missing

3. Concrete abutment or piling:

Drains or weep holes:

o Drains and weep hole clogged o Signs of water stain on the face of abutment around cracks o Visible signs of water seeping through cracks or joints in the abutment

Erosion or scouring at abutment or wingwalls, voids, undermining of abutment Cracks and spalling:

o Staining of concrete surface with signs of efflorescence deposit and spalling of cracks o Reinforcing bars exposed Scaling and popouts:

o Loss of mortar o Exposed aggregate o Reinforcing bars exposed

Backwall and wingwall joints: joint separation or movement Rotational movement (some abutments are constructed with battered or slope front face):

o Abutment walls rotated inward or outward o Wingwalls rotated inward or outward

Breast wall bearing seat (critical where beam bears directly on the abutment wall):

o Light spalling and chipping of concrete o Dirt and debris accumulated on bearing seat o Spalling, cracking of concrete at edge of seat o Severe spalling and cracking with crushing of concrete and exposed reinforcing bars Collision damage: member out of alignment; member cracked, crushed or missing

4. Connections:

Corrosion on gussets or connection plates:

Trails (2100) Asset Category Inspection Guidance 22

1201 Eye Street, NW, 10th Floor Washington, DC 20005 o Surface rust, no pitting evident o Corrosion evident, pitting and blistering of base material o Corrosion evident with loss to base section

Corrosion on bolts:

o Surface rust, no pitting evident o Corrosion evident, pitting and blistering of base material o Corrosion evident with loss to base section

Connectors or fasteners:

o Loose bolts or fasteners o Missing fasteners or connectors

5. Bearings:

Expansion or fixed metal bearing:

o Surface rust, no evidence of pitting, expansion bearing free to rotate o Dirt and debris accumulated around base of bearing o Corrosion, pitting, and blistering of base metal, expansion bearing free to rotate o Corrosion with loss to base section, expansion bearing frozen o Excess rotation of expansion bearing o Loss of bearing area due to lateral or longitudinal movement

Elastomeric bearing:

o Bulging of the bearing o Splitting or tearing of the bearing, including interior steel shims bond o Bond to the sole and/or masonry plate failed o Excessive longitudinal movement

Excessive rotation movement, loss of bearing area due to lateral or longitudinal movement

Pin and link bearing:

o Surface rust, no pitting evident, joint free to rotate o Corrosion evident, pitting and blistering of base material o Corrosion evident with loss to base section, joint frozen

Corrosion on sole and masonry plates:

o Surface rust, no pitting evident o Corrosion evident, pitting and blistering of base material o Corrosion evident with loss to base section

Anchor bolts:

o Surface rust, no pitting evident o Loose anchor bolts, nuts or bearing o Corrosion evident, pitting and blistering of base material o Corrosion evident with loss to base section o Missing or broken anchor bolts

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1201 Eye Street, NW, 10th Floor Washington, DC 20005

6. Timber deck:

Weathering and wear:

o Surface of wood is rough and corrugated and member may be warped o Surface of wood is rough and corrugated with cracks partially through the wood member, may have minor section loss to the top surface o Warped members o Large cracks extend deeply or completely through the wood o Wood is crumbly and seriously deteriorated

Vibration per span:

o Slight vibration in deck when users pass o Noticeable vibration in deck when users pass o Excessive vibration in deck when users pass

Collision damage: member out of alignment; shattered or injured timber member Decay (decay from rot/fungus is most likely to occur at connections, splices, support points or around bolt holes – this may be due either to the tendency of such areas to collect and retain moisture or to bolt holes or cuts being made in the surface after the preservative treatment has been applied):

o Moist and stained or discolored area, signs of fungi, surface is solid o Surface spongy, member may show signs of crushing o Brown and white discolored area, member may show section loss and crushing Connections:

o Loose fasteners o Member broken, split or damaged o Missing fasteners or anchorage

Parasites (termites, carpenter ants, powder post beetles):

o Pinholes with dark stain area around the holes o Holes, surface sag, and sawdust observed o Surface channels, and crushing of the member

Deck missing: hole in deck

7. Timber railing and post:

Weathering:

o Surface of wood is rough and corrugated and member may be warped o Surface of wood is rough and corrugated with cracks partially through the wood member, may have minor section loss o Warped member o Large cracks extend deeply or completely through the wood o Wood is crumbly and seriously deteriorated

Decay (decay from rot/fungus is most likely to occur at connections, splices, support points or around bolt holes – this may be due either to the tendency of such areas to collect and retain moisture or to bolt holes or cuts being made in the surface after the preservative treatment has been applied):

o Moist and stained or discolored area, signs of fungi, surface is solid o Surface spongy, member may show signs of crushing

Trails (2100) Asset Category Inspection Guidance 24

1201 Eye Street, NW, 10th Floor Washington, DC 20005 o Brown and white discolored area, member may show section loss and crushing

Parasites (termites, carpenter ants, powder post beetles):

o Pinholes with dark stain area around the holes o Holes, surface sag, and sawdust observed o Surface channels, and crushing of the member

Post connections:

o Loose fasteners o Broken, split, or damaged o Missing fasteners or anchorage

Corrosion at post anchors:

o Surface rust, no pitting evident o Corrosion evident, pitting and blistering of base material o Corrosion evident with loss to base section

Collision damage:

o Railing out of alignment o Post out of alignment o Railing shattered or damaged o Post shattered or damaged member

Vertical joint displacement due to substructure or bearing settlement Horizontal joint misalignment due to substructure or bearing settlement

Wall

Retaining Walls

These are structures used to prevent the flow or lateral movement of soil.

Trail retaining walls are typically made from wood, concrete, brick, flagstone, gabion, granite, metal, stone (drywall and mortared), or masonry/stone. The basic principles of dry laid (drywall) rockwork (utilizing the weight and the shape of the rock to create strong and long-lasting retaining walls) apply to all types of rock retaining walls.

Types of retaining walls include single-tier walls, multi-tier walls, and pinned walls.

Single-tier walls are most frequently used to hold trail tread to a sloping sidehill with an outside wall. Multi-tier walls are used as outside walls holding trail tread; inside walls are used to protect the trail from slough-off, inside switchback corner walls, and in other situations, including fords, culverts, and causeways. Pinned walls are utilized over slick bedrock with few anchor points. Key rocks are pinned to the bedrock to “lock” the wall in place.

Log retaining walls (cribbing) are a stack of logs and rails tied and locked together and backfilled as with multi-tiered wall construction. Switchback corners are often a combination of these walls. Switchback corners are complex walls that may include an outside wall on the lower switchback, a nearly level landing with a waterbar or other

Trails (2100) Asset Category Inspection Guidance 25

1201 Eye Street, NW, 10th Floor Washington, DC 20005 drainage structure, an inside-outside wall between the two switchbacks, and an inside wall above the upper trail.

Checks to be made:

1. Stone retaining walls:

Foundation movement indicated by changes in gradient of top tier o Eroding/missing layer of soil underneath foundation (footing) o Overhanging or loose rocks in foundation (footing)

Slipping joints/poor contact between rock on wall Loose or missing rocks on wall Missing fill between rocks on wall Collapsing of wall Loose or missing cap stones

2. Pinned rock retaining walls:

Loose or damaged pins Exposed (hazardous) pins

3. Log retaining walls (cribbing):

Foundation movement indicated by changes in gradient of top tier Eroding/missing layer of soil underneath foundation (footing) Loose or deteriorating logs on wall Loose or missing chinking on wall

Figure 17. Log Retaining Wall (© Acadia National Park)

4. Switchback corners:

Signs of switchback cutting and erosion Check for roots/brush Waterbar blocked causing drainage to flow through switchback corner (ice buildup) Check for debris; sediment should be distributed over trail under the drainage or added to backfill Check if soil if too compacted/rocky

Trails (2100) Asset Category Inspection Guidance 26

Figure 18. Switchbacks (© AMC)

Surface

Land Surface

Paved and Unpaved Surfaces – Tread

Tread is material that is placed atop the base layer to provide the walking, riding, or driving surface. Options include asphalt, concrete, gravel, native, paver block (cobble or other block stone), riprap (native rocks embedded in the ground), wood chips, or other materials (if other materials are used, these should be described in the inspection documentation).

For each trail, the management standards should define the frequency of obstacles and hazards protruding through the trail surface. As mentioned above, these standards should be based on Interagency Trail Data Standards guidelines for different classes of trails and/or the park’s Trail Management Plan. For example, in general, for Class III through Class V trails, tread should be clear of loose rock, from roots protruding more than two inches, and from other obstructions that might be a hazard to trail users.

Native and gravel trails must be checked for gullies, berms, sloughing, and muddy or washed-out areas. Gullies should be repaired to prevent continued erosion and wash-outs. Gullies are natural ditches created by water rapidly eroding a section (or the entire width) of a trail. Gullies may be converted into inside (uphill) drainage channels.

Berms should be removed because they alter the natural drainage and runoff patterns across and off the trail and lead to severe erosion. Berms are accumulations of displaced soil that build up on the downhill side of a trail. They range in height from a few inches to six inches or more.

Slough is soil, rock, and silt that have accumulated on the inside of the tread at the base of the backslope, narrowing the width of the trail tread. Slough, muddy areas, and washed-out trail sections all force users to move upslope or down slope of the original trail tread and should be remedied.

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1201 Eye Street, NW, 10th Floor Washington, DC 20005

Checks to be made:

1. Paved surfaces:

Alligator cracking: a series of interconnecting cracks resembling alligator skin or chicken wire, which usually occur in the wheel path Longitudinal cracking: cracks that are parallel to the pavement centerline or asphalt lay down direction Transverse cracking: cracks perpendicular to the pavement centerline Potholes (or patches): a bowl-shaped hole in the pavement surface Rutting: surface depressions in the wheel paths

2. Unpaved surfaces:

Minor surface hazards (exposed roots and loose rocks) Gullies Berms Poor drainage, bogs, and mud holes Sloughing Washed-out/eroded trail sections(from heavy use or improper drainage) Braids or social paths: multiple parallel trails caused by users avoiding obstacles described above Trail width, either too narrow or too wide

Rock Excavation & Disposal

As with vegetation, boulder blockages force hikers and horses to move upslope or downslope of the original trail, potentially causing severe impact both to surrounding resources and to the trail itself.

Checks to be made:

1. Rock excavation and disposal:

Boulders blocking trails, forcing users off-trail, or creating safety hazards for stock and users

For user-specific design criteria and measurements, refer to the Forest Service Handbook and other applicable agency references.

Plant or Vegetation

Social Trails

Social trails are paths created not by the park but by trail users, often as shortcuts or as short extensions beyond the main trail. They are not maintained routes. If the park plans to leave the social trail intact, it should be listed as a trail asset and maintained as such. Otherwise, the park should block and rehabilitate the unauthorized trail. There are no specification templates for this category of trails. Instances of social paths are

Trails (2100) Asset Category Inspection Guidance 28

1201 Eye Street, NW, 10th Floor Washington, DC 20005 deficiencies and should be noted as such. Work orders for repair of social paths can be linked to an asset record of tread or linked directly to the asset’s location record.

Checks to be made:

1. Social trails:

Paths needing to be blocked that have been clearly established on the ground, or evidence of vegetation that has been cleared or damaged as a result of unplanned use

Clearing

Clearing is the removal of aboveground vegetation, including stumps. Cutting limbs and woody vegetation, and meeting clearance standards along the trail, should be considered cyclical maintenance. However, if needed brushing has not occurred regularly over an extended period, clearing (as required for a new trail) may be necessary.

Checks to be made:

1. Clearing:

Overgrowth from woody vegetation and other brush covering more than 20 percent of trail corridor

Tree Removal

Tree removal is the selective removal of trees on the site. Hazard trees are those in imminent danger of falling within the trail. “Leaner” trees are those that may interfere with the trail within 10 years. The NPS policy dictates that as much vegetation as possible should be retained. NPS staff with special training to recognize trees needing removal should participate in these assessments. When hazard trees are identified, there is a very short time frame in which they have to be removed. Any identified hazard tree deficiencies should be removed as soon as possible.

Checks to be made:

1. Tree removal:

Hazard and “leaner” trees that pose a danger to trail users or threaten to cause substantial damage to park resources

Stump Removal

Stump removal is the selective removal of stumps on the site.