US3906067A - Bridge icing deterrent - Google Patents

Abstract

This invention relates to the prevention of the pavement on bridges and overpasses from freezing before the pavement approaches thereto by the application of an insulating bed of an expandable or foamed resin to the underside thereof.

Description

United States Patent Alspach BRIDGE ICING DETERRENT Inventor: Howard E. Alspach, 4399 W.

Lincoln Hwy., Gomer, Ohio 45809 Filed: Oct. 29, 1973 App]. No.: 410,381

US. Cl. 264/465; 14/6; 14/73;

264/35; 264/467; 264/50; 404/27 Int. Cl. B27D 27/00 Field of Search 14/6, 73; 52/309, 404,

References Cited UNITED STATES PATENTS 6/1895 Platt 52/339 X 1 Sept. 16, 1975 3,070,196 12/1962 Switzgable 52/404 3,110,981 11/1963 Lm'ncr 14/73 X 3,122,073 2/1964 Masse 404/18 X 3,619,437 11/1971 McDonald... 52/309 X 3,626,702 12/1971 Monahan 61/50 3,783,569 1/1974 Roussin 52/404 X Primary ExaminerPaul R. Gilliam Assistant ExaminerDavid H. Corbin Attorney, Agent, or Firm-Francis M. Crawford [57] ABSTRACT This invention relates to the prevention of the pavement on bridges and overpasses from freezing before the pavement approaches thereto by the application of an insulating bed of an expandable or foamed resin to the underside thereof.

3 Claims, 1 Drawing Figure BRIDGE ICING DETERRENT The present invention relates to the insulation of the undersides of highway bridges and overpasses. More particularly, it relates to the prevention of the pavements on highway bridges and overpasses from freezing over before the freezing of the connecting highway roadbeds by the application to the undersides thereof of an insulating bed of expandable or foamed resin, such as styrofoam.

It is well recognized that intermittent freezing and thawing greatly increases the hazards of winterdriving and it is estimated that 23,000 accidents result annually from localized icing or frosting of bridge or overpass decks. Most of these result from the fact that the pavement on bridges and overpasses can become coated with frost, ice or snow sooner and more often than their approach pavements, with the result that the unwary driver frequently skids upon entering the bridge or overpass. The magnitude of this problem differs widely not only from state to state, but from location to location, or bridge to bridge. This is due to the microclimate associated with an individual bridge, in part, as well as to other local and roadway and traffic conditions, bridge construction, and the like.

The above hazards result from the fact that particularly during the fall and early winter and during warm periods during the winter the ground and roadbed contain sufficient heat so that ice and frost do not form as readily thereon as on the bridges and overpasses which have no protection on their undersides from the cold air and winds with the result that frost and ice form more quickly on the roadbed over the bridges and overpasses, with the result that the motorist may pass from a relatively dry, safe roadway pavement onto a slick, icey bridge or overpass pavement surface.

Numerous efforts have been made in the past to overcome these recognized hazards of winter driving, as for example, by using special paving materials on the paved surface of the bridge or overpass, such as, abrasives, cinders, crushed rock, or the like. Deicing chemicals, such as sodium chloride and calcium chloride, have likewise been used. However, the latter are definitely detrimental to Portland cement concretes and materially increase maintenance and repair costs because of accelerated scaling and spalling caused thereby. Techniques to prevent the formation of ice, frost and the like, such as heating the paved surfaces of the bridges or overpasses by electricity or pipes embedded in the pavement carrying hot liquids have been tried. None of these procedures, however, has been completely satisfactory for various reasons.

I have now discovered that the hazards resulting from the formation of ice, frost and snow on the pavements of bridges and overpasses can be largely and economically eliminated by the application to the undersides thereof of an insulating material comprising an expanded or foamed resin. This results in keeping the temperature of the pavement on the bridge or overpass comparable to that of the pavements leading onto the bridge or overpass so that the motorist does not immediately pass from a relatively safe road pavement to a hazardous bridge pavement.

The types of expandable or foamed resins which may be suitably used as insulating materials for the above purpose are well known to those skilled in the art and include such materials as polystyrene, polyurethane, polyethylene, cellulose acetate, epoxy, silicone and phenolic resins. For most purposes, however, it has been found most practical to use the material known in the trade as styrofoam, because of its availability and ease of application.

The methods of applying expanded or foamed resins are well known by those skilled in the art and it is understood that the method of application most suitable for a given instillation may be employed in accordance with the present invention. Suitable methods include mechanical, physical or chemical foaming. In mechanical foaming, the resin, as a solution or emulsion in liquid form, is vigorously agitated until it becomes a foam of air bubbles. Fusing of the foamed resin is generally accomplished by heat leaving the foam in a solid foam form. Polyvinyl chloride foam is suitably prepared in this manner.

Physical foaming usually is accomplished by forcing compressed nitrogen gas into molten resin; As the pressure is released the gas expands and foams the resin.

I In chemical foaming a chemical which will form a gas is dissolved in a liquid resin. The resultant gas causes the resin to foam.

In applying the foamed resin insulation to the underside of bridges and overpasses according to the present invention it is first necessary to prepare a form underneath the roadbed over the bridge or overpass to support the foamed insulation during application and setting thereof, as well as to prevent easy removal of the insulation bed by vandals after formation. This form can be installed in any convenient manner. However, a convenient and economical method of preparing a suitable form comprises suspending bars on the lower I s of the I-beams supporting the bridge or overpass. Such suspension bars, suitably spaced from each other, serve as supports for the bottom of the form, which may be of any conventional material, such as a fine wire mesh through which the unset foam does not readily pass. Preferably, a coarse wire mesh is placed on the supporting bars and over this is placed a thin, light, solid sheet of wood, paper or metal to support the insulation during formation thereof without substantial loss of the unset resin and which also serves as a protection after formation of the insulating bed.

When I-beams are not used in the construction of the bridge or overpass supports for the lower side of the form may be constructed in various manners well known to those skilled in the art, it only being necessary or desirable that the lower side of the form be at a distance from the pavement serving as the upper side of the form approximately that of the lower I s of the conventional I-beams used in constructing bridges and overpasses, and of sufficient strength to support the insulating bed during construction thereof. Generally, the forms may be constructed in any conventional manner well known to those skilled in theart.

Holes are left or made at intervals through the form so that tubes for the admission of the unset foam into the space between the lower surface of the pavement and the above-specified supporting form. The number and spacing of these holes will be dependent largely upon convenience but should generally be located within the range of a few feet from each other so as to facilitate rapid filling of the form and completion of the formation of the insulating bed. If desired, but less conveniently, the holes for admission of the foamed resin into the form may be made through the pavement to be protected.

After completion of the above-described form, unset resin foam is introduced into the form through the holes until the space formed underneath the pavement by the form support described above is completely or substantially filled with the foamed resin, using any of the convential foamed resins and means for the formation of molded foam resin objects therewith. In the present instance, it is preferred to use a resin foam which sets without the application of heat. Such systems are well-known to those skilled in the art.

The accompanying drawing will serve to illustrate somewhat more clearly the instant invention. It is distinctly understood, however, that the claimed invention is not limited to the exact means shown therein.

In the drawing, 1 represents a conventional I-beam used in the construction of bridges and overpasses. The pavement over the bridge or overpass is represented by the numeral 2. The lower lip 3 of the l-bearn supports the bars or slats 4 resting thereon and used as supports for the coarse wire mesh 5 on which rests a thin layer of wood veneer, heavy paper or thin metal 6. The openings through the bottom of the form and through which the resin foam is introduced into the form are repre sented by the numerals 7 and the foamed resin filling the form by the numeral 8.

The insulating effect of the insulating bed of set foamed resin 8 delays the cooling of the pavement 2 and the formation of ice and frost thereon at a rate faster than on the approach pavement so that the motorist will drive onto a bridge or overpass pavement which is less slick than the approach pavement, and thus materially reducing the usual hazards of driving over bridges and overpasses during periods of ice or frost formation.

What is claimed is:

1. Method for reducing the formation of localized ice and frost deposited during freezing weather on pavements on roads over bridges and overpasses supported on l-beams parallel to the direction of the road, which comprises constructing immediately underneath said pavements over said bridges and overpasses a box-like form of predetermined thickness, wherein the lower side of said box-like structure is a thin, light sheet of material capable of holding a resin during introduction and setting of same in said box-like structure, said sheet being supported on bars the ends of which rest on the lower lips of the I-beams supporting the structure on which the said pavements are laid, and the lower surface of said pavement constituting the upper portion of said box-like structure, and introducing into said boxlike structure, through a plurality of holes located in the bottom of said box-like structure a resin in fluid form selected from the group consisting of polystyrene,

polyurethane, polyethane, cellulose acetate, epoxy, silicone and phenolic resinous material in an amount sufficient to fill said box-like structure completely when in foam form, converting said resin to foam form and permitting said foamed resin to set in solid form in contact with the lower surface of said pavements constituting the upper portion of said box-like structure.

2. Method according to claim 1, wherein said sheet is supported by a coarse wire mesh resting on said bars the ends of which rest on the lower lips of said I-beams.

3. Method according to claim 1, wherein said sheet is a coarse wire mesh.

Claims (3)

1. METHOD FOR REDUCING THE FORMATION OF LOCALIZED ICE AND FROST DEPOSITED DURING FREEZING WEATHER ON PAVEMENTS ON ROADS OVER BRIBGES AND OVERPASSES SUPPORTED ON 1-BEAMS PARALLEL TO THE DIRECTION OF THE ROAD, WHICH COMPRISES CONSTRUCTING IMMEDIATELY UNDERNEATH SAID PAVEMENTS OVER SAID BRIDGES AND OVERPASSES A BOX-LIKE FROM OF PREDETERMINED THICKNESS, WHEREIN THE LOWER SIDE OF SAID BOX-LIKE STRUCTURE IS A THIN, LIGHT SHEET OF MATERIAL CAPABLE OF HOLDING A RESIN DURING INTRODUCTION AND SETTING OF SAME IN SAID BOX-LIKE STRUCTURE, SAID SHEET BEING SUPPORTED ON BARS THE ENDS OF WHICH REST ON THE LOWER LIPS OF THE 1-BEAMS SUPPORTING THE STRUCTURE ON WHICH THE SAID PAVEMENTS ARE LAID, LAID, AND THE LOWER SURFACE OF SAID PAVEMENTT CONSTITUTING THE UPPER PORTION OF SAID BOX-LIKE STRUCTURE, AND INTRODUCING INTO SAID BOX-LIKE STRUCTURE, THROUGH A PLUALITY OF HOLES LOCATED IN THE BOTTOM OF SAID BOX-LIKE STRUCTURE A RESIN IN FLUID FORM SELECTED FROM THE GROUP CONSISTING OF POLYSTYRENE, POLYURETHANE, POLYETHANE, CELLULOSE ACETATE, EPOXY, SILICON AND PHENOLIC RESINOUS MATERIAL IN AN AMOUNT SUFFICIENT TO FILL SAID BOX-LIKE STRUCTURE COMPLETELY WHEN IN FOAM FORM, CONVERTING SAID RESIN TO FOAM FORM AND PERMITTING SAID FOAMED RESIN TO SET IN SOLID FORM IN CONTACT WITH THE LOWER SURFACE OF SAID PAVEMENTS CONSTITUTING THE UPPER PORTION OF SAID BOX-LIKE STRUCTURE.

2. Method according to claim 1, wherein said sheet is supported by a coarse wire mesh resting on said bars the ends of which rest on the lower lips of said I-beams.

3. Method according to claim 1, wherein said sheet is a coarse wire mesh.

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