S-10-0296 913_turnpike_std.doc

Section C

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Section 913 -- Turnpike

Description

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

Materials

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

Construction

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

Prepare trailbed wide enough to allow for ditches where required and to have adequate undisturbed ground to support retainer stakes on both sides. Trailbed shall be constructed so that retainer logs are supported full length and not placed on a fill.

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. Use only single high retainers except at overlap sections with steps. Avoid sharp bends along the length of the turnpike and at the approaches.

Where logs butt to one another they should be approximately the same diameter and top elevation. Except where constructing steps or where forming a bend in the turnpike, use side retainers at least 10 feet long.

When retainers are constructed of rocks, adjacent rocks should be at approximately the same top elevation. Interlock each rock with adjacent rocks, and minimize voids. Use smaller rocks to fill voids before placing geotextile and backfill.

On grades greater than 8% or where NOTED ON THE TRAIL LOG install cross retainer logs at 6-foot intervals and install an end retainer log. Cross and end retainer logs shall be approximately the same diameter as the adjacent side retainer logs and the tops shall be installed flush with top the side retainers.

913.06 Geotextiles. Place geotextile fabric flat and parallel to centerline of the trail and under the log or rock retainers before placing backfill. Place, cover, or trim fabric so that it will not be visible upon completion of the turnpike. Overlap adjoining pieces of fabric a minimum of 24 inches.

913.07 Backfill. Fill the space between the retainers with compacted select borrow. As an alternative, the space may be filled to one-half the required depth with rock, then capped with select borrow. All voids in the rock shall be filled with the select borrow.

Obtain select borrow from borrow sources NOTED ON THE TRAIL LOG. Material from tread excavation and ditches, with the exception of rock, shall not be used for backfill.

913.08 Drainage. Construct side ditches, cross-drainage, and culverts at locations NOTED ON THE TRAIL LOG or DESIGNATED ON THE GROUND.

Construct outlet ditches from side ditches on the lower side of trail as necessary to provide drainage. Where outlet ditches will not drain within 20 feet of the turnpike, construct an 18-inch diameter drain sump to a minimum depth of 24 inches and located at least 5 feet from turnpike side ditch. Fill sump with coarse rock.

Measurement

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

Payment

913.10 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.

The following will be considered incidental to the PAY ITEMS SHOWN IN THE SCHEDULE OF ITEMS and extra payment will not be given:

(a) Side ditches, outlet ditches, drain sumps, select borrow, and geotextile fabric constructed or installed as part of the turnpike.

(b) Any clearing or grubbing necessary in the reconstruction segments.

Make payment under:

PAY ITEM

PAY UNIT

913(01) Turnpike - Log or Rock Retainer

LF

913-1 (12/12/2009)