WO2002061204A1

WO2002061204A1 - Process for making resilient synthetic beds

Info

Publication number: WO2002061204A1
Application number: PCT/HR2002/000004
Authority: WO
Inventors: Radomir Mladenovic
Original assignee: Radomir Mladenovic
Priority date: 2001-01-29
Filing date: 2002-01-17
Publication date: 2002-08-08
Also published as: YU56703A; EP1356162A1; HRP20010072A2

Abstract

Tram grooved rail (1) is installed on a resilient bed containing the following elements: 4 mm thick reinforced neoprene tie-plate (6), and 9 mm thick neoprene toe-plate (5). The tie-plate (5) lays on a smooth surface of chemically stable 340x140 mm polymer slab (7). The slab lays on polymer mass (8) which is made in situ and which is monolithically bounded in its entirety, forming a polymer 'chair'. A clamp support (3) is put on an anchored screw (4), and then SKL-2 clamp (2) is put on the clam support and is fastened by a nut. A cap protecting from corrosion is put on the clam support and is fastened by a nut. A cap protecting form corrosion is put on the upper part of the threaded screw. During construction of the synthetic bed the track is temporarily supported on wooden chocks.

Description

PROCESS OF MAKING RESILIENT SYNTHETIC BEDS

DESCRIPTION OF THE INVENTION

1) FIELD TO WHICH THE INVENTION RELATES

In a larger sense, the invention relates to the field of fixed constructions, and in the narrower sense, it relates to the field of construction and reconstruction of tramways and subways, by fastening the rails by means of resilient supports.

According to the International Patent Classification, the invention is classified in E01B 9/62.

2) TECHNICAL PROBLEM The technical problem to be solved by this process is construction of resilient beds on tram and subway tracks.

3) STATE OF THE ART

Since the very introduction of trams, and later on of subways in the city traffic, there has been a problem of constructing tracks and fastening the rails to their foundations, respectively.

With regard to the identity of structural elements (steel rails and wheels), it was considered that the construction of railway tracks would satisfy the needs of trams and city trains used in the city traffic, so the construction of tracks included the use of wooden, and later on of concrete sleepers on the gravel paving. The practice has shown that trams substantially differ from trains due to, first of all, their timetable. Trams stop more frequently, and therefore their speed is limited to apprpx. 40 km/h. Frequent stops and speed oscillations result in a special dynamic loading.

Construction of tracks on sleepers wasn't satisfactory. Tram tracks in city areas had to be embedded in the road surface, because the maintenance of the track was very difficult. Tram rails were laid on tamped buffer layer. All the deficiencies were shown very quickly. A better solution was chosen. The construction of a continued concrete foundation on an appropriately prepared foundation made the track more stable but at the same time stiffen

The GRAZ system has been designed to diminish the negative stiffening effects. This system includes pieces of old, used rails approx. 40 cm long, which are laid in a reversed position along the future rail track and are concrete in a concrete slab. Pieces of rails are prepared as to be fastened by the known railway fastening means. 6-10 mm thick rubber tie-plate is put between a rail and a built in steel piece.

With regard to the fact that the tram track is embedded in the pavement structure, so that the upper rim of the rail is levelled with a road surface, the rails and the fastening means are in a 60 cm wide trench containing humidity and various chemical solutions. Precipitation water assumes electrolytic features creating galvanic cells, i.e. producing electric current from substances generating chemical energy - galvanic current. Galvanic current activates galvanic corrosion, which destroys rubber (neoprene) tie-plate. The resilient system becomes stiff and the railway track is being destroyed.

The engineers of the Zagreb Electric Tram (ZET) have introduced and applied simplified steel fastening means called Zg-3 consisting of a U-shaped screw on which a 10 mm thick steel slab is put serving as foundation to a rubber (neoprene) tie-plate. All the elements, except the tie-plate, are made of steel.

Obviously, designers haven't recognized and noticed the cause of the GRAZ system decay, so they repeated the same fault allowing the occurrence of the previously described process. The system was applied for, and was granted a patent in 1985. It was entered in the register of the Federal Patent Office and was published in the Patent Gazette N° 2/88, under N° 934/85, in 1988.

The system continues to be applied, while the galvanic corrosion is destroying the expensive structures. The destruction of a neoprene tie-plate makes the system stiff, significantly damaging the vehicles and the rails as well as the pavement - the creation of potholes and the like. 4) DISCLOSURE OF THE ESSENCE OF THE INVENTION

The novelty of this invention lies in the prevention of galvanic corrosion that damages the rails and the fastening means. This has been achieved by the elimination of steel elements from the fastening system in the way that the steel slab serving as the foundation to the rubber tie-plate is replaced by a manufactured, synthetic, and chemically inert slab that is resistant to environmental influences.

The creation of electrolytes in the trench is inevitable, but there the chemical activity caused by the galvanic corrosion doesn't exist. Neoprene tie-plates have smooth and chemically stable foundation so that in a stable environment (protected from insolation, usual humidity) they may maintain the required resilient characteristics for a very long time. The whole fastening system remains resilient and long lasting.

If the track is regularly maintained, the rails formed in a strait line may be used for approx. 20 years, while the use of their curved parts, including switches and crossings depends on the traffic intensity, as well as of the quality of steel.

The durability of synthetic beds, comparing them with the steel ones is higher.

5) THE PROCESS OF CONSTRUCTINGA SYNTHETIC BED

The process of manufacturing the synthetic support comprises a technology, which may be applied without stopping the tram traffic. When constructing a new track, this process is performed more quickly and more simply and doesn't prevent the movement of vehicles.

6) METHOD OF CONSTRUCTING A NEW TRACK

After 30 cm thick permanent foundation slab is concreted and solidified, the rails are set in pairs. The rails are welded together in segments as decided by the producer, to form an endless rail line. The rails are put on chocks, approximately to a designed level, as to direction and height. They are temporarily interconnected with metal joints or with special distance keepers. Special levelling slabs for fine levelling (Fig. 1) are used to bring the track to a designed level as to height. The levelling slab also forms part of the present technological invention. The levelling slabs are used to include the calculated inclinations in curves. The places of future beds are marked on the rails. 25 cm deep holes are drilled on the places marked on the concrete slab by a ø 32 mm pneumatic hammer. The part of the slab around the holes is cleaned and coated with delude synthetic resin to provide adhesion of the synthetic rail chairs. Prefabricated synthetic slabs (Fig. 2) of several characteristic thickness to fit with uneven spots of the concrete slab are laid above the drilled holes. The slabs contain two elliptical openings. The holes drilled in the concrete are fitted with the holes made in the slabs, the liquid polymer is poured therein to fill 2/3 of the hole. Steel screws are put through the holes and are carefully mounted to be in a required position after the solidification of the mass.

The composition of the mass to be poured is very similar, as to its formulation, to the components of the synthetic slab. High reacting polyester type resins of the duroplast family are used. A catalyser

METHYLETHYLKETONPEROXLDE, in quantity 2-4% of the quantity of resin, is used to activate polymerization of binders, whereby the accelerator is COBALT OCTOATE, in quantity, which depends on the weather, 0,4-1,5% of the quantity of resin.

The filler is burned quartz sand containing 0,04-0,5 mm sized grains, constituting 60% of the total mass to be poured.

After the solidification of the poured mass, the screws are permanently and very safely fixed in the concrete foundation. Spring supports (Fig. 3/11) are screwed on the screws. 8 mm thick and 70 S chore strong neoprene tie-plates are put on synthetic slabs (Fig. 4/7), and 4 mm thick reinforced tie-plates (Fig. 4/6) are put on them. The two tie-plates are very important for the improved overtaking of dynamic forces transferred through the rail from the steel vehicle wheel to the constructed bed, and through it, to the concrete slab put on the resilient foundation, where they are finally lost in the soil thereunder.

Reinforced neoprene tie-plate is put under the rail foot to be adapted to the lower surface of the foot, which is damaged by atmospheric corrosion. Non-reinforced neoprene tie-plate is put under this tie-plate on the smooth synthetic slab surface to ensure "soft" and even transfer of dynamic forces generated by the movement of the vehicle. Steel clamps (Fig. 3/15) are drawn through the holes made in synthetic slab and springs are fastened to them, then being pulled tight on both screws parallelly, the synthetic slab with both tie- plates is put under pretension to ensure complete adhesion to the rail foot (Fig. 3/12).

After synthetic slab with tie-plates is mounted, a formwork made of waterproof plywood or sheet metal, high as required in situ (Fig. 3/13), is put around the bed. The formwork is joined by two stirrups (Fig. 3/14). Dry quartz sand is put around the formwork to prevent the leakage of the polymer mass (Fig. 3/9).

A polymer mass is prepared in situ, and contains:

1) High reactive polyester resins with 10% styrene monomer

2) Catalyser METHYLETHYLKETON PEROXIDE 2 - 4% of the resin mass 3) ACCELERATOR COBALT OCTOATE 0,01 - 1% of the resin mass

4) FILLER - burned QUARTZ SAND ø 0,02 - 0,6 m/m 30% of the total pouring mass

- BURNED QUARTZ SAND ø 1 -2m/m 50% of the total pouring mass

- PC 450 concrete 5% of the total pouring mass

The viscosity of the polymer mass allows it to be self-levelled in the hole in which it is poured.

It is very important that the previously mounted synthetic slab be immersed in the poured mass with its whole lower surface. The poured mass has very good adhesion properties, ensuring therewith a permanent connection between the bed and the concrete slab.

Within several hours the polymer composite mass achieves necessary solidification, so the formwork, the tension springs and their support may be removed.

The final fastening of the rails is performed by means of resilient clamps SKL-2 produced by UTENZILIJA - ZAGREB (Fig. 4/2).

The clamp is mounted on a specially designed plastic support (Fig. 4/3) which also forms part of this invention. The clamp is fastened with a nut over the plane tie-plate.

A plastic cap covered with machine grease is put on the nut and screw for protection. Then the levelling slabs are dismounted and the track is cleaned whereby the process of constructing resilient beds on the tram permanent way structure is completed.

7) THE METHOD OF USING THE INVENTION

Resilient system of fastening rails performed in such a way will satisfy a very demanding exploitation of the city rail transportation the track structure of which must be built in the road structure.

It will meet the environmental protection requirements as to vibration and noise.

This system results from a longtime work and observance of all the systems designed to perform this very complex task both in Croatia and in the world. There is a great need for the implementation of this system in all the cities, which intend to or are introducing the transportation by rails.

Analyses of the system key segments guarantee the quality of the system and increased exploitation span, resulting in achieving significant economic effects.

8) A LIST OF DRAWINGS

Fig 1 Prefabricated levelling slab.

Fig 2 Synthetic polymer slab.

Fig 3 Cross-section of the bed. Graphical presentation of the process of making the bed.

Fig 4 Plan view of the bed. Fig 5 Cross-section of the bed.

Claims

1. Process of making synthetic resilient beds for tram track both in the case of construction and reconstruction whereby this process allows continued moving of trams in the way that a continued, at least 30 cm thick concrete slab is previously prepared by MB 30 concrete. Then the tram rails are welded in an endless rail line and interconnected by transversal joints or special means, characterized by the fact, that track is temporarily put on wooden chocks, allowing the construction of the resilient synthetic bed.

2. Process of making synthetic resilient bed according to claim 1, characterized by the fact, that the prepared track is put on levelling slabs and is brought to designed level, that ø 32 mm, and 25 cm deep holes are drilled on places marked on the concrete slab, and that the place of the future bed is cleaned and coated with primer.

3. Process of making synthetic resilient bed according to claims 1 and 2, characterized by the fact, that synthetic slabs are put above the holes drilled in concrete, and that synthetic mass is poured through openings to fill 2/3 of the hole depth, and that ø 22 mm, c - 545 steel screws with threads on one end are brought to appropriate position.

4. Process of making synthetic resilient bed according to claims 1-3, characterized by the fact, that two neoprene tie-plates, 8mm thick lower one, and 4 mm thick upper reinforced one are put on the synthetic slab.

5. Process of making synthetic resilient bed according to claims 1-4, characterized by the fact, that spring supports are winded on fixed screws.

6. Process of making synthetic resilient bed according to claims 1-5, characterized by the fact, that steel clamps are inserted in the holes made on synthetic slabs and that the lower part of the spring is attached to them, and that simultaneously with the clamp fastening it is put on the upper part of the support, whereby the synthetic slab with two neoprene tie-plates are fastened to the lower surface of the rail foot, and is put under pretension.

7. Process of making synthetic resilient bed according to claims 1-6 characterized by the fact that a formwork made of plywood is put around the synthetic slab and that it is joined with two stirrups.

8. Process of making synthetic resilient bed according to claims 1-7 characterized by the fact the polymer mass i.e. polymer compost which is prepared in situ is poured in the formwork and that it includes the following characteristics

Components: -high reaction polyester-type resin - burned quartz sand ø 0,04-0,5 mm

- burned quartz sand ø 0,5-2,0 mm Ratio 1:3, constituting 70-80%o of the total mass

- PC 450 concrete, 5% of the sand mass

- to activate polymerization the quantity of resin is added a catalyzer METHYLETHYLKETONE PEROXIDE 2-4% of the resin quantity

- accelerator COBALT OCTATE 0,04-1% of the resin quantity provided that the pouring mass is solidified within 1-2 hours at the temperature of 20°C.

9. Process of making synthetic resilient bed according to claims 1-8 characterized by the fact that after dismantling the springs, synthetic support of clamp SKL-2 is put on the screw, and that the clamp is fastened by a nut put over plain tie-plate.