BRPI0706980A2 - single span free span suspended bridge - Google Patents

Abstract

Arch bridge with suspended floor and single span. A single-span arch bridge, of a type with a suspended floor, with foundations on the banks, intended to cross bodies of water that are also very extensive (> 3 km). Floating foundations and anti-slip diaphragms make it insensitive to possible soil liquefaction. The bridge can be built in cantilever and self-supporting mode, therefore without scaffolding or temporary supports and poles and without the need for underwater operations. A preferred structural modality, but not exclusive, provides for the balance of the thrusts by means of independent struts from the floor, thus forming a prestressed arch bridge. Groups of monkeys, arranged in the closing switch, induce a permanent and variable restrictive condition, adjusted to optimize, in real time, the stress condition of the bridge, which, therefore, behaves as an intelligent structure. The presence of several tensioned structural components such as rods, vertical cables and trusses predispose the structure to a selective use of innovative materials with very good mechanical properties, very light, resistant to fatigue and the aggressiveness of the environment, and free of maintenance.

Description

Single-span and free-span arched bridge.

TECHNICAL FIELD

Area of suspended floor arch bridges in structural engineering.

ART GROUNDS

In the state of the art a number of accomplishments are known for suspended crossings with large clearances (> 500 m); these are mainly suspended bridges, which, among all bridges, are those with the largest free spans (> 1000 m). Of these so-called suspension bridges, only a portion of them are designed to allow train transit, but only four of these are actually made (Tagus Bridge, Lisbon - 1013 m; São Francisco Bay Bridge - 704 m; Ponte Tsing Ma in Hong Kong - 1377 m; one of the Seto-Ohashi system bridges in Japan - 1100 m). In this way the trains traveling overest are light trains (about 500 t against the heaviest freight trains with 5,000 t). Symptomatically, the Akashi-Kaikyo Bridge in Japan, with 2000m of clear span, the largest suspension bridge in the world, does not allow trains to travel.

Although very few arched bridges have been built with free spans of about 500 m, they are much less than the large suspended bridges. For cable suspension bridges, or suspension bridges, their maximum free span is about 1200 m (Ting Kau Bridge in Hong Kong, 1177 m, where trains are not allowed). The modalities of construction of said suspension bridges necessarily implies in a condition of tension of the axial compression force for all the floor. Said flooring, before being joined to the intermediate clearance, presents problems of lateral instability, the more serious the larger the clearance, so that the construction of very large openings becomes very complicated, unless duplication of the floor is performed. which is one of the main features of the invention.

In addition to that, some bridge cranes were also built, the largest of which have a maximum span of about 750 m (Tappan Zee Bridge). The architecture of cantilever bridges implies the presence, at the center of each span, of a single support element, the length of which is a significant percentage of the entire bridge.

If this is not the case (if it is much shorter than the entire span) it becomes a variant of suspension bridges, with the problems already mentioned for these bridges, even with a mitigated aspect. Thus, for large spans, cantilever bridges have the following problems:

- the cantilever, to be supported by means similar to those used in suspension bridges, presents the same problems, with the worst case being that the central element with only one support is not fixed in order to react against the potential lateral instability of the cantilever bear, due to the lack of continuity of the spans, which on the contrary typifies the suspension bridges;

- Moreover, this central element, which for large spans must be of enormous length, implies considerable installation difficulties, provided that the use of temporary scaffolding is not permissible as it is not compatible with navigability.

Thus, it can be inferred that the cantilever bridges, although not many, have probably already exhausted their full potential. Therefore, they are much less likely to construct very large clearances. The largest pontescantiléver are as follows:

Tappan Zee Bridge (New York - USA) - 736 m: bus stationPont Quebec (Quebec - Canada) - 549 m: bus stationPonte Forth (Firth of Forth - Scotland - United Kingdom) - 521 m: railwayPonte Comodoro Barry (Delaware River - USA) ) - 501 m: bus stationPonte Grande New Orleans (New Orleans - USA) - 480 m: bus stationPonte Howrah (Calcutta - India) - 457 m: bus station (until some time ago also bus station).

Regarding arch bridges, the largest are as follows:

Lu Pu Bridge (Shanghai, China) - 550 m: suspended bridge arch bridge; Sydney Harbor Bridge (Sydney, Australia) - 530 m: suspended bridge arch bridge; road and rail (light trains)

New River Gorge Bridge (West Virginia, USA) - 510 m: tympanic arch bridge;

DESCRIPTION OF THE INVENTION

In accordance with the main embodiment of this invention, the structure is composed of two equal, flat, parallel and vertical arcs. Each twin even arch features, in the center of the span, a special joint equipped with a set of hydraulic jacks which exert permanent and variable horizontal thrusts at the corresponding arcs, balanced by equal horizontal tensile forces on the horizontal risers positioned at floor level. The thrust at the closing level can be modulated by means of special powered controleretro systems, which act in real time, according to the variation of the loads, mainly the trains and the wind, in order to obtain the optimization. of the depression line, particularly reducing the bending moment in the arch thrusts.

A system of vertical and horizontal plates, equipped with slots and pins, is positioned on the closing switch to compensate for relative transverse displacements between the half-arches opposite each other in the closing switch to allow instead of the offsets. relative horizontal lengthwise, to allow monkeys to exert only coplanar horizontal forces to the arches.

A second variant presents the installation of the jacks at the ends of the tie rods, therefore at the same level as the floor. In one case, in the locking key a structural continuity is prescribed so that an internal torsion moment can be generated in said locking key in order to balance the external moment generated in the tie rods by the pulling force in the jacks. With regard to joints, they can be designed in various forms without departing from the scope of this invention. However, it is specified that said joint is made up of two separate joints, one for each arc, so as to allow only rotations in the closing switch of the ends of the arcs around a horizontal axis and transverse to the bridge. Conveniently trussed upright rods adjust to withstand compressive forces and connect arches to the floors below, positioned in the center of the span and quarters of the span, to withstand potential upward displacement of the floor, thus preventing the emergence of air elastic instability ( flutter), integrating the similar compensating action exerted by the vertical cables that we support downward shifts. Thus, full compensation is achieved for large deformations due to shape change, which are not removable on the suspended bridges.

The floor is divided into two parts, one in each direction, each positioned in the vertical projection of an arc and supported by the upper vertical cables fixed in said arc. This duplicity makes it possible to properly separate the two twin arcs so as to achieve a relationship between the span and its overall length to ensure an overall transverse stiffness adjusted to withstand winds and seismic transverse forces.

A preferred but not restrictive solution is that one of the two floors is separated into two levels, one upper for vehicles and one lower for trains. The transverse stiffness of the bridge as a whole is ensured by means of a first system of transverse trusses connecting the two arches, a second system arranged in a horizontal plane connecting the two floors and a third system connecting vertically, preferably in the center of the bridge. vain and in the vain rooms, the arches with the floors.

The two parallel and twin floors extend from the margins, supported by two parallel and subhorizontal straight support struts which form the structural continuation of the corresponding arches, and with which they are joined and in continuity. In addition, the horizontal floor plan trusses can be extended, but not necessarily, to these continuous breaks. At the ends of these continuous struts, and with a convenient length, which is a relevant percentage in relation to the arc span, these are attached to large vertical ground anchoring cables, which perform a counterweight action necessary to make use of the proposed construction modalities. .

The two arches are on four points, two in each margin, on imposed sections of said arches. Thus, in total, the structure has eight supports, four close to the edges to support the arches and four outer ends of the continuous struts.

Seismic support devices are provided according to a preferred but not exclusive mode (seismic insulators):

- Reinforced or similar reinforced neoprene mounts conforming to solid technologies arranged directly on the foundations, such as four imposed lower arches and four arranged below the ends of the continuous cross members, eight seismic mounts. In this way, seismic isolation of the entire structure is achieved.

In the case of loose soils, if liquefied by seismic action, hollow floating foundations are provided such that, in use, the lithostatic pressure at the level of the foundations equals the pressure action in dithoplane. This implies offsetting the vertical displacements of the foundations in the solid. Finally, and in order to compensate for the drift of the floating foundations and thus of the entire structure caused by wind that may appear after an earthquake, it is envisaged to place flat vertical diaphragms around at least two of these foundations. floating, positioned under the imposed arches, on to each bank. Said diaphragms may extend into depths to the extent that they reach non-liquefying soils and to penetrate them with an adequate depth of attachment depth.

The vertical gap between the horizontal extraction of the foundations and the horizontal intrusion of the structure supports is such that it ensures, with a marbled design, the entry of one person and robotic devices. It follows that, tending, this gap also corresponds to the height of the seismic insulators, preferably arranged in some lines, and spaced to ensure the possibility of a man and equipment, especially with the purpose of performing the total or partial maintenance of the insulators, both by obsolescence as for the damage of any nature.

For this purpose, each foundation is equipped with a group of short vertical displacement jacks of small vertical size but large capacity (flat jacks) arranged at the top of the supports high enough to ensure contact of the jacks with the inside. the brackets. Its synchronized activation allows the entire structure to be raised for almost unlimited time, and thus allows the removal and replacement of non-operational insulators and ultimately the progressive lowering of the entire structure, thus restoring its normal use configuration.

The thrust of the bow is completely balanced by horizontal parallel risers, one or more, preferably but not limited to two single bow, independent of the floor and fixed in the imposition of said arches.

The construction is carried out according to the following main steps, starting from each of the two margins and preferably in synchronized forms:

- construction of the ground anchor lines, the foundations of the arches and the possible non-slip vertical diaphragms, not necessary for non-liquefying, typically rocky, desolation. In the latter case, the foundations may be solid rather than hollow foundations;

- installation of scaffolding for the construction of continuous bars;

- installation of seismic insulators and flat jacks;

- segmented construction of the continuous crosspieces through various heavy lifting techniques, possibly combined with the use of heavy-duty helicopters, which can currently lift and transport 20 t loads. Within a logic of global cost optimization, it could be proposed to design dedicated and larger capacity helicopters. Concurrently, the construction, within continuous indents, of floors belonging to continuous indentations;

- installation of temporary stops on the foundation extractors, prepared to compensate for transverse and / or longitudinal wind displacements in the upper structures (crosspieces and arches) in relation to the foundations, as explained below;

- synchronized segmented construction, in swing mode, of the half-arcs to their union of the closing switch;

This type of construction is possible due to the counterweight and lever action of continuous struts and anchor ropes, and is one of the main features of the invention.

So it is a matter of balancing the great moment of rotation or displacement, induced by the action of the semi-arc in swing mode, which in general can be much larger than the stabilizing action of the continuous beam only, so it can be combined with the action of counterweight of the vertical anchor line and, possibly, the weight of the foundations. A preferred but not exclusive mode of relocation provides for handling by means of a mobile crane which moves over a rack positioned on the half-arch extractor and dosemi-bow.

The segments can be raised directly from the margins, from prefabricated yards possibly arranged near the continuous crossings. In this way any interference with navigation is avoided.

- Concomitant installation of the transverse trusses that connect the two twin arcs, said trusses being fabricated and mounted on land, between the continuous crosspieces.

This installation is characterized by a progressive feeding of the trusses, laterally equipped with self-propelled motorized pinions, which move in the racks fixed in the arches.

This mode of operation (rack and pinion) is transferred by the applied technologies of jacketed drilling rigs related to the offshore oil industry.

- removal of provisional scaffolding from continuous struts, said struts being self-supporting;

- installation on the locking switch of the jack groups and slotted plates.

According to the aforementioned variant: the structural continuity in the locking switch and installation of the jacks on the toe ends.

- installation of the vertical cables, handled by provisional reels acting on the intro of the semi-arches;

- installation of the risers, already equipped with their terminals, by dragging them from the edges, keeping them in the sub-horizontal arrangement by means of the vertical cables at such a level as not to interfere with navigation;

- secure the tie rods with the corresponding anchor points arranged vertically from the arches;

- eliminate bulging by the weight of the risers by means of temporary sub-vertical cables (possibly also some of the vertical cables);

- Tensioning the risers through the activation of the jacks, with the consequent elimination of the bending moment, acting on the arches and the permanent compressive activation of the foundations arranged at the ends of the continuous crossings.

The tension is progressive to check and to guarantee, with the possible provisional unilateral stop devices, the structure positioning project with respect to the foundations. This function can be performed using the above provisional keys. Said stops also have the function of reacting possible shifts of the structure over the seismic insulators during the long time prior to the fixation of the seismic insulators at their top end by means of collars and vertical claws.

This is possible since the risers undergo significant lengths at all, due to the long length of said risers, so that the displacement of the supports on seismic insulators can be much greater than the height of said insulators. Large bending of the insulators, induced by horizontal frictional forces, not compatible with the purpose of ditosisolators, may be followed, which could be drastically mitigated by coating the substrate intruders with a sheet of smooth material of a suitable thickness and with a coefficient of friction. very low, such as preferably, but not restrictively, teflon.

fixing the seismic insulators to the horizontal support surfaces overlapped by collars arranged on the stops of said insulators and fixed by vertical bolts which fix said surfaces and penetrate upwards into the bridge supports;

- removal of temporary stops;

- Release and release action of the anchor lines, made despite the induced decompression reaction and guaranteed by the permanent action of the jacks.

Release is prudent since a possible liquefaction of the soil could transfer the weight of the cable and its anchor bulb to the continuous transom and, consequently, to the floating foundations, which could also be designed considering this additional weight. Moreover, it makes sense to evaluate the pros and cons of this possibility.

- installation of the floor by mounting the raised segments from a barge, arranged close to the bank, by a convenient combined action between cranes and mobile cranes, said segments being attached to the vertical cables and fixed by welding or bolts to the floor already installed. In this way navigability in the water body is guaranteed even at this stage;

- Concomitant installation of the various horizontal transverse trusses that connect two floors, through similar modalities to those used for the arches.

The floors, directly supported by the arches through the vertical heads, are in structural and functional continuities with the floor having within and sustaining the continuous crossbars. The floor as a whole, with a preferred but not exclusive variant, does not behave like a tie rod, so it must be independent of both the tie rods and the main supporting structures as a whole, ie the continuous arches and struts. , with respect to which, therefore, said floor must be able to expand longitudinally, except for fixed points within said continuous indents, in order to avoid the uncontrolled longitudinal movements, thus remaining only the possible relative longitudinal displacements caused by the distinct thermal expansions.

- transferring the weight of the provisional cable ties to the special vertical support rods, positioned on the sides of the floors and fitted with collars and adjustment saddles to control and maintain the wires without giving rise to anomalous nostalgic or floor restrictions;

- installation of anti-slip rods;

- construction of connected ramps on existing road and rail infrastructure;

- adjustment of finish and rails; test and bridge opening for traffic.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be further explained by way of the accompanying drawings, which illustrate some preferred embodiments, which are merely exemplary, but not restrictive, while some technical and constructional variations can always be realized without thereby departing from the scope of this invention. .

In said figures:

- Figure 1 shows a side view of the prestressed arch bridge. At the top is shown a variant of the continuous transom, inserted into a tunnel and without the counterweight;

- Figure 2 shows a plan view of the prestressed arch bridge of figure 1. On the left of the symmetry axis is shown an extraction of the structure, on the left side of the symmetry axis is shown the floor, the vertical support cables and horizontal astrellars. of said floor, and furthermore the two continuous indents within the corresponding tunnel;

Figure 3 shows a cross-sectional view of the prestressed arch bridge made in accordance with section AA of Figure 1 and Figure 2;

Figure 5 shows a generic cross section of one of the two floors enlarging a detail of Figure 3;

Figures 5bis and 5ter show two embodiments of the rampashelicoids;

Figures 4, 6, 7, 8, 9 and 10 show significant cross sections of the main support structure (arc and continuous crossbar), the floor inside and the structural dependence of said floor relative to the support structures;

Figure 11 shows a stress condition occurring in the structure due to the monkey-induced force, which induces a noticeable equal equilibrium extension force and a form of compression in the closing switch. Further, the same and opposite vertical reactions acting on the supports and also balancing the restrictive conditions induced by apes throughout the structure are also shown;

Figures 12, 13 and 14 show an embodiment (floating version) of the anti-seismic counterweight foundation disposed at the end of the continuous member, and the devices connecting said foundation to said member (anchor cable and seismic insulators made of neoprene reinforced material or any equivalent material). In addition, the temporary stops and the anchor line housing niche are shown;

Figure 15 shows the arrangement of seismic insulators and flat jacks on foundation extrusions;

Figures 16, 17 and 18 schematically show a variant (floating variant) of the main seismic foundation consisting mainly of seismic isolates made of reinforced neoprene or an equivalent material interposed between the foundation and the structure. These also show the non-slip diaphragms and the temporary stops;

Figure 19 shows the proposed placement for the non-slip vertical diaphragms;

Figure 20 shows the construction in cantilever mode, that is, without the scaffolding, semi-arches and with the aid of the mobile crane represented in two subsequent (non-simultaneous) positions;

Figures 21 and 22 show some pre-tensioned provisional reinforcements adjusted to counterbalance the strong bending forces acting on the half arches during their construction in the swing mode. This is an alternative option that allows the reduction of the weight of said half-arches and still allows to recycle said provisional reinforcements after the construction of the half-arches, their union with the locking key, and the subsequent extension action on the risers and optimization follows the pressure line. The removed reinforcements may then be recycled, preferably, but not restrictively, in the form of vertical and backward truss cables. The possible use of innovative materials for these reinforcements may imply a substantial overall weight reduction for the entire structure, in the logic of selective reinforcement;

Figures 23, 24, 25, 26 and 27 show the installation of prefabricated semi-arch trusses in the on-site courtyard, equipped with self-propelled motorized pinions and advancing over some racks disposed on the inner sides of the semi-archs. synchronized with the advancement of the segmented construction of the half-arches; Figures 28, 29, 30 and 31 show the characteristics of the slotted plates positioned on the locking key to compensate for relative vertical and transverse displacements between the ends of the half-arches facing each other in said lock key, while said plates allow relative longitudinal horizontal displacements, nominally parallel to the planes of the arches, and also relative rotations of the ends of the half arcs. All this allows the jacks arranged in the closing switch to induce the necessary restrictive condition, consisting mainly of the change of the horizontal-longitudinal span between the ends of the half-arches;

Figures 29 and 30 show the configuration of the group of jacks arranged in the locking key;

Figures 32 and 33 show an alternative embodiment conferring exclusively on the jacks, with a convenient configuration, the control of relative displacements in the closing switch, thus abolishing the slit plates;

Figures 34 and 35 show the installation of the self-moving floor trusses, carried out in a similar manner to those already described for the semi-arch trusses;

Figures 36 and 37 show the installation modalities of the rods with the aid of winding spools and pilot cables;

Figures 38, 39 and 40 show the configuration of the group of jacks disposed at the ends of the risers according to a variant of this invention;

Figures 41 and 42 show the modalities of fastening the tie rods;

Figures 43 and 44 show the construction in segments of the floor and the engagement of its segments with the corresponding vertical cables, carried out by barges carrying said segments and which are anchored close to the bank. From these barges, and with a convenient combined action of the self-propelled cranes, the segments are lifted and moved along the already constructed floor sill to their final place where they are hooked into the vertical cables, then connected by welding, nuts. or other equivalent operations on the floor already built. And so on until the floor is finished;

Figures 45, 46, 47 and 48 show the rods interposed between the arches and the floor, in the center of the room and in the rooms of said free space, to integrate the action of the vertical cables turned to counteract the oscillation of said floors; and

Figures 49, 50 51, 52, 53 and 54 show the main steps of the construction of the structure, until its completion and opening for traffic.

In more detail, and with respect to FIGS. 1 and 2, the resulting structure is comprised mainly of two half-arches 1, continuous cross-sections 2, floors or runways 3 attached to half-arches 1 by means of vertical cables 4, as well as risers 5 arranged at the same level as runways 3 and fixed at their ends 6 to the half-arches imposts 1. The frame can be extended at the ends of the continuous struts 2 to the helical ramps 7 which constitute a preferred embodiment but not exclusively for connecting road lanes and tracks with existing similar infrastructures. The structure is preferably but not exclusively supported by foundations laid on the coast, main foundations 8 and outer foundations 9 in the variant with floating foundations and / or variant with solid foundations, both equipped on the extractor through neoprene supports. reinforced or similar 10 (seismic insulators).

The anchor lines 11, disposed at the ends of the continuous struts 2, contribute decisively to the stability against tilting or tilting of the system consisting of said continuous strands 2 and half-strands 1 during the construction of said half-arches in swing mode.

The possible presence of a raised natural terrain 12 near the structure may be convenient for extending the continuous struts 2 into the raised terrain 12 by means of tunnels 13 which may provide, as an alternative to the anchor lines 11, a counter reaction equivalent.

A preferred, but not exclusive, architecture shown in Figures 1 and 2 of the arch bridge is divided into two planes 1, vertical, parallel, arranged side by side, spaced apart at the support joints 14 and, at the closing, with the joints 15, connected by the trusses 16 and 16 ', formed as reinforced structures or as light box or other shapes.

The continuous struts 2, formed as armored structures, or as light box or other shaped structures, preferably, but not necessarily, form a unique development in the extent between the support joints 14 and the support joints 17 disposed on the cables. anchor 11 (Figures 12, 13 and 14).

Internally to the crossbars, the floor 3 is extended as far as necessary to reach the helical runways 7.

Simply put, the entire structure could be supported at eight points on the same number of foundations, all of which are arranged in the margins, four on each edge, two for the support joints 14 in the imposed half-joints 1 and two in the support joints 17. , at the ends of the continuous bars 2.

The two floors 3, or runways, connected by the trusses 56 and 56 ', are supported by the arches 1 through vertical cables 4; said floors are therefore arranged in a vertical projection of said arcs 1, then extend into continuous crossings 2 and reach the ramps 7 of figures 5bis and 5ter, which show some modalities of connection between the floors 3 and the remaining infrastructure.

According to a preferred but non-exclusive architecture, said floors 3 are made with a box-like structure, internally with trusses, as shown in figures 5, 6, 7, 8, 9 and 10, relative to the transverse sections AA -BB-CC on half-arcs 1, section DD on brackets 14, sectionEE on continuous dashes 2 and section FF on brackets 17.

Figures 5, 6, 7, 8, 9 and 10 show the position of the moving loads, with the road 18 moving over the floor 3 and the rail 19 moving over the floor 3.

In addition, figures 3, 4 and 5 show the positions of the vertical heads 4 that support the floor 3 and the trusses 66 'arranged in the center of the gap and the quarters of said gap.

Figure 6 anticipates some details of trusses 16 and 56 described in more detail in the following figures.

In relation to the static aspect, the pulls induced in the arches 1 by the floor 3 and the shifting loads 18 and 19 contained therein are entirely counterbalanced or neutralized by the horizontal risers 5, which can also counterbalance those induced by the weight of said arches 1, according to a preferred but not exclusive variant of this archprotected bridge.

In this way, and therefore it is possible to prevent the floors 3 from being subjected to relevant permanent horizontal axial forces.

If, instead, one wants to behave like a bow with three joints, that is, a double joint 15 in the closing switch (one for each arc), a double support joint 14 (one for each arc) at one edge and another double support joint 14 at the other edge, it is possible to induce, after the installation of tie rods 5, horizontal forces on the locking key 15 by means of suitable capacity hydraulic jacks, or by equivalent means, balanced by tension forces. acting on the risers 5, such as the amount shown in Fig. 11. In this way a more centralized pressure line can be obtained, particularly by reducing the large bending moments imposed by the arcs 1 and which are induced by their own Weight.

Hydraulic pallets, or equivalent systems, can be permanently active in joint 15 and can be inserted into an integrated system that extends across the bridge, along with sensors, or other devices, for overall frame monitoring to optimize the condition of the bridge. dynamically compensating for the variation of external forces induced mainly by rolling loads, wind, earthquakes, thermal variations, material deformation, differentiated soil compositions or other environmental factors. Figures 12, 13 and 14 show a mode of foundation realization. A counterweight fitted with an anchor line 11 which supports and / or holds the continuous cross member 2 at its outer end, ie where said cross member is joined with raceways 7. In addition, the provisional stops 20 for adjusting are shown. counterbalance, before activating the risers, the possible long displacements Itudinal and / or transverse winds induced due to a temporary condition of possible slippages of the entire structure in the seismic isolates, not yet fixed to their tops by means of nails and collars, in the superstructure.

The counterweight foundation, according to this embodiment, may be performed, preferably, but not restrictively, by composing the counterweight action of a vertical anchor line 11 grounded through the bulb .21, realized by known technology, by means of injection of cementitious mortar with sufficient quantities and depth, with that of foundation 9 shown in the drawings as a floating hollow foundation, but substantially similar to that solid provided for non-liquefied solids, typically of rocks.

Figure 15 shows the pattern for seismic insulators 10, supported by the basements 22, contoured at the top by the collars 23 fixed to the inside of the frame supports by vertical jaws 24 which penetrate the smooth sheet 25. Said basements 22 have a height conditioned by the optimization of the insulators 10 and by the practicality requirements for the free space interposed between the foundation extrusion and the structure intrusion. The regular lines of the insulators 10 are interposed by regular lines of hydraulic jacks 26 supported by the pillars 27. The upper part of the figure shows the set in use and the lower part of this shows the bridge lifting operation by activating the flat jacks.

Figures 16, 17 and 18 show a realization embodiment for the floating hollow foundations 8, which directly support the arcs1 and part of the continuous struts 2, through the support joints 14 (figure 1), made by seismic insulators 10. Vertical diaphragms 28 involving floating hollow foundations 8 are required only for these non-sliding floating foundations and are inserted into the non-liquefied soil 29. Provisional stops 20, whose function has already been described above, are also shown.

Figure 19 shows the plane of the eight foundations, indicating the main foundations 8, two of which are circumvented or surrounded by the anti-slip diaphragms 28, and the outer foundations 9. Between the main foundations 8 the water flow 30 is shown.

Figure 20 shows the lifting, transfer and installation modalities of the segments 31 foreseen for the semi-arch wrap-up construction 1, by means of a self-propelled crane 32, equipped with a rotating arm allowing it to lift the pre-segments. manufactured from the production yard next to the continuous bars 2. Said crane moves on a rack installed on the extractor of the continuous bars 2 and the half-arches 1.

This preferred mode of installation of the segments

avoids interference with navigation.

Figure 21 shows a first cable configuration.

pre-tensioned 34 which are extended to the outer end 35 of the last installed segment 36, conveniently tensioned and secured. These are cables of different lengths, extended from one common end 37. Obviously, the longest are extended from the common end 37 to the arc lock 15.

Fig. 22 shows a second configuration for pre-tensioned strands 38, fixed to the end 39 of a specific segment 40, with an additional cable stretch 41 extending throughout the next segment 42 and attached to the anterior segment anchor 39. A Connection to the anchor device 39 implies the use of special joints made by known technologies.

For any of the embodiments proposed and illustrated respectively by FIGS. 21 and 22, reuse of these cables 34 and 38 may be assumed, subject to their removal after tensioning of the risers 5, such as the vertical cables4 supporting the floor 3 and the components of the trusses. or horizontal lashings 56 '(figures 34 and 35).

Figures 23, 24, 25, 26 and 27 show the modalities of installation between the half-arches 1 and the prefabricated articulated trusses 16 and 16 ', between the continuous bars 2, laterally equipped with pinions 43 actuated by motors 44 ( preferably electric) coaxial to said trusses, and advanced along the racks 45 so that they can be arranged near the ends of the half-arches 1 in progress, thereby assuming a permanent stiffening or fortification of said half-arches 1 to better counteract wind action also during construction in diosemi-arc swing mode. In addition, clamping devices (between each forward and next operation) shall be provided between pinions 43 and half-arches 1. Such clamping operation shall be final after the end of the half-arches and their joints in the closing switch.

Figures 28, 29, 30 and 31 show a preferred but non-restrictive embodiment of the joints 15 arranged in the locking key. This is the same case in which a locking switch is fitted with jacks 46 as illustrated in figures 29 and 30.

Each of the two twin joints 15 is comprised of a system of fixed vertical plates 47, and in continuity with half-arches 1, and horizontal plates 48 joined at half-arches 1 by auxiliary joints 49. All these plates are equipped with slots 50 and cylindrical pins 51, and are coupled according to a male-female embodiment.

The female plates are double, equipped with slots 50 and not with pins 51; the male plates are simple and equipped with pins 51, but not with slots 50. Said pins enter the slots without transverse clearance, thereby blocking the relative potential transverse displacements in said slots. Upright plates 47, equipped with horizontal slots, thus block the relative vertical displacements between the two ends of the half-arches 1 facing each other at the twin joints 15.

The horizontal plates 48, equipped with longitudinal slits, similarly block relative horizontal transverse displacements. Thus, the relative horizontal longitudinal displacements remain free, subject to the length of the slits, which imposes a higher limit than said displacements, compatible with the monkey's path that indirectly and thus controls the tension on the risers and therefore their elongation. .

In addition, the relative rotation around the transverse horizontal axis remains free, compatible with the configuration of all slots and aided by the auxiliary joints 49, with which the horizontal plates 48 are fitted. Thus, the joint function for the twin joints 15 is allowed, so that the pressure line results in the closing switch. Pins 51 are subjected to shear stresses induced by relative displacements articulated by said pins. The ends of said pins are equipped with heads 52 in the form of large screws, particularly capable of reducing the gap between said heads and said plates.

The relative rotations around the vertical axes of the ends of the half-arcs 1, induced by the horizontal forces, transverse to the bridge such as wind, are compensated by the induction at each of the twin joints by means of the jacks 46 of different horizontal longitudinal thrusts. , sufficient to induce a signal reaction moment opposite to that domination induced by external transverse forces.

Figures 29 and 30 show the configuration of the jacks 46 arranged in the twin keys 15 and inserted into the slotted plate system 47 and 48, in which each of the jacks integrates the stress condition control action in the locking key. Said slit plates mainly guarantee that the macaques can be able to induce only axial forces, while the cross-sectional macaques are directly counteractuated by the slit plates themselves. The preferred but not restrictive configuration chosen provides two groups of bottle jack arranged in longitudinal and parallel horizontal axes, one for each pair of halfarches 1. Their arms 53 act through two ends54 in the halfarches 1 opposites. Therefore, these are two independent groups, one for each twin joint. Each of the monkeys can then be independent of all the others, so as to be able to willingly obtain, locally or globally, the total resulting strength of both groups.

The two groups can then, in particular, synchronously induce two different forces, which is a necessary condition for inducing a key closing moment capable of counteracting the transverse shapes of the wind.

Thus, within the same group, it is possible to differentiate the forces between the various monkeys so that, in particular, the forces on the extractor are different from those on the intruder, thus allowing to eliminate the relative rotation of the closing key between the half-arcs 1.

Proper redundancy in the total number of monkeys can also counteract potential failures that could disable some of the monkeys. The number of monkeys in figures 29 and 30 is given as an indication only. Moreover, a radical alternative can be chosen, allowing removal of all cracked plates and transferring exclusively to the conveniently configured jacks full control of the relative displacements in the closing switch. This is particularly accomplished by a convenient system of partially vertical and partially horizontal monkey-forked pairs 55, as illustrated by Figures 32 and 33.

Said pairs have the main function of blocking the relative horizontal and vertical displacements, through a convenient differentiation in the projection of the corresponding rams in order to induce transverse opposing forces.

Figures 34 and 35 show the installation of motorized self-propelled trusses 56 and 56 'in the horizontal plane of the floors 3, realized similar commodities to those provided for the half-arch trusses 1. In addition, in this case, said trusses are pre-arranged. manufactured and mounted on the ground and transferred through racks 57 and motorized pinions 43 to the most advanced position and synchronized with the advance of the floor installation 3.

Figures 36 and 37 show the installation modalities of the rods with the help of winding spools and pilot cables. Fig. 36 shows the advance of the rod 5, drawn by the pilot cable 58 wound on the reel 59, said then unwound rod of the reel 60, disposed on the side of the continuous beam 2, deflected into the opening 61, inserted in the tunnel 62 shown 38,39 and 40, dragged outwardly of the bow 1, coupled to the vertical cables 4 and progressively transferred to the opening 63, and then successively attached to the openings 61 and 63, to the sleeves 64 and 65, as shown in the figure 37

Figures 38, 39 and 40 show an alternative embodiment for the extension or tensioning of the tie rods and for the control of this tensioning in use. Jack groups 46 are installed at the ends of tie rods 5, the ends of which 6 are attached to sleeves 64 which act directly on rams 53. The number of cylindrical jacks shown in the figure is only an indication, and may be characterized by proper redundancy.

However, said alternative embodiment implies either the structural continuity of the lock key (deletion of the joint 15) or the presence of other monkey groups, as illustrated in Figures 29, 30, 31, 32 and 33. In the latter case, there are thus two complementary monkey systems, partly on the locking key 15 and partly on the backward ends 6. The increase in operational complexity that follows can be offset by a more effective system reactivity.

Said groups are housed within the openings 61, disposed next to the half-arc 1 and positioned approximately vertical of the support joint 14. After installation of the jacks in said opening 61, it is possible to perform their tensioning. Only one group of jacks is provided for each tie 5. After the next installation of floor 3, tie 5 will be laid on the guide arms 66 projecting upwards from said floor 3 for its entire exposed length, thereby eliminating the great own weight of the said risers.

All of this ensures much greater effectiveness for the action of jacks, considerably reducing the forces required to obtain the elastic elongation prescribed for the tie rods 5.

Figures 41 and 42 show the modalities of fastening the terminal 6 of the tie rods 5 to the sleeves 65 disposed within the opening 53.

Figures 43 and 44 show the installation of floors 3 by mounting segments 67.

Each segment is raised from a barge 68, anchored close to the seat 69, by means of a counterweight fork 70, raised by means of hooks 71 arranged on the already mounted floor sill. Said winches are positioned vertically from the location designated for said segment 67, in which a mobile crane 72, which travels over the floor extractor 3 and between the pair of vertical cables, picks up the segment 67 and releases the fork 70, which can be repositioned on barge 68 for further operation.

Mobile crane 72 then lifts and moves segment 67 upwards from its final position, where it is to be fixed to the vertical cables 4 and secured to the preceding segment by welding or screwing, or by other means. Upon completion of the installation of the floor 3, it is possible to lay the tie rod 5 on the guide arms 66 shown in figures 38, 40, 41 and 42, by means of a provisional subvertical cable, thus transferring the weight of the tie rods to the floor and indirectly to the semi- bows 1.

Figures 45, 46, 47 and 48 show the light rods 73 secured in the half arches 1 and inserted below into coaxial cavities 74 protruding outward from the floor extractor 3. Between the lower end of the rod and the cavity bottom is A span is provided which houses a metering spring 75, which allows the axial force induced by the oscillating potential above the floor to be gradually transferred to the rod, which can thus be eliminated.

The rod, in the event of incipient oscillation, behaves like a strut, so that it needs an appropriate truss 76 against lateral instability. In the absence of oscillation, the rods are subjected only to their own weight-induced compression forces, as they are simply maintained through their upper extremity.

The vertical cables 4 block, as already mentioned, the oscillation-induced downward shifts.

Said rods are arranged in the center of the span, that is, on each side of the locking key and close to said locking key, in addition to the spaces of the clearance, such as how striped by Figure 48.

In addition, the risers 5, by means of the guide arms 66, assist in the elimination of oscillation as the greatest force applied to the risers and its elastic module.

Figures 49, 50, 51, 52, 53 and 54 show the modalities of arch bridge construction in a chronological sequence, and with respect to their main aspects. The construction is performed with synchronized tendency and symmetry in relation to the two margins. In more detail:

Figure 49 shows the concomitant trend construction at each margin of the main foundations shown in figures 16, 17 and 18, and counterweight foundations shown in figures 12, 13 and 14.

Figure 50 shows the construction of the continuous struts 2e of the respective floor sections 3.

Fig. 51 shows the semi-arc construction of the semi-arcs 1 carried out by the embodiments shown in Figs. 20, 21 and 22. Fig. 52 shows the completion of the semi-arcs 1 to their fitting in the lock key 15 of the vertical cables 4 and the installation of said locking switch of the neutralizing jacks, and further the installation of the tie rod 5 through the necessary modalities to avoid any interference with the navigation of the water body 30.

In addition, it shows the configuration of the ostentatious bridge 5 in its final arrangement after its tensioning by the jacks installed on the locking key 15 (or, according to an alternative embodiment already described, installed at the end of the tie rod) and kept in a horizontal arrangement by the vertical cables installed at this stage, or by means of the provisional sub-vertical cables adjusted to eliminate the bending that the very weight of the risers 5 induces in risers.

Fig. 53 shows the construction by means of segments 67 of the floor 3, carried out through the embodiments already shown by Figs. 43 and 44, in addition to the construction of the helical ramps 7 at the bridge ends.

Similar arrangements allow the trusses 56 and 56 'to be raised and arranged at the same time in relation to the floor 3 (figures 34 and 35). In this joint step, the segments 67 of the floor 3 are mutually joined (figure 43 ), said floor being then made monolithically and joined at the horizontal trusses 56 and 56 '.

Figure 54 shows the finished arch bridge ready for testing and opening for traffic after the installation of the rails and finishing, such as paving, rails, lampposts, and various infrastructural technologies.

Claims (39)

1. Single span arch bridge, including two twin (1) planes, vertical and parallel, the bridge being characterized by the fact that it is equipped with actuators (46, 55) adjusted to tension at least some of the elements that make up said bridge. . Bridge according to Claim 1, characterized in that it includes two twin (1) planes, vertical and parallel, each arch (1) being divisible into two half-arches; and in which each of the half-arches (1) has, in the closing spanner in the center of the gap between the two half-arcs, a respective joint (15) including, in turn, the actuators (46, 55), which produce variable permanent forces in the respective half arches. Bridge according to Claim 1, characterized by the fact that there are some actuators (46) at the ends of the tie rods (5), whose terminals (6) are fixed to some sleeves (64) in which some rams (53) act directly. said actuators (46). Bridge according to claim 2, characterized in that the permanent variable horizontal forces produced by the actuators (46) are balanced by equal horizontal tensile forces acting on the tie rods (5). Bridge according to Claim 4, characterized in that said tie rods (5) are arranged at floor level (3). Bridge according to Claim 2 or 3, characterized in that each of the two joints (15) incorporates a system of vertical plates (47) fixed in continuity with the half-arches and vertical plates (48). ) joined in the half-arches through some auxiliary joints (49); said plates (47, 48) being equipped with slots (50) and cylindrical pins (51); said plates (47, -48) being coupled together according to a male-female embodiment. Bridge according to claim 6, characterized in that the female plates (47, 48) are double and are equipped with slots (50) and not with pins (51); whereas the male plates (47, 48) are simple and are provided with corresponding pins (51) but not with slots (50); said pins (51) being inserted into said slots (50) through a transverse gap to compensate for relative transverse displacements to said slots (50). Bridge according to Claim 7, characterized in that the vertical plates (47) fitted with the horizontal slots (50) compensate for some relative vertical movements between the two ends of the half-arches facing one another. the other on the closing switch (15). Bridge according to Claim 7 or 8, characterized in that the horizontal plates (48), equipped with the horizontal slits (50), similarly compensate for the relative transverse horizontal displacements and thus the relative displacements are free. longitudinal lines, compatible with the length of the slots (50), which imposes an upper limit on said displacements, and compatible with the displacement of the actuators (46) which thus indirectly control the tensile force on the risers (5) and therefore its elongation. Bridge according to Claim 9, characterized in that the rotation relative to a horizontal transverse axis, compatible with the arrangement of all slots (50) and according to the auxiliary slots (49), is also free. which the horizontal plates are fitted (48). Bridge according to claim 2, characterized in that said actuators (46) are mounted in two independent groups, one for each of the twin joints (15), and having a longitudinal-horizontal arrangement with parallel axes, one group for each pair of half-arcs, each ram (53) of the actuators (46) acting through the end (54) in the opposite half-arc. Bridge according to Claim 11, characterized in that the two groups jointly carry out two different forces, which is necessary to form a pair in the locking switch adjusted to balance the transverse wind forces. Bridge according to claim 11 or 12, characterized in that, in the same group, the forces of the various actuators (46) are different from each other, so that the forces acting on the pullers are different from those which they act on the intruders, thus allowing the cancellation of the rotating switch on the half-arch closing switch. Bridge according to Claim 2 or 3, characterized in that there is a system incorporating in the joint (15) a plurality of bifurcated pairs of actuators (55) arranged partially vertical and partially horizontal to block relative displacements. horizontal and vertical, even more so whatever the relative rotation, conveniently differentiating the displacement of the corresponding ram to induce the transverse antagonistic forces; This system can totally or partially replace the system of plates (47, -48), auxiliary joints (49), slots (50) and pins (51). Bridge according to any one of claims 1 to 14, characterized in that said arches (1) are connected together by trusses (16, 16 '); This configuration of these trusses is not limiting and could also be different. Bridge according to any one of claims 1 to 15, characterized in that to each arch (1) belongs a corresponding floor (3) engaged in said arch by corresponding vertical cables (4). Bridge according to claim 16, characterized in that the two floors (3) are connected to each other by trusses (56, 56 '). This configuration of these trusses is not imitative and could also be different. Bridge according to claim 16 or 17, characterized in that both floors (3) contribute to the horizontal total transverse stiffness of the bridge with the aid of the trusses (56, 56 '). Bridge according to any one of claims 1 to 18, characterized in that there is a plurality of truss rods (73) engaged in the half-arches and inserted below into coaxial cavities (74) projecting upwards from between the lower end of each rod (73) and the bottom of the corresponding axial cavity (74) there is a gap housing a measured spring (75) which allows the gradual transfer of each rod (73) the axial compression force induced by the corresponding upward potential displacement of the corresponding floor (3), adjusted to counteract the aeroelastic instability (oscillation). Bridge according to claim 19, characterized in that each floor (3) as a whole is independent of both the risers (5), the arches (1) and the continuous crossings (2) with respect to the which, then, the diptych (3) may shift due, for example, to thermal expansion, except for a dotfix arranged in one of the two continuous dashes (2). Bridge according to claim 19 or 20, characterized in that the rods (73) are arranged in the center of the span, nominally on both sides of the joint (15), and in the quarters of the span. 22. Bridge, according to any one of the preceding claims, characterized in that it has eight foundations (8, 9), four foundations (8) near the banks as supports for the arches (1), and four foundations (9) in the outer ends of the four continuous dashes (2). Bridge according to claim 22, characterized in that each foundation (8, 9) is equipped with at least one seismic insulator (10). Bridge according to Claim 23, characterized in that each seismic insulator (10) includes a plate made preferably, but not exclusively, of reinforced elastomeric materials. 25. Bridge according to any one of claims 22 to 24, characterized in that at least one of the eight foundations (8, 9) in soils subject to liquefaction is a hollow floating foundation designed to transfer to the ground. , in use, at the level of the foundation impost, the same vertical pressure that acts before the excavation of the soil, due to the soil itself. Bridge according to claim 25, characterized in that at least two hollow floating foundations, one on each bank, are equipped with non-slip vertical diaphragms (28) fixed to the non-liquefying ground (29). Bridge according to Claim 26, characterized in that each foundation (8, 9) is equipped with lifting devices (26) set to lift the entire bridge to allow replacement of seismic isolators (10). 28. Bridge according to any one of claims 1 27, characterized in that the actions of the actuators (46, 55) are modulated through a feedback control system acting in a temporary manner on said actuators (46, 55). depending on the variation in live loads, especially of vehicles crossing the bridge and / or wind, in order to optimize the pressure line, in particular up to a bending moment equal to imposed zerones of the arc (1). A bridge according to claim 28, characterized in that said feedback control system is an integrated system extending across the bridge incorporating actuators (46, 55), sensors or other devices for global monitoring of the structure, so as to advise the optimization of the stress condition in said structure that unaccountably changes in external forces mainly due to loads, winds, earthquakes, thermal variations, deformation of materials, soil adjustments and other environmental factors. A bridge according to any one of claims 1 to 29, characterized in that the total width of said bridge and the oval between the arches (1) is proportional to the length of the single clearance, with consequent great transverse stiffness for each one. go free, even big. 31. Bridge according to any one of claims 1 30, characterized in that at least one of the continuous crossings (2) extends into adjoining high ground (12) and is inserted into a tunnel (13) whose top and base fixes the ends of said crossbar by insulating seismic (10), instead of the anchor lines (11). Bridge according to any one of claims 5 to 31, characterized in that the guide arms (66) are arranged between the risers (5) and the floors (3), thus the risers (5) interact with the arms. guide (66) and, due to the high tensile forces to which the tie rods (5) are subjected, help to protect the floors (3) against aero-elastic instabilities, interrupting the upward displacement of said floors (3), and thus assisting ashastes (73). 33. Method for carrying out the construction of a single free span bridge, characterized in that the method includes the following steps, on each of the two banks and tending in a synchronized manner: - construction of the anchor lines (11, 21); from the foundations (8) to the arches (1), to the foundations (9) to the continuous struts (2) and possibly the non-slip vertical diaphragms (28) - laying the scaffolding for the construction of the continuous struts (2); - placement of seismic insulators (10) and lifting devices (26) - construction of continuous cross member (2) of the arches (1) - concomitant construction, within continuous member (2), of floors (3) belonging to continuous struts (2), - placing the temporary stops (20) on the foundation extractor, adjusted to compensate for the transverse and / or longitudinal displacements due to the wind of the overlapping structures (struts and arches) in relation to - Segmented construction in cantilever mode by means of the semi-arched segments (31) synchronously until they are joined to the closing switch; possible concomitant placement of pre-tensioning cables (34, 38) - concomitant placement of prefabricated transverse trusses (16, 16 '), connecting two twin arches (1); the placement carries out a progressive movement towards the transverse trusses (16, 16 ') by means of self-propelled motorized pinions (43) engaged with the racks (45) arranged on the same arches (1) - removal of the provisional scaffolding for the cross members - Inserting the locking key (15), the actuators (46) and the plates (47, 48), equipped with slots (50) and pins (51); or alternatively only of the actuators (46) and (55) - laying of the vertical cables (4) carried by provisional cranes which move through the half-arm intruders - laying of the tie rods (5), already fitted with the terminals (6 ) by misaligning and unwinding said tie rods from the margin, keeping them in a horizontal arrangement by means of the vertical cables (4), - securing the tie rods (5) at the corresponding anchor points arranged proximal to the vertical ones of the arches (1); - adjustment of the bulging due to the weight of the risers (5) to zero by means of temporary subverse cables - tensioning of the risers (5) by means of the actuators (46) with the following zero adjustment of the twisting moment of the arches (1) ), and activation of a permanent compression reaction on the foundations arranged at the ends (9) of the continuous struts (2) - fixing the seismic insulators (10) on the horizontal surfaces of overlapping supports; the removal and removal of the provisional pre-tensioning cables (34, 38), rendered useless due to the induced compression reaction and guaranteed by the permanent action of the actuators (46) - laying of the floor (3) by mounting the segments (67), raised by means (70, 71, 72), said segments (67) being joined to the floor (3) already assembled and to the vertical cables (4) due - concomitant placement of the transverse horizontal trusses (56, 56 ') which We connect two floors (3) using similar modalities to those already considered for the arches (1) - Transfer the weight of the risers (5) from the provisional sub-vertical cables to the convenient vertical supports (66), arranged on the sides of the floors (3). - laying of a plurality of rods (73) - construction of the ramps (7) connecting the road and rail infrastructure, removal of the temporary stops (20) - laying of the finishes and rails, testing and opening to traffic. Method for carrying out a bridge construction according to claims 14 and 33, characterized in that the placement of the tumblers (46) is also or exclusively fitted to the ends (6) of the tie rods (5). A method of carrying out a bridge according to claim 33 or 34, characterized in that the relocation phase of the segments (31) is carried out by a mobile crane (32) which moves over a rack (33). disposed on the extruder of the half-arches, and possibly on the continuous transom. 36. Method for carrying out the construction of the floors (3), characterized in that it is through the segmented operation of the segments (67) raised by the mobile cranes (70, 72) supported by the floor already built, without interference with navigation. A method of constructing a bridge according to any one of claims 33 to 36, wherein the half-arch is constructed as a self-supporting cantilever structure without the aid of temporary towers and temporary support cables or other external devices without interfering with navigation. 38. A method of constructing a bridge according to any one of claims 33 to 37, characterized in that the beam is displaced by the trusses (16, 16 ") of the half-arches (1) and the trusses (56). , 56 ') of the floors (3) through the ground mounting of said trusses and their progressive forward movement, synchronized with one of the corresponding support structures, arches (1) and floors (3), said movement being actuated by a compound of racks (45) and (57) and motorized pinions (43), said trusses being then fixed to the corresponding support structures, arches (1) and floors (3) after reaching the final position near the center of the free span. Method for carrying out a bridge construction according to any one of claims 33 to 38, characterized in that the self-supporting construction of the half-arches (1) is combined with the pre-tensioning action of the cables ( 34) or (38), removable and recyclable as the tensioning elements of the floor trusses (3), or as the vertical cables (4), after the closing of the half-arcing locking key (1) and the tensioning (4) 5).