Standard Trail Specs.pdf

United States Department of Agriculture

Forest Service

Engineering Staff

Washington, DC

September 1996

EM-7720-103

Standard Specifications for Construction and Maintenance of Trails

CONTENTS

Section

Page

General Specifications

Abbreviations, Acronyms, and Terms 902 Definitions

Intent of Contract

Maintenance for Traffic

Control of Materials

Measurement and Payment 907 Quality Assurance and Quantity Measurement

Staking, Flagging, and Cleanup

Construction Specifications

910 Earthwork

Clearing and Grubbing

Excavation and Embankment 913 Turnpike 914 Switchbacks

Existing Trail Restoration

Removal of Structures and Obstructions

920 Drainage

921 Culverts 922 Waterbars ................................:

923 Rock Spillways 924 Underdrain

930 Structures

Log Stringer Bridge 932 Puncheon 933 Trail Stairways

Log Retaining Walls

Rock Retaining Walls

Wire Baskets

940 Surfacing

Aggregate Surfacing and Base Course

Hot Bituminous Plant Mix Trail Surfacing

Cold Bituminous Mix Trail Surfacing

Grid Pavement Units

Incidental Construction

951 Mobilization 952 Sign, Post, and Cairn Installation 953 Barriers

Obliteration of Abandoned Trailways

Seeding and Mulching

Materials

Rock, Grid Pavement Units, and Aggregate

Material for Timber Structures

Drainage Pipe 964 Geosynthetics

Wire Baskets

Maintenance Specifications

Brush Cutting

Logging Out

Danger Tree Removal

Loose Rock Removal

Rock and Root Removal

Borrow

Slide Maintenance

Slough and Berm Removal

Turnpike Maintenance

Switchback Maintenance

Drainage Maintenance

Rock Retaining Wall

Sign Repair and Placement

Barrier Maintenance

Section 900 General. Specifications

Section 901-Abbreviations, Acronyms, and Terms

901.01 Terms, Organizations, and Standards

(a) Specification Terms. These specifications are generally written in the imperative mood.

In sentences using the imperative mood, the subject "the Contractor," is implied. Also implied in this language is "shall," "shall be," or similar words or phrases. In material specifications, the subject may also be the supplier, fabricator, or manufacturer supplying material, products, or equipment for use on the project:

Wherever "directed," "required," "prescribed," or similar words are used, the "direction," "requirement," or "order" of the CO is intended. Similarly, wherever "approved," "acceptable," suitable," "satisfactory," or similar words are used, they mean "approved by," "acceptable to," or "satisfactory to" the CO.

The word "will" generally pertains to decisions or actions of the CO.

Whenever in these .specifications, or in other contract documents, the following terms (or pronouns in place of them) are used, the intent and meaning shall be interpreted as follows:

reference to a specific standard, test, testing method, or specification shall mean the latest published edition or amendment that is in effect at the solicitation issue date for the public works contracts.

(b) Abbreviations and Acronyms

AASHTO American Association of State Highway and Transportation Officials

ABS Acrylonitrile-Butadiene-Styrene

AQ

Actual Quantities

APA

American Plywood Association

ASTM

American Society for Testing and Material

AWPA

American Wood Preservers Association C.F.

Cubic Feet

CO

Contracting Officer C.Y

Cubic Yards

DQ

Design Quantities EA Each f () feet

HDPE

High-Density Polyethylene gal gallon hr hour in (") inches lb pounds L.F.

Linear Feet

LS

Lump Sum

LSQ

Lump Sum Quantities mi miles

NBS

National Bureau of Standards

NCMA

National Concrete Masonry Association PE polyethylene

PS

Product Standard issued by the U.S. Department of Commerce

PVC

polyvinyl chloride S.F.

square feet

SQ

Staked Quantifies S.Y

Square Yards

WCLIB

West Coast Lumber Inspection Bureau

W WPA

Western Wood Products Association

(c) Slope notation (horizontal: vertical).

Section 902-Definitions

When the following terms, or pronouns in place of them, are used in these specifications or in other contract documents, the intent and meaning are as follows:

Base Course. The layer or layers of specified material of designed thickness placed on a trailbed to support surfacing.

Batter. A backward and upward slope of the face of a wall.

Berm. The ridge of material formed on the outer edge of the trail that projects higher than the tread.

Borrow. Suitable materials taken from approved sources designated on the drawings or on the ground, to be used for embankments and backfilling.

Bridge. A structure, including supports, erected over a depression or stream, and having a deck for carry traffic.

Cap Rock Rock placed in the top or uppermost layer in a constructed rock structure, such as a talus or rubble rock section or rock retaining wall.

Catch Point. The outer limits of a trailway where the excavation and/or embankment intersect with the ground line.

Clearing Limit. The area over and beside the trail that is cleared of trees, limbs, and other obstructions.

Climbing Tern. A reverse in direction of trail grade without a level landing used to change elevation on a steep slope.

Compacted. Consolidation that is obtained by tamping or rolling suitable material until no noticeable displacement of material is observed.

Contracting Officer (CO). An official of the Government with the authority to enter into, administer, and/or terminate contracts and make related determinations and findings. The term includes certain authorized represen-tatives of the CO acting within the limits of their authority as delegated by the CO.

Culvert. A drainage structure composed of rock, metal, or wood that is placed approximately perpendicular to and under the trailway.

Cushion Material. Native or imported .material, generally placed over rocky section of unsurfaced trail. to provide a usable and maintained traveled way.

Danger Eree. An unstable tree 5" or greater in diameter at breast height that is likely to fall across the trail.

Designated on the :Ground. The location of materials, work areas, and construction items, including lines and grades, marked on the ground with stakes, flagging, tags, or paint.

http://trail.to http://trail.to http://trail.to http://trail.to

Drawings. Documents showing details for construction of a facility, including but not limited to straight-line diagrams, trail logs, standard drawings, construction logs, plan and profile sheets, cross-sections, diagrams, layouts, schematics, descriptive literature, and similar materials.

Duff. Organic material overlying rock or mineral soil.

Embankment. A structure of suitable material placed on the prepared ground surface and constructed to the trailbed elevation.

Excess Excavation. Material in the trailway in excess of that needed for construction of designed trailways.

Ford. A water-level stream crossing constructed to provide a level surface for safe traffic passage.

Full Bench. Trailbed constructed entirely on undisturbed material.

Grade. The verticaldistance of ascent or descent of the trail expressed as a percentage of the horizontal distance.

Header Rock. Rock laid with the narrow end towards the face of the wall.

Inslope. Where the trail tread is sloped downward toward the backslope.

Mineral Soil. Soil or aggregate that is free from organic substances and contains no particles larger than 2" at their greatest dimension.

Outslope. Where the trail tread is sloped downward toward the embankment or daylight side of the trailway.

Sideslope. The natural slope of the ground, usually expressed as a percentage.

Slough. That material from the backslope or the area of the backslope that has raveled onto the trailbed

Slump. Where the trailbed material has moved downward, causing a dip in the trail grade.

Special Project Specification. Specifications that detail the conditions and requirements peculiar to an individual project, including additions and revisions to the standard specifications.

Surfacing. Material placed on top of the trailbed or base course that provides the desired tread.

Suitable Material. Rock that can be accommodated in the trail structure, and soil free of duff with a recognizable granular texture.

Switchback. A reverse in direction of trail grade with a level landing used to change elevation on a steep slope, usually involving special treatment of the approaches, barriers, and drainages.

Trailbed. The finished surface on which base course or surfacing may be constructed. For trails without surfacing the trailbed is the tread.

Trailway. The portion of the trail within the limits of the excavation and embankment.

Tread. The surface portion of the trail upon which traffic moves.

Turnout. A short section of extra trail width to provide for passage of trail users.

Waterbar. A structure used for turning water off the trail, usually made of logs or stones.

Water Courses. Any natural or constructed channel where water naturally flows or will collect and flow during spring runoff, rainstorms, etc.

Section 903-Intent of Contract

903.01 Intent. The intent is to provide for the completion of the project described in the contract. Furnish all labor, materials, equipment, tools, transportation, and supplies and perform all work required to complete the project in accordance with drawings, specifications, and provisions of the contract.

Section 904-Maintenance for Traffic

904.01 General. Keep existing trails that are undergoing improvements open and maintained in such a condition as to safely accommodate traffic. Provide and maintain temporary detours, approaches, or crossings and intersections with trails, roads, businesses, parking lots, and campgrounds in a safe and passable condition. Perform no work that interferes or conflicts with traffic until a plan for handling traffic has been submitted and approved. Specific requirements for detours or closures are SHOWN ON THE DRAWINGS or in the SPECIAL PROJECT SPECIFICATIONS.

Before any suspension of work take precautions necessary to prevent damage to the project, such as temporary detours, approaches, crossings, or intersections, and make provisions for normal drainage and to minimize erosion. Leave all trailways in a condition suitable for traffic unless otherwise specified.

The Government may permit use of portions of the project during periods when operations are shut down. All maintenance attributable to permitted. use during periods of work suspension willbe provided by the Government. The contractor is responsible for any maintenance that is not attributable to use or that is necessary during suspensions resulting from fault or negligence of the contractor.

Section 905-Control of Materials

905.01 Handling Materials. Transport and handle all materials to preserve their quality and fitness for the work Stockpile, load, and transport aggregates in a manner that will preserve specified gradation and avoid contamination.

Store materials to assure the preservation of their quality and fitness for the work Locate stored materials to facilitate their prompt inspection. Sites on Government-administered land that are not already designated may be. used for storage purposes and for placing of equipment only when approved in advance by the CO. Restore all storage sites in accordance with requirements SHOWN ON THE DRAWINGS or as otherwise specified. Arrangements for storage on other than designated sites are the responsibility of the contractor.

905.02 Material Sources

(a) Designated Sources. Sources for materials such as, but not limited to, soil, rock, or logs that are not available from trailway excavation or clearing operations will be designated.

Sources of local materials designated in the SPECIAL PROJECT SPECIFICATIONS or SHOWN ON THE DRAWINGS are guaranteed by the Government for the quality and quantity of material in the source.

Use all needed suitable material from the source. The designation of a source includes the right to use areas SHOWN ON THE DRAWINGS for the purposes designated (such as plant sites, stockpiles, haul roads). Operations are restricted to the confines of the area(s) designated.

(b) Contractor-Furnished Sources. Furnish material that produces an end product equivalent in performance to that specified.

905.03 Restoration. Shape and grade borrow areas on Government-administered land to make them stable and to minimize future erosion. Dispose of debris resulting from development of material sources by scattering, unless otherwise specified. Do not scatter debris within the clearing limits of trails or within roadsides. Cut off stumps to less than 1' above the ground as measured on the uphill side of the stump.

Section 906-Measurement and Payment

906.01 General. Measurement and payment for contract work will be made only for and under those pay items included in the SCHEDULE OF ITEMS. All other work and materials will be considered incidental and included in the payment of the PAY ITEMS in the

SCHEDULE OF ITEMS.

When more than one class, size, or thickness is specified in the SCHEDULE OF ITEMS for any PAY ITEM, suffixes will be added to the item number to differentiate between the items.

906.02 Determination of Quantities. The following measurements and calculations are to be used to determine contract quantities for payment:

Make measurements for seeding, geotextiles, and erosion control blankets along slope lines.

For retaining walls, measure by the square meter of front wall face.

Measure structures according to neat lines SHOWN ON THE DRAWINGS or as altered by the CO in writing to fit field conditions. Make measurements along the centerline and parallel to the specified grade or foundation or as SHOWN ON THE DRAWINGS.

Deduct lengths for stairways, turnpike, puncheon, retaining walls, wire baskets, switchbacks, bridges, and bridge approaches from the measurement of excavation in Section 912 unless these items are specified as incidental to excavation in Section 912.

For standard manufactured items, such as fence, wire, plates, rolled shapes, and pipe conduits identified by gage, weight, section dimensions, and the like, such identification shall be considered the nominal weights or dimensions. Manufacturer's tolerances will be accepted unless controlled by tolerances in the cited specifications.

906.03 Units of Measurement. Payment will be made by units defined and determined according to standard metric measure and by the following:

(a) Cubic Yard. A measurement computed by one of the following methods:

(1) Excavation, embankment, or borrow. The measurement computed by the average-end-area method from measurements made longitudinally along a centerline or other reference line.

(2) Material in place or stockpiled The measurement computed with the dimensions of the in place material using average-end-area method or prismodial formula.

(3) Material in the Delivery Vehicle. The measurement computed using measurements of material in the hauling vehicles at the point of delivery. Vehicles shall be loaded to at least their water-level capacity. Leveling of the loads may be required when vehicles arrive at the delivery point.

(b) Each (EA). One complete unit, which may consist of one or more parts.

(c) Lump Sum (LS). The quantities that denote one complete unit of work as required by or described in the contract, including necessary materials, equipment, and labor to complete.

thejob.

906.04 Methods of Measurement. One of the following methods of measurement for determining final payment is DESIGNATED ON THE SCHEDULE OF ITEMS for each

PAY ITEM:

(a) Designed Quantities. These quantities denote the final number of units to be paid for under the terms of the contract. They are based upon the original design data available prior to advertising the project. Original design data include the preliminary survey information, design assumptions, calculations, and drawings. Changes in the number of units DESIGNATED IN THE SCHEDULE OF ITEMS may be authorized under the following conditions:

(1) As a result of changes in the work approved by the CO.

(2) As a result of the CO determining that errors exist in the . original design that cause a PAY ITEM quantity to change by 15 percent or more.

(3) As a result of the contractor submitting to the CO a written request showing evidence of errors in the. original design that cause a PAY ITEM quantity to change by 15 percent or more. The evidence must be verifiable and consist of calculations, drawings, or other data that show how the designed quantity is believed to be in error. -

(b) Staked Quantities (SQ). These quantities are determined from staked measurements prior to the construction.

(c) Actual Quantities (AQ). These quantities are determined from measure-ment of completed work.

(d) Vehicle Quantities. These quantities are measured or weighed in hauling vehicles:

(e) Lump Sum Quantities (LSQ). These quantities denote one complete unit of work as required by or described in the contract, including necessary materials, equipment, and labor to complete the job.

906.05 Government-Furnished Materials. When materials are furnished by the Forest Service, the note "Government-Furnished Materials" will be added to the description of the PAY ITEM.

Section 907-Quality Assurance and Quantity Measurement

Description

907.01. Work. Work consists of providing certification that the quality and quantity of construction conform to the drawings, specifications, and requirements of the contract.

Construction

907.02 Certification and Measurements

(a) Offsite-Produced Materials. Furnish signed certificates executed by the manufacturer, supplier, or vendor, stipulating that all offsite-produced materials incorporated in the work meet applicable requirements SHOWN ON THE DRAWINGS or stated in the specifications. Furnish a certificate for each commodity or invoice.

(b) Quantity Measurements. Submit quantities to the CO for periodic progress payments, and the CO will compute payments. Quantities are subject to verification.

907.03 Records. Maintain a set of contract drawings depicting as-built conditions resulting from approved changes. Maintain the drawings in a current condition and indicate changes from the original contract drawings in red. Give the drawings to the CO upon the completion of the contract work.

Measurement

907.04 Method. There will be no separate measurement for this item.

Payment

907.05 Basis. Payment will be considered incidental to other pay items in this contract.

Section 908-Staking, Flagging, and Cleanup

908.01 Work. This work consists of establishing any control points needed in addition to existing staking, and removing and disposing of all construction stakes, tags, flagging, and plastic ribbon from the project area.

Construction

908.02 General. The Government will set initial construction stakes or flagging, and control points, and furnish the contractor with all necessary information relating to lines, slopes, and grades. These stakes and flagging constitute the field control.

Furnish and maintain all additional stakes, flagging, templates, batter boards, and other materials and supplies necessary for marking and maintaining points and lines established.

Do not perform work in the absence of control points. If any-construction control points are destroyed, displaced, or erroneous, notify the CO. Uniformly contour alignment and construct grade from control point to control point.

Remove all construction stakes, tags, flagging, and plastic ribbon from the project area within 7 days after the final inspection of all other work on the project. Dispose of all stakes, tags, flagging, and plastic ribbon off Government-administered lands unless otherwise designated.

Measurement

908.03 Method. There will be no separate measurement for this item.

Payment

908.04 Basis. Trail staking, flagging and cleanup will be considered incidental to other pay items in this contract, and additional payment will not be made.

This page intentionally le=ft blank.

Section 910 Earthwork

Section 911-Clearing and Grubbing

911.01 Work. Work consists of clearing, grubbing, trimming, removing, and treating trees, logs, limbs, branches, brush, plants, and other vegetation within the clearing limits. Work includes the felling and treatment of designated trees outside the clearing limits. Also included are the protection from injury or defacement of trees and other objects not designated for removal and the treatment of damaged trees.

Construction

911.02 Clearing Limits. Clear to the dimensions SHOWN ON THE DRAWINGS or 12" beyond the fill and backslope catch points, whichever is greater.

911.03 Material to Be Cleared. Remove and dispose of trees, logs, limbs, branches, brush, herbaceous plants, and other vegetation within the clearing limits, except for the following:

a) Live, sound, and firmly rooted trees of the size SHOWN ON THE DRAWINGS.

b) Live brush, herbaceous plants, and trees between the trailway and the clearing limits that are less than 12" in height and less than %Z" in diameter at ground line.

Except as provided above, cut all limbs and branches more than i/2" in diameter that extend into the clearing limits. Cut limbs flush with the tree trunks or stems or cut at the ground surface as SHOWN ON THE DRAWINGS.

Fall and limb designated trees.

911.04.Damaged 1Yees. When felling, cutting, or trimming, do not cause bark damage to standing timber. If damage does occur to standing trees, treat the injured trees as SHOWN ON THE DRAWINGS. Remove and dispose of trees with major roots exposed by construction that are rendered unstable.

'911.05 Removal of Stumps. Remove all stumps within the trailbed. Remove stumps located between the edge of the trailbed and the edge of the tramway that cannot be cut flush with the finished slope or that are not tightly rooted.

911.06 Disposal of Clearing Slash, Logs, Stumps, Brush, and Roots. Limb all felled trees to a 4" diameter top, including designated trees outside the clearing limits.

Do not place clearing slash, logs, stumps, brush, or roots in concentrated piles. Scatter all logs, limbs, lopped tops, brush, and grubbed stumps and roots below the trailway and outside the clearing limits, with the following exceptions:

(a) Where the sideslope above the trail is less than 10 percent, material may be scattered above the trail.

(b) Logs may be left on the uphill side of the trail if they are placed so that they will not move into the clearing limits.

Do not place clearing and grubbing debris in water courses, snow ponds, lakes, meadows, or in locations where it could impede the flows to, through, or from drainage structures.

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Measurement

911.07 Method. Measure the quantities in accordance with Section 906.

Payment

911.08 Basis.

Pay for the accepted quantities in accordance with Section 906 at the contract unit price for each PAY ITEM SHOWN IN THE SCHEDULE OF ITEMS.

Make payment under:

PAY ITEM

PAY UNIT

911(01)

Clearing and Grubbing................................................... mi

911(62)

Clearing and Grubbing............................................... . ... L.F.

911(03)

Clearing and Grubbing................................................... LS

911(04)

911(05)

911(06)

911(07)

911(08)

911(09)

Clearing .................::................................................. ..... mi

Clearing ..................................................................... . ... L.F.

Clearing ......................................................................... LS

Grubbing......................................................................... mi

Grubbing......................................................................... L.F.

Grubbing........................................................................ LS

Individual Removal and Disposal .............................. ... EA911(10)

911(11)Individual Removal and Disposal

Section 912-Excavation and Embankment

912.01 Work. Work consists of the excavation and placement of excavated material, regardless of its nature, from within the trailway or from other sources, except for material included under other pay items SHOWN IN THE SCHEDULE OF ITEMS.

Includes excavation, embankment, and backfill construction required to shape and finish the trailbed, ditches, backslopes, fill slopes, drainage dips, trail passing sections, and turnouts.

Also includes excavation and embankment work required to construct shallow stream fords and gully crossings, talus and rubble rock sections, and climbing turns.

Materials

912.02 Requirements. Use materials meeting the requirements of the following sections:

961 - Rock, Grid Pavement Units, and Aggregate 962 - Material for Timber Structures 964 - Geo synthetics

Construction

912.03 Use and Disposal of Excavated Material. Conserve and use all suitable material for specified work Conserve excess excavated rock suitable for specified project work and use in place of materials from designated sources.

Remove all duff and debris from within trailway limits and uniformly spread outside the clearing limits, not more than 4" in depth (unless otherwise SHOWN ON THE DRAWINGS). Do not obstruct drainage or create piles, berms, or windrows of debris.

Place excess and unsuitable excavation beyond the downslope edge of the trailbed Do not obstruct drainage and spread to a depth not exceeding 4". This includes any material removed in the grubbing operation and deposited in the same area.

Place rocks over 4" in greatest dimension not used in construction beyond the hinge point on the downslope side. Place rocks so that the tops are at least 6" lower than the trailbed surface.

Ensure that no blockage of drainage or creation of a windrow effect occurs.

912.04 Trailway Excavation and Embankment. Minor deviations of f 12" in vertical alignment and 36" in horizontal alignment with smooth transitions of at least 30' on each side of the deviation are acceptable unless otherwise SHOWN ON THE DRAWINGS.

Construct embankments with suitable compacted material. Compact all disturbed soil within the trailbed area.

Remove any rock within or above the backslopes that is unstable. Use or dispose of rock in accordance with Subsection 912.03.

Leave the finished slope in a uniform and roughened condition.

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Make necessary adjustments of horizontal or vertical alignment, within the tolerances specified in this subsection, to produce the designed trailway section and balance earthwork.

Such adjustments shall not be considered as changes.

912.05 Trailbed Finish. Fill holes with suitable material, compact, and cut high points to provide a uniform trailbed finish.

912.06 Talus or Rubble Rock Sections. Through talus or rubble rock slide areas, fill all voids with suitable material to the depth SHOWN ON THE DRAWINGS. Use cap rocks that weigh a minimum of 130 lbs and have a length of at least twice their width. At least 50 percent of all hand placed outer rocks should weigh a minimum of 1301bs. Construct tread by building out rather than by removing material from the inner bank.

912.07 Ditches. Construct ditches to be free of loose rocks, roots, sticks, and other obstructions.

912.08 Geosynthetics. Where SHOWN ON THE DRAWINGS, place geosynthetics flat and parallel to centerline of the trail before placing embankment. Overlap geosynthetics a minimum of 24". Install anchors or fasteners as recommended by the geosynthetic manufacturer.

Measurement

912.09 Method. Measure the quantities in accordance with Section 906.

Payment

912.10 Basis. Pay for the accepted quantities in accordance with Section 906 at the contract unit price for each PAY ITEM SHOWN IN THE SCHEDULE OF ITEMS.

912(01)Excavation

912(02)

Excavation mi

912(03)

Excavation

912(04)

Trail Turnout ............................................:

912(05)

Trail Turnout

EA

912(06)

Rolling Dip

912(07) . Shallow Stream Ford and Gully Crossing Structure ...............................................:........ EA

912(08)

Shallow Stream Ford and Gully Crossing Structure ........................................................ LS

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912(09)

Ditch

912(10) Borrow...............................::.......................................... C.Y.

912(11) Borrow........................................................................... LS

912(12)

Grade Dip

FA

912(13)

Geosynthetics, Type

......................................... S.Y.

912(14)

Trail Passing Section..................................................... L.F.

912(15)

Talus or Rubble Rock Section

Section 913-Turnpike

913.01 Work. Work consists of constructing turnpike sections, including excavation, embankment, retainers, geosynthetics, backfill, and drainage features.

Materials

913.02 Requirements. Use materials meeting the requirements of the following sections:

961 - Rock, Grid Pavement Units, and Aggregate 962 - Material for Timber Structures 964 - Geosynthetics

Construction

913.03 Excavation and Embankment. Perform excavation and embankment in accordance with Section 912.

913.04 Retainers. Place log, sawn timber, or rock retainers in a continuous row along each shoulder of the turnpike section as SHOWN ON THE, DRAWINGS. Bed the parallel retainers so they are stable and at approximately the same top elevation. When retainers are constructed of logs or sawn timber use lengths greater than or equal to 10'.

913.05 Geosynthetics. Where SHOWN ON THE DRAWINGS, place geosynthetics flat and parallel to centerline of the trail before placing embankment. Overlap geosynthetics a minimum of 24". Install anchors or fasteners as recommended by the geosynthetic manufacturer.

913.06 Backfill. Backfill and compact with suitable material.

913.07 Drainage. Construct side ditches, cross-drainage, and culverts at locations SHOWN ON THE DRAWINGS and/or DESIGNATED ON THE GROUND. Provide leadoff ditches from side ditches on the lower side of trail at points DESIGNATED ON THE GROUND or SHOWN ON THE DRAWINGS.

913.08 Method. Measure the quantities in accordance with Section 906.

913.09 Basis. Pay for the accepted quantities in accordance with Section 906 at the contract unit price for each PAY ITEM SHOWN IN THE SCHEDULE OF rFEMS.

PAY ETEM

913(01)

Turnpike -Retainer, Type ............................... L.F.

913(02)

Side Ditch ...................................................:

913(03)

Geosynthetics, Type ...................................... S.Y.

913(04)

Leadoff Ditches ...... :........................................ .............. L.F.

913(05)

Borrow .......................................................................... C.Y.

913(06)

Borrow ....................................................................:..... LS

Section 914-Switchbacks

914.01 Work Work consists of construction of switchbacks, including excavation, associated barriers, ditches, retaining walls, and approach sections.

Materials

914.02 Requirements. Use materials meeting the requirements of the following sections:

961 - Rock, Grid Pavement Units, and Aggregate 962 - Material for Timber Structures

Construction

914.03 Excavation and Embankment. Perform excavation and embank-ment in accordance with Section 912.

914.04 Retaining Walls. When SHOWN ON THE DRAWINGS, construct retaining walls in accordance with Section 934 or Section 935.

914.05 Barriers. When SHOWN ON THE DRAWINGS, construct barriers at each switchback in accordance with Section 953.

914.06 Ditches.. When SHOWN ON THE DRAWINGS, construct ditches in accordance with Section 912.07.

914.07 Limits of Switchback Beginning and ending of switchback will be as SHOWN ON THE DRAWING or as DESIGNATED ON THE GROUND.

Measurement

914.08 Method. Measure the quantities in accordance with Section 906.

Payment

914.09 Basis. Pay for the accepted quantities in accordance with Section 906 at the contract unit price for each PAY ITEM SHOWN IN THE SCHEDULE OF ITEMS.

914(01)

Switchbacks, Type

............................. Ea

914(03)

Ditch ......................................................................... L.F.

914(05)

Barriers, Type

.................................... L.F.

914(06)

Retaining Walls, Type

........................ S.Y.

Section 915-Existing Trail Restoration

915.01 Work Work consists of restoring the original trail template, including clearing, removing slough and berm, borrow, filling ruts and troughs, reshaping backslopes, excavation, reshaping trail tread, restoring drainage and other trail structures, constructing check dams, and removing protruding rocks, roots, stumps, slough, and berets.

Materials

915.02 Requirements. Use materials meeting the requirements of the following sections:

961 - Rock, Grid Pavement Units, and Aggregate 962 - Material for Timber Structures

Construction

915.03 Clearing and Grubbing. Clear and grub in accordance with the requirements of Section 911 and as SHOWN ON THE DRAWINGS.

915.04 Excavation and Embankment. Excavate and place all excavated material in accordance with the requirements of Section 912 and as SHOWN ON THE DRAWINGS.

915.05 Rock and Root Removal. Uniformly scatter the removed rocks and roots below the trailway and distribute to ensure no blockage of watercourses or creation of a windrow. Fill holes with suitable material and compact.

915.06 Slough and Berm Removal and Excess Material. Use suitable slough and beret material within the trailway to restore the trailbed as SHOWN ON THE DRAWINGS. Place all unsuitable and excess material beyond the downslope edge of the trailbed and uniformly spread to a depth not exceeding 4" and so as not to obstruct drainage or interfere with the drainage of outsloped tread.

Remove berm when daylight can be obtained within a distance of 5' from the outslope edge of finished tread unless otherwise DESIGNATED ON THE GROUND or SHOWN ON THE

DRAWINGS.

915.07 Fill Material and Borrow. Use suitable material to fill ruts, troughs, and potholes in the tread that cannot be leveled and outsloped through performance of work in Subsection

915.06. Compact and shape as SHOWN ON THE DRAWINGS.

Obtain borrow from areas SHOWN ON THE DRAWINGS or DESIG-NATED ON THE

GROUND.

915.08 Drainage. Restore drainage dips and ditches to reestablish drainage as SHOWN ON THE DRAWINGS by removing obstructions such as rocks, roots, and sticks to make ditches and culverts free draining.

Restore rock spillways in accordance with Section 923 and as SHOWN ON THE

DRAWINGS.

915.09 Stream Channel Cleaning. Clean channel of obstructions in areas SHOWN ON THE DRAWINGS. Remove debris and rocks from the stream channel and scatter outside of the side slopes of the stream channel and beyond the clearing limits.

915.10 Check Dams. When constructing check dams for gullies, use dimensional lumber, sound peeled logs, or a row ofstones placed across the gully in the subgrade with the ends securely embedded in the banks as SHOWN ON THE DRAWINGS and at locations

STAKED ON THE GROUND.

Use suitable material for backfill as SHOWN ON THE DRAWINGS. Place and compact backfill to meet the density of the existing trailbed and to form a smooth tread.

915.11 Switchbacks. Restore switchbacks in accordance with Section 914 and as SHOWN

ONTHE DRAWINGS.

915.12 Waterbars. Restore waterbars in accordance with Section 922 and as SHOWN ON THE DRAWINGS. Reestablish drainage by removing accumulated material and replacing loose or missing rocks, unsuitable logs, and deteriorated rubber belting.

915.13 Turnpikes. Restore turnpikes in accordance with Section 913 and as SHOWN ON THE DRAWINGS by replacing missing, rotten, or loose retainer logs and stakes, or missing or loose retainer rocks. Backfill with suitable material.

915.14 Trail Structures. Restore all trail structures at locations SHOWN ON THE DRAWINGS or DESIGNATED ON THE GROUND.

915.15 Reshaping and Finishing Trailbed and Backslopes. Provide a firm and uniformly finished trailbed in accordance with cross-sections SHOWN ON THE DRAWINGS.

Provide a uniform and roughened surface on disturbed backslopes in accordance with cross-sections SHOWN ON THE DRAWINGS. Gut all roots flush.

Measurement

915.16 Method. Measure the quantities in accordance with Section 906.

Payment

915.17 Basis. Pay for the accepted quantities in accordance with Section 906 at the contract unit price for each PAY ITEM SHOWN IN THE SCHEDULE OF ITEMS.

915(01)

Trail Restoration............................................................ L.F.

915(02)Trail Restoration

915(03) Check Dams

915(04)Borrow........................................................................... C.Y.

Section 916-Removal of Structures and Obstructions

916.01 Work Work consists of removal and disposal of existing structures, including turnpikes, walkways, bridges, culverts, signs and posts, and other material within the trailway, above or below ground. Work also includes salvaging DESIGNATED materials and backfilling the resulting trenches, holes, and pits.

Construction

916.02 Removal of Culverts and Bridges. Remove existing culverts within embankment areas at locations SHOWN ON THE DRAWINGS.

Remove existing structures down to the natural stream bottom, and remove parts outside the water course to at least 12" below natural ground surface or finish ground surface, whichever is lower. Where portions of an existing structure he wholly, or in part, within the limits of a new structure, remove parts to accommodate the installation of the proposed structure.

Avoid damage to bridges being dismantled for salvage. Matchmark steel and/or wood members and prepare drawings showing the structural location of each member.

916.03 Signs and Posts. Remove signs, posts, and associated hardware at locations SHOWN ON THE DRAWINGS or DESIGNATED ON THE GROUND. Backfill post hole, compact, and contour area to match existing ground.

916.04 Removal of Other Obstructions. Remove other obstructions at locations SHOWN ON THE DRAWINGS or DESIGNATED ON THE GROUND.

916.05 Disposal. Dispose of native log and rock material by scattering below the trailway and outside clearing limits. Do not place debris in water courses, snow ponds, lakes, meadows, or locations where it could impede the flow to, through, or from the drainage structures. Dispose of metal, treated timber, and other manufactured products by removing from Government-administered lands and placing in approved waste disposal sites.

Measurement

916.06 Method. Measure the quantities in accordance with Section 906.

Payment

916.07 Basis. Pay for the accepted quantities in accordance with Section 906 at the contract unit price for the PAY ITEM SHOWN IN THE SCHEDULE OF ITEMS.

916(01)

Removal of Structures and Obstructions ..................... LS

916(02)

Removal of

................ EA

916(03)

Removal of

............... L.F.

Section 920 Drainage

Section 921-Culverts

921.01 Work Work consists of furnishing and installing culverts, including excavation and backfill, selecting and hauling of log and rock materials, and constructing catch basins, and headwalls.

Materials

Construction

921.02 Requirements. Use materials meeting the requirements of the following sections:

961 - Rock, Grid Pavement Units, and Aggregate 962 - Material for Timber Structures 963 - Drainage Pipe 964 - Geo synthetics

921.03 Excavation and Embanl ment. Perform excavation and embank-ment in accordance with Section 912.

921.04 Placement. Place culverts to provide for unobstructed inlet and outlet flow. Remove logs, debris, soil, rock, and other obstructions above and below the culvert that would impede flow into the culvert or away from the trailway. Minimize disturbance to streambeds.

Construct a catch basin to facilitate flow from trail ditches into the culvert.

921.05 Pipe Culverts. Install pipe culverts at the locations SHOWN ON THE DRAWINGS or as DESIGNATED ON TILE GROUND.

(a) Placing. Skew ditch relief culverts as staked to provide a downgrade equal to or greater than the uphill ditch. Place culverts at stream crossings in the natural streambed on stream grade.

Attach end sections to the pipe by connecting bands or other means as recommended by the manufacturer.

(b) Bedding. Excavate and remove all unsuitable material and rocks over 3" to a minimum depth of 6" below the pipe invert and to a minimum width of 1.5 pipe diameters. Bed pipe with compacted suitable material free of rocks larger than 3" and in a stable foundation of undisturbed or compacted soil. Make the bed shaped to fit the lower quadrant of the pipe exterior and provide uniform continuous support along the entire length of the pipe.

921.06 Rock Culverts. Install rock culverts at the locations SHOWN ON THE DRAWINGS or as DESIGNATED ON THE GROUND.

Firmly embed selected sidewall rocks below the natural ground or streambed as SHOWN ON THE DRAWINGS. Use flat cover rocks long enough to bridge between outside faces of the sidewalls. Select and place rocks so as to fit snugly with firm bearing on underlying rocks. Fill voids with small rock to prevent entry of soil into the culvert.

921.07 Treated Timber Box Culverts. Install box culverts at the locations SHOWN IN THE DRAWINGS or as DESIGNATED ON THE GROUND.

Place the box culvert walls on a firm foundation of undisturbed or compacted suitable material shaped to fit the bottom of the culvert walls and free of rocks larger than 3" in size.

921.08 Backfilling Culverts. Backfill and compact around culverts with suitable material that is free of rocks over 3". Provide for the cover height as SHOWN ON THE DRAWINGS.

921.09 Headwalls. Install headwalls at the locations SHOWN ON THE DRAWINGS or as

DESIGNATED ON THE GROUND.

Provide a compacted bench as a foundation for the wall.

Select rocks that have a general rectangular shape with flat top and bottom faces. Place the largest rocks on the bottom. Lay each rock stable on the course that supports it, interlocking with surrounding rocks. Do not break, jar, or displace rocks already set. Place the exposed face of each rock parallel to the face of the wall. Stagger vertical joints a minimum of 4" horizontally from vertical joints in adjoining courses.

Measurement

921.10 Method. Measure the quantities in accordance with Section 906.

Payment

921.11 Basis. Pay for the accepted quantities in accordance with Section 906 at the contract unit price for each PAY ITEM SHOWN IN THE SCHEDULE OF ITEMS.

921(01) inches Corrugated, Type Pipe -inches Thickness................................ L.F.

921(02) inches Non-Corrugated, Type Pipe -____inches Thickness .............................. L.F.

921(03) inches End Section, Type

................... EA

921(04)

Rock Culverts ................................................ EA

921(05)

Rock Culverts ................................................. L.F.

921(06)

Treated Timber Box Culverts .............................. EA

Section 922-Waterbars

922.01 Work: This work consists of installing waterbars, including excavation and backfill;

selecting log and rock materials; and furnishing treated timber, belting, and other materials.

Materials

961 - Rock, Grid Pavement Units, and Aggregate 962 - Material for Timber Structures

Use rubber belting that is single-ply, non-reinforced material 3/8" to 1/2" thick.

Construction

922.03 General. Install waterbars of the types and at the locations SHOWN ON_ THE DRAWINGS or as DESIGNATED ON THE GROUND.

Measurement

922.08 Method. Measure the quantities in accordance with Section 906.

922.02 Requirements. Use materials meeting the requirements of the following sections:

922.04 Excavation and Embankment. Perform excavation and embank-ment in accordance with Section 912. Around waterbars, backfill and compact suitable material that is free of rocks larger than 3" in size. Compact material on the downgrade side of rock, log, and treated timber waterbars, flush with the top of waterbars.

Outslope the trailbed on the upgrade side of the waterbar with a slope equal to or greater than the trail grade leading into the waterbar. Provide a uniform outsloped plane that forms a gutter against the waterbar.

922.05 Rock Waterbar. Tightly embed selected rocks into the trailbed Place waterbar rocks with tops relatively even, with no sharp points. Use rocks with lengths greater than or equal to 1.5 times the width.

922.06 Log or Treated Waterbar. Embed peeled native logs or treated timbers into the trailbed to form a waterbar across the trail. Use anchor methods as SHOWN ON THE DRAWINGS at log or timber ends outside the trail tread. Pre-drill pilot holes (for steel pins) through timbers prior to treatment. Anchor stakes firmly in the ground, and tightly nail to the log without splitting. In the absence of a backslope, anchor the upgrade end of the log or timber waterbar in the same manner as the downgrade end.

922.07 Rubber Belting Waterbars: Tightly secure one continuous piece of rubber belting between treated timbers as SHOWN ON THE DRAWINGS.

922.09 Basis. Pay for the accepted quantities in accordance with Section 906 at the contract unit price for each PAY ITEM SHOWN IN THE SCHEDULE OF ITEMS.

922(01)

Native Log Waterbar ........................................ EA

922(02)

Rock Waterbar ................................................ EA

922(03)

Treated Timber Waterbar ................................... EA

922(04)

Rubber Belting Waterbar ................................... EA

Section 923-Rock Spillways

923.01 Work. This work consists of constructing rock spillways, including selecting, excavating, and placing rock material.

Materials

923.02 Requirements. Use materials meeting the requirements of Section 961.

Construction

923.03 General. Construct rock spillways at locations SHOWN ON THE DRAWINGS or DESIGNATED ON THE GROUND. Construct spillways so the flow of water from the facility being drained is centered on and flows down the full length of the spillway.

923.04 Excavation. Excavate for the spillway in accordance with Section 912. Construct a horizontal bench into undisturbed material and compact it as a foundation for the toe of the rock spillway.

923.05 Rock Placement. Construct the spillway by hand-placing rock, with the larger rock in the bottom layers. Place each rock to provide a stable course. Interlock each rock with adjacent rocks, and minimize voids. Use small rocks to fill voids. Do not break, jar, or displace rocks already set.

Measurement

923.06 Method. Measure the quantities in accordance with Section 906.

Payment

923.07 Basis. Pay for the accepted quantities in accordance with Section 906 at the contract unit price for each PAY ITEM SHOWN IN THE SCHEDULE OF ITEMS.

923(01)

Rock Spillway .............:.................................................. EA

923(02)

Rock Spillway ................................................................ S.Y.

Section 924-Underdrain

924.01 Work This work consists of constructing underdrains and associated drainage ditches, including excavation and backfill and obtaining and installing filter rock, geosynthetics, and drainpipe with necessary fittings.

Materials

924.02 Requirements. Use materials meeting the requirements of the following sections:

961 - Rock, Grid Pavement Units, and Aggregate 963 - Drainage Pipe 964 - Geo synthetics

Construction

924.03 General. Construct underdrains at locations SHOWN ON THE DRAWINGS or

DESIGNATED ON THE GROUND.

924.04 Excavation and Embankment. Perform excavation and embank-ment in accordance with Section 912.

924.05 Trench Construction. Grade underdrain trenches to provide complete drainage of the underdrain system. Obtain CO approval of the trench system prior to placement of underdrain materials.

924.06 Pipe Installation. Ensure positive drainage from the underdrain pipes and drainage system. Place pipe in the trench with the perforations down.

Measurement

924.07 Method. Measure the quantities in accordance with Section 906.

Payment

924.08 Basis. Pay for the accepted quantifies in accordance with Section 906 at the contract unit price for each PAY ITEM SHOWN IN THE SCHEDULE OF ITEMS.

924(01)

Rock Underdrain

L:F.

924(02)

Rock Underdrain, Type

Drain Pipe .................... L.F.

" diameter

924(03) Geosynthetic,Type

........................................... S.Y.

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Section 930 Structures

Section 931-Log Stringer Bridge

931.01 Work. This work consists of constructing log stringer bridges, including mud sills, bulkheads, rails, curbs, decking, excavation, backfill, and approach fills as SHOWN ON

THE DRAWINGS.

Materials

931.02 Requirements. The location of trees for native timber materials will be SHOWN ON THE DRAWINGS and DESIGNATED ON THE GROUND. Use materials meeting the requirements of Section 962.

Construction

931.03 General. Construct log stringer bridges at locations SHOWN ON THE DRAWINGS or DESIGNATED ON THE GROUND. Pre-drill holes for fasteners when necessary to prevent splitting and drive spikes flush. Use washers with lag screws and bolts.

931.04 Excavation and Embankment. Perform excavation and embank-ment in accordance with Section 912.

931.05 Mud Sills. Construct mud sills at each end of the span in the location staked on the ground. Construct mud sills to be level, bedded evenly, and buried to the depth necessary for the bottom of the log stringers to clear the ground surface by a minimum of 6".

Hew sill logs to provide a bearing surface for the log stringers and to provide the log stringers with a level top surface. Do not hew sill logs more than one-third their diameter. Do not level the top surfaces of the log stringers by shimming or notching their ends.

931.06 Stringers. Fasten each log stringer to each mud sill with drift pins that penetrate a minimum of 4" into the mud sill.

When plank decking is used, hew the top surfaces of log stringers up to 2" deep, as necessary, to provide bearing surfaces for deck planks.

931.07 Decking. Spike decking evenly at right angles to each stringer, unless otherwise

SHOWN ON THE DRAWINGS.

Lay split log decking alternately flat side down first, then round side down, ending with a flat side down. When the round side is down, provide a bearing surface that is between 1'/Z" and 2" wide.

Lay split and sawn deck planks on the stringer to provide bearing for the full width of the plank.

Trim protruding ends of the decking to give a straight-line appearance to the edges of the structure, except for decking that extends out to provide handrail support.

931.08 Curbs. Construct curbs with logs or sawn timber as SHOWN ON THE DRAWINGS. Use lengths greater than or equal to 10' and splice with a 6" half-lap joint at a spacer location. Match diameters of logs at lap joints and trim excess to provide a smooth transition between logs.

Counterbore lag screws in curbs so that heads are flush with the surface.

Finish curbs smooth and free from splinters and sharp projections.

931.09 Handrails. Construct rails with logs or sawn timber as SHOWN ON THE DRAWINGS and use lengths greater than or equal to 10'

When rails are constructed of logs, splice them with…