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TRENCH SYSTEMINSTALLATION GUIDELINES

#0347.45 (2/12)

Trench Installation Guidelines

2Trench System

EMAIL:info@concastinc.com WEB: www.concastinc.com

Fibercrete®

The following guideline is provided to assist in the installation of the Concast Trench Distribution System. Please read through the guideline in its entirety before beginning the installation.

Drainage of the entire yard should be considered. The trench should slope away from the control house and utility buildings, and the substation yard should drain away from the trench. For installations where the yard is not draining away from the trench, installations where the trench will be subjected to flooding, or for installations in soils containing clay; a drain system will be required around the trench. The drain system should be built by placing a 4" perforated pipe along the base of the trench. The pipe should drain the water away from the trench walls. A minimum of 4 inches of coarse stone should be placed under and around the perforated pipe. A minimum of 8 inches of coarse stone should be placed against the walls of the trench. A geotextile filter fabric should be installed between the coarse stone and any soil containing fine particles such as clay, top soil, silt, or sand. Drain tile can be used for certain sub soil condi-tions. It is to be placed beneath the trench channel and can run parallel or perpendicular to the trench.

A polyurethane caulk such as Vulkem is recommended for use as a joint sealant in special cases where fine sand or silty conditions exist, and in areas where there is often heavy run off situations.

Concast provides you with large scale installation drawings and details of all typical layouts. Each trench part is labeled so its position can be easily located. Review all drawings before beginning installation, as they will aid in the location and depth of excavation.

There are five basic parts to the Fibercrete ® trench system:

Standard Channels•Universal Channels•Transition Channels•Covers•End Plates•

Fibercrete ® trench channels have male and female interlocking ends to help in the alignment of each section and to "key" the channels. This effectively reduces the possibility of shifting when backfilling; thus adding to the future stability of the system.

The universal channel is used to form ells, tees, and crosses. Any combination of standard width openings can be made in any uni-versal channel to form a smooth transition from one trench to another. The transition can be made in the form of either an ell, tee, or cross. If an ell, tee or cross must be located precisely, it is recommended to begin with the universal channel. All of the universal channels have a cover support bar(s) spanning the sidewall opening.

Concast trench can be placed above or below grade, to any depth that does not exceed the overall channel depth. No special hardware or parts are required for an above grade installation.

A use of a level bed of porous sand and gravel mix 4 inches deep is recommended to allow for drainage and leveling. The porous material should be laid over a firm level, and mechanically compacted earth.

For below grade trench installation, the excavation should be 8-10 inches wider then the overall trench width, and 4-6 inches deeper then the specified trench base elevation.

Place 2x4 screeds along the edge of the excavated area to support a sand bed. Use a transit or level to set the screed grade. After setting the screed elevations, add sand be-tween the screeds and rake off the excess, leaving the screeds slightly overfilled.

Installation Guidelines

3Trench System

PHONE: 507-732-4095 FAX: 507-732-4094

Fibercrete®

Compact the sand either by hand or with mechanical com-pactors. After compacting, add additional sand as required to maintain a level sand bed be-tween screeds.

After completing the compacting and leveling of the sand bed, the trench is ready to be set in place. To keep the trench properly aligned, the use of a sting line is highly recom-mended.

The light and heavy traffic channels are used in areas of traffic or heavy stress. The finished grade of the traffic rated channel depends on the user's preference. The bottom of all traffic rated channels has a much thicker base than the pedestrian rated channel. There-fore, the sand bed must be screeded at a lower elevation for traffic rated channel to align properly with the pedestrian rated channel.

It is generally preferred to have traffic rated and pedestrian rated trench covers flush (at the same grade). To accomplish this, the traffic rated channel's base is set lower than pedestrian channels base (refer to the channel drawings). Concast manufactures a pedestrian rated transition channel to provide a smooth internal transition between the two. If it is preferred to have the traffic rated channel at a higher elevation than the pedestrian channel, adjust the sand bed elevation accordingly.

A light duty crane or fork lift truck with a jib extension is required for installing traffic rated channel. Lifting inserts are cast into the base of each channel. Thread four eyebolts or hoist rings (Concast part number 9002) all the way into the threaded inserts before lifting. Then use a cable sling or spreader bar with hooks for lifting. For installations where traffic rated trench is used in the entire system, Concast swivel hoist rings and 4 way chains are recommended.

If partition boards are to be used for cable separation, they should be set in place before the cable is laid in the trench. Place the parti-tion boards in the channel where required.

After partitions have been set, place an additional bed of sand over the partition's base to hold them in place, and to serve as a level bed for the cables. This internal sand bed should be a minimum of 2 inches deep, or greater, depending on the internal trench depth required.

PART NO. 9002

4Trench System

EMAIL:info@concastinc.com WEB: www.concastinc.com

Fibercrete®

Concast Trench Installation

Standard pedestrian channels have notches for cable clips. Flush pedestrian channels are pre-drilled for clips. Traffic rated channel have threaded inserts cast into the sidewalls for cable clips. Ground cable clips can be included when requested. Mounting hardware is provided for traffic rated and flush designs.

End plates are designed to bulkhead all dead ends. The open bottom channel design allows cable to make an easy transition from channel to direct burial at these points. End plates are also used to close unused openings in universal channel. End plates are secured in place by the backfill material.

Before backfilling, covers should be set in place on their corresponding channels. Covers are sized to eliminate any need for span-ning the channel joints. Special length covers are provided for special length channels. A very slight difference in elevation at channel joints due to ground settling will cause covers to rock if joints are spanned. Only place the required number of covers per channel. Otherwise, large gaps will occur between covers on longer trench runs. The ribbed design on the pedestrian cover's bottom surface serves as a spreader support for the channel's sidewalls. All pedestrian rated channels are packaged with wood spreader boards that are banded to the channel for shipping and handling. The spreader boards should be left on the channels until backfilling is complete or covers are installed.

Backfill by hand or with light equipment only.

Backfilled area should be com-pacted upon completion.

A bed of coarse rock is recommended to bring yard up to final grade. The final grade must be maintained flush with the top of the road crossing sections. At high frequency traffic areas, the earth should be well compacted. A cement slurry or a concrete apron is also recommended. This will reduce impact loading and possible chipping and cracking on the edges of channels.

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Zumbrota, MN 55992-0069