Gold Course Bunker Edge Stabilization Materials, System and Method

Information

  • Patent Application
  • 20170225051
  • Publication Number
    20170225051
  • Date Filed
    February 10, 2017
    8 years ago
  • Date Published
    August 10, 2017
    7 years ago
Abstract
Apparatus and associated methods relate to adapting a planar structure section to be retained against a cavity wall, stacking a first layer of the planar structure section and a second layer of a granular substance against the cavity wall, and constructing a barrier based on securing the stacked layers against the cavity wall with a barrier edge formed based on applying a coating of a viscoelastic substance and a coating of a loose-fill material to the stacked layers. In an illustrative example, the cavity wall may be a golf course bunker wall. The planar structure section may be, for example, carpet. In some embodiments, the granular substance may be sand. In various designs, the viscoelastic substance may be a prepolymer, and the loose-fill material may be peat moss. Various examples may advantageously provide more durable golf course bunker edges having improved playability at reduced maintenance effort and lower cost.
Description
TECHNICAL FIELD

Various embodiments relate generally to barrier construction and more particularly to golf course bunker edge stabilization.


BACKGROUND

Golf is a target game played on a tract of land known as a golf course. A player of golf may be known as a golfer. A golfer may play golf based on hitting a golf ball from a teeing area to reach the target. A golf course designer may challenge the golfer's skill by placing obstacles, known as golf course hazards, between the teeing area and the target. Some golf course hazards take the form of excavated cavities known as golf course bunkers. Some bunkers may be filled with sand. Sand in a golf course bunker may present a difficult playing condition to a golfer hitting a golf ball from the sand.


Golfers may prefer bunker edge characteristics that remain consistent over time. The rules of golf require a distinctive bunker edge to aid in determining whether a golfer's ball is within the hazard. Natural bunker edges may deteriorate due to environmental exposure, turf growth, erosion, and wear and tear due to player activity. Golf courses may employ maintainers known as green keepers to install, repair, and replace golf course bunker edges as they degrade. Maintaining sharp, vertical golf course bunker edges for consistent playability and appearance over time may be very costly. Deeper bunkers having larger bunker edges may be prohibitively expensive to maintain.


SUMMARY

Apparatus and associated methods relate to adapting a planar structure section to be retained against a cavity wall, stacking a first layer of the planar structure section and a second layer of a granular substance against the cavity wall, and constructing a barrier based on securing the stacked layers against the cavity wall with a barrier edge formed based on applying a coating of a viscoelastic substance and a coating of a loose-fill material to the stacked layers. In an illustrative example, the cavity wall may be a golf course bunker wall. The planar structure section may be, for example, carpet. In some embodiments, the granular substance may be sand. In various designs, the viscoelastic substance may be a prepolymer, and the loose-fill material may be peat moss. Various examples may advantageously provide more durable golf course bunker edges having improved playability at reduced maintenance effort and lower cost.


Various embodiments may achieve one or more advantages. For example, some embodiments may reduce the cost of maintaining the original playability and appearance of golf course bunker edges. This facilitation may be a result of installing a durable golf course bunker edge formed from stacked layers of carpet and sand. In some embodiments, the golf course bunker edge may retain an original soil-like appearance. Such persistent original appearance may be a result of securing stacked layers of carpet and sand against the sand bunker wall with coatings of a prepolymer and peat moss. Some embodiments may reduce environmental waste. This facilitation may be a result of re-purposing used carpet for golf course bunker edge construction.


In some embodiments, the golf course bunker design options may be expanded. Such golf course bunker design improvement may be a result of golf course architect's ability to design larger and deeper bunkers having reduced maintenance cost. Various embodiments may reduce environmental contamination. This facilitation may be a result of reduced bunker edge erosion. Some examples may improve the playability of existing golf courses. Such improved playability may be a result of repairing existing bunker edges.


The details of various embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.





BRIEF DESCRIPTION OF THE DRAWINGS


FIG. 1 depicts an illustrative installation of an exemplary golf course bunker edge based on adapting a planar structure section to be retained against a cavity wall, stacking a first layer of the planar structure section and a second layer of a granular substance against the cavity wall, and constructing a barrier based on securing the stacked layers against the cavity wall with a barrier edge formed based on applying a coating of a viscoelastic substance and a coating of a loose-fill material to the stacked layers.



FIG. 2 depicts a side view of an exemplary golf course bunker edge.



FIG. 3 depicts a front view of the face of an exemplary golf course bunker edge.



FIG. 4 depicts a top view of an exemplary golf course bunker edge.





Like reference symbols in the various drawings indicate like elements.


DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

To aid understanding, this document is organized as follows. First, an illustrative installation of an exemplary golf course bunker edge is briefly introduced with reference to FIG. 1. Second, with reference to FIGS. 2-4, the discussion turns to exemplary embodiments that illustrate golf course bunker edge construction.



FIG. 1 depicts an illustrative installation of an exemplary golf course bunker edge based on adapting a planar structure section to be retained against a cavity wall, stacking a first layer of the planar structure section and a second layer of a granular substance against the cavity wall, and constructing a barrier based on securing the stacked layers against the cavity wall with a barrier edge formed based on applying a coating of a viscoelastic substance and a coating of a loose-fill material to the stacked layers. In FIG. 1, a green keeper 105 installs an exemplary golf course bunker edge formed from planar structure sections 110 and granular substance 115 against cavity wall 120. In the depicted embodiment, the planar structure sections 110 are carpet sections. In the illustrated example, the granular substance 115 is sand. In the depicted example, the cavity wall 120 is a golf course bunker wall. In the depicted example, the carpet sections 110 have been cut to a length adapted to be retained against the cavity wall 120. In an illustrative example, the green keeper 105 adapts the carpet sections 110 to form a barrier against the cavity wall 120 based on folding the carpet sections 110. In the depicted example, the green keeper 105 stacks layers of the carpet sections 110 against the cavity wall. In the illustrated embodiment, the green keeper 105 uses sand bag 125 to pour a layer of granular substance 130 over the carpet sections 110. In the depicted embodiment, the granular substance layer 130 is sand. In the illustrated example, the green keeper 105 stacks multiple layers of the carpet sections 110 and sand 130 against the golf course bunker wall 120. In the depicted embodiment, the green keeper 105 uses sprayer 135 to apply a first coating of viscoelastic material 140 to the carpet sections 110. In the illustrated example, the viscoelastic material 140 is a prepolymer. In the illustrated example, the green keeper 105 uses blower 145 to apply a second coating of loose-fill material 150 to the carpet 110. In the depicted embodiment, the loose-fill material 150 is peat moss. In the illustrated example, the green keeper 105 uses turfgrass seed bag 155 to plant turfgrass 160 on top of the golf course bunker edge. Some embodiment barrier structures may be prefabricated before installation. In some embodiments, barrier structures may be custom prefabricated based on golf course bunker design parameters.



FIG. 2 depicts a side view of an exemplary golf course bunker edge. In FIG. 2, an exemplary golf course bunker edge 205 includes layers of folded carpet sections 110 and sand 130 stacked against golf course bunker wall 120. In the depicted example, the stacked layers of folded carpet sections 110 and sand 130 are retained against golf course bunker wall 120 by at least one coating of peat moss 150 applied over at least one coating of prepolymer 140. In the illustrated example, sprayer 135 is applying an additional prepolymer 140 coating. In an illustrative example, blower 145 is applying an additional peat moss 150 coating. In the illustrated embodiment, the embodiment golf course bunker edge retains bunker sand 210 within the bunker. In an illustrative example, turfgrass 160 grows at the top bunker edge surface.



FIG. 3 depicts a front view of the face of an exemplary golf course bunker edge. In FIG. 3, an exemplary golf course bunker edge 205 is illustrated with horizontally offset stacked carpet section layers 110. In some embodiments, offsetting the stacked carpet section layers 110 may provide increased structural strength and durability of the bunker edge wall. In various examples, offsetting the stacked carpet section layers 110 may provide more durable retention of the prepolymer 140 and peat moss 150. In the depicted embodiment, the sub-base 215 may include graded and packed native sub-soil retaining bunker sand 210. In the illustrated example, turfgrass 160 grows at the top bunker edge surface.



FIG. 4 depicts a top view of an exemplary golf course bunker edge. In FIG. 4, an exemplary bunker edge wall 205 formed from layered carpet sections 110 retains bunker sand 210 against a bunker wall with cured coatings of prepolymer 140 and peat moss 150. In the depicted example, a carpet section layer 110 has been allowed to air dry before being treated with an isocyanate polymer, or similar spray polymer or pre-polymer sprays, using a pressure sprayer. In an illustrative example, the polymer is applied to the carpet around the bunker causing the edges around the bunker to become highly stabilized as the treated area of the bunker is allowed to cure.


Although various embodiments have been described with reference to the Figures, other embodiments are possible. For example, some embodiments of the present invention relate generally to golf course sand bunkers. Various embodiments relate to a method and materials of construction and renovation of a sand trap or sand bunker edge stabilization system for use on a golf course to prolong the life of its bunkers and to save considerable cost to the operation of the golf course.


It is a known fact in the golf industry that the demand for high quality golf course bunkers has increased and all levels of golfers demand the same excellent bunker characteristic as found on championship golf courses. Golf courses spend an enormous amount of money and resources trying to keep sand bunkers in excellent playable conditions.


Green keepers and maintenance crews frequently spend considerable time and resources in maintaining sand bunkers and attempting to preserve the configuration and aesthetics of the bunkers, often at enormous costs. It is a matter of common experience that evolution, weather, the act of playing golf and maintenance jeopardizes the structural integrity of the edges of the bunker.


Just from the growth of turf, traffic of golfers, the mowing and edging of the bunker edges, greenkeepers and maintenance crews have a difficult time keeping the exact edge of the bunker static. This changes the architectural look and playability of the bunker.


One problem associated with golf course bunkers i s the normal maintenance practice of using a power or hand edging device to maintain clean crisp edges. The game of golf and the rules require a clear definite edge to determine if a golfer's ball is in the hazard known as a bunker.


After even a few years, the common practice of edging results in the loss of the original edge. The bunker edge then takes on a new shape and the potential for soil to erode into the bunker sand become probable.


Another problem associated with golf course bunkers is that due to the demand of special very white, angular, and well-drained sands by many golf courses, and the limited number of suppliers, these sands must be shipped from distances that can cause exorbitant shipping cost making sand replacement cost to be very expensive.


Another problem associated with golf course bunkers is that some golf course designers insist on designing edges of bunkers to be very steep so that the edge can be seen from fairways or teeing ground. Soil eventually becomes exposed and edges erode into the bunker.


A problem associated with golf course bunkers when using other types of materials for edges are that often used fabric or geotextile edges have a short life when exposed to sunlight. The become torn easily and require repair or replacement often.


Another problem associated with golf course bunkers is erosion of native soil around the edges of the bunker from normal maintenance practices of edging or making a vertical cut in the sod of grass to make a clean edge. Green keepers often edge bunkers leaving exposed soil that erodes and contaminates the bunkers. Multiple techniques are currently employed in the prior art to design, construct, renovate, drain and maintain golf course sand bunkers and their edges.


Almost all techniques tried in the past have short or limited life or are costly to maintain or replace, however, various types of materials have been used with limited success.


Accordingly, it is an object of the present application to disclose a unique construction or renovation method of sand bunkers edges, and to disclose a construction method to improve bunker edge life and reduce maintenance cost of golf course bunkers.


It is another object of the present application to disclose a method that utilizes the cleaver technique to use stacked carpet layers, that when sprayed with a single component polymer and peat moss film, forms an almost permanent edge for bunkers, substantially reducing the required maintenance due to damage from traffic, heavy rainstorms and routine maintenance, and to maintain the stability and configuration of the bunkers.


It is also an object of the present application to disclose a method that employs the use of old or new carpets to eliminate the disposal of carpet into landfills thus being more environmentally friendly.


In various embodiments, methods and materials are provided for treating golf course bunkers edges to prolong the life of the sand bunker edges. In some embodiments, the design of the bunker's edges may be determined that are to become a permanent edge allowing space for the depth of the carpet to be laid. In some examples, the subgrade of the bunker edge may then be graded or shaped or reshaped in any artistic shape. In some designs, the floor may be smooth and compacted. In some designs, the floor of the bunker may have excavated drainage trenches with proper drainage pipe.


In some embodiments, a layer of carpet may be laid upon the subgrade and sandy soil placed over half of the carpet. In various examples, any soil may work but sandy soils could serve well due to the draining ability. In an illustrative example, once a row of carpet is laid, the carpet may then be rolled back. In some designs, another layer of sand may be placed to make the ring of the bunker level. In various implementations, the next layer of carpet may then be laid in an offset fashion and rolled back. In some designs, the offset may occur not only horizontal but vertically. In an illustrative example, the vertical offset may be typically about 75-90 degrees but this may be altered depending on the desired look of the Architect or user.


In some examples, once the desired layers are installed, a final layer of soil and live turf may be planted. In an illustrative example, the turf may be sodded or seeded.


In some embodiments, after the layers of carpet are in place, a pre-polymer may be applied to exposed edge portion of the carpet. In various embodiments, the pre-polymer may be applied using a pressure spray gun to spray the portion of the bunker edges to be sprayed. In some designs, all areas of the carpet bunker edges visible may be sprayed. In an illustrative example, the treated area portion of the bunker may then be treated with a layer of peat moss. In some embodiments, any type of peat moss may be used and may be applied using a blower type applicator or could be placed on by hand. The peat moss may be applied at a rate high enough to be absorbed by the polymer. The polymer may be allowed to cure. Generally, the curing process may take several hours to a day or longer. Curing time may be affected by numerous variables, such as weather, humidity, type of pre-polymer used and amount of pre-polymer used. Multiple layers of the polymer and peat combination may be applied to achieve the desired strength and appearance.


In some embodiments, an isocyanate polymer may be used. In an illustrative example, the polymer may be raised to a suitable temperature with a suitable temperature range being between 65F.-145F. and a preferred temperature range being between 72F.-120F. Usage of a polymer of the appropriate temperature range has the advantage of allowing for the appropriate penetration of the polymer onto the carpet and allowing the peat moss to tact.


In an illustrative example, turf grass sod may be placed along the top of the edge of the bunker where the soil and carpet meet. Various embodiments may reduce or eliminate the likelihood of the edge to deteriorate due to superior stability.


In some embodiments, damaged bunkers edges may be re-treated with an isocyanate polymer or other spray polymer or pre-polymer by spraying the polymer onto damaged areas and placing peat moss over the damaged area.


In various embodiments, a bunker edge that may be stronger than a standard bunker edge may be made by spraying a thin coat of isocyanate polymer or other spray polymer or pre-polymer on a carpet edge, then blowing a thin layer of sphagnum peat moss or similar loose-fill material onto the bunker edge then repeating the process until the bunker edge reaches the desired thickness. A normal thickness may be as little as ¼ “thick or up to ½ thick. This process creates a thick wall of soil looking barrier that holds up well for golf and looks like an earth edge which some architects like to use in their designs.


Various embodiments provide a golf course bunker designed and built to withstand golfer traffic, such as when golfers walk on the slopes and edge, and will not erode when golf course green keepers rake the bunkers either by hand or with a machine; the edges stay strong.


In some embodiments, a bunker edge may be topped by turfgrass growing in sand. In various designs, carpet may be stacked in layers starting with a soil base. In an illustrative example, carpet may be laid and a layer of sand placed between the carpet and rolled back onto the layer of carpet. In some examples, the stacking may continue to the desired or designed height. In various designs, a layer of polymer may be sprayed to secure and stabilize the carpet as it is stacked. In some embodiments, once the entire face is completed, the exposed carpet face may be sprayed with the polymer and then a layer of peat moss may be lightly sprayed to an absorption level of the polymer. In an illustrative example, multiple layers of the polymer and peat moss may be applied as desired. In some implementations, bunker sand may be installed in the floor of the bunker.


In various embodiments, carpet may be sprayed with an isocyanate polymer or similar spray polymer or pre-polymer. In some examples, a pressure sprayer may be used to apply the isocyanate polymer or similar spray polymer or pre-polymer. In some embodiments, sod may be placed around the top edge of the bunker. In various implementations, a sub-base may include a native sub-soil base that has been graded and packed to the proper compaction level.


In some embodiments, a layer of carpet may be allowed to air dry before being treated with an isocyanate polymer or similar spray polymer or pre-polymer sprays. In various examples, the application of the isocyanate polymer or similar spray polymer or pre-polymer may be completed by using a pressure sprayer and may be applied to the carpet around a bunker causing the edges around the bunker to become highly stabilized. In an illustrative example, once the spraying is completed, the treated area of the bunker may be allowed to cure. In some examples, the curing process may take several hours to a day or longer. For example, curing time may be affected by numerous variables, such as weather, humidity, type of pre-polymer used and amount of pre-polymer used. In general, the isocyanate polymer or similar spray polymer or pre-polymer material described above may be applied by spraying onto the carpet in climatic conditions that allow the material to be sprayed uniformly.


Rates of polymer that have proven successful are 0.03-0.04 gallons of chemical per square foot per layer but other rates may be successful as these rates are not for purposes of limiting the current invention. The preferred pre-polymer is an isocyanate polymer or similar spray polymer or pre-polymer.


In various embodiments, other compositions of pre-polymers may work so long as the composition will lock the peat moss and carpet together forming a durable and substantially solid face mass of a bunker edge.


In some embodiments, the makeup of the isocyanate polymer or similar spray polymer or pre-polymer may have the following ranges of materials from the specific composition described above that will perform the function: is preferred that the liquid isocyanate polymer or similar spray polymer or pre-polymer be a single component, wherein the isocyanate polymer or similar spray polymer or pre-polymer is a moisture curing, solvent free, medium viscosity isocyanate polymer or similar spray polymer or pre-polymer based on MDI (Methylene Diphenyl Diisocyanate). In various examples, it is specifically used as a moisture curing binder.


In an illustrative example, the liquid polymer may comprise isocyanate polymer or similar spray polymer or pre-polymer component 60.0-90.0%, ethylenediphenyl diisocyanate (MDI) 10.0-30.0% 4,4′-Methylenediphenyl diisocyanate 10.0-20.0%. One of ordinary skill in the art would appreciate that there are numerous isocyanate polymer or similar spray glue adhesives or pre-polymers that could be utilized with embodiments of the present invention, and embodiments of the present invention are contemplated for use with any appropriate isocyanate polymer or similar spray polymer or pre-polymer.


In some embodiments, a golf course bunker may be constructed from carpet, polymer, and peat moss. In various embodiments, bunker sand may be placed over the subgrade or drainage layer. In an illustrative example, sod turf grass or other similar material may be placed on new sand and grown to eliminate the potential contamination of soil into the sand from edging. In some examples, a width of sod is placed over the new sand and cultivated for good root growth. In various implementations, because the grass may be growing in new sand, the root system may be intact and strong enough to maintain a strong and clean vertical edge that golf course green keeper's demand.


In some embodiments, when bunkers become damaged, whether through general wear and tear occurring through usage of the course, or through other occurrences, such as storm damage or accident, the methods described herein may be used to repair such damaged areas of the bunkers. In an illustrative example, damaged bunkers may be treated with an isocyanate polymer or other spray polymer or pre-polymer by spraying the polymer onto damaged areas or coating additional carpet and placing the peat moss on or over the damaged area. In various examples, this works to repair the damaged areas and prevent the spread of damage to other areas surrounding the damaged area.


In some embodiments, after washed sod is in place, proper cultivation practices occur to encourage deep and fast rooting of the sod into the sand. In some examples, among these cultivation practices would be watering, fertilizing, and the use of pesticides. In some designs, once the sod has rooted, a greens keeper may edge the bunker vertically lightly but no deeper or further back than the treated peat moss.


In some embodiments, a bunker edge that may be stronger than the standard bunker edge may be made by spraying a thin coat of isocyanate polymer or other spray polymer or pre-polymer on the carpet wall, then blowing a thin layer of sphagnum peat moss or similar material onto the bunker edge, and repeating the process until the bunker edge reaches the desired thickness. In some examples, this process may create a thick wall of soil looking barrier that holds up well for golf and looks like an earth edge which some architects like to use in their designs. Advantageously, various embodiments of the improved bunker edge may work to reduce overall maintenance requirements as well as reduce the chance the bunker edges will be damaged in the ordinary course of play and maintenance.


In some embodiments, using this method to build a golf course bunker and by applying the isocyanate polymer or other spray polymer or pre-polymer in liquid form to the carpet, peat moss, and polymer edge of a golf course bunker, the probability that the sand will become contaminated by the soil from the eroding edges may be substantially reduced.


In some embodiments, a treated carpet edge may not be torn around the edges, and may be superior to other methods. In an illustrative example, it has been found that by applying this construction method to a golf course bunker, the probability that the sand will become contaminated from edge erosion may be substantially reduced. In various examples, it is also expected to extend the life of the sand and ultimately the life of the bunker saving golf courses tens of thousands of dollars in renovation and annual maintenance. In addition, some embodiments may further reduce or eliminate the likelihood of soil contamination.


A number of implementations have been described. Nevertheless, it will be understood that various modification may be made. For example, advantageous results may be achieved if the steps of the disclosed techniques were performed in a different sequence, or if components of the disclosed systems were combined in a different manner, or if the components were supplemented with other components. Accordingly, other implementations are contemplated, within the scope of the following claims.

Claims
  • 1. A method to construct a golf course bunker edge, comprising: adapting a carpet section to be retained against a golf course bunker wall based on folding the carpet section;stacking at least one first layer of the carpet section and at least one second layer of sand against the golf course bunker wall; and,constructing a golf course bunker edge based on securing the stacked layers against the golf course bunker wall with a barrier edge formed by applying a coating of a prepolymer and a coating of peat moss to the stacked layers.
  • 2. The method of claim 1, wherein applying a coating of a prepolymer further comprises applying the coating of a prepolymer using a spray-gun.
  • 3. The method of claim 1, wherein applying a coating of a prepolymer further comprises applying the coating of a prepolymer using a spray-gun at a discharge rate of 0.03-0.04 gallons per square foot.
  • 4. The method of claim 1, wherein applying a coating of a prepolymer and a coating of peat moss to the stacked layers further comprises applying the peat moss to areas coated with the prepolymer.
  • 5. The method of claim 1, wherein applying a coating of a prepolymer further comprises applying the coating of a prepolymer using a spray-gun to the carpet surface exposed to the golf course bunker wall.
  • 6. The method of claim 1, wherein constructing a golf course bunker edge further comprises allowing the golf course bunker edge to cure for a period of time before use.
  • 7. The method of claim 1, wherein the prepolymer further comprises prepolymer isocyanate.
  • 8. The method of claim 1, wherein the peat moss is selected from the group consisting of organic peat moss, and inorganic peat moss.
  • 9. A method to construct a barrier, comprising: adapting a planar structure section to be retained against a cavity wall;stacking at least one first layer of the planar structure section and at least one second layer of a granular substance against the cavity wall; and,constructing a barrier based on securing the stacked layers against the cavity wall with a barrier edge formed based on applying a coating of a viscoelastic substance and a coating of a loose-fill material to the stacked layers.
  • 10. The method of claim 9, wherein the planar structure section is carpet.
  • 11. The method of claim 9, wherein adapting a planar structure section to be retained against a cavity wall further comprises folding the planar structure section.
  • 12. The method of claim 9, wherein the planar structure section further comprises carpet.
  • 13. The method of claim 9, wherein the granular substance further comprises sand.
  • 14. The method of claim 9, wherein the loose-fill material further comprises peat moss.
  • 15. The method of claim 9, wherein the viscoelastic substance further comprises a substance selected from the group consisting of a polymer, and a prepolymer.
  • 16. The method of claim 9, wherein the cavity wall further comprises a golf course bunker wall.
  • 17. A golf course bunker edge, comprising: at least one golf course bunker edge layer, comprising: a first layer of a planar structure section; and,a second layer of a granular substance; and,a barrier edge retaining the at least one golf course bunker edge layer stacked against a golf course bunker wall.
  • 18. The golf course bunker edge of claim 17, wherein the barrier edge further comprises a coating of a viscoelastic substance.
  • 19. The golf course bunker edge of claim 17, wherein the barrier edge further comprises a coating of a loose-fill material.
  • 20. The golf course bunker edge of claim 17, wherein the planar structure section further comprises carpet that has a backing, and which carpet will not dissolve after burial.
CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 62/293,369, titled “Golf Course Bunker Edge Stabilization Materials, System and Method,” filed by Gerald Lemons, on Feb. 10, 2016. This application incorporates the entire contents of the foregoing application herein by reference.

Provisional Applications (1)
Number Date Country
62293369 Feb 2016 US