Patent Grant
9422680
The present invention relates to a deck suitable for supporting a carriageable surface and comprising first structural girders defining a support surface for the carriageable surface; at least a second structural girder suitable to position itself on the opposite side to the carriageable surface in relation to the first structural girders; diagonal girders integrally connecting the structural girders to each other, defining, for the deck, a truss; the deck defining a support surface. In particular, the invention relates to a structure suitable to define a substantially horizontal plane on which to make the carriageable surface and used for the construction of bridges.
As known, bridges are used to overcome an obstacle, such as a watercourse or a valley, which prevents the continuity of a communication route such as a road or a railway network.
These consist of a carriageable surface suitable to connect portions of the communication route separated by said obstacle; one or more decks suitable to define the support structure on which to make the carriageable surface: and pylons, abutments or other similar structural elements designed to sustain the deck and thus the carriageable surface suspended over the obstacle.
One of the most important structures is the deck which consists of a single body made of concrete/reinforced concrete and a having a flat upper surface on which to build the carriageable surface and a cross-section of maximum width at the end and minimum width in the centre so as to define a substantially arc-shaped profile for the deck.
Alternatively, the deck has a slab in reinforced concrete defining said flat upper surface and a steel skeleton suitable to absorb the weight of the deck and the loads acting on it.
The prior art mentioned above has several significant drawbacks.
A first significant drawback is the difficulty of transporting and installing the deck.
This problem is caused by the fact that the decks, on account of the complexity of construction, are made in special factories and must therefore be transported on site arranging expensive and challenging oversized transport.
This problem is further increased by the fact that once brought on-site the decks, having to be lifted and placed on pylons and abutments, require special and expensive lifting means.
This drawback is particularly relevant in the case of reinforced concrete decks where the high density of said reinforced concrete makes it even more complex and difficult to transport and install.
Another drawback is that the decks, especially when made of reinforced concrete, are subject to deterioration from exposure to the elements, to structural movements or exceptional events such as earthquakes.
The deterioration factor is further increased by the action of oxygen leading to the formation of rust on the iron reinforcement of the concrete.
The formation of rust also causes an increase in volume in the iron reinforcement giving rise to blistering and flaking of the concrete, which interrupts the structural continuity thereof reducing its mechanical strength.
In this situation the technical purpose of the present invention is to devise a deck able to substantially overcome the drawbacks mentioned above.
Within the sphere of said technical purpose one important aim of the invention is make a deck which is easy to transport and install.
Another important purpose of the invention is to make a deck practically immune to deterioration phenomena and thus characterised by high reliability and durability.
The technical purpose and specified aims are achieved by a deck suitable for supporting a carriageable surface and comprising first structural girders defining a support surface for the carriageable surface; at least a second structural girder suitable to position itself on the opposite side to the carriageable surface in relation to the first structural girders; diagonal girders integrally connecting the structural girders to each other, defining, for the deck, a truss; the deck defining a support surface; wherein the structural girders comprise a core in concrete material, an external reinforcement partially cladding the core leaving a portion of the core visible, connection means between portions of the first structural girders and the projecting diagonal girders comprising connection elements projecting from the support surface.
The characteristics and advantages of the invention are clearly evident from the following detailed description of a preferred embodiment thereof, with reference to the accompanying drawings, in which:
With reference to said drawings, reference numeral 1 globally denotes the deck according to the invention.
It is suitable to be used to support a carriageable surface such as a road or a railway network and thus to make a bridge, preferably, a bridge or deck with substantially continuous girders and at a variable height, and more preferably, a deck arch bridge.
The bridge includes a carriageable surface, one or more decks 1 suitable to support the carriageable surface and defining a support surface 1a, preferably substantially flat and support structures comprising pylons, abutment and other similar elements positioned at the ends of each deck so as to keep said deck 1 raised from the ground.
The deck 1 comprises first structural girders 2 defining a support surface, preferably practically flat, for the carriageable surface; at least one second structural girder 3 suitable to position itself on the opposite side to said carriageable surface in relation to the first structural girders 2; and diagonal girders 4 integrally connecting the structural girders 2, 3 to each other, defining, for the deck 1, a truss and connection means 7 between the structural girders 2 and/or 3 to each other and/or to the diagonal girders 4, suitable to integrally connect said elements to each other by means of screws and bolts, welding, or otherwise.
In detail, the deck 1 comprises two first structural girders 2 and one second structural girder 3 substantially equally spaced from the first structural girders 2.
Each of the structural girders 2 and 3, as described below, has a core in concrete material and an external reinforcement made of metal material and partially cladding the core so as to leave a portion thereof visible.
The cores of the structural girders 2 and 3, just as their external reinforcements are made of the same material. In particular, they are in self-compacting concrete which, thanks to a high degree of fluidity, is able to fill the formwork merely by effect of its weight and, therefore, without external energy input or mechanical vibration.
The external reinforcements are open sections, preferably made by press-forming, and in steel, to be precise, in weathering steel and, more precisely, in Cor-Ten Steel®.
The first structural girders 2 preferably have an equal cross-section, are specular and comprise a first core 21 and a first external reinforcement 22.
The first external reinforcement 22 is a section, with a constant cross-section, open at the top, i.e. with the opening at the top so that the concrete material of the core 21 is cast inside by gravity. It has a thickness comprised between about 1 and 3 cm and, more specifically, practically equal to 1.6 cm.
It is preferably a substantially U-shaped section defining an inner lateral side 221 facing the other first girder 2 and vertical, i.e. substantially parallel to the gravitational gradient; an external lateral side 222, inclined, preferably by 30°-60° with respect to the inner side 221; at least one slab 223 substantially perpendicular to the sides 221 and 222 to which the diagonal girders 4 are connected; and one bottom side 224 connecting the lateral sides 221 and 222 and practically perpendicular to the external lateral side 222. Said slab 223 forms part of the connection means 7 between the structural girders 2 and/or 3 to each other and/or with the diagonal girders 4.
The first external reinforcement 22 is, at the ends, devoid of partitions so as to allow the concrete material cast into it and constituting the core 21 to spill outside the external reinforcement 22.
The second structural girder 3 comprises a second core 31 and a second external reinforcement 32. These are preferably made by the press-forming of steel plates. They are also, preferably, filled with self-compacting concrete (SCC).
The second external 32 reinforcement comprises a hollow body 321 open at the top comprising partitions 322 closing the ends so as to prevent the concrete material cast inside it from spilling; and, arranged inside the section, a lamina 323 extending over the entire length of the exterior reinforcement 32 and welded to the base of the section.
Said hollow body 321 has a practically pentagonal cross-section with a horizontal base, i.e. practically perpendicular to the gravitational gradient, and an opening made at the vertex opposite the base so that the concrete material of the core 31 can be cast inside it by gravity.
The hollow body 321, the partitions 322 and the lamina 323 have a thickness at least equal to the first external reinforcement 21. In detail, substantially between 100% and 150%, and preferably substantially equal to 125% of the thickness of the first formwork 21. Said thickness of the second formwork 32 is practically comprised between 1.5 and 4 cm and, in particular, practically equal to 2 cm.
The second external reinforcement 32 and, therefore, the second girder 3 have a first tapered portion 3a with its maximum cross-section at the ends of the deck 1; and a second portion 3b with a constant cross-section equal to that the minimum cross-section of the first portion. Alternatively, the second girder 3 has two first portions 3a and one second portion 3b interposed between the portions 3a.
The diagonal girders 4 integrally connect the structural girders 2 and 3 so as to define, for the deck 1, a truss, appropriately, a substantially triangular truss.
The diagonal girders 4 (
In particular, they are at least partially housed in the external reinforcements 22 and 23 and protrude from them through respective first openings 22a and second openings 32a of the external reinforcement 32 counter-shaped to the diagonal girders 4. More specifically, the diagonal girders 4 have one end integral with the formworks 22 and protruding from them so as to be embedded in the concrete material constituting the carriageable surface.
Each diagonal girder comprises a section 41; and a first plate 42 and a second plate 43 integrally connected, preferably by welding, and more preferably by full penetration welding, at the ends of the section 41 closing the ends, and respectively, to the first external reinforcement 22 and the second external reinforcement 32.
The section 41 is identifiable in a section open at the top, appropriately with a U shape, having a thickness between 1 and 3 cm and, more precisely, practically equal to 1.6 cm.
The first plate 42 is a flat plate made integral with the slab 223 by bolts and to another first plate 43 so as to enclose the slab 223 between two first plates 42.
Said plates 42 and 43 thus form another part of the connection means 7.
Advantageously, the connection means 7 comprise connection elements 7a, not parallel, and preferably perpendicular to the main direction of extension of the deck 1, composed in particular of the plates 42, 43 and the slab 223, projecting from the support plane 1a, and possibly also from the surface of the second structural girders 3, and suitable to create a support for external elements.
Each second plate 43 is an L-shaped plate made integral, preferably by bolting on one side to the panel 323 and on the other to another second plate 43 so that four diagonal girders 4 are connected to the same portion of panel 223 forming the apex of a pyramidal architecture 4a.
The plates 42 and 43 have a thickness substantially comprised between 1.5 cm and 4 cm and preferably substantially equal to 3 cm.
The section 41 and the plates 42 and 43 are made of the same material as the formworks of the external reinforcements 22 and 32. Consequently, they are made of steel and, to be precise, weathering steel and, more precisely, Cor-Ten Steel®.
Additionally, the diagonal girders 4 may provide for a third core filling the space defined by the section 41 and by the plates 42 and 43 and made of concrete material and, to be precise, in self-compacting concrete.
The deck 1 may lastly provide for stiffeners 5 of the truss and, in detail, of the pyramidal architectures 4a suitable to connect the vertexes of the base of each pyramidal architecture 4a to each other; and supports 6, preferably one for each end of the first girders 2, defining the support surfaces of the deck 1 on the support structures.
Preferably, the deck 1 has four stiffeners subtended between the internal lateral sides 221.
These are identifiable in single or double T sections connected by welding and in particular by full penetration welding to opposite first external reinforcements 22.
The supports 6 are substantially similar to the girders 2, 3 and 4 and, therefore comprise an additional core 61 in concrete material and, in detail, in self-compacting concrete; and an additional formwork 62 suitable to clad, preferably exclusively, a limited portion of the additional core 61 and made of steel and, to be precise, of weathering steel and, more precisely, Cor-Ten Steel®.
The additional external reinforcement 62 is a section open at the top, of a thickness substantially equal to that of the second external reinforcement 32. Said thickness is therefore substantially comprised between 1.5 and 4 cm and, in particular, practically equal to 2 cm.
In particular, the additional external reinforcement 62 is identifiable in a U shape open section suitable to contain, for each first girder 2, one end and having lateral sides 621 suitable to keep in the concrete material of the additional core 61 preventing it from spilling outside before hardening.
The functioning of a bridge provided with a deck, described above in a structural sense, is as follows.
In particular, such embodiment defines an innovative method of constructing a bridge comprising an assembly step in which the external reinforcements 22, 32 and diagonal girders 4 are connected to each other creating one or more trusses; a foundation step in which the pylons, abutments or other support structures for the trusses are made; a transport step in which said truss is transported close to the construction site of the bridge; a laying step in which the ends of each girder are laid and connected to the support structures; a casting step in which the concrete material is cast into the truss forming the deck 1; and a final step in which the carriageable surface is made on the deck 1.
In the assembly step the sections 41 are integrally connected, using the connection means 7, in particular by welding (appropriately full penetration welding), to the plates 42 and 43 forming the diagonal girders 4, which are then inserted through the openings 22a and 32a in the first external reinforcements 22 and in the second external reinforcement 32 and connected to them by bolting or full penetration welding making the pyramidal architecture 4a and thus a truss (
It is to be noted how, to prevent unwanted spillage of the concrete material from the openings 22a and 32a, the diagonal girders 4 and in particular the sections 41 are welded, preferably with full formwork penetration welding to the external reinforcements 22 and 32 at said openings 22a and 32a.
Lastly, this step is completed by welding, appropriately full penetration welding, stiffeners 5 to the internal lateral sides 221 and two additional formworks 62 to the ends of the first formworks 22.
After completing this assembly step the transport and laying steps are performed in which the truss, i.e. the deck 1 without concrete material, is transported and then firmly attached to the support structure.
After completing these steps, the method provides for casting the concrete material which when solidified will constitute the cores 21, 32 and 61 (
In particular, at this step the concrete material is cast, by gravity, inside the second external reinforcement 32 and the first external reinforcements 21 from the ends of which it escapes to fill the additional external reinforcements 62. Even the diagonals 4-4a are appropriately filled with concrete.
Lastly, the method provides for the laying step in which the carriageable surface is made by casting concrete material onto the first structural girders 2 so as to encompass within it the ends of the diagonal girders 4 protruding from said first girders 2, also constituting the connection means 7 for upper portions of the carriageable surface 7.
The invention achieves important advantages.
A first advantage is the fact that the deck 1, by permitting the definition of an innovative method, is simple and quick to build, and, in particular, does not require plants fitted with expensive machinery.
This advantage is given by the special girders 2 and 3 and, additionally, by the stiffeners 5 which, having a core 21, 31 and 61 in concrete material and an external reinforcement 22, 32 and 62 cladding only partially said cores, makes it possible to make the core at a later time.
In fact, as may be seen from the method, such a solution makes it possible to create a truss 4a which being devoid of cores 21, 31 and 61, is lightweight and easy to transport.
This aspect has been further increased by the use, as concrete material, of self-compacting concrete which shrinks whatever the shape of the formworks 22, 32 and 62 by effect of its own weight and without the input of external energy or vibrations.
Another advantage is given by the conformation of the connection means 7 and connection elements 7a, which permits the connection of elements above the support surface 1a.
A further advantage, given by the use of external reinforcements 22, 32 and 62 and diagonal girders 4 in weathering steel and, more precisely, Cor-Ten Steel®, is identifiable in the high resistance to external agents, and thus, in the long duration of the deck 1. All the external reinforcements in steel sheeting are preferably made by press-forming sheets of suitable thickness. This solution makes it possible to reduce by about 50% the usual quantities of structural metalwork.
The invention is susceptible to variations within the inventive concept. All the elements as described and claimed may be replaced with equivalent elements and the details, materials, shapes and dimensions may be as desired.
| Number | Date | Country | Kind |
|---|---|---|---|
| MI2014A0691 | Apr 2014 | IT | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 354558 | Latimer | Dec 1886 | A |
| 3103025 | Gassner | Sep 1963 | A |
| 3111207 | Braddon | Nov 1963 | A |
| 3257764 | Cripe | Jun 1966 | A |
| 3872532 | Cornelius | Mar 1975 | A |
| 3893276 | Brown | Jul 1975 | A |
| 4282619 | Rooney | Aug 1981 | A |
| 4349996 | Lautensleger | Sep 1982 | A |
| 4481899 | Einstabland | Nov 1984 | A |
| 4741063 | Diana | May 1988 | A |
| 4912794 | Thivans | Apr 1990 | A |
| 4993094 | Muller | Feb 1991 | A |
| 20110196561 | Jorgensen | Aug 2011 | A1 |
| Number | Date | Country |
|---|---|---|
| 189118 | May 2013 | SG |
| 2012044013 | Apr 2012 | WO |
| Entry |
|---|
| The Italian Search Report for Italian Application No. MI20140691; two pages; competed Dec. 4, 2014. |
| Number | Date | Country | |
|---|---|---|---|
| 20150292168 A1 | Oct 2015 | US |
