ES2580927T3 - Transition structure and construction method - Google Patents

Abstract

Transition structure and construction procedure, which refers to a transition structure consisting of prefabricated reinforced concrete elements arranged in areas where there is a transition of rigidity in the track, whether it is rail or road traffic, as well as the necessary procedure for its construction

Description

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Transition structure and construction method DESCRIPTION

Object of the invention

The present invention relates to a transition structure as is generally known from US 2004/109730 A1, consisting of prefabricated reinforced concrete elements arranged in areas where there is a transition of rigidity in the track, either railway or road traffic, as well as to the method necessary for its construction, manufacturing, transportation, storage and placement.

Given the problematic existing in the stiffness transitions, the main objective of this solution is to obtain a transition that allows the variation of rigidities (vertical) to occur gradually between the earthworks and the works of factory (viaduct, underpass, drainage elements, etc.), minimizing the seats and maintenance work suffered by the current design of transitions, actions framed within the civil works construction sector.

The present invention is applicable both in the construction and repair of railroad tracks and on highways and roads.

State of the art

In the state of the art, different methods and devices designed to minimize the variation of rigidities, mainly vertical, existing between the land works and the factory works are known.

The vertical stiffness of the track, rail or road, is understood as the resistance provided by the whole of the built structure, rail or road, to deform under the force / load applied in the vehicle-infrastructure contact area (by a wheel of a railway vehicle), this value being one of the most relevant indicators of the quality and safety of infrastructure (railway), said value being minimally related to the dimensioning of the infrastructure elements.

If we take the railway infrastructure, as is well known by the technicians in charge of the construction of railway platforms, a value of the vertical stiffness of the road as homogeneous as possible should be guaranteed, as far as possible, avoiding changes significant. Transversal works and structures that save existing geographical features or infrastructures, particularly their stirrups, tend to have high rigidity, with zero or very small vertical movements. On the contrary, the embankments of access to these works have much higher displacements and, therefore, lower vertical stiffness. This fact causes that, in an area of reduced length, an important variation of the vertical stiffness occurs.

To avoid the harmful effects (reduction of comfort, lower speed of movement, greater wear and tear of the mobile material and the road, higher maintenance costs, etc.) that this sudden change generates, an element that distributes the most homogeneously must be arranged on the track possible the change in stiffness being, the so-called "transition structures or cradles" on which this function falls.

Currently in Spain, the cradle typology, its constructive form and the method of execution and testing are typified by the Railway Infrastructure Manager (ADIF) in the Technical Specifications Sheet for Platform Projects (PGP 2008), as well as in the Instructions and Recommendations for the Drafting of Platform Projects (IGP 2008) also prepared by ADlF, discretizing the stiffness transitions in 4 main cases, said solutions being formed by various granular materials arranged in the form of "cradle". In an analogous way, the rest of the main railway administrations have elaborated some cards in which the main characteristics to construct the transitions are collected, varying the type of material in each one of them and its disposition.

The operation of these granular cradles, from the theoretical point of view, fulfills its function, allowing the rigidity of the factory work to be achieved gradually, adapting the deformability of the road to which it has on the work in question.

However, experience has revealed, probably due to the difficulty of correctly executing these work units (materials and execution times) that despite the adoption of the different solutions proposed, there are still important variations of rigidity that do, in many of the cases, that the problem is not solved and cause a series of problems both to the infrastructure and to the vehicles and travelers that circulate on them. This is mainly due to the fact that the construction of granular cribs has associated a series of problems that cause, in most cases, that it does not materialize properly.

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In the state of the art no solution is known as the one raised in the present application, although solutions that use granular cradle systems for the materialization of a gradual transition in the vertical stiffness of railroad tracks are known, which They comprise a system for executing the embankment adjacent to the point of maximum stiffness (factory work) through the proper placement and compaction of granular materials with concrete features treated or not treated with cement.

However, this system of granular cribs presents certain problems such as:

• High economic costs (extraction, acquisition and transport of materials, qualified personnel, machinery, frequent maintenance).

• High execution periods, which expose the materials to the action of climatological factors (causing excessive execution times and frequent delays).

• High susceptibility to weather attacks, mainly water.

• Difficulty of the quality control of the final product and the execution process.

• Decrease in user comfort and safety.

• Uncertainty in their behavior during exploitation.

• Large environmental costs due to the difficulty of obtaining granular material, which entails the opening of new quarries and prohibitive transport costs and with their high CO2 emissions.

• Need to manufacture the material treated with cement in plants, which entails the new construction of these if the infrastructure is far from the concrete production centers.

With the fundamental objective of boosting economic profitability, both of the conventional lines and the new high-speed lines that are being developed throughout the world, as well as to ensure and maintain their success in a future scenario and, since It is clear that terra-structure transitions are a source of great maintenance needs, causing a high increase in costs, the present invention is proposed as a solution to the existing problems. This solution is not exclusively applicable to railroad tracks, but as also mentioned, it also applies to road traffic routes such as roads and highways.

Description of the invention

The present invention has as its object a transition structure or cradle for the materialization of the vertical stiffness transition constituted by precast concrete modules by means of which the effects of deformations produced in the superstructure (of the track) as a consequence of variations are achieved Large-scale discontinuous along a piece of land as a result of the presence of cross-sectional works, the junction with an overpass or viaduct, etc.

The premises that mark the design of the transition cribs object of this application, as well as their dimensions, are those of creating a stable structure as a whole, capable of resisting and transmitting the efforts correctly, achievable with the current technology under a structural and economic efficiency. The choice of the most appropriate cradle has been raised through a decision-making problem with multiple or multicriteria criteria.

The calculation results are based on the regulations regarding the materials used:

• EHE-08. EHE structural concrete instruction.

• EC-2. Eurocodigo 2, "Concrete Structures Project".

• IGP-2008. Instructions and Recommendations for writing platform projects.

The transition structure proposed by the present invention is composed of at least two slabs or precast reinforced concrete slabs, located one above the other determining two heights and two rows, the width of the slabs being equal between them and preferably in turn of, at least, the width of the sleeper in the case of railroad tracks because the maximum tensions are concentrated in the central part, an area that must be covered with the solution and, at least, the width of the roadway in the case of Roads of road traffic. Likewise, in those cases in which the width of the track is greater than the widest possible width of the slabs for constructive or transport reasons, they may be arranged in parallel, increasing their width, being able to be or not mechanically joined or coupled.

The structure is formed by solid slabs stacked on each other properly, the structure or cradle being made up of prefabricated pieces with at least one of its different dimensions, preferably the length, being conveniently aligned next to the face of the workmanship. This type of solution allows an important variability, being able to increase the number of heights formed by slabs or prefabricated plates to adapt, in each specific case, to the difference of rigidities of the work in question. The slabs are arranged in rows and in height such that the length of the row of lower slabs is greater than the length of the row of

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upper slabs, determining the transition structure at the opposite end of the wall of the work site a succession of steps. Each height will be formed by at least one row of equal length.

In the event that the arrangement of the road, rail or road, with respect to the transition was shifted (angle of deviation between 0 and 45 °), the solution is equally valid since the shape of the first slabs, external slabs of the cradle or structure, so that it will adjust to the required angle of deviation and therefore to the arrangement of the road. The system of placement of successive slabs will be the same.

In the event that the structure needs to be built on a land of insufficient bearing capacity, an improvement of the platform (replacement of the same by a more suitable one, add cement, etc.) will have to be done and even support the solution, if deemed necessary, so as to ensure in all cases that the transition has an adequate bearing capacity.

It should be considered that these slabs, in principle, are placed without any connection element, provided that at least one of the surfaces of the slab has a rough surface, so that its behavior as a continuous joint structure is due exclusively to the friction mobilized between the contact surfaces between the slabs. Likewise, it is possible to introduce some element or material between the slabs during the construction phase that increases the capacity to mobilize tensions between some slabs and others, preventing displacement between slabs.

In the event that the friction between the slabs could not be guaranteed, it is possible to size the slabs with through holes that subsequently allow the sewing or joining of the slabs by metal bolts, pins or any other device, as well as the case of building the plates with a morphology that allows a tongue and groove system in both the horizontal and vertical plane such that, when joining the slabs, the assembly works as a whole. Said tongue and groove can be performed both in the vertical plane and in the horizontal plane, so that the slabs can be coupled with other slabs located above or below them as well as with other slabs located in the same plane.

With this configuration it is intended to solve the different types of transitions defined by the infrastructure manager of each country. In the case of the Railway Infrastructure Administrator (ADIF) in Spain, it defines 4 prototypes of transitions, where H is the height of land located above the transition structure:

• Case 0 <H <0.5.

• Case 0.5 <H <2.

• H> 2.

• Stapes.

A basic solution of a transition structure according to the present invention consists of a cradle formed by at least two precast reinforced concrete slabs, with the same width and preferably the same thickness, but the first slab having a length of approximately twice as long as the second slab, and the first slab being arranged as a base and the second slab on it, thus defining two rows.

Said first slab can be supported on the stratum where the work is supported (viaduct, underpass, drainage element, among others ...) or on at least one pillar or improved ground with sufficient bearing capacity, in turn supported on the stratum where said work is supported, one alternative or another depending on the height of the work and the quality of the support stratum.

If it is necessary to construct a transition structure with a greater number of prefabricated slabs, determining more than two rows, said slabs will be arranged in such a way that the contact areas of the slabs of a row do not coincide with the contact areas of the slabs of the upper or lower row, taking advantage of the slabs for said construction with at least two different lengths. This will prevent the creation of a continuous vertical joint along the entire cradle.

An alternative to the previous solution, and that could be useful in certain circumstances, is the possibility of arranging slabs that have the same width and the same length, not having to be said dimensions equal to each other. Thus, when creating the Different rows and heights, placing one slab over another, will create continuous vertical joints that separate columns of slabs.

Likewise, the method for the installation of these elements for the formation of the transition structures or cradles object of the present invention does not require construction methods that differ significantly from those already known, hence their advantages in terms of time reduction and greater control both in manufacturing and in execution. Said installation method comprises the following stages:

• Manufacture of the necessary prefabricated concrete modules (in prefabricated plants) destined to the

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configuration of the complete structure (cradle), with an adequate quality control of materials, process and finished product, under seal of quality. These elements will be available prior to the start of the work carried out in the construction of the work.

• Transport and placement of said concrete elements in the design of the work, according to the final disposition adopted for them, and according to what is described in terms of the arrangement of the slabs.

• Extended granular material and compaction with suitable tools.

The different phases show the simplicity of the manufacturing, transportation and assembly system as well as the improvements in terms of reduced execution times and lower costs. This is because the precast concrete companies are very familiar with the manufacture of these parts and the transport requires the use of common vehicles as well as the placement and assembly. From all this, an “industrialized” process can be created, which translates into a reduction in the times of each of the phases and the cost reduction.

The main advantages derived from the solution described mainly result in the minimization of the risk of differential seats, which will achieve:

• Reduction of vertical vibrations in the mobile material.

• Increased levels of comfort and safety in travelers.

• Reduction of infrastructure and superstructure maintenance needs.

• Better planning of maintenance operations.

• Reduction of execution times and construction cost.

• Greater control of performance and behavior throughout the useful life.

Likewise, and in more detail, these advantages are manifested in:

• Cost competitiveness:

o The lower demands or possibilities of pretreatment and alternatives for obtaining concrete aggregates increase their availability and reduce their cost, reducing the possibility of excessive transport costs of certain aggregates from far away sources.

o The prefabrication of the solution involves optimizing the costs of running the solution, as a result of the entire industrial process.

o Prefabrication reduces the maintenance needs of the railway superstructure, which directly influences a decrease in costs. This aspect also has a direct impact on the lower deterioration of the vetucles.

• Competitiveness in installments:

o The prefabrication of part of the components of the solution devised supposes its disposition prior to the beginning of the works of the ground work.

o The simple and rapid placement of the elements facilitates the execution of the commissioning and reduces the deadlines for the termination of the unit and, therefore, of the complete performance.

o The prefabricated compositions suppose a greater control of execution and a better planning of the works of maintenance with guarantees to reduce unforeseen.

• Competitiveness in quality control and safety operations:

o The solution contemplates the suppression of materials treated with cement, which means that there is no need to control its contents, simplifying quality control.

o In successive auscultations, it can be verified that, the improvement in the control of the stiffness in these transitions, causes smaller differential seats which results in a reduction of the vibrations and, therefore, in an improvement of the comfort of the traveler. In the same way, there will be less defects in vertical leveling, reducing the risk of derailment.

o These prefabricated designs allow greater control of the behavior of the road during its useful life.

• Lower environmental costs:

o The volume of exclusively granular transitions itself requires a large number of aggregates that must be covered. The presence of prefabricated elements in the new structure considerably reduces this volume of granular material, reducing the degree of impact on the weather and the environment. o The greater availability of aggregates for concrete, together with the elimination of materials treated with cement, implies the use of aggregates of greater accessibility reducing transport demand as well as

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its noise level and greenhouse gas emissions (CO, CO2, etc.).

o The reduction of maintenance operations reduces the transport of the necessary mobile material and associated with these activities contributing to the decrease in emissions.

In view of the above, the invention object of the present patent application, responds to the problems caused by the stiffness transitions currently existing, by incorporating transition cradles that incorporate precast concrete elements that replace the Current transition cribs made with granular materials.

Description of the drawings

To complement the description that is being made of the invention and to help a better understanding of the characteristics that distinguish it, the present descriptive report, as an integral part of it, is accompanied by a set of drawings, in which Illustrative and non-limiting character has represented the following:

Figure 1 shows the solution of the invention to a general case of transition cradle object of the invention with a height of land H on it.

Figure 2 shows a perspective view of an alternative structure isolated from the environment.

Figure 3 shows a side view of an alternative structure to that shown in Figure 1 without pillars.

Preferred Embodiment of the Invention

In view of the aforementioned figures, and according to the numbering adopted, an example of the described invention can be observed therein, which comprises the parts and elements that are indicated and described in detail below.

Figure 1 represents an example of embodiment of a structure or cradle 10 object of the present invention in which a set of slabs 1, 2 of two lengths, prefabricated of reinforced concrete, stacked one on top of the other in this example determining three heights is observed with three rows of slabs per height. On one of its longitudinal ends a set of slabs are aligned with the face of the work site 3 and on the opposite longitudinal end, other slabs determine three steps, one per height, the length of the lower height being greater than the height higher.

As mentioned, said structure comprises slabs 1, 2 of two types, in this case having a first slab 1 of a length that is approximately double the second slab 2. The width of the slabs is identical and the thickness of they are preferably identical also, the width of the slabs being at least equal to the width of the crossbar in the case of railroad tracks and at least equal to the width of the roadway or road in the case of roadways. The slabs 1, 2 are arranged in such a way that the joint created by the contact of two of the slabs of a row, does not coincide with that created by the slabs of the upper or lower row, taking advantage of to achieve said construction the slabs 1, 2 with two different lengths.

Thus, the lower height of the structure has a lower row with three aligned slabs 1 of greater length, on which a second row of slabs are arranged, as described above, with two slabs 1 of greater length in the center and two slabs 2 of shorter length at the sides, and on this second row three slabs are again arranged with the same configuration as the first (slab 1 of greater length). On this lower height there is a second intermediate height comprising a first lower row with a slab 1 of a greater length flanked by two slabs 2 of shorter length, on which a second row with two slabs 1 of greater length is arranged, and a third row is arranged on this second row with the same constitution as the first lower row of this second height. The last height, also composed of three rows of slabs, has three rows each formed by a slab 1 of greater length.

The different rows constituted by the slabs are aligned in one of their ends with the work of factory 3, determining the different heights of the structure by the opposite end.

In this example, the slabs of the lower row are supported on pillars 5, in turn supported on the substrate 4 where the work is supported 3. Also, on the structure a layer of soil 6 with a variable height is arranged and that depends on the specific application, on which a layer 7 is applied on which a protective sheet 8 is arranged. On this last sheet 8 the track is arranged, either by rail or road.

The dimensions of the slabs are variable, but because they are precast reinforced concrete slabs the thickness must be at least 0.2 meters. The width of the slab depends on the length of the crossbar in railroad applications and the width of the roadway in road or road traffic applications.

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In those cases in which the road is of greater width than the maximum possible width of the slab, for constructive or transport reasons, mainly in the case of road traffic applications, the largest dimension of the slab can be arranged transversely to the track, this width becomes the largest dimension and the smallest dimension the length, unlike what has been described so far in this document where the length dimension of the slab in the direction of the track has been considered. It is also possible to arrange slabs in parallel to achieve the width of the track.

As for the length of the slabs that make up the structure, this can also be variable, but there must be at least two types of slabs with different lengths, and preferably two types of slabs where the length of one of the types 1 is approximately the double that of another type 2, in order to be able to build the structure object of the invention. The relationship of length between the different types of slabs may not be from 2 to 1 and there may also be more than two types of slabs with different lengths.

An example of slab dimensions for application on a railroad track is of a first type 1 with a length of 7.2 meters, a width of 2.5 meters and a thickness of 0.2 meters, while the second type of slab 2 has a length of 3.6 meters, width of 2.5 meters and thickness of 0.2 meters. Likewise, it is possible to include in the structure slabs with other lengths and dimensions depending on their application, although it is convenient that said slabs have the greatest possible dimensions since the larger these dimensions are, the better the slabs that make up the structure will behave as a unique set, that is, as a whole, and when presenting the larger slabs, a greater friction between slabs is guaranteed due to their greater weight.

Also, the width of the slabs is determined by the need to cover the area where the stresses are concentrated, and in order that the smaller the number of slabs, the better the behavior of the structure as a single element or set . The minimum thickness of the slabs will be mainly determined also by the constructive conditions or requirements thereof.

The maximum dimensions of the slabs will be limited by the maximum weight of the slab and the length of the slab since they must be transportable by land, and in particular by road. The preferable transport is through non-special vehicles that do not need transport permits for simplicity and ease, but if necessary, depending on the case, the slabs can be transported in special vehicles.

On the other hand, the dimensions of the transition structure will be limited in terms of their width by the width of the slabs, but in regards to their length and height, these will be variable so that it adapts to the necessary height that requires each work in question, being conveniently arranged next to the face of the work of factory. Due to the ease of manufacturing and commissioning, the adaptation to the height of the stirrup or step work is simple and does not require any special calculation.

Figure 2 shows another construction of a structure 10 according to the present invention, also with three heights and three rows stacked by height, in which the lower height of the structure is formed by a lower row that only has two slabs, a slab 1 of longer length and another slab 2 of shorter length, on which a second row is also arranged with two slabs 1, 2 but alternated with respect to the first lower row so that the contact areas of the slabs of the second row they do not coincide with the contact areas of the slabs of the lower row, and a third row with the same arrangement as the lower row. On this first height a second height of three stacked rows is arranged, each row being formed by a slab 1 of greater length. The last height is formed by three stacked rows, each row formed by a slab 2 of shorter length.

The third example of construction of a structure according to the present invention, shown in Figure 3, is a structure like the one shown in Figure 1, but instead of being placed on pillars 5, it rests directly on the support layer 4 of the work structure 3.

An alternative to the previous solutions, not shown in the figures, is the possibility of arranging slabs that have the same width and the same length, not having to be said equal dimensions between st In this way, when creating the different rows and heights , placing one slab on another, vertical joints that separate columns from slabs will be created.

To prevent the slabs of the structure from moving or moving relative to each other once installed, different solutions have been devised to ensure friction between the slabs. These solutions do not condition the operation of the slab as a whole so that any of those that will be named below can be valid and will be applied depending on the availability or construction processes of the company responsible for its manufacture:

- not include any material or element to increase friction,

- manufacture the slabs with at least one surface of greater roughness than another or with sufficient roughness to

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ensure friction between slabs,

- introduce some element or material between the slabs during the construction phase that increases the ability to mobilize tensions between some slabs and others,

- dimension the slabs with through holes that subsequently allow sewing or joining of the slabs by metal bolts, injection or other system,

- Shaping the plates to allow the tongue and groove in the vertical plane and / or in the horizontal plane, so that the slabs can be coupled with other slabs located above or below them as well as with other slabs located in the same plane.

The method of construction of the transition structures between land works and factory works shown in the figures and object of the present invention, comprises at least the following steps,

- manufacture of precast reinforced concrete slabs necessary for the configuration of the structure,

- transport of said slabs to the work where the transition structure will be built,

- placement of at least two slabs in the trace of the work, according to the final disposition adopted for them, in such a way that said at least two first slabs have the same width and different length, placing the slab of smaller length on the slab of greater length determining at least two rows of slabs that determine at least two heights, with a longitudinal end of said two slabs aligned with the workmanship, the width of the slabs being at least equal to the width of the track, and centering the slab longitudinally with respect to said pathway,

- extended granular material on the slabs, and

- surface compaction.

As in the transition structure described above, it can have several rows and several heights, such that the rows can have more than one slab in longitudinal contact with at least one other slab at least one of the two longitudinal ends , in order that the longitudinal contact areas of the slabs of a row do not coincide with the longitudinal contact areas of the slabs of an upper or lower row.

Claims (14)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 1. A transition structure (10) of the type used in the construction and repair of roads to reduce the variation of the vertical stiffness between a land work and a factory work, characterized in that it comprises: - at least two first prefabricated reinforced concrete slabs (1, 2) having the same width, one slab being located on the other slab determining at least two rows of slabs that determine at least two heights, with a longitudinal end of said two slabs aligned with the workmanship. 2. The structure (10) according to claim 1, characterized in that the slabs (1, 2) have different lengths, the slab of smaller length being located on the slab of greater length. 3. The structure (10) according to claim 1, characterized in that the slabs (1, 2) have the same length. 4. The structure (10) according to the preceding claims, characterized in that the rows can have more than one slab (1, 2) in longitudinal contact with at least one other slab by at least one of the two longitudinal ends. 5. The structure (10) according to the preceding claims, characterized in that it has at least two heights each height comprising at least one row. 6. The structure (10) according to claims 2 to 5, characterized in that each height has a length other than the other heights that are determined by the length of the rows of each height, in turn determined this length by the number of slabs (1, 2) and their length in each row, the lower height being longer than the immediately higher height. The structure (10) according to claims 1, 2 and 4 to 6, characterized in that the longitudinal contact areas of the slabs of a row do not coincide with the longitudinal contact areas of the slabs (1, 2) of a upper or lower row. 8. The structure (10) according to claim 1, characterized in that the opposite surfaces of the slabs (1, 2) have different roughness. The structure (10) according to claim 1, characterized in that the slabs (1, 2) have at least one through hole (3) for the introduction of a pin or an injection material. 10. The structure (10) according to claim 4, characterized in that the slabs (1, 2) have recesses or projections at their longitudinal ends that allow the tongue and groove thereof. 11. The structure (10) according to claim 1, characterized in that the slabs (1, 2) have recesses or projections on their surfaces that allow the tongue and groove of the slabs. 12. The structure (10) according to claim 1, characterized in that the width of the slabs (1, 2) is at least equal to the width of the track. 13. The structure (10) according to claim 1, characterized in that the width of the slab (1, 2) is equal to the length of a crossbar of the railway track. The structure (10) according to claim 1, characterized in that the width of the slab (1, 2) is equal to the width of the roadway of the road or road traffic. 15. A method of construction of transition structure of the type used in the construction and repair of rods to reduce the variation of vertical stiffness between land works and factory works, characterized in that it comprises the stages of: - manufacture of precast reinforced concrete slabs (1, 2) necessary for the configuration of the structure, - transport of said slabs (1, 2) to the work where the transition structure will be built, - placement of at least two slabs (1, 2) in the design of the work, according to the final disposition adopted for them, in such a way that said at least two first slabs have the same width, placing one slab on another slab determining the at least two rows of slabs that determine at least two heights, with a longitudinal end of said two slabs aligned with the workmanship, the width of the slabs being at least equal to the width of the track, and centering the slab longitudinally with respect to said way, - extended granular material on the slabs, and - surface compaction. 16. The method according to claim 15, characterized in that the rows can have more than one slab (1, 2) in longitudinal contact with at least one other slab by at least one of the two longitudinal ends, such that the zones of longitudinal contact of the slabs of a row do not coincide with the zones of longitudinal contact of the slabs of an upper or lower row.