Process for installing bridge

Abstract

A process for installing at least one portion of an arch structure (10) for constructing a bridge (20), wherein a deck (25) is supported by said arch structure (10) to connect the two banks (30a, 30b) opposite and separated by an intermediate zone (31) to be crossed, said bridge (20) being installed at a reinforcement referred to as the shoulder (21a, 21b) made on each bank (30a, 30b), said process provides for providing a first arch portion (10a) and / or a second arch portion (10b), and for positioning it on the shoulder (21a, 21b) so that a first end thereof (11a, 11b) faces the bank (30a, 30b) and a second end thereof (12a) faces the opposite bank (30a, 30b), and performing a first rotation (R1a, R1b) of the arch portion (10a, 10b) about a first fulcrum (C1a, C1b) so that the second end (12a, 12b) lowers and the first end (11a, 11b) rises, and continuing said first rotation (R1a, R1b) until the second end (12a, 12b) reaches a second fulcrum (C2a, C2b), and performing a second rotation (R2a, R2b) of the arch portion (10a, 10b) about the second fulcrum (C2a, C2b) so that the first end (11a, 11b) lowers, until reaching the final installation position.

Description

FIELD OF APPLICATION OF THE INVENTION

[0001] The present invention pertains to the field of bridge or viaduct construction, particularly for installing at least one portion of an arch structure adapted to support the deck of a bridge.STATE OF THE ART

[0002] Different types of bridges and different processes for the installation thereof are known to the state of the art.

[0003] Generally speaking, the term bridge refers to a typical civil engineering infrastructure adapted to connect two opposite ground sides or banks, separated by an intermediate zone to be crossed.

[0004] Said intermediate zone to be crossed can be an obstacle, either natural or artificial, that interrupts the continuity of a communication route.

[0005] Generally, we speak of bridges when the intermediate zone to be crossed is a watercourse, whereas if it is a valley or an orographic discontinuity, it is referred to as a viaduct. If it is another communication route of the same type as the one being crossed, it is referred to as an overpass.

[0006] Henceforth, we will generically use the term bridge to refer to all of the aforementioned types.

[0007] The installation processes are linked to the type of bridge, but primarily are functional to the environmental conditions in which the bridge must be installed.

[0008] It is indeed different to install a bridge in a flat land, compared to installing it in mountainous areas where the slopes require more complex means and processes.

[0009] More specifically, hereinafter we will refer to an arch bridge.

[0010] Generally, a so-called arch bridge is a stationary bridge comprising a deck supported by said arch structure 10.

[0011] This static scheme allows to transfer part of the weight of the bridge and loads, such as people, cars, or trains, into horizontal forces, counteracted by the base of both banks.

[0012] The development of the arch 10 can be circular, such as an arch of a circle, or it may follow a conical curvature, such as, for example, a parabola.

[0013] The process that is the object of the invention is particularly suitable for installing an arch bridge in an environment where the intermediate zone is inaccessible to operators or operational means, for example, a river, a gorge, a deep valley.

[0014] Processes for installing an arch bridge in environments with an inaccessible intermediate zone are known to the state of the art.

[0015] A known process provides for making and installing a semi-arch 10c, 10d from each ground side, and then connecting the two semi-arches 10c, 10d together.

[0016] The known process provides for each of the two semi-arches 10c, 10d to be made directly in situ during the installation, by assembling a plurality of lengths of a semi-arch, also referred to as segments 100.

[0017] This process is due to the fact that installing lifting means or temporary supports in the intermediate zone in order to be able to handle and to position the semi-arch 10c, 10d is not feasible, or not cost-effective.

[0018] The positions that are normally accessible to the lifting means 300, for example, a crane, are the two ground sides.

[0019] In challenging environmental situations, such as those depicted in Fig. 6, where the slope drops steeply, even the use of lifting means, such as a crane, becomes complex and very costly.

[0020] In fact, it is necessary to ensure a levelled and clear area for the assembly of the machine body and the boom of the cranes.

[0021] Additionally, due to the large distance between the anchoring position of the machine body and the installation position of the semi-arch 10c, 10d, it is not advisable to lift the entire semi-arch 10c, 10d due to its high weight and bulk. This would require the use of high-load-capacity cranes, which pose positioning issues and result in very high costs.

[0022] Therefore, according to the prior art, the lifting means 300 position one segment 100 at a time so as to create the semi-arch 10c, 10d directly in the intermediate installation zone of the bridge.

[0023] This allows for using a crane of a type that is easier to source and with lower costs.

[0024] A known process provides for making on each bank a reinforcement on which the first segment 101 can be installed, for example, as depicted in Figure 6, at the base of a stack.

[0025] The first segment 101 is rotatably secured, for example, by a hinge.

[0026] Once all the segments 100 are welded and the semi-arch 10c, 10d is formed, it will be moved to the final position by rotating it about the hinge of the first segment 101 to which it is attached.

[0027] Said rotation is generally carried out by a winch 301.

[0028] During the assembly of the semi-arch 10c, 10d, each segment 100 is positioned adjacent to the previous one and secured to the previous one by the intervention of an operator who performs welding or mechanical fitting, working in a suspended position.

[0029] Therefore, additional means are necessary to safely and functionally position the operator above the intermediate zone and perform the welding.

[0030] It is clear that this operation involves not only high costs, but also high risks, both because the operator must perform the assembly operation while in a suspended condition, and due to the accuracy of the installation.

[0031] In fact, successfully joining the segments 100 and, finally, the two semi-arches 10c, 10d assembled in the above-described manner, while respecting tolerances in the order of a centimetre, is far from simple and straightforward.

[0032] It must be considered that during the installation, the issue of wind must also be managed, which is always present in certain environmental contexts, especially in mountainous environments.

[0033] Not to mention the possible adverse weather conditions, such as strong wind or rain, which are frequent occurrences in mountainous environments.

[0034] All of this also adds to the installation times, making them extremely lengthy.

[0035] Installing a semi-arch 10c, 10d, using the process described and depicted in Fig. 6, may take several weeks, even without particularly adverse weather conditions.

[0036] The making and installation steps of the arch 10 of a bridge according to the prior art, as depicted in Fig. 6, are summarized herein below.

[0037] The process provides for assembling the first semi-arch 10c, 10d and the second semi-arch 10c, 10d by performing the steps described below.

[0038] Step 1: Assembly of the first segment 101: the first segment is taken from behind the crane, the first segment is positioned on the hinge, stabilization by using safety ropes.

[0039] Step 2: Assembly of the second segment 100: the second segment is taken from behind the crane, the second segment is positioned adjacent to the first segment and the edges to be welded are aligned, the welding operations between the first and the second segment are performed, connection by using ropes with a winch of the second segment to ensure the stability of the semi-arch length, release of the second segment from the crane and wind bracing by means of ropes.

[0040] Step 3: Assembly of the third segment 100: the third segment is taken from behind the crane, the third segment is positioned adjacent to the second segment and the edges to be welded are aligned, the welding operations between the second and the third segment are performed, connection by using ropes with a winch of the third segment to ensure the stability of the semi-arch length, release of the third segment from the crane and wind bracing by means of ropes.

[0041] STEP 4: Assembly of the fourth segment 100: the fourth segment is taken from behind the crane, the fourth segment is positioned adjacent to the third segment and the edges to be welded are aligned, the welding operations between the third and the fourth segment are performed, connection by using ropes with a winch of the fourth segment to ensure the stability of the semi-arch length, release of the fourth segment from the crane and wind bracing by means of ropes.

[0042] STEP 5: Assembly of the fifth segment 100: the fifth segment is taken from behind the crane, the fifth segment is positioned adjacent to the fourth segment and the edges to be welded are aligned, the welding operations between the fourth and the fifth segment are performed, connection by using ropes with a winch of the fifth segment to ensure the stability of the semi-arch length, release of the fifth segment from the crane and wind bracing by means of ropes.

[0043] Once both semi-arches 10c, 10d are assembled, it is provided to assemble the complete arch 10.

[0044] Step 6: Assembly of the two semi-arches 10c, 10d: rotation via a winch of the first and the second semi-arches 10c, 10d about the hinge until the final position of both semi-arches 10c, 10d is reached; the first semi-arch 10c, 10d is positioned adjacent to the second semi-arch 10c, 10d and the edges to be welded are aligned; the welding operations between the first and the second semi-arches 10c, 10d are performed; release of the semi-arches 10c, 10d from the crane. DISCLOSURE AND ADVANTAGES OF THE INVENTION

[0045] The technical problem underlying the present invention is to provide a process for installing at least one portion of an arch structure for constructing a bridge, which is structurally and functionally devised to overcome one or more of the limitations set forth above with reference to the mentioned prior art.

[0046] In the context of the aforementioned problem, main object of the invention is to develop a process for installing at least one portion of an arch structure for constructing a bridge, which allows for reducing the risks for operational personnel.

[0047] Further object of the invention is also to provide to the art a process for installing at least one portion of an arch structure for constructing a bridge in the context of a solution flexible to various operational situations, including the most challenging environmental conditions.

[0048] It is also an object of the invention to reduce errors in assembling the semi-arches or arch portions, allowing for the adherence to more stringent assembly tolerances, to make the closure welding of the two semi-arches with considerably improved tolerances.

[0049] Moreover, object of the invention is also to create an installation process with reduced cost and time.

[0050] In particular, one of the objects of the invention is to eliminate the need for large-sized lattice cranes, which require reinforcement of the bank near the shoulder and obstruct access to the bridge itself.

[0051] As a consequence, this eliminates the need to prepare a levelled and clear area for the assembly of the machine body and the boom of the cranes.

[0052] Additionally, one of the objects of the invention is to allow launching under less restrictive wind conditions compared to those typical of lattice cranes, thus shortening construction times.

[0053] In particular, it is the object of the invention the process for installing at least one portion of an arch structure for constructing a bridge.

[0054] The bridge preferably comprises a deck supported by said arch structure to connect the two banks opposite and separated by an intermediate zone to be crossed.

[0055] Said bridge is preferably installed at a reinforcement referred to as the shoulder made on each bank.

[0056] Said process preferably provides for providing a first arch portion and / or a second arch portion; said process preferably provides for positioning the arch portion on the shoulder, so that a first end thereof faces the bank and a second end thereof faces the opposite bank.

[0057] Said process preferably provides for performing a first rotation of the arch portion about a first fulcrum so that the second end lowers and the first end rises.

[0058] Said process preferably provides for continuing said first rotation until the second end reaches a second fulcrum.

[0059] Said process preferably provides for performing a second rotation of the arch portion about the second fulcrum so that the first end lowers, until reaching the final installation position.

[0060] Said process preferably provides for performing the installation of a first arch portion and of a second arch portion simultaneously or successively.

[0061] Said process preferably provides for coupling the first ends of the first and second arch portions and performing the securing to one another to make the arch.

[0062] In particular, it is the object of the invention the apparatus for installing at least one portion of an arch structure for constructing a bridge, according to the described process.

[0063] Said apparatus preferably comprises lower tensioning means, preferably located below the shoulder, preferably at the base of the stack.

[0064] Said apparatus preferably comprises upper tensioning means, preferably installed on the tower.

[0065] Such and other objects are achieved by the features of the invention set forth in the independent claims. The dependent claims define preferred and / or particularly advantageous aspects of the invention.

[0066] Said objects and advantages are all achieved by the process for installing at least one portion of an arch structure for constructing a bridge, which is the subject matter of the present invention, which is characterized by what is specified in the claims set forth herein below.BRIEF DESCRIPTION OF THE FIGURES

[0067] These and other features will be more clearly highlighted by the following description of some embodiments illustrated, merely by way of exemplary, non-limiting example, in the attached drawing tables. Figure 1: illustrates in side view an arch bridge; Figure 2: illustrates in side view an initial installation step providing for the preparation of an arch portion; Figure 3: illustrates in side view an installation step where a first rotation of the arch portion is performed; Figure 4: illustrates in side view an installation step where the first rotation of the arch portion is completed; Figure 5: illustrates in side view an installation step where a second rotation of the arch portion is performed and completed; Figure 6: illustrates in side view the installation of an arch bridge, according to the prior art. DESCRIPTION OF THE INVENTION

[0068] Referring in particular to Figure 1, an arch bridge 20 is depicted.

[0069] As defined above, the term arch bridge 20 means a stationary bridge comprising a deck 25 supported by an arch structure 10.

[0070] In particular, a deck arch bridge 20 is depicted in Figure 1.

[0071] The construction of the bridge 20 is influenced by the environmental conditions in which the bridge must be installed.

[0072] The installation process is influenced in particular by the banks or ground sides 30a, 30b that the bridge 20 must connect and the intermediate zone 31 that the bridge 20 must span.

[0073] The process is also influenced by the installation in environments where wind or frequent weather disturbances are present.

[0074] It is the object of the invention a process for installing at least one portion of an arch structure 10, which is applicable both in favourable environmental conditions and in extreme conditions, such as, for example, steep banks separated by deep gorges.

[0075] The bridge depicted in Figure 1 comprises the deck 25 supported by said arch structure 10 to connect two banks or ground sides 30a, 30b opposite and separated by the intermediate zone 31 to be crossed.

[0076] As stated above, the development of the arch 10 can be circular, like an arc of a circle, or it may follow a conical curve, such as, for example, a parabola.

[0077] Furthermore, the bridge 20, and in particular the arch 10, generally has a symmetrical structure with respect to the centreline axis, or it may be bilaterally symmetrical or very similar, but not necessarily.

[0078] Therefore, the numbering given herein below to the several elements that define the bridge 20 or the installation environment will be accompanied by the letter "a" to indicate everything installed or present on a side, as depicted in the figures for the left side, and by the letter "b" to indicate everything installed or present on the opposite side, as depicted in the figures for the right side.

[0079] Therefore, elements having a same number, but accompanied by a different letter, are substantially very similar, if not identical or symmetrical, and / or installed in a symmetrical manner.

[0080] The bridge 20 can be secured directly on a reinforcement referred to as the shoulder 21a, 21b, which is made on each bank 30a, 30b.

[0081] In an alternative embodiment, depicted in the Figures, a first deck stretch 23a, 23b extending horizontal from the bank 30a, 30b towards the intermediate zone 31 can be secured to the shoulder 21a.

[0082] Said first deck stretch 23a, 23b is preferably backed by a vertical backing member referred to as the stack Pa, Pb, which is located away from said ground side 30a, 30b.

[0083] As a function of the environmental condition, and in particular of the configuration of the bank, the process can be implemented both directly on the shoulder 21a, 21b, and on the first deck stretch 23a, 23b as depicted in the Figures.

[0084] Hereinafter, for simplicity, we will always refer to the shoulder 21a, 21b to indicate both the reinforced zone of the bank 30a, 30b, and the first deck stretch 23a, 23b, where applicable.

[0085] The arch 10 generally consists in a plurality of segments 100 assembled together.

[0086] Said segments 100 are typically connected to one another, preferably by welding, to form arch portions 10a and 10b.

[0087] Said arch portions 10a and 10b are preferably two semi-arches as depicted in the Figures, which, when assembled, form the complete arch 10.

[0088] Said arch portions 10a and 10b are preferably installed symmetrically one to the other to make the complete arch 10, which is made by joining an end thereof.

[0089] The last segment 100, composing each arch portion 10a and 10b, may comprise, as depicted in the Figures, a deck stretch 25 previously installed above the segment 100.

[0090] In particular, a first end 11a, 11b and a second end 12a, 12b are defined for each arch portion 10a and 10b.

[0091] By second end 12a, 12b is meant the end, which is generally located and constrained at each corresponding bank 30a, 30b.

[0092] By first end 11a, 11b is meant the end, which is opposite the previous one.

[0093] In particular, said first end 11a, 11b is the one where the joining of the arch portions 10a, 10b to make the arch 10 occurs.

[0094] The prior art described herein above provides for the arch portions 10a and 10b to be made by assembling the segments 100 directly at the intermediate zone 31.

[0095] Therefore, the operator must weld the segments 100 while being suspended on the intermediate zone 31, thus working in critical conditions, being subject to oscillations caused, for instance, by the wind, and with limited equipment.

[0096] This results in inaccuracies in execution, risks, high costs and times.

[0097] The process that is the object of the invention, unlike the prior art, provides for installing each arch portion 10a, 10b, already assembled, directly at the intermediate zone 31.

[0098] Therefore, the assembly of the segments 100 for making the arch portion 10a and 10b takes place in a suitable assembly zone, which can be a construction site or an area near the zone where the bridge 20 is being installed.

[0099] This is, however, an assembly zone that can benefit from the necessary facilities and equipment for an assembly process that is simplified, precise, and safe compared to assembling with the operator suspended in the installation zone.

[0100] As will be described herein below, this is made possible by the fact that the process is designed so that the weight of the assembled arch portion 10a and 10b does not burden the installation means and does not require the use of large lattice cranes, which would necessitate reinforcements of the shoulder and obstruct access to the bridge itself.

[0101] The process provides for bringing each arch portion 10a and 10b, already assembled, to the installation zone, in particular on the bank 30a, 30b.

[0102] According to an aspect of the invention, the process provides for positioning the first arch portion 10a on the shoulder 21a, so that the first end 11a thereof faces the bank 30a and the second end 12a thereof faces the opposite bank 30b.

[0103] In the same manner, the process provides for positioning the second arch portion 10b on the shoulder 21b, so that the first end 11b thereof faces the bank 30b and the second end 12b thereof faces the opposite bank 30a.

[0104] For simplicity of description, hereinafter we will refer to the process for installing only one arch portion 10a, for example, the first arch portion 10a. However, it should be noted that all the installation steps are equally replicable for the second arch portion 10b.

[0105] A preferred installation form provides for positioning the arch portion 10a and 10b on the shoulder 21a, 21b, preferably by sliding.

[0106] In particular, sliding means 40a, 40b can be present, for example, means that operate with rolling friction or low-friction sliding, such as rolls or wheels, or spheres that allow to translate the arch portion 10a, 10b to a suitable position on the shoulder 21a, 21b.

[0107] Said sliding means 40a, 40b are means that are known to those skilled in the art, and therefore we will not go into further detail regarding their making.

[0108] Moreover, these are simple, inexpensive, and easily available means, which do not add to installation costs or times.

[0109] According to an aspect of the invention, the process provides for installing the arch portion 10a, 10b by performing, in succession, two rotations R1a, R1b and R2a, R2b.

[0110] In particular, during said first and second rotations R1a, R1b and R2a, R2b, the arch portion 10a, 10b transfer its wight, or part of it, onto the shoulder 21a, 21b.

[0111] The first rotation R1a of the first arch portion 10a preferably occurs about a first fulcrum of rotation C1a, so that the second end 12a lowers and the first end 11a rises, as depicted in Figure 3.

[0112] According to a preferred embodiment, the process provides for positioning the first arch portion 10a on the shoulder 21a, so that the concave part faces upward.

[0113] The first arch portion 10a is preferably located so that the second end 12a protrudes from the shoulder 21a.

[0114] This allows to have the first arch portion 10a supported by the shoulder 21a, and simultaneously permits rotating the second end 12a downwardly.

[0115] Further preferably, it is provided for positioning said first arch portion 10a on the shoulder, 21a so that a center of gravity Ba thereof falls internally to the shoulder 21a, 21b.

[0116] This allows for securely maintaining said first arch portion 10a in place, and prevents the first rotation R1a from starting uncontrollably under the action of the force of gravity Fg alone.

[0117] A preferred aspect of the process provides for performing the first rotation R1a about the first fulcrum C1a, by rotatably connecting the first arch portion 10a to the shoulder 21a.

[0118] Said first fulcrum C1a can be, for example, a hinge, i.e., a member that allows rotation about one, or two, or three axes and prevents translations.

[0119] The first fulcrum C1a may comprise a pin, or a sphere, etc., without going into further detail, as these are known to those skilled in the art.

[0120] Moreover, these are simple, inexpensive, and easily available means, which do not add to installation costs or times.

[0121] In particular, the process provides for the first fulcrum C1a to be located on the shoulder 21a, at an outer flank 22a thereof facing the intermediate zone 31.

[0122] This position facilitates the rotation of the first arch portion 10a reducing the possibility of interference with the same shoulder 21a, and allows, at the end of the rotation R1a, to have the first arch portion 10a positioned spatially continuous to the shoulder 21a.

[0123] In order to optimize and control the first rotation R1a, the first arch portion 10a is preferably connected to the first fulcrum C1a, at a position comprised between the center of gravity Ba and the second end 12a.

[0124] The first rotation R1a preferably ends when the second end 12a has reached a second fulcrum of rotation C2a to which it is connected.

[0125] Therefore, the second rotation R2a occurs about a different fulcrum from the first rotation R1a.

[0126] In particular, said second fulcrum of rotation C2a is positioned so that the second end 12a, once connected, is substantially in a final installation position, or very close to it, except for minor adjustments, as depicted in Figure 4.

[0127] An advantageous embodiment provides for the second fulcrum C2a to be located in the proximity of the bank 30a below the shoulder 21a.

[0128] In particular, in the Figure a possible installation is depicted, in which the second fulcrum C2a is located at a base P1a of the stack Pa of the first deck stretch 23a.

[0129] According to a preferred aspect, it is provided to rotatably connect said second end 12a to the second fulcrum C2a, and to disconnect the first arch portion 10a from the first fulcrum C1a.

[0130] At this point, the process provides for performing the second rotation R2a of the first arch portion 10a.

[0131] The second rotation R2a preferably occurs about the second fulcrum of rotation C2a, so that the first end 11a lowers, until reaching the final installation position as depicted in Figure 5.

[0132] According to an installation form, exactly the same operations can be performed simultaneously or successively for the second arch portion 10b until it reaches its installation position.

[0133] Since, during the first rotation R1a, R1b and / or the second rotation R2a, R2b, the weight of the arch portion 10a, 10b always at least partially rests on the shoulder 21a, 21b, the installation of handling means capable of supporting the total weight of the arch portion 10a, 10b is not required.

[0134] Further characteristics of the process described herein below highlight that said process is designed to use handling means that are simple, easily available, and inexpensive.

[0135] In particular, said handling means may comprise lower tensioning means T1a, T1b, and preferably, upper tensioning means T2a, T2b.

[0136] The process preferably provides for connecting the arch portion 10a, 10b in the proximity of the second end 12a, 12b to lower tensioning means T1a, T1b, located below the shoulder 21a, 21b.

[0137] The process preferably provides for connecting the arch portion 10a, 10b in the proximity of the first end 11a, 11b to the upper tensioning means T2a, T2b.

[0138] During all or part of the first rotation R1a, R1b, the upper tensioning means T2a, T2b preferably are inactive, i.e., they are loose, while the lower tensioning means T1a, T1b are operating, i.e., they are under tension.

[0139] Vice versa, during the second rotation R2a, R2b, the upper tensioning means T2a, T2b are active, i.e., they are under tension, while the lower tensioning means T1a, T1b are inactive, i.e., they are loose or preferably disconnected.

[0140] As depicted in Figures 2 and 3, the lower tensioning means T1a, T1b are preferably installed in the proximity of the second fulcrum C2.

[0141] For example, in the Figures, they are installed at the base P1a, P1b of the stack Pa, Pb.

[0142] In this manner, said lower tensioning means T1a, T1b take advantage of a secure and solid anchorage, such as the base P1a, P1b of the stack Pa, Pb, without the need for additional installations on the banks 30a, 30b.

[0143] Said lower tensioning means T1a, T1b can be, for example, strand jacks, i.e., hydraulic jacks equipped with one or more lifting cables, as used in the industry.

[0144] Strand jacks are typically used for heavy-duty applications, for example, lifting and lowering heavy loads.

[0145] They perform a function similar to that of a crane but are much smaller and more inexpensive. Despite its reduced size and footprint, the strand jack is capable of lifting a much heavier load compared to an average crane.

[0146] By virtue of the action of said lower tensioning means T1a, T1b, it is provided for performing all or part of the first rotation R1a, R1b of the arch portion 10a, 10b about the first fulcrum C1a, C1b by exerting a first force F1a, F1b in the proximity of the second end 12a, 12b.

[0147] Advantageously, said first force F1a, F1b, as depicted in the Figures 2 and 3, comprises at least one vertical component facing downwards and preferably a horizontal component facing the respective side 30a, 30b.

[0148] As described herein above, an advantageous form provides for the arch portion 10a, 10b to be located so that the second end 12a, 12b protrudes from the shoulder 21a, 21b, thus reducing the force Fa1, F1b that the lower tensioning means T1a, T1b must exert in order to activate the initial part of the first rotation R1a, R1b.

[0149] In particular, when the center of gravity Ba, Bb of the arch portion 10a, 10b reaches the vertical line on which the first fulcrum C1a, C1b is located, as depicted in Figure 4, the lower tensioning means T1a, T1b become loose, ending their tensioning action.

[0150] On the contrary, when the center of gravity Ba, Bb of the arch portion 10a, 10b reaches the vertical line on which the first fulcrum C1a, C1b is located, the upper tensioning means T2a, T2b, are activated, i.e., they come under tension.

[0151] From that moment onward, said upper tensioning means T2a, T2b substantially exert a holding and stabilizing action of the arch portion 10a, 10b.

[0152] In particular, said upper tensioning means T2a, T2b exert a second holding and stabilizing force F2a, F2b, as depicted in the Figures 4 and 5.

[0153] In particular, said second force F2a, F2b, comprises at least one vertical component facing upwards and preferably a horizontal component facing towards the corresponding bank 30a, 30b.

[0154] The first rotation R1a, R1b about the first fulcrum C1a, C1b, can end when the center of gravity Ba, Bb of the arch portion 10a, 10b reaches the vertical line on which the first fulcrum C1a, C1b is located.

[0155] In the case depicted in Figure 4, the first rotation R1a, R1b continues, moving the center of gravity Ba, Bb beyond the first fulcrum C1a, C1b.

[0156] In such a case, the latter stretch of the first rotation R1a, R1b preferably occurs under the action of the force of gravity Fg, and concomitantly under the action of the second force F2a, F2b of the upper tensioning means T2a, T2b.

[0157] According to a further alternative, the first rotation R1a, R1b about the first fulcrum C1a, C1b can end before the center of gravity Ba, Bb has reached the vertical line on which the first fulcrum C1a, C1b is located, since the second end 12a, 12b has already reached the second fulcrum C2a, C2b.

[0158] Once the first rotation R1a, R1b about the first fulcrum C1a, C1b is completed, and with the second end 12a, 12b that has reached the substantially final installation position, it is provided for connecting the arch portion 10a, 10b to the second fulcrum C2a, C2b at said second end 12a, 12b, and for disconnecting it from the first fulcrum C1a, C1b.

[0159] The connection of the second end 12a, 12b to the second fulcrum C2a, C2b is made possible in that the lower tensioning means T1a, T1b have ceased their tensioning action, they are loose, and can also be disconnected.

[0160] The second rotation R2a, R2b of the arch portion 10a, 10b about the second fulcrum C2a, C2b is preferably performed under the action of the force of gravity Fg.

[0161] In fact, the center of gravity Ba, Bb of the arch portion 10a, 10b is located beyond the vertical line onto which the second fulcrum C2a, C2b is located, towards the intermediate zone 31, as depicted in Figure 5, and this causes the force of gravity Fg to set it in rotation, lowering the first end 11a, 11b.

[0162] Therefore, during the second rotation R2a, R2b the upper tensioning means T2a, T2b exert the second force F2a, F2b, which counterbalances the force of gravity Fg in order to perform a controlled rotation.

[0163] In the case that the first rotation R1a, R1b about the first fulcrum C1a, C1b ends before the center of gravity Ba, Bb has reached the vertical line on which the first fulcrum C1a, C1b is located, in order to start the second rotation R2a, R2b, the action of thrusting means acting on the arch portion 10a, 10b may be required at least until the center of gravity Ba, Bb has passed beyond the second fulcrum C2a, C2b.

[0164] Said thrusting means can be hydraulic jacks.

[0165] As depicted in Figures 4 and 5, the upper tensioning means T2a, T2b are preferably installed on a tower Ta, Tb.

[0166] Said tower Ta, Tb is preferably positioned on each ground side 30a, 30b, respectively.

[0167] Said upper tensioning means T2a, T2b can be, for example, strand jacks installed on the tower Ta, Tb.

[0168] The tower Ta, Tb does not have heavy installation requirements and has significantly lower costs compared to those of a crane.

[0169] In fact, the installation of the tower Ta, Tb does not require any reinforcement of the bank 30a, 30b near the shoulder 21a, 21b, and does not require the preparation of a levelled and cleared area for its assembly.

[0170] Therefore, an aspect of the invention provides, once that the second rotation R2a, R2b is also completed, for coupling the first ends 11a, 11b of the first and second arch portions 10a, 10b, respectively, and for performing the securing to one another.

[0171] In particular, this occurs when the arch portions 10a, 10b are two semi-arches that together form the complete arch 10.

[0172] In particular, said process provides for performing the securing of the first ends 11a, 11b of the arch portions 10a, 10b to one another, by welding or by mechanical fastening.

[0173] Said fastening is performed by an operator positioned above the intermediate zone 31.

[0174] Compared to the prior art, which provides for performing in-situ, above the intermediate zone 31, all the weldings between a segment 100 and the next one in order to construct each arch portion 10a, 10b, said process provides that only the welding of the first ends 11a, 11b of the arch portions 10a, 10b is performed in situ above the intermediate zone 31.

[0175] Therefore, the operator is exposed to challenging conditions only for a single operation and for a short period of time.

[0176] For example, if each arch portion 10a, 10b is composed of five segments 100 as set forth in Figure 6, this means that the operator must remain suspended for a time 8 times longer, as they must perform 9 welding operations instead of just one.

[0177] Therefore, by virtue of this process, it is possible to fully assemble the arch portion 10a, 10b on the ground, thus reducing risks to personnel, costs, and assembly times.

[0178] Moreover, more stringent assembly tolerances can be met.

[0179] By virtue of said process, in addition to the several advantages outlined above, the wind bracing structures and ties of the arch portion 10a, 10b can be reduced, as it remains exposed to the wind without wind-braces for a shorter period, which is predefined in advance based on analysis of the weather forecast for that area.

[0180] Furthermore, it is also possible to perform the launching under less restrictive wind conditions, compared to those specific for lattice cranes, allowing for shorter construction times.

[0181] As a result, the stand-by costs for the installation are much lower than those of installations made according to prior art.

[0182] Additionally, the handling of the arch portion 10a, 10b involves stresses similar to those generated using prior-art methodologies during the lowering of the arch portion 10a, 10b with winches, especially in favourable environmental conditions, such as in flat areas.

[0183] As such, the above-described is intended to be exemplary and non-limiting. Therefore, any detail variations that may be required for technical and / or functional reasons are hereby considered to fall within the same protection scope as defined by the claims set forth herein below.

Claims

1. A process for installing at least one portion of an arch structure (10) for constructing a bridge (20), wherein a deck (25) is supported by said arch structure (10) to connect the two banks (30a, 30b) opposite and separated by an intermediate zone (31) to be crossed, said bridge (20) being installed at a reinforcement referred to as the shoulder (21a, 21b) made on each bank (30a, 30b), said process providing for: - Providing a first arch portion (10a) and / or a second arch portion (10b); - Positioning the arch portion (10a, 10b) on the shoulder (21a, 21b), so that a first end (11a, 11b) thereof faces the bank (30a, 30b) and a second end (12a) thereof faces the opposite bank (30a, 30b); - Performing a first rotation (R1a, R1b) of the arch portion (10a, 10b) about a first fulcrum (Cla, C1b) so that the second end (12a, 12b) lowers and the first end (11a, 11b) rises; - Continuing said first rotation (R1a, R1b) until the second end (12a, 12b) reaches a second fulcrum (C2a, C2b); - Performing a second rotation (R2a, R2b) of the arch portion (10a, 10b) about the second fulcrum (C2a, C2b) so that the first end (11a, 11b) lowers, until reaching the final installation position.

2. The process according to claim 1, which provides for performing the installation of the first arch portion (10a) and the second arch portion (10b) simultaneously or successively.

3. The process according to any one of the preceding claims, which provides for coupling the first ends (11a, 11b) of the first and second arch portions (10a, 10b) and performing the securing to one another to make the arch (10).

4. The process according to any one of the preceding claims, which provides for positioning the arch portion (10a,10b) on the shoulder (21a, 21b) so that the concave part faces upward, and preferably so that the second end (12a, 12b) protrudes from the shoulder (21a, 21b).

5. The process according to any one of the preceding claims, which provides for positioning said arch portion (10a, 10b) on the shoulder (21a, 21b) so that a center of gravity (Ba, Bb) thereof falls internally to the shoulder (21a, 21b).

6. The process according to any one of the preceding claims, which provides for performing the first rotation (R1a, R1b) about the first fulcrum (Cla, C1b) by rotatably connecting the arch portion (10a, 10b) to the shoulder (21a, 21b).

7. The process according to any one of the preceding claims, which provides that the first fulcrum (Cla, C1b) is positioned on the shoulder (21a, 21b), at an outer flank (22a, 22b) thereof facing the intermediate zone (31).

8. The process according to any one of the preceding claims, which provides that the arch portion (10a,10b) is connected to the first fulcrum (Cla, C1b) in a position ranging between the center of gravity (Ba, Bb) and the second end (12a, 12b).

9. The process according to any one of the preceding claims, which provides, when the second end (12a, 12b) has reached a substantially finale installation position, for rotatably connecting said second end (12a, 12b) to the second fulcrum (C2a, C2b) and disconnecting the arch portion (10a,10b) from the first fulcrum (Cla, C1b).

10. The process according to any one of the preceding claims, which provides for connecting the arch portion (10a,10b) in the proximity of the second end (12a, 12b) to lower tensioning means (T1a, T1b), which are located below the shoulder (21a, 21b) preferably positioned at the base (P1a, P1b) of the stack (Pa, Pb).

11. The process according to claim 10, which provides for performing the first rotation (R1a, R1b) of the arch portion (10a,10b) about the first fulcrum (Cla, C1b) by exerting a first force (F1a, F1b) onto the second end (12a, 12b) by the lower tensioning means (T1a, T1b), said first force (F1a, F1b) comprising at least one vertical component facing downwards and preferably a horizontal component facing the respective ground side (30a, 30b).

12. The process according to any one of the preceding claims, which provides for connecting the arch portion (10a,10b) in the proximity of the first end (11a, 11b) to upper tensioning means (T2a, T2b) which are preferably installed on a tower (Ta, Tb), preferably positioned on each ground side (30a, 30b), respectively.

13. The process according to claim 12, which provides for actuating the upper tensioning means (T2a, T2b) during the first rotation (R1a, R1b) of the arch portion (10a,10b) about the first fulcrum (Cla, C1b), when the center of gravity (Ba, Bb) reaches the vertical line onto which the first fulcrum (Cla, C1b) is located, by exerting a second holding and stabilizing force (F2a, F2b).

14. The process according to any one of the claims 12 to 13, which provides for performing the second rotation (R2a, R2b) of the arch portion (10a,10b) about the second fulcrum (C2a, C2b) under the action of a force of gravity (Fg) and performing a control action of said second rotation (R2) with the upper tensioning means (T2a, T2b).

15. An apparatus (1) for the installation of at least one portion of an arch structure (10) for making a bridge (20), according to the process described in claim 1, comprising lower tensioning means (T1a, T1b), preferably located below the shoulder (21a, 21b) preferably at the base (P1a, P1b) of the stack (Pa, Pb) and upper tensioning means (T2a, T2b), preferably installed on the tower (Ta, Tb).

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