GB2065901A - Weighbridge - Google Patents

Abstract

A weighbridge has a deck (20) below which are lengthwise strengthening beams (21) each of which near its ends has a cut-out (23) to receive the upper end of a respective load cell. The deck (20) and beams (21) constitute a one-piece prestressed reinforced concrete structure. <IMAGE>

Description

SPECIFICATION Weighbridge This invention relates to a weighbridge.

It is usual to make a vehicle-weighing weighbridge with a fabricated steel frame and with deck members of metal or concrete. It is known to mount the steel frame on load cells for the weighing function. It is also known to mount a combined frame and deck structure made of prestressed reinforced concrete on two spaced lateral steel beams, which in turn are mounted at each end on a respective one of four load cells.

It will be understood that for weighing a heavy goods vehicie, a weighbridge is a large and substantial structure. Known weighbridges are usually of considerable depth in relation to their length and width, and usually have to be accommodated in quite a deep pit. Thus not only the size of a weighbridge but the need for such a pit makes the weighbridge expensive, as does the cost of transporting large and heavy components to a site, and as also does the cost of assembling those components on site.

It is an object of this invention to provide a weighbridge which reduces the effect of the above-mentioned disadvantages.

According to this invention a weighbridge comprises a deck, strengthening beams and/or ribs below the deck, and load cells engaged with respective ribs or beams, the deck and beams and/or ribs being constituted by a one-piece structure of prestressed or reinforced concrete.

Preferably the ratio of length to depth of the onepiece structure is in the range 15:1 to 30:1 ,for example 21:1,so that for example a weighbridge would have a deck 16000 mm. long, 3000 mm.

wide, and 750 mm. deep.

Also according to this invention a weighbridge comprises two or more decks disposed one adjacent another in the length direction of the weighbridge, strengthening beams and/or ribs below each deck, and load cells engaged with respective beams or ribs of at least two decks, each deck and beams and/or ribs being constituted by a one-piece structure of prestressed or reinforced concrete. Thus the weighbridge of the invention may have a single deck, or it may have two or more decks placed one adjacent another in the lengthwise direction. The use of two or more decks for the weighbridge permits the use of smaller, lighter and shallower decks. Thus for example a weighbridge could be formed of three decks arranged in the length direction of the weighbridge, and the two outer or end decks would have load cells, whilst the centre deck could be without load cells.A weighbridge in accordance with the invention could also be made up of a group of decks placed side by side, and also by a group of decks placed end to end and side by side. Thus four decks could be arranged each to support one wheel of a 4-wheel vehicle.

In a preferred form of the invention a weighbridge comprises a deck, strengthening beams and/or ribs below the deck, and load cells, wherein the deck and beams and/or ribs are constituted by a one-piece structure of prestressed or reinforced concrete, and wherein beams or ribs have cut-outs in which respective load cells are at least partly received so as to be engaged with the beams or ribs. By virtue of the cut-outs the total depth required by the structure and the load cells can be reduced considerably as compared with known weighbridges. The reduction in depth may be such that in some cases a pit will not be needed.

Three embodiments of the invention will now be described by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a top plan of a first embodiment; Figure 2 is a side elevation; Figure 3 is a section on plane Ill-Ill of Figure 2; Figure 4 is a section on plane IV-IV of Figure 2; Figure 5 is an enlarged section on plane V-V of Figure 4; Figure 6 is an enlarged part elevation as seen in the direction VI in Figure 4; Figure 7 is a top plan of a second embodiment; Figure 8 is a side elevation; Figure 9 is an enlarged section on plane IX-IX of Figure 8; Figure 10 is an enlarged cross-section on plane X-X of Figure 8; Figure 11 is a top plan of a third embodiment;; Figure 12 is a side elevation; Figure 13 is an enlarged section on plane XIIl-XlIl of Figure 12; and Figure 14 is an enlarged section on plane XIV-XlV of Figure 12.

Referring firstly to Figures 1 to 6, a first embodiment of weighbridge in accordance with the invention comprises a deck 1, two or three lengthwise strengthening beams 2, and two transverse strengthening ribs 3. The beams 2 may be tapered upward as shown at each end 2A. The deck 1, beams 2 and ribs 3 are constituted by an integral or one-piece structure of prestressed concrete. The cross-sectional shape of the lengthwise beams 2 is seen in Figures 3 and 4.

Each transverse rib is thicker at its ends, see particularly Figures 1 and 4 to 6. At each end, each transverse rib may have a cut-out 3A which receives the upper part of a respective one of four load cells 4. The bottom of each load cell rests on an appropriate concrete base or foundation (not shown).

The second embodiment is shown in Figures 7 to 10 and has a deck 10 and a "waffle" type arrangement of lengthwise beams 11 and transverse ribs 12. This type of arrangement gives good torsional stiffness and permits reduced deck thickness since each enclosed area is spanned in both directions. Further it gives the possibiiity of cheaper production, by using standard, readily available "waffle" forms instead of expensive purpose-built moulds. The two outer beams 11 each have two cut-outs 1 2A to receive load cells 13. As before, the ends of the lengthwise beams may be tapered at 11 A. Also as before, the deck, beams and ribs are formed by an integral or onepiece structure of prestressed concrete.It will be noted that each load cell cut-out is located between a pair of transverse ribs 12 and that the ribs of each such pair are closer together than the remaining transverse ribs. This will be apparent from Figures 7 and 8. It will also be noted that in this embodiment the two outer lengthwise beams 11 may be at the side edges of the deck. The transverse ribs may be shallower than shown.

Although in this embodiment the cut-outs 1 2A are shown, it would be possible for the load cells to engage the deck other than at a beam or rib cutout. For example, four of the "waffle" areas (delineated by portions of beams and ribs) could be made thicker and stronger, to abut the load cells. For example, in another arrangement, a weighbridge could comprise 4 "waffle" type decks in a side by side and end to end layout, each with the necessary strengthened areas to abut the load cells.

The third embodiment will now be described with reference to Figures 11 to 14.

The weighbridge has a deck 20 and two lengthwise strengthening beams 21. There are no transverse ribs, but the ends 22 of the deck may be slightly thickened as shown for strength. The structure is again a one-piece structure of prestressed concrete. The lengthwise beams 21 may have tapered portions 21 A towards their ends and each tapered portion has a cut-out 23 to receive a load cell, not shown. The cross-sectional shape of deck and lengthwise beams is seen in Figures 13 and 14.

Each cut-out 23 has a steel bearing or locating plate 23A where the relevant load cell abuts. The plates 23A are fixed accurately to the prestressed concrete one-piece structure. Although such bearing plates are not shown in the embodiments of Figs. 1 to 6 and 7 to 10, they would be present and fixed in the appropriate places. In this third embodiment the beams 21 are located approximately beneath the wheels of a normal heavy goods vehicle when in position on the weighbridge. The line of action of the load from the wheels of the vehicle will be in vertical planes down through the beams 21 to the load cells.

It will be understood that the weighbridge is made by moulding or casting the one-piece deck and beams and/or ribs structure with load cell cutouts, and by fixing in place the steel bearing plates, in a factory, whence it is transported as required to the site, which will have been provided with the necessary sub-structure on which the load cells rest.

All three embodiments have the following dimensions: length: 16000 mm.; width: 3000 mm.; depth: 750 mm. Thus the ratio of length to depth is 21:1: this is the preferred ratio, but other ratios could be used to give a shallower structure.

Although the embodiments described are of prestressed concrete, reinforced concrete could also be used. The shapes of the several embodiments are suitable for long-line prestressed concrete production, using moulds capable of adjustment for various deck lengths. In each embodiment prestressing is by means of the usual prestressing wires or cables. Also each deck would be provided with the usual access manhole or manholes (not shown), preferably circular. In addition each deck would have steel tips (not shown) at the ends of the deck or the beams or both, to act as protective buffers.

The several embodiments described above all have cantilevered ends, as shown, but this is not an essential feature, especially in a weighbridge having several shorter decks placed end to end in the lengthwise direction of the weighbridge.

An advantage of the embodiments described is that the load cells are accessible from the sides of the structure. Thus when the structure has to be located in a pit, the pit can be relatively shallow, since there is no need for service access to the load cells from below.

Other advantages of weighbridges in accordance with the invention are as follows:- A) Reduction in tota' depth of the weighbridge, since the load cells are partly accommodated within the depth of the structure.

B) A reduction in the size and thus the cost of the pit, where one is necessary.

C) A total depth of structure which for some applications will be acceptable above ground and will therefore not require a pit.

D) A saving in cost because lateral steel beams are not required.

E) A saving in construction time on site because no side welding is required.

F) Economy in the design of the or each deck, because there will be maximum load distributing across the deck width since each is a one-piece structure with its beams and/or ribs.

G) The amount of assembly to be carried out on site is reduced because the load cells are fitted to the or each deck when it is manufactured and before it is transported to the site.

H) The weighbridge is readily re-locatable since it is in one integral piece, or in several smaller integral pieces.

Claims (11)

1. A weighbridge comprising a deck, strengthening beams and/or ribs below the deck, and load cells engaged with respective ribs or beams, the deck and beams and/or ribs being constituted by a one-piece structure of prestressed or reinforced concrete.

2. A weighbridge comprising two or more decks disposed one adjacent another in the length or width direction, or both, of the weighbridge, strengthening beams and/or ribs or other strengthened portions below each deck, and load cells engaged with respective beams, ribs or other strengthened portions of at least two decks, each deck with beams, ribs, or other strengthened portions being constituted by a one-piece structure of prestressed or reinforced concrete.

3. A weighbridge comprising a deck, strengthening beams and/or ribs below the deck, and load cells, wherein the deck and beams and/or ribs are constituted by a one-piece structure of prestressed or reinforced concrete, and wherein beams or ribs have cut-outs in which respective load cells are at least partly received so as to be engaged with the beams or ribs.

4. A weighbridge according to any preceding claim wherein a steel bearing plate is fixed to a respective beam or rib between the latter and a load cell.

5. A weighbridge according to claim 3 having two spaced parallel lengthwise beams, each beam having a cut-out near each end, and the load cells being four in number, with one to each cut-out.

6. A weighbridge according to any preceding claim wherein each end portion of the deck is thickened in the transverse direction of the deck.

7. A weighbridge according to claim 3 having three spaced parallel lengthwise beams and two spaced parallel transverse ribs, each beam having a cut-out at each end, and the load cells being four in number, with one to each cut-out.

8. A weighbridge according to claim 3 having three spaced parallel lengthwise beams and a plurality of spaced parallel transverse ribs, the beams comprising two outer beams and a centre beam, the two outer beams each having two spaced cut-outs, and the load cells being four in number, with one to each cut-out.

9. A weighbridge according to claim 8 wherein each cut-out in a beam is disposed between a pair of adjacent transverse ribs.

10. A weighbridge according to claim 9 wherein the spacing between a said pair of transverse ribs is less than that between other adjacent transverse ribs.

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11. A weighbridge constructed and arranged substantially as herein described and shown in Figs. 1 to 6, or 7 to 10, or 11 to 14.