Specifications_Sand_Bunkers.pdf

The Better Billy Bunker Specification

Sand Selection for Bunker

Testing procedure of the bunker sand must be completed in accordance with the specifications for proper particle size, color, drainage characteristics, angularity, angle of repose and bridging with the drainage stone. A “column test” can also be one of the tests on the sand to determine the perched water table over the approved stone. The goal is to have at least an inch of dry sand above the perched water table. It is also important to determine the angle of repose to be tested while the sand is relatively dry.

A simple method is to pile the sand on a level surface and measure the angle of the pile using a measuring device such as a calibrated digital level. Testing of the sand and its characteristics should be accomplished by an accredited lab prior to final selection.

Subgrade of Bunker

The subgrade of the bunker shall be graded or shaped or reshaped in according to plans and artistic shaped as described by the golf course architect. The floor of the bunker’s slopes where bunker sand will ultimately be placed must be equal to or be less than 100% of the angle of repose of the tested sand (80% of the sand’s angle of repose is suggested). The floor should be smooth and compacted.

Drainage

The floor of the bunker must have excavated drainage trenches that are wide enough so that the perforated drain pipe can be installed and surrounded by gravel. The pattern is such that the perforated drain pipes do not exceed 12’ (4M) from the edge of the bunker or from other perforated drain pipe. All loose soil shall be removed so that the floor of the bunker is smooth.

A four-inch (101 mm) or greater perforated drain pipe should be installed in the trenches and be surrounded by pea gravel. Gravel surrounding the pipe shall be washed pea gravel as approved and not exceeding ½ “ (12mm) in size. A locater wire shall then be laid and connected in the trench with the p

The specified product, material, or system sets a standard for quality, functionality, and performance. Bidders may propose alternatives that are of equal or superior quality and meet or exceed the specifications outlined. Proposed alternatives must be accompanied by supporting documentation, including detailed specifications, test results, and certifications, to demonstrate equivalency. The final determination of equivalency shall be at the sole discretion of the City of Edinburg.

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Gravel Blanket Layer

A layer of clean approved gravel (3/16”-3/8”) (4.5mm-9.53mm) shall be placed over the entire floor of the bunker at least 2” (two inches ) (51mm) deep. This gravel should be brought up within 4" of the edge of the bunker (to account for 4" of bunker sand). The gravel selected is to be tested by an accredited soils lab for bridging with the selected sand. This common criterion is based on engineering principles that rely on the largest 15% of the sand particles "bridging" with the smallest 15% of the gravel particles. 100% of gravel particles should pass 1/2”. The gravel must be placed evenly and raked smooth.

ST410 POLYMER Binder Application

ST410 POLYMER shall be sprayed by a certified and trained installer. Using proper pressure spray equipment, a uniform layer of ST410 POLYMER shall be applied to the gravel in the bunker at a rate 1 gallon of ST410 POLYMER per 30-35 square feet. The gravel must be dry (less than 15% as tested by the certified installer) at application time.

The treated bunker shall be allowed to cure for approximately 24 hours prior to sand installation. NOTE: ST410 POLYMER will penetrate approximately ½ - 1” (12mm - 25mm) depth of the gravel. A sturdy pliable layer of glued gravel will be the result.

Sand Installation

The tested and approved bunker sand is installed in the bunker and compacted at least four inches deep. Care must be taken to prevent damage to the gravel layer, perforated drain pipe, and bunker edge while sand is being installed.

Existing fabric liners

(OPTION – not required) The architect or owner may elect to keep part of an existing liner in a bunker should it be deemed beneficial. The liner will act only as a barrier between the subgrade and the gravel layer. All sand should be total removed above the liner and the two inch layer of stone placed over the liner. No liner should be left over trenches or within three feet of any edge. If a liner is left in an existing bunker it should be smooth and secure in a manner so that it is never exposed. In all cases, BBB Inc. will be notified that an existing liner is to remain.

Sodding

Washed turf grass sod is preferred and is to be placed around the bunker as shown in the approved profiles. Unwashed sod may be used as approved by the golf course architect as long as no contamination will occur. No exposed soil edges should be left without sod or treated gravel or the sand will become contaminated.

Post-Testing, Quality Control, and Maintenance

Inspection and Quality Control

After 12-24 hours, the ST410 POLYMER application will have cured and an inspection must occur

Every Square foot (meter) of every bunker MUST be inspected prior to the job being considered complete.

Improper application can leave areas weak and rock loose. Those areas must be touched up with more ST410 POLYMER.

Loose rock on the soil or grass next to the bunker that was not treated must be blown away from the bunker or the sand will be contaminated.

It is installer’s responsibility to inspect and maintain the highest standards on when installing the Better Billy Bunker.

Sand Installation

Once the bunkers have been inspected and are deemed to be ready for sand, and the ST410 POLYMER has cured for 24 hours, sand may be installed. Sand should always be installed when it is slightly damp. Dry sand should never be installed in the Billy Bunker gravel floor. Installing dry sand will allow some particles to move through the glued stone and may reduce the drainage capabilities of the gravel. Sand may be installed in a number of methods, but at no time may any heavy equipment be allowed to cross the edges of the stone.

Small pronovost wagons with light loads may be used to dump sand along the sides of the bunkers. Once an adequate amount of sand is in the bunker, plywood may be placed over at least twelve inches of sand and the carts may run over the sand and plywood.

Conveyor augers are a very good way to install the sand in the bunkers. The installer must make sure that the sand is moist when installing sand using a conveyor.

Sand Compaction

The sand should be compacted in a manner that is consistent with normal practices. We do suggest using a plate tamper on wet sand. Some sands may require no tamping. The lab that did the testing will likely have a recommendation.

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