Classifications

• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
  • E01C9/00—Special pavings; Pavings for special parts of roads or airfields
  • E01C9/04—Pavings for railroad level-crossings
• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
  • E01C5/00—Pavings made of prefabricated single units
  • E01C5/06—Pavings made of prefabricated single units made of units with cement or like binders
  • E01C5/08—Reinforced units with steel frames
  • E01C5/085—Reinforced units with steel frames on prefabricated supporting structures or prefabricated foundation elements except coverings made of layers of similar elements

Definitions

• This invention relates to panels incorporated in railway or railroad level crossings.
• Such level crossings comprise a number of pre-cast concrete components of which the largest and heaviest are the panels which are mounted above the sleepers of the rail track and extend between and are mounted on the side flanks of the rails. Other panels forming parts of the crossing assembly are also liable to be heavy enough to render weight-saving desirable.
• Such crossings are disclosed in GB-A-1 281 940 and GB-A-1 494 667 and in various equivalent patents elsewhere.
• polyester concrete which has a higher tensile strength for a given weight, than conventional Portland cement-based concrete and this has resulted in a reduction in weight, but not to a sufficient degree to enable easy manhandling of the panels on site. At least a part of the weight reduction has been made possible by omission of the external frame hitherto used. The remainder of the weight saving has been achieved in this relatively recent proposal by the use of polyester concrete and a slight reduction in thickness of the panel.
• a partial weight reduction for a given size of panel is, however, not of real value either technically or commercially since the speed of installation on site is not materially increased, mobile cranes still being required and as a . result hindrance to other work which could otherwise be carried out simultaneously. It must, of course be remembered, that site work on railway lines is often restricted because of the need to maintain rail services while at the same time enabling road traffic either to continue use of the crossing or to be disrupted for diversions for as short a time as possible.
• a concrete panel for incorporation in a rail level crossing structure comprising polyester concrete with recesses in the undersurface and appropriate reinforcement at least at or adjacent the top and bottom surfaces.
• Figure 1 is a plan view of a concrete panel in accordance with the present invention.
• Figure 2 is a fragmentary section illustrating an edge portion of the panel of Figure 1 and in vertical section;
• Figure 3 is a fragmentary view illustrating one feature of the present invention.
• Figure 4 is a plan view, to an enlarged scale, illustrating a portion of the panel shown in outline in Figure 1;
• Figure 5 is a partial side view also illustrating the internal reinforcing rods.
• Figure 6 is an end elevation also indicating the locations of internal reinforcements.
• a concrete panel in ' accordance with the invention generally referenced 10 is rectangular in plan view but has four ears or lateral projections 12 by which opposed edges of the panel are supported by the opposed flanks of the rails of the associated railway track though the intermediary of hard rubber wedges (not shown) .
• the underside of the panel has six recesses 14 with the objective of reducing the overall weight of the panel which is in addition to the weight saving enabled by the omission of the conventional outer steel frame and the use of polyester concrete.
• the recesses 14 in the undersurface are trapezoidal in both orthogonal sections and extend towards the upper surface so that at maximum depth the panel has a thickness of approximately one quarter the maximum depth at the ribs or lands 20, between the recesses.
• the panels are so constructed that they follow, on the undersurface, the shape of a conventional prestressed concrete -railway sleeper although m there is no contact between the sleeper and the undersurface.
• Fig. 3 illustrates this feature.
• the edge portion 15 of the panel is as shown in Figures 2 and 3 120 mm thick while the central portion or rib 20 where the recesses are provided is 135 mm thick, and this provides an important advantage from the point of view of improved tensile strength by the inclusion of reinforcement rods see Figures 4 to 6 at a lower level in relation to the load-receiving upper surface than would be possible if the undersurface were plane over its whole extent.
• the shape in this respect also ensures that the highest strength is available where the stresses are highest.
• the need for greater depth, particularly at the central area of each panel results from the lower modulus or stiffness of polyester concrete.
• the ears or projections 12 are generally conventional and as shown in Figure 2 are provided on the undersurface with a recess 16 and on the upper surface with a chamfer 18, the recess and the chamfer being adapted generally to the cross-sectional shape of the wedge (not shown) engaged against the flank of a conventional rail.
• Panels in accordance with the present invention are preferably made of polyester concrete and require no external frame. Reinforcement is entirely internal and because of the higher impact resistance of polyester concrete the risk of chipping at the edges during installation or subsequent use is substantially eliminated.
• the concrete may alternatively, although not preferably, be of the kind which is basically made of Portland cement and is impregnated with polymer after setting. The polymer may otherwise be added to the mix of cementitious concrete prior to setting. Normally the polymer will be a polyester. Polyester concrete gives rise to the additional advantage that the electrical resistance is higher than that of conventional concrete mixes and the omission of the external frame also gives rise to advantage of reduced risk of leakage currents. Because of the electrical resistance advantage it is desirable that all panels of a crossing should be made of polyester concrete.
• a reinforcing rod loop 26 is provided towards the bottom of the panel and a plurality of U-shaped rods 28 are welded to these loops and extend into the ears 12 so that the bottoms 30 of the "U"s lie closely adjacent the free edge of a respective U.
• the adjacent limbs of adjacent U-shaped rods 28 may touch one another and the bottoms 30 may be interconnected by welding by a transverse rod 32.
• a further transverse rod 34 may be provided which is welded at mid-height of the Us.
• the reinforcement at the edge portions extending orthogonally to the edges carrying the ears will take the form of two larger diameter rods 38,40 disposed substantially at the same depth location as the rods in the lands. As best shown in Figure 5, however, one rod 38 extends into one of the ears 12 while the other 40 is cranked and extends only into the edge portion itself.
• a standard internal panel for a level crossing as hereinbefore particularly described has been found to have a weight saving in relation to conventional panels of approximately 25%. This is sufficient to enable manhandling by three or four men without risk of back damage. Other panels of a crossing will also give a simil.ar weight saving, while still providing adequate strength. The use of polyester concrete gives a higher electrical resistance and the reduced weight also cuts transportation cost.

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• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Road Paving Structures (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 1986
  • 1986-01-20 GB GB08601281A patent/GB2185510A/en not_active Withdrawn
• 1987
  • 1987-01-20 WO PCT/GB1987/000035 patent/WO1987004477A1/en unknown
  • 1987-01-20 EP EP19870900853 patent/EP0258286A1/de not_active Withdrawn
  • 1987-01-20 AU AU68923/87A patent/AU6892387A/en not_active Abandoned

Non-Patent Citations (1)

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