US 3260023 A
Description (OCR text may contain errors)
July 12, 1966 H. S. NAGIN BRIDGE FLOOR AND SURFACING COMPONENT THEREFOR l5 6 II 6 -=fif Filed Aug. 15. 1962 INVENTOR. HARRY 5. NAGIH.
3,260,023 Patented July 12, 1966 3,260,023 BRIDGE FLOOR AND SURFACING COMPONENT THEREFOR Harry S. Nagin, Merion, Pa., assignor to Reliance Steel Products Company, McKeesport, Pa., a corporation of Pennsylvania Filed Aug. 15, 1962, Ser. No. 217,021 2 Claims. (Cl. 52-181) This invention relates to bridge floors comprised of metal gratings, and is for an improved bridge floor construction and surfacing component therefor.
Highway bridge floors are commonly constructed with metal gratings carried on stringers, which in turn are carried on floor beams or main structural framing for supporting the deck of the bridge. The grating comprises spaced parallel relatively deep sections, called bearer bars or main bearing bars and there are cross bars or diagonal bars at regular intervals intersecting the bearer bars, the latter being of less depth than the bearer bars or rivetted diagonal bars. Generally, the gratings are made by welding, interlocking of the main and cross bars, or in the case of diagonal bars, rivetting is used, all as well known in the art. The surface of the grating is therefore comprised of square, rectangular or trapezoidal like cells defined between the bearing bars and the cross bars. Sometimes there may be one or two auxiliary bearing bars between parallel main bearing bars. These gratings are widely used and well known in the art. They may be open gratings, or they may be filled with concrete which after a time becomes worn and cupped from the movement of traffic thereover. To render such grating when exposed to traffic more skid-resistant and less likely to cause side sway of a vehicle due to the rear wheels imperfectly tracking the front ones, the edges of one or both sets of bars is sometimes notched, but in time these notches may become worn and rounded.
The present invention has for its object to provide an improved traffic bearing surface especially useful for those bridge floors which are constructed with grating. The invention is applicable to new bridges or existing structures and is especially useful in the repair of existing highway bridges.
A further object of the invention is to provide a unique surfacing panel or unit which, with similar units, can be applied to the grating on a bridge floor to make it safer and smoother, while a still further object is to provide a unit which may be prepared in a shop or central place of manufacture and shipped out, ready for installation in the field.
The further objects and advantages of my invention will be more fully understood and appreciated by those skilled in the art from the more detailed dsecription hereinafter set forth. Generally, however, the invention provides an elongated panel comprised of spaced parallel side bars with an undulated or corrugated strip between them, the corrugations at the top terminating below the tops of the side bars, thus providing a channel with a corrugated bottom. This channel is filled with a mixture of resin and aggregate, preferably epoxy resin and abrasive grains, which mixture is then cured to form a hardened dense traffic bearing surface. The distance between the side bars may be slightly less than the distance between centers of the main bearing bars of the grating so that the panels may be placed side by side on the grating with their side bars extending lengthwise of said bearing bars, and with a slight space between each two panels. The side bars of the panels can be welded to the top of the grating at points along the length of the panel where the corrugations are closest to the top of the side bars and the resin-abrasive mix is most shallow, whereby the resin is far enough removed from the welding heat that it is not impaired. The
crevices between adjacent panels are filled after the panels have been installed with either a similar resin-abrasive mix or some other filling compound.
The invention may be more fully understood by reference to the accompanying drawings in which:
FIG. 1 is an isometric view representing a portion of a bridge floor embodying my invention, the view showing a vertical transverse section through the floor in the plane of line II of FIG. 2;
FIG. 2 is a longitudinal vertical section with the bearer bars in elevation and the filling between sections removed in substantially the plane of line II-II of FIG. 1;
FIG. 3 is a longitudinal vertical section through a panel showing its construction before the surfacing material is placed in it, the view being in the plane of line IIIIII of FIG. 4;
FIG. 4 is a transverse vertical section in the plane of line IV-IV of FIG. 3;
FIG. 5 is a fragmentary view similar to FIG. 3 showing the channel above the corrugated bottom sheet filled with the surfacing compound; and
FIG. 6 is a fragmentary top plan view of a portion of a panel showing a part only of the filling material, the remainder being broken away to show the metal parts.
In the drawings 2 designates generally the grating forming a bridge floor. It has parallel bearer bars 3 and cross bars 4 of less depth than the bearer bars. The cross bars are pressure-welded into the tops of the bearer bars. There may be spaced load-distributing bars 5 extending between the bearer bars at intervals less frequent than the cross bars. This grating is a known type of construction, and the products of different manufacturers may vary in different respects immaterial to this application. Auxiliary bearing bars 6 are here shown between the main bearing bars. The bearer bars or main bearing bars 3 are typically rolled sections with a flanged top and flanged base, the top usually having a central rib. Specifications generally provide that the bearer bars be on six-inch centers, and typically the narrower cross bars may be on fourinch centers.
According to an example of thi invention there is a panel comprised of two side strips 10 formed of bar stock set edgewise at a distance slightly less than the distance between centers of the bearer bars on the grating with which the panel is to be used. With bearer bars on sixinch centers, the distance from the outer edge of one side bar 10 to the other may be of the order of five and onehalf inches. Extending between these bars is a bottom plate 11 that is preferably formed of rolled sheet metal, perhaps of a copper-bearing rust-resistant alloy or galvanized sheet. Typically the sheet metal bottom strip may be fourteen gauge. It is of a corrugated or undulating shape with the corrugations extending crosswise of the length of the side bars. The lowest portions of this sheet, i.e., the valleys, may be, but need not necessarily be, level with the bottom edges of the side bars 10; they should not extend lower than the bottom edges of the side bars but could be slightly higher. The tops or peaks of the corrugations are below the top edges of the side bars. Typically, and only by way of illustration and not as limiting the invention, the side bar may be of an inch to M of an inch deep while the tops of the corrugations are of an inch below the tops of the side bars. Thus there is provided between the side bars a channel 12 the minimum depth of which is in some places at least substantially less deep than the vertical height of the side bars. As here shown, this bottom is a regularly corrugated or undulated bottom with the peaks and valleys being flat on the tops and bottoms respectively. Sinuous corrugations may be used just as well.
In assembling the metal elements of the panel the corr-ugated sheet is tack-welded at intervals to the side bars as indicated for example at 13. This welding need be only suflicient to keep the parts assembled and may be more or less haphazardly located.
After the metal parts have been thus assembled, the channel 12 is packed with a mixture comprising principally of epoxy resin, either with or without an extender or plasticizer, aggregate, this preferably being coarse abrasive grains, and a curing agent, as disclosed for example in my joint patent with Donald H. Russell, No. 2,948,201, granted August 9, 1960. This mix is filled to and may be slightly above the level of the side bars. It may cure in the open air or in a heated environment, and is indicated in the drawings at 14. Epoxy resin is desirably used for this purpose because of its high adhesion to the metal, thus holding the metal parts together even in the absence of any welding and for which reason the welding at 13 need be only adequate to temporarily keep the parts in assembled relation. Secondly, because of its adhesion to metal, it will not break loose or spall under the impact of traific. resin and abrasive grains has a high tensile strength as well as high compressive strength. It is not too brittle, especially if any one of several known plasticizers i used. When the surface is densely covered with abrasive grains,
as disclosed in the above patent, it is highly resistant to weather, its co-eflicient of expansion is compatible with the metal to which it is adhered; it is not attacked by oil, grease or gasoline; and has good impact resistance. Important is the fact that it has good wear resistance and provides a skid-resistant urface.
Other mixes may be used, especially resinous materials having comparable qualities, or different aggregate. As an example, epoxy resin and asphalt may be mixed and abrasive grains pressed into the surface of the mix before the resin cures. duce the rigidity of the epoxy resin are desirable.
In use, the elongated panels which are preferably completely fabricated in a shop, are shipped to the job. They are laid lengthwise of the bearer bars so that the ide bars 10 rest on the flanges of two parallel main bearer bars 3. The side bars are tack-Welded in the field to the bridge floor at intervals along their length as indicated at 15. These welds are located along the bottom edges of the bars 10 at points where they are below the ridge-forming portions of the corrugations, so that the heat of welding is removed from the immediate location of the mix 14, that is the welds are located between the valleys and below the high points of the ridges. Since the width of the panels is slightly less than the distance between centers of the bearing bars, there is preferably a narrow crevice 16 between adjacent panels to facilitate welding. After the panels are installed this crevice is filled to the level of the surface of the panels with an air-curing mix of resin and abrasive grains similar to material 14, or with other suitable filling. The epoxy resin abrasive mix, however, is desirable because it adheres the panels to the grating and thus augments the welding to hold the panels in place and effectively exclude water.
The panels may be made in any convenient lengths, and their square ends may be butted together when two or more are aligned on the bridge floor, and the caulking mix similar to 16 may, if desired, be filled into the end joints. Since they are shallow in depth, they increase the height of the floor very little and not enough to materially decrease bridge clearance in most cases. add very :little to the dead weight of the bridge floor.
The combination of this Such extenders or additions as re- Because of the long wearing quality and traffic resistance of the panels, they are economical, and they add substantially to safety since the bridge floor grating is not exposed. Since in most cases the bearer bars extend crosswise of the bridge floor, the panels will extend crosswise. While the panels could be welded to the cross bars, installation would be more difficult because of the cross bars being of narrow section and welding, to be removed from the filling material, would have to be done from under the bridge floor. The corrugated bottom not only enables welds to the bearer bars to be located away from the resin-abrasive filling, but provides substantial increase in strength transversely of the panel. With the particular grating here shown the bottoms of the corrugations may contact the auxiliary bearer bars 6, but there may be installations where such auxiliary bearer bars are not .present.
While I have shown and specifically described one construction embodying my invention, it is to be understood that this i by way of illustration and the invention is not restricted to the specific construction here shown.
1. A bridge floor comprising a grating constituting a deck support, the grating having parallel main bearing bars and cross bars, the main bearing bars having a lateral flange portion at the top thereof extending from each side of the vertical central plane of the bar the grating being covered by panels welded thereto providing a traffic bearing surface, said panels each comprising parallel spaced side bars and a transversely-corrugated sheet metal bottom member extending between the side bars and joining them, the ridges of the corrugations terminating below the top edges of the side bars and the bottoms of the corrugations being at a level such that the panel sets on the grating with the side bars resting on the lateral flanges of the main bearing bars and bottoms of the sheets are supported by the grating between the main bearing bars, a filling in the space between the side bars and above the bottom comprised of epoxy resin and an aggregate cured in situ in the panel, the bottom edges of the side bars being welded to the grating bars at intervals therealong at points under the ridges of the corrugated bottom where the filling is at a level above the point of welding.
2. A bridge floor as defined in claim 17in which the side bars of the panels extending lengthwise of the main bearing bars are so spaced as to be slightly narrower than the distance between centers of the main bearing bars whereby two panels placed side by side may have the confronting side bars thereof extending along the flanges of the same unain bearing bar have a space between to facilitate the welding of the panels to the grating.
References Cited by the Examiner UNITED STATES PATENTS 508,502 11/1893 Crittendon et al 52-338 545,873 9/1895 Brown 52-328 1,191,283 7/1916 Conwell 52-336 2,017,832 10/1935 Hovey 52-3l8 2,017,833 10/1935 Hovey 52318 2,645,985 7/1953 Beebe et al 52667 2,960,919 11/1960 Nagin 5218l FRANK L. ABBOTT, Primary Examiner.
JACOB L. NACKENOFF, Examiner.
I. L. RIDGILL, Assistalnt Examiner.