Method for producing a prestressed bridge

Abstract

In order to produce a prestressed bridge (21) from reinforced concrete with the static system of a continuous beam or frame with at least two fields, at least two longitudinal beams (11) are installed with a crane, with a launching device or with the incremental launching method. At at least one end, the longitudinal beams (11) are produced with recesses (16) in the base plate (13) and / or the cover plate (14). A deflection point (40) having a connection reinforcement (31) is produced in the region of the join (24) between the at least two longitudinal beams (11). External tendons (36) are installed and partially prestressed in the cavity (17) formed in the longitudinal beams (11) by the wall panels (12), the base panels (13) and the cover panels (14). Roadway slab elements (2) are then placed on the at least two longitudinal beams (11). A reinforcement is then laid on the roadway slab elements (2). Finally, the top concrete layer (9) is applied to the roadway slab elements (2) and the final prestressing is applied to the external tendons (36).

Description

[0001] Method for manufacturing a prestressed bridge

[0002] The invention relates to a method for manufacturing a prestressed bridge made of reinforced concrete with a deck slab having at least one cantilever. At least two longitudinal girders are arranged one behind the other beneath the deck slab. The longitudinal girders are arranged approximately parallel to or along the longitudinal axis of the bridge. In its completed state, the bridge has the structural system of a continuous beam or a frame with at least two spans.

[0003] A method for constructing a prestressed bridge from longitudinal girders and deck slab elements is described in WO 2024112989 A1. This method is used to construct a multi-span bridge in sections, the length of which is approximately equal to the distance between two piers. The construction of a bridge section is illustrated by way of example in Figures 1 to 3 of WO 2024112989 A1. In the method described in WO 2024112989 A1, the tendons arranged longitudinally along the bridge are slightly longer than the span of a section. Each tendon has either one anchorage and one end anchorage or two anchorages. To accommodate the anchorages of the tendons arranged longitudinally along the bridge, either transverse frames are formed in the longitudinal girders, as shown in Figures 1 to 3.Figure 11 of WO 2024112989 Al is required if the tendons are arranged above the piers or of pier segments (see Figure 18 of WO 2024112989 Al). The tendons cross over the piers in the transverse frames or in the pier segments.

[0004] When constructing a multi-span bridge in sections using the method described in WO 2024112989 Al, the transverse frames must be integrated into the longitudinal girders at the precast plant. This is because manufacturing the transverse frames after the longitudinal girders are installed would be too time-consuming due to the preparation of the reinforcement, formwork, and concrete, as well as the time required for the concrete to harden. The weight of the transverse frames increases the weight of the longitudinal girders, which is disadvantageous for lifting the longitudinal girders at the precast plant, transport, and assembly operations on the construction site.

[0005] The use of pier segments (see Figures 15 to 18 of PCT / AT2023 / 060405) avoids the increased weight of the longitudinal girders caused by the installation of transverse frames. The length of the longitudinal girders is reduced by the dimension of the pier segments measured along the bridge's length, which has a positive effect on the girders' weight. A disadvantage of using pier segments is that two additional joints are present in each construction phase, which must be filled after the longitudinal girders are installed. Filling these joints is a time-consuming step that slows down construction progress.

[0006] Compressive stresses in the longitudinal direction of the bridge must be present in the joints between adjacent longitudinal girders and between longitudinal girders and pier segments to allow the transfer of shear forces and torsional moments in the joints. Multiplying the compressive stresses by a coefficient of friction yields the shear stresses that can be absorbed in the joints. In the ultimate limit state, it must be assumed that the joints will partially open. By using longitudinal prestressing and adding longitudinal reinforcement, this opening of the joints is minimized. In the ultimate limit state, it must be verified that the shear stresses that can be absorbed in the joints are less than the shear stresses caused by shear forces and torsional moments.

[0007] In the first embodiment of WO 2024112989 A, shown in Figures 1 to 5, the joints between adjacent longitudinal girders are located next to the piers. This arrangement is particularly unfavorable for the structural analyses at the joints because high shear forces and bending moments occur at these locations, necessitating the installation of additional tendons in the longitudinal direction of the bridge to satisfy the structural analyses at the joints. The installation of these additional tendons results in high resource consumption.

[0008] The construction method described in WO 2024112989 Al is characterized by the installation of longitudinal reinforcement, which crosses the joint between two construction sections, above the base plates of the longitudinal girders and within the deck slab. The longitudinal reinforcement of the deck slab can be installed quickly and easily with crane support. In contrast, installing the longitudinal reinforcement above the base plates inside the box girders is time-consuming because the reinforcement must be transported manually from the front of the girders to the joint between the new and existing construction sections without crane support. The longitudinal girders have small cross-sectional dimensions because two longitudinal girders are arranged in each cross-section through the completed bridge. The execution of the reinforcement, formwork, and concreting work inside the box girders is laborious and therefore detrimental to rapid construction progress.

[0009] In the description of the third embodiment of WO 2024112989 Al, where the longitudinal girders are installed using the incremental launching method, the temporary bearings are removed after the longitudinal girders have been launched and bridge bearings are installed. The subsequent installation of bridge bearings necessitates the integration of steel plates into the underside of the base plates of the longitudinal girders. During the installation of the bridge bearings, these steel plates are welded to the upper steel plates of the bridge bearings, similar to the process used in a steel-concrete composite bridge. Subsequently, while the weight of the longitudinal girders is still being supported by the temporary bearings, bearing bases are installed beneath the bridge bearings. Welding the steel plates of the bridge bearings and fabricating the bearing bases after the longitudinal girders have been installed are time-consuming steps that hinder rapid construction progress.

[0010] Methods for manufacturing a prestressed bridge with longitudinal girders, which in the construction state have a trough-shaped cross-section with corrugated webs and a concrete base slab, are described in JP 2006265976 A. Three methods for the assembly of the longitudinal girders are described.

[0011] In the first method, shown in Figures 7 to 9, segments of the longitudinal girders are first mounted on the piers using cranes, and then the span segments are lifted into place. Figure 7 shows that temporary supports are required for these assembly operations. The deflection points located above the piers are already integrated into the pier segments at the precast plant. There are two joints between the segments in each span. Figure 9 shows that the external tendons are installed and prestressed section by section to absorb the loads that occur during the construction of the deck slab. The external tendons can be installed in the trough-shaped longitudinal girders with crane support. A crane can also be used for the prestressing work. The deck slab is constructed with precast slabs over the longitudinal girders and a cast-in-place concrete topping layer.For the cantilevered parts of the road slab, scaffolding and formwork must be used, which is very time-consuming.

[0012] In the second method, shown in Fig. 11, the pier segments are supported on temporary supports, and the span segments are inserted using a launching nose. After the entire longitudinal girder is installed, the external tendons are installed from above into the trough-shaped longitudinal girders with crane support. The external tendons run the entire length of the bridge and are anchored only in the end crossbeams. In the next step, partial prestressing is applied to the external tendons. Subsequently, the deck slab is constructed in the same way as in the first method. In the third method, longitudinal girders, whose length corresponds to the distance between two piers, are installed using a launching device. The joint between two longitudinal girders is located at approximately 20% of the span length. With this method, there is only one joint in each span, as can be seen in Fig. 21.The bridge is constructed in sections, each section corresponding to the span length. In each section, the external tendons are installed and prestressed within the trough-shaped longitudinal girders. Their length is approximately equal to the span length. The deck slab is constructed with cast-in-place concrete, as shown in Fig. 21c, after all the longitudinal girders have been installed.

[0013] Due to the use of temporary supports and the construction of the road slab with cast-in-place concrete, rapid construction progress is not possible with the first two methods described in JP 2006265976 A. Rapid construction progress is also not possible with the third construction method shown in JP 2006265976 A, because the construction of the road slab with cast-in-place concrete takes place in a separate step after the installation of the longitudinal girders.

[0014] Due to the use of corrugated steel webs with top chords made of steel sheets and the statically unfavorable trough-shaped cross-sections of the longitudinal beams in the construction stages, the construction method described in JP 2006265976 A also has a high resource consumption.

[0015] A method for constructing a prestressed bridge using the incremental launching method is described in JP 2005264533 A. The deflection points for the external tendons, which are located above the piers in the completed bridge, are constructed before the single-cell box girder is launched. According to Fig. 2a of JP 2005264533 A, the anchorages for the external tendons are also located in the deflection points. Fig. 5a shows that the portion of the concrete volume of the deflection point located below the area where the external tendons are deflected and adjacent to the wall plates of the box girder can be installed after launching to reduce the weight of the bridge during the launching process.During the launching process, the bridge is centrally prestressed by straight internal post-tensioned tendons located in the base and deck slabs, and by straight external tendons located above the base and below the deck slab. Additional external tendons, which have a curved path, are already installed during launching, but not yet prestressed, as shown in Fig. 2a of JP 2005264533 A. After launching, the straight external tendons are released, reinstalled in a curved position, and then prestressed. Fig. 10 shows an example of a three-span bridge constructed from three prefabricated segments. The straight internal tendons and the external tendons are installed and prestressed in each construction phase, which corresponds to the length of a segment.The external tendons with curved tendon guides, present during the insertion process, have anchorage points in each construction segment. They are prestressed in each segment during insertion. These tendons thus each have three anchorage points or two tendon couplers and one anchorage point. Releasing the tension, installing the curved tendons, and then prestressing the straight external tendons inside the box girder without crane support are very time-consuming steps, which hinders rapid construction progress. The use of external tendons whose length approximately corresponds to the span length requires a large number of anchorage points, resulting in high resource consumption.Sliding the bridge into place with its final cross-sectional dimensions requires a large number of tendons for centric prestressing, which also causes high resource consumption.

[0016] The object of the present invention is therefore to provide a method for manufacturing a prestressed bridge that enables faster production and lower resource consumption than the methods described in WO 2024112989 Al, JP 2006265976 A and JP 2005264533 A.

[0017] This problem is solved by the process steps specified in claim 1. Advantageous embodiments of the invention are set out in the dependent claims and the description.

[0018] To create a shear-resistant connection between a longitudinal girder and the bridge deck, DE 2520104 proposes arranging stirrups in at least one longitudinal girder. Figure 9 of DE 2520105 shows the arrangement of a stirrup in the longitudinal girder of a bridge whose cross-section in its final state is formed by a single-span slab girder. The stirrup has two short anchorage lengths in the longitudinal girder. The larger part of the stirrup is arranged above the longitudinal girder. The upper horizontal part of the stirrup is positioned just below the upper reinforcement layers of the bridge deck, which are installed on site. No reinforcing bars arranged longitudinally in the bridge direction are shown in the two upper corners of the stirrup.

[0019] The connection between the longitudinal beam and the deck slab shown in Fig. 9 of DE 2520105 A1 is not functional because the upper horizontal part of the stirrup is located below the upper longitudinal reinforcement, thus failing to meet the fundamental requirement for a shear-resistant connection between the longitudinal beam and the deck slab. Eurocode 2, section 9.2.2 (shear reinforcement), requires that the stirrups encompass the longitudinal tensile reinforcement and the compression zone. Furthermore, the Eurocode 2 requirement that reinforcing bars perpendicular to the plane of the stirrups be arranged at the corners is not met by the embodiment shown in Fig. 9 of DE 2520105 A1.

[0020] The shear connections between the longitudinal girders and the roadway slab shown in Fig. 10 (bridge with two-webbed plate girder cross-section) and Fig. 11 (bridge with box cross-section) of DE 2520105 Al correspond to the embodiment shown in Fig. 9 and therefore do not have sufficient shear capacity.

[0021] Another method for manufacturing bridges from longitudinal girders and deck slab elements is described in AT 526142 Bl. In this method, the upper transverse reinforcement of the deck slab is arranged within the deck slab elements. The upper longitudinal reinforcement of the deck slab is installed at the installation site in the first layer from above, on top of the upper transverse reinforcement of the deck slab.

[0022] The shear-resistant connection is ensured by stirrups arranged in the longitudinal girders and projecting into the concrete topping of the deck slab. The stirrups have loops at their upper ends. In contrast to the usual design, the loops are arranged longitudinally along the bridge, as can be seen in Figures 6 and 7 of AT 526142 Bl. To comply with the Eurocode 2 requirement that the stirrups must encompass the longitudinal tensile reinforcement, additional loops are arranged in the concrete topping. With the embodiment shown in AT 526142 Bl, the verification of the shear connection between a longitudinal girder and the deck slab elements can be carried out using the design rules contained in Eurocode 2.A disadvantage of this design is the large distance between the stirrups, which results from the rotation of the loops in the longitudinal direction of the bridge, the arrangement of the upper transverse reinforcement of the deck slab between the stirrups, and the gap between the stirrup loops and the transverse reinforcement bars necessary to compensate for manufacturing tolerances. The method described in AT 526142 Bl is therefore only suitable for bridges with small spans where only small shear forces occur.

[0023] Therefore, a further object of the present invention is to provide a method for producing a shear-resistant connection between the longitudinal beams and the roadway slab elements of a bridge, which is suitable for absorbing higher shear forces than the known methods.

[0024] The inventive method for producing a prestressed bridge made of reinforced concrete

[0025] - with a roadway slab having at least one cantilever; - with at least two longitudinal beams arranged one behind the other under the roadway slab, wherein the at least two longitudinal beams are arranged approximately parallel to the longitudinal axis or in the longitudinal axis of the bridge and a joint is formed between each pair of adjacent longitudinal beams;

[0026] - with the static system of a continuous beam with at least two spans or a frame with at least two spans; comprises the following steps: a. Provision of roadway slab elements,

[0027] - wherein a roadway slab element comprises at least two slabs and at least one crossbeam and preferably two crossbeams;

[0028] - the slabs are made of reinforced concrete or prestressed concrete;

[0029] - wherein at least one crossbeam is made of reinforced concrete, prestressed concrete, structural steel, lattice girders or reinforcing bars;

[0030] - the slabs are designed with four corner points in the floor plan;

[0031] - wherein at least two plates are connected by at least one crossbeam;

[0032] - wherein at least one crossbeam is arranged in plan view at an angle of 80° to 90° to the longitudinal axis of the bridge;

[0033] - wherein at least one crossbeam is arranged above the plates;

[0034] - wherein two opposite edges of a plate are arranged at an angle of 80° to 90° to the longitudinal axis of the bridge;

[0035] - wherein the two remaining opposite edges of each plate are arranged at an angle of 0° to 10° to the longitudinal axis of the bridge; and

[0036] - wherein an edge of a first slab and an edge of a second slab are spaced apart from each other at a distance approximately equal to the width at the top of a longitudinal girder, the edges being arranged at an angle of 0° to 10° to the longitudinal axis of the bridge; b. providing at least two prefabricated, thin-walled longitudinal girders made of reinforced or prestressed concrete, having a single-cell, box-shaped cross-section along their longitudinal extent,

[0037] - where the length of a longitudinal beam is at least twice the width of the longitudinal beam;

[0038] - wherein at least two longitudinal beams are manufactured with a width of less than 3.51 m;

[0039] - wherein at least one longitudinal beam is manufactured with a recess in the base plate and / or with a recess in the top plate at at least one end;

[0040] - wherein the recess is produced with a length of 0.1 m to 3.0 m measured in the longitudinal direction of the bridge, and preferably with a length of 0.5 m to 1.0 m; and - wherein the recess is produced with a width of 0.2 m to 3.0 m measured in the transverse direction of the bridge, and preferably with a width of 0.5 m to 2.4 m; c. Installing the at least two longitudinal girders with at least one crane, with at least one lifting device, or with the incremental launching method,

[0041] - wherein in the completed bridge the joint between the at least two adjacent longitudinal beams is formed above a pier and

[0042] - wherein the at least two adjacent longitudinal beams are supported on the pier by means of temporary support structures; d. installation of connecting reinforcement in an area next to the joint between the at least two longitudinal beams,

[0043] - the connecting reinforcement is installed approximately in the longitudinal direction of the bridge,

[0044] - wherein the connecting reinforcement is butted and / or force-fitted with the longitudinal reinforcement installed in the adjacent longitudinal beams and

[0045] - where, when using the incremental launching method for installing the longitudinal beams, the connecting reinforcement can optionally be installed before the longitudinal beams are inserted; e. Creating a deflection point made of reinforced concrete in the area of ​​the joint between the at least two longitudinal beams, wherein the connecting reinforcement installed in work step d is arranged in the deflection point; f. Installing external tendons in the cavity formed by the wall panels, the floor panels and the cover panels in the at least two longitudinal beams,

[0046] - with the external tendons extending over the entire length of the bridge;

[0047] - wherein each external tendon has at least one anchorage and

[0048] - wherein, in the completed bridge, in a cross-section through a longitudinal girder above a pier, the sum of the prestressing forces in the external tendons extending over the entire length of the bridge is at least 20% of the total prestressing force present in this cross-section, acting in the longitudinal direction of the bridge; g. optionally, applying partial prestressing to the external tendons; h. placing the deck slab elements on the at least two longitudinal girders, whereby placing the deck slab elements can begin as soon as all longitudinal girders have been installed in at least one span of the bridge; i. optionally, applying further partial prestressing to the external tendons; j.Laying reinforcement, preferably longitudinal and transverse reinforcement, on the deck slab elements and over the cover plates of the at least two longitudinal girders, wherein the laying of the reinforcement can begin as soon as at least one deck slab element has been placed on the longitudinal girders; k. optionally applying further partial prestressing to the external tendons; l. applying the topping concrete to the deck slab elements and over the cover plates of the at least two longitudinal girders to produce the deck slab, wherein the application of the topping concrete can begin as soon as the reinforcement has been laid on at least one deck slab element; and m. applying the final prestressing to the external tendons.

[0049] The method according to the invention is suitable for the production of bridges with spans of 25 m to 60 m and preferably of 30 m to 50 m.

[0050] For a bridge with a length of, for example, more than 200 m, it can be advantageous to construct a tendon from two sections, each with a prestressing anchor and an end anchor. At a deflection point, a lap splice is created using the end anchors of the two sections, where the two sections cross each other. The two sections are anchored to the end crossbeams of the bridge using prestressing anchors. A tendon coupler can also be used instead of the lap splice.

[0051] An advantageous application of the method according to the invention is made possible when a longitudinal beam is assembled from segments on the construction site. The segments can be connected to each other by longitudinal prestressing.

[0052] Applying a layer of concrete to at least part of the base plate of a longitudinal beam on the construction site before or after installing the longitudinal beam can be advantageous for rapid construction progress.

[0053] To minimize bending stress in a pier when a longitudinal beam is placed upon it, it can be advantageous to position the central axis of the support structures at a distance of no more than 200 mm from the pier's midplane, measured along the bridge's longitudinal axis. Planned bending stresses in a pier are avoided if the support structures are located in the pier's midplane.

[0054] Advantageously, when applying the method according to the invention, a support structure with at least one steel plate and at least one elastomer bearing can be produced. Placing the roadway slab elements onto the longitudinal beams without the use of a crane is made possible if the roadway slab elements are transported using a transfer trolley.

[0055] - wherein the transfer carriage is moved on at least one longitudinal beam in the longitudinal direction of the bridge;

[0056] - the wheels of the transfer trolley roll on the cover plate of at least one longitudinal beam during transport; and

[0057] - at least one road surface element is transported to the installation site.

[0058] The advantageous design of a lifting point for lifting a longitudinal beam is made possible if

[0059] - two loops with sufficient anchoring lengths are installed in a wall panel;

[0060] - the loops protrude from the wall panels at the top of the longitudinal beam;

[0061] - the loops are arranged approximately perpendicular to the central plane of the cover plate of the longitudinal beam;

[0062] - the loops in the upper area have a constant radius of curvature;

[0063] - in the loops, in the areas that have a constant radius of curvature, a round steel bar is installed; and

[0064] - a tension member is attached to the round steel approximately in the middle between two loops.

[0065] When applying the method according to the invention, it may be advantageous if

[0066] - the concrete topping is applied in two layers;

[0067] - the first layer of topping concrete is applied over the cover plates of the at least two longitudinal beams and, if applicable, over a part of the slabs of the roadway slab elements adjacent to the at least two longitudinal beams; and

[0068] - the thickness of the first layer of concrete over the cover plates of at least two longitudinal beams is at least 80 mm.

[0069] An advantageous application of the method according to the invention is made possible if part of the upper transverse reinforcement is installed in the second layer from the top in the roadway slab elements and the remaining part of the transverse reinforcement is installed on the construction site in the first layer from the top.

[0070] In the method according to the invention, it can be advantageous if, at the upper end of at least two stirrups and preferably of all stirrups that protrude from the wall panels on the upper side of the longitudinal beam, at least one cotter pin, the length of which is at least 20 mm shorter than the distance between two crossbeams of the deck panel elements measured in the longitudinal direction of the bridge, is installed inside the stirrups before the deck panel elements are installed, and in a subsequent step, at least one reinforcing bar of the longitudinal reinforcement, which has a length at least 1.0 m greater than the at least one cotter pin and is arranged in the same reinforcement position as the at least one cotter pin, is installed next to the at least one cotter pin.

[0071] Further details, features, and advantages of the invention will become apparent from the following explanations of exemplary embodiments schematically illustrated in Figures 1 to 44. The drawings show:

[0072] Fig. 1 shows a view of a first embodiment according to the invention after the installation of five longitudinal beams and during the lifting of the sixth longitudinal beam;

[0073] Fig. 2 shows detail A of Fig. 1

[0074] Fig. 3 shows a view of the first embodiment according to the invention after the manufacture of the deflection points, the crossbeams and the end crossbeams.

[0075] Fig. 4 shows a view of the first embodiment according to the invention after laying down part of the roadway slab elements;

[0076] Fig. 5 shows a view of the first embodiment according to the invention after the application of a concrete topping layer to the roadway slab elements and the cover plates of the longitudinal beams;

[0077] Fig. 6 shows a longitudinal section of the first embodiment according to the invention along the section line VI-VI shown in Fig. 3;

[0078] Fig. 7 shows a longitudinal section of the first embodiment according to the invention along the section line VII-VII shown in Fig. 1;

[0079] Fig. 8 shows a cross-section of the first embodiment according to the invention along the section line VIII-VIII shown in Fig. 7;

[0080] Fig. 9 shows detail B of Fig. 8; Fig. 10 shows a longitudinal section of the first embodiment according to the invention along the section line XX shown in Fig. 3;

[0081] Fig. 11 shows a cross-section of the first embodiment according to the invention along the section line XI-XI shown in Fig. 10;

[0082] Fig. 12 shows a longitudinal section of the first embodiment according to the invention along the section line XII-XII shown in Fig. 1;

[0083] Fig. 13 shows a longitudinal section of the first embodiment according to the invention along the section line XIII-XIII shown in Fig. 3;

[0084] Fig. 14 shows a cross-section of the first embodiment according to the invention along the section line XIV-XIV shown in Fig. 13;

[0085] Fig. 15 shows a longitudinal section corresponding to Fig. 7 with an alternative arrangement of the support structures;

[0086] Fig. 16 shows a longitudinal section corresponding to Fig. 10 with an alternative arrangement of the support structures;

[0087] Fig. 17 shows a cross-section along the section line XVII-XVII shown in Fig. 16;

[0088] Fig. 18 shows a longitudinal section corresponding to Fig. 7 with a further alternative design of the support structures;

[0089] Fig. 19 shows detail C of Fig. 18;

[0090] Fig. 20 shows a view of a second embodiment according to the invention after the installation of a longitudinal beam;

[0091] Fig. 21 shows a view of the second embodiment according to the invention after the installation of two longitudinal beams;

[0092] Fig. 22 shows a view of the second embodiment according to the invention after the installation of four longitudinal beams;

[0093] Fig. 23 shows a cross-section of the second embodiment according to the invention along the section line XXIII-XXIII shown in Fig. 22; Fig. 24 shows detail D of Fig. 23;

[0094] Fig. 25 shows a section of a field of the bridge produced with the second embodiment according to the invention, which is subjected to a uniform load, and the associated course of the bending moment;

[0095] Fig. 26 shows the truss model for the shear force transfer in the wall panels of detail F shown in Fig. 25;

[0096] Fig. 27 shows a top view of the frame model in the cover plate according to the section line XXVII-XXVII shown in Fig. 26;

[0097] Fig. 28 shows a cross-section of the second embodiment according to the invention along the section line XXVIII-XXVIII shown in Fig. 22;

[0098] Fig. 29 shows a cross-section corresponding to that of Fig. 28 after the installation of a lowering device;

[0099] Fig. 30 shows detail E of Fig. 23 with the upper transverse reinforcement installed in the roadway slab element;

[0100] Fig. 31 shows detail E of Fig. 23 after the installation of part of the upper longitudinal reinforcement;

[0101] Fig. 32 shows detail E of Fig. 23 after the installation of the upper transverse reinforcement on site;

[0102] Fig. 33 shows detail E of Fig. 23 after the remaining part of the upper longitudinal reinforcement has been laid;

[0103] Fig. 34 shows a view of a third embodiment according to the invention after assembling two longitudinal beams from four segments;

[0104] Fig. 35 shows a view of the third embodiment according to the invention after the installation of two longitudinal beams and the placement of three roadway slab elements;

[0105] Fig. 36 shows a view of the third embodiment according to the invention after the installation of four longitudinal beams; Fig. 37 shows a view of the third embodiment according to the invention after the installation of six longitudinal beams and the placement of part of the road surface elements;

[0106] Fig. 38 shows a view of the third embodiment according to the invention after the placement of further roadway slab elements;

[0107] Fig. 39 shows a view of the third embodiment according to the invention after the entire roadway slab elements have been laid down;

[0108] Fig. 40 shows a plan view of a fourth embodiment according to the invention during the installation of the longitudinal beams using the incremental sliding method and a schematic representation of the tendons for the centric prestressing of the longitudinal beams;

[0109] Fig. 41 shows a plan view of the fourth embodiment according to the invention after placing three roadway slab elements on the longitudinal beams;

[0110] Fig. 42 shows a cross-section of the fourth embodiment according to the invention along the section line XLII-XLII shown in Fig. 40;

[0111] Fig. 43 shows a longitudinal section of a fifth embodiment according to the invention, corresponding to Fig. 10, with an alternative design of the deflection point; and

[0112] Fig. 44 shows a horizontal section according to the section line XLIV-XLIV shown in Fig. 43.

[0113] A first embodiment of the inventive method for producing a prestressed bridge 21 with three spans is shown schematically in Figures 1 to 19.

[0114] In the first step, the longitudinal beams 11 are installed as shown in Fig. 1. Fig. 1 shows a construction stage in which five longitudinal beams 11 are supported in their final position on temporary bearing structures 41. A sixth longitudinal beam 11 is lifted into place using two mobile cranes, which are not shown in Fig. 1 for clarity. The weight of the longitudinal beams 11 is transferred from the temporary bearing structures 41 to the abutments 19 and the piers 22. The longitudinal beams 11 have a single-cell, box-shaped cross-section along their length. Each longitudinal beam 11 consists of six wall panels 12, one bottom panel 13, and one top panel 14. The longitudinal beams 11 are manufactured in a precast concrete plant. For lifting the longitudinal beams 11 in the precast plant and for transport to the construction site, it is advantageous if the weight of the longitudinal beams 11 is no greater than 80 t to 130 t.Longitudinal beams 11, which have a greater transport weight, can, for example, consist of individual segments 18. The segments 18 can be joined together on the construction site to form a longitudinal beam 11 using longitudinal prestressing. The joints 24 between the individual segments 18 can, for example, be sealed with a grout. It can also be advantageous to assemble a longitudinal beam 11 on the construction site from segments 18, which, for example, have a weight of only 20 t.

[0115] The wall panels 12 of the longitudinal beams 11 are manufactured horizontally from C80 / 95 concrete. The wall panels 12 could also be made from an ultra-high-performance concrete with a compressive strength of, for example, 150 N / mm². 2The wall panels 12, which in this example have a thickness of 120 mm, are manufactured. After the concrete has hardened, the wall panels 12, which in this example have a thickness of 120 mm, are placed on a formwork base. The base panel 13 and then the top panel 14, made of C50 / 60 concrete, are first constructed between the wall panels 12. The length of the base panel 13 and the top panel 14, measured along the longitudinal direction of the longitudinal beam 11, is shorter in the central area between the wall panels 12 than the combined length of three wall panels 12, measured along the longitudinal direction of the longitudinal beam 11. This creates recesses 16 in the base panel 13 and the top panel 14 at the ends of the longitudinal beams 11. It would also be possible to create the recesses 16 with a width corresponding to the distance between the wall panels 12.

[0116] Due to the horizontal manufacturing process, the length of the wall panels 12 is limited to 12 m to 15 m in most precast concrete plants. Therefore, four joints 24 are present between the wall panels 12 in each of the longitudinal beams 11 shown in Fig. 1. It would also be possible to manufacture the wall panels 12 of the longitudinal beams 11 vertically. In this case, it would be possible to produce the wall panels 12 of the longitudinal beam 11 without joints 24; however, special measures would have to be taken for concreting the thin-walled wall panels 12.

[0117] The sixth longitudinal beam 11 is lifted into place using two mobile cranes, which support the weight of the longitudinal beam 11 at four lifting points 50. A lifting beam 51 is positioned over each pair of lifting points 50 located in the end regions of the longitudinal beam to prevent oblique tension during lifting.

[0118] One possible configuration for a lifting point 50 is shown in Fig. 2. Two loops 53 are installed in the wall plate 12 with a sufficient anchorage length. The loops 53 are positioned in the area of ​​the recess 16. The loops 53 can be made of reinforcing steel. A round steel bar 54 is installed in the upper region of the loops 53, which has a constant radius of curvature. A tension member 52 is attached to the center of the round steel bar 54 and connected to the lifting beam 51. The configuration of the lifting point 50 shown in Fig. 1 and Fig. 2 ensures that the eight loops 53 required for lifting the longitudinal beam 11 are subjected to a uniform load.

[0119] It would also be possible to rotate the loops 53 in the floor plan by 90° in order to form a lifting point 50 in a very thin wall panel 12.

[0120] It would also be possible to design a bracket 33 built into a wall plate 12 such that the bracket 33 has a loop 53 with a constant radius of curvature at its upper end.

[0121] If the load-bearing capacity of two loops 53 at a lifting point 50 is insufficient for lifting a longitudinal beam 11, a lifting point 50 can also be produced with four, eight or sixteen loops 53, in accordance with the embodiment shown in Fig. 2, which ensures a uniform load on the loops 53.

[0122] In the second step, as shown in Fig. 3, deflection points 40 are installed in the longitudinal beams 11 above the piers 22, and the crossbeams 27 and the end crossbeams 28 are constructed. The installation of the deflection points 40 closes the joints 24 between the longitudinal beams 11 and rigidly connects the adjacent longitudinal beams 11. The recesses 16 are advantageous for the execution of the formwork, reinforcement, and concrete work for the production of the concrete joints 45 and for the production of the deflection points 40 inside the longitudinal beams 11.

[0123] In the third step, tendons 36 are installed in the longitudinal beams 11. The recesses 16 facilitate the installation of the tendons 36. Without the recesses 16, the sheathing for the tendons 36 would have to be transported through the through-openings 60 in the end crossbeams 28 into the interior of the longitudinal beams 11. After the sheathing is installed, the strands are inserted into it. Subsequently, partial prestressing is applied to the tendons 36.

[0124] In the fourth work step, the temporary support structures 41 are replaced by concrete joints 45.

[0125] In the fifth step, a layer 10 of C40 / 50 concrete with a thickness of 180 mm is installed on the base slab 13. The recesses 16 in the cover plates 14 of the longitudinal girders 11 can be closed after the layer 10 has been completed. Subsequently, further partial prestressing is applied to the tendons 36. In the sixth step, as shown in Fig. 4, deck slab elements 2 are placed on the longitudinal girders 11. The use of deck slab elements 2 for the construction of a deck slab 1 for a bridge is described, for example, in WO 2022256851 A1 and AT526252 B1. Fig. 4 shows a construction stage in which 24 deck slab elements 2 have been placed on the longitudinal girders 11 and another deck slab element 2 is lifted by a mobile crane, which is not shown in Fig. 4 for clarity.After the partial or complete placement of the roadway slab elements 2, a further partial prestressing can be applied to the tendons 36.

[0126] In the seventh step, the connecting reinforcement of the lower reinforcement of the roadway slab 1, the longitudinal reinforcement 32, and the transverse reinforcement 34 of the upper reinforcement of the roadway slab 1 are laid on the roadway slab elements 2 and over the cover plates 14 of the longitudinal beams 11. If necessary, further partial prestressing can then be applied to the tendons 36.

[0127] In the eighth step, as shown in Fig. 5, a concrete topping 9 is applied to the roadway slab elements 2 and over the cover plates 14 of the longitudinal beams 11 to produce the roadway slab 1. After the concrete topping 9 of the roadway slab 1 has hardened, the final prestressing can be applied to the tendons 36.

[0128] A longitudinal section at an exaggerated scale through three longitudinal girders 11 is shown in Fig. 6. The tendon 36 shown in Fig. 6 has an end anchorage 39 on the left side and a tension anchorage 37 on the right side. The height of the end anchorage 39 and the tension anchorage 37 corresponds to the height of the centroid of the completed bridge 2. Eight deflection points 40 for the tendons 36 are provided in the three longitudinal girders 11. Two deflection points 40 are arranged above the piers 22. Six deflection points 40 are located at the quarter points of the longitudinal girders 11, which are connected to the base plates 13 and the wall plates 12 of the longitudinal girders 11.

[0129] Fig. 7 shows a longitudinal section through the end regions of two longitudinal beams 11, the support structures 41, and the pier 22. The support structures 41 are arranged beneath the wall plates 12 of the longitudinal beams. According to the manufacturing process shown in Fig. 1, the longitudinal beam 11 shown on the right side of Fig. 7 is installed first. The weight of this longitudinal beam 11 causes normal forces and bending moments in the pier 22. Because the distance of the support structure 41 from the center plane of the pier 22 is small, no tensile stresses arise in the pier 22 as a result of the weight of the longitudinal beam 11. This is advantageous because no additional reinforcement is required in the pier 22 to absorb tensile stresses.Tensile stresses in pier 22 would arise after the installation of a longitudinal beam 12 if the distance between the central axis of the support structure 41 and the central plane of pier 22 is greater than one sixth of the thickness of pier 22 measured in the longitudinal direction of the bridge 21. Therefore, it is advantageous if this distance is at most 200 mm.

[0130] Figure 7 shows that in this embodiment, recesses 16 are arranged in the base plate 13 and in the cover plate 14. The width of the recess 16, measured in the transverse direction of the bridge 21, is smaller than the distance between the wall plates 12. The distance between the wall plates 12, measured in the longitudinal direction of the bridge and forming the joint 24, is 50 mm. This distance could also be smaller, for example 10 mm, or larger, for example 300 mm, depending on the project.

[0131] Fig. 8 shows a cross-section through the joint 24. The support structures 41 are arranged centrally under the wall panels 12. The width of the column 22 is greater than the width of the longitudinal beam to allow the dead weight of the longitudinal beam 11 to be transferred through the support structure 41 into the column 22.

[0132] Detail B of Fig. 8, shown in Fig. 9, reveals that the support structure 41 consists of a bearing base 42, an elastomeric bearing 43, and two steel plates 44. The upper steel plate 44 is positioned centrally beneath the wall plate 12. The width of this steel plate 44 is less than the thickness of the wall plate 12 to prevent spalling of the concrete in the support area. The lower steel plate 44 distributes the proportional weight of the longitudinal beam 11 approximately evenly onto the elastomeric bearing 43. The bearing base 42 is positioned beneath the elastomeric bearing 43.

[0133] The installation of the elastomer bearing 43 in the support structure 41 is advantageous because it allows construction tolerances to be compensated for and accommodates the changes in length in the longitudinal beam 11 that occur during construction as a result of shrinkage and creep of the concrete as well as temperature changes.

[0134] Fig. 10 shows a longitudinal section corresponding to Fig. 7 after the installation of the connecting reinforcement 31, the deflection point 40, the installation of the concrete hinge 45, and after the subsequent removal of the support structures 41. The connecting reinforcement 31 is installed in an area next to the joint 24, which is located between the wall panels 12 and the cover panels 14 of the adjacent longitudinal beams 11. In the final state, the connecting reinforcement 31 is located within the deflection point 40. In this embodiment, connecting reinforcement 31 is also arranged in layer 10 on the base slabs 13. Fig. 11 shows a cross-section after the installation of the concrete hinge 45 and the deflection point 40 and after the subsequent removal of the support structures 41. Connecting reinforcement is installed in the deflection point 40 in the longitudinal direction of the bridge 21.The connecting reinforcement 31 is butted with the longitudinal reinforcements 32 embedded in the wall panels 12 of the longitudinal girders 11. After the concrete at the deflection point 40 has hardened, the longitudinal girders are rigidly connected to each other in this way. A passage opening 60 is provided between the deflection points 40, which is required for further construction work such as the installation of the tendons 36 and the application of layer 10 to the base panels 13 of the longitudinal girders 11. Even after the completion of the bridge 21, the passage opening 60 has an important function because it allows for the inspection of the longitudinal girders 11 from the inside.

[0135] The longitudinal beams 11 are connected above the pier 22 by a crossbeam 27. If the concrete hinge 45 can transfer the torsional moments occurring in the longitudinal beam 11 to the piers 22 without a gaping joint in the concrete hinge 45, the construction of the crossbeam 27 can be omitted.

[0136] The recesses 16 in the base plates 13 of the longitudinal beams 11 enable the production of the concrete joint 45.

[0137] The recesses 16 in the cover plates 14 of the longitudinal beams 11 allow access to the cavity 17 inside the longitudinal beams 11 from above. This simplifies and accelerates the construction work for the production of the concrete hinge 45, the deflection points 40, the base plate 13, the subsequent installation of the tendons 36 and the subsequent production of the layer 10 of concrete on the base plates 13 of the longitudinal beams.

[0138] Fig. 12 shows a longitudinal section through the end region of a longitudinal beam 11 above an abutment 19. Support structures 41 are arranged beneath the wall plates 12 of the longitudinal beam 11. The support structures 41 each consist of two steel plates 44 and a round steel bar 54 arranged between the steel plates. Recesses 16 are arranged in the bottom plate 13 and in the top plate 14, the width of which, measured in the transverse direction, corresponds to the distance between the wall plates 12.

[0139] Fig. 13 shows a longitudinal section corresponding to Fig. 12 after the installation of the end crossbeam 28, after the installation of the bridge bearing 29, and after the subsequent removal of the support structure 41. Fig. 14 shows that a through-opening 60 is present in the end crossbeam 28. The through-opening 60 is used for further construction work, such as the installation of the tendons 36 and the application of the layer 10 of concrete to the base plates 13 of the longitudinal girders 11. Even after the completion of the bridge 21, the through-opening 60 has an important function because it allows the inspection of the longitudinal girders 11 from the inside. End anchorages 39 or prestressing anchorages 37 for the tendons 36 are installed in the end crossbeam 28.

[0140] Figure 15 shows an alternative arrangement of the support structures 41 compared to Figure 7. The support structures 41 are positioned at a greater distance from the central plane of the pier 22 than the support structures 41 shown in Figure 7. This results in larger bending moments in the pier during the installation of the longitudinal beams 11. Figures 16 and 17 show that this alternative arrangement of the support structures 41 provides more space for the fabrication of the concrete hinge 45. Therefore, the concrete hinge 45 can be fabricated with a greater width than the concrete hinge 45 shown in Figure 11.

[0141] Figure 18 shows a longitudinal section corresponding to Figure 7 for a further alternative design of the support structure 41. Steel plates 44 are installed on the top of the pier 22. Tilting strips 55 are placed and fastened on the steel plates 44 in the center plane of the pier 22. Steel sheets 57, protruding from the wall panels 12, are installed in the longitudinal beams 11 during precasting. The steel sheets 57 can be connected to the concrete of the wall panels 12 by welded reinforcing bars. When the first longitudinal beam 11 is installed, half the weight of the longitudinal beam 11 is transferred into the pier 22 via the steel sheets 57 and the tilting strips 55. No planned bending moments occur in the pier 22 during the installation of the first longitudinal beam 11. This is advantageous because it allows for the construction of very slender piers 22.Longitudinal deformations of the bridge 21, resulting from temperature changes, compression during prestressing, concrete shrinkage, and concrete creep, can be absorbed by slender piers through bending deformations. This eliminates the need for bridge bearings 29. During the installation of the second longitudinal girder 11, the steel plates 57 installed in the second longitudinal girder 11 are positioned on top of the steel plates 57 in the first longitudinal girder 11 in such a way that no bending moments occur in the pier 22. It can be advantageous to arrange an additional tilting strip 55 between the two superimposed steel plates 57.

[0142] Fig. 19 shows the support structure 41 depicted in Fig. 18, comprising steel plates 57, tilting strips 55, and steel plates 44, on an enlarged scale. The width of the joint 24 between the adjacent longitudinal beams 11 is dimensioned such that the steel plates 57 projecting from the wall panels 12 can be arranged within the joint 24, taking into account installation tolerances. A second embodiment of the inventive method for manufacturing a prestressed bridge 21 with four spans is shown schematically in Figures 20 to 33. In its final state, the bridge 21 has a cross-section with a single-cell box girder and a deck slab 1 with two cantilevers.

[0143] Figure 20 shows a construction stage after the installation of the first longitudinal girder 11. A bridge 21, already completed using the inventive method, can be seen on the left edge of Figure 20. The depiction of the pier 22 on the right edge of the image indicates that, after the construction of the bridge 21 shown in Figures 20 to 33, another bridge 21 is built using the inventive method. Therefore, the inventive method makes it possible to build very long bridges 21, composed of a plurality of bridges 21 with, for example, four or more spans.

[0144] Figure 21 shows a construction stage after the installation of the second longitudinal beam 11. The longitudinal beams 11 are installed using a lifting device. For clarity, the lifting device is not shown in Figures 20 and 21.

[0145] Fig. 22 shows a construction stage after the installation of four longitudinal beams 11 and during the placement of the deck slab elements 2 onto the longitudinal beams 11. The deck slab elements 2 are moved along the longitudinal beams 11 in the longitudinal direction of the bridge 21 using a transfer carriage 61. Fig. 22 also shows a construction stage after the placement of two deck slab elements 2 and during the transport of the third deck slab element 2.

[0146] Figure 23 shows a cross-section through the completed bridge 21. Bridge bearings 29 are arranged below the deflection points 40. The bearing forces from the bridge bearings 29 are transferred to the pier 22 via bearing bases 42. The concrete topping 9 is applied in two layers 10. The first layer 10 of the concrete topping 9 is applied over the deck slab 14 of the longitudinal girder 11 and partially over the slabs 5 of the deck slab elements 2. The deck slab 1 is completed with the second layer 10 of the concrete topping 9.

[0147] Fig. 24 shows detail D of Fig. 23, with the second layer 10 of the topping concrete 9 and part of the reinforcement omitted for clarity. The transverse reinforcement 34 is installed above the longitudinal reinforcement 32 in the first layer from the top. A cotter pin 35 is installed at the upper end of the stirrups 33 embedded in the wall plate 12 of the longitudinal beam 1. The cotter pin 35, which is positioned above the wall plate 12, is encompassed by the stirrups 33. The tensile forces contained in the stirrups 33 are transferred to the cotter pins in the second layer 10 of the topping concrete 9.

[0148] The brackets 33 shown in Fig. 24 have two legs. It would also be possible to install brackets 33 with only one leg in the wall panels 12.

[0149] The distribution of bending moments in an interior span of the completed bridge 21 with the static system of a continuous beam as a result of the loading with a uniform load is shown in Fig. 25.

[0150] Fig. 26 shows the compression members 70, the tension members 71, and the zero-force members 72 in a truss model, which simplifies the modeling of the shear force transfer in the wall panels 12 of detail F shown in Fig. 25. No forces are present in the zero-force members 72. Zero-force members 72 are present in the top chord of the truss model because, according to the invention, a cotter pin 35 is installed in the stirrups 33. Insignificantly small longitudinal tensile forces occur in the cotter pin 35 because it is only arranged between the crossbeams 3 of the roadway slab elements 2. The truss model shown in Fig. 26 cannot satisfy the static equilibrium conditions.

[0151] Fulfilling the equilibrium conditions is only possible with a three-dimensional truss model. The truss model shown in Fig. 27 demonstrates how tensile forces, required to establish equilibrium in the truss model shown in Fig. 26, can be absorbed by reinforcing bars arranged next to the cotter pin 35, which form part of the upper longitudinal reinforcement 32 of the roadway slab 1.

[0152] According to the invention, it is thus possible to demonstrate a high shear load-bearing capacity in the longitudinal direction of the completed bridge 21 using standard methods. The installation of cotter pins 35 eliminates the need to thread reinforcing bars into the stirrups 33, which would be very time-consuming and would only work if the height of the crossbeams 3 were reduced.

[0153] The cotter pins 35 can be installed in the precast plant or on the construction site, but in any case before the roadway slab elements 2 are placed on the longitudinal beams 11.

[0154] The transport of the roadway slab elements 2 using a transfer trolley 61 on the longitudinal girders 11 is shown in Figures 22 and 28. The transfer trolley 61 transports the roadway slab elements 2 from the already completed bridge 21, where the roadway slab elements 2 are delivered, to the planned installation location. The weight of the transfer trolley 61 and the roadway slab element 2 is transferred via ten wheels 62 into the deck plates 14 of the longitudinal girders 11.

[0155] The transfer carriage 61 consists of a steel structure. The track panel element 2 is supported at four points on the transfer carriage 61. To compensate for construction tolerances, the support is provided by elastomer bearings 43 and steel plates 44. The spacing of the wheels 62 shown in Fig. 28 should be as large as possible so that the wheels 62 roll close to the wall panels 12, thereby minimizing bending stresses in the thin-walled deck panels 14. Sufficient clearance must be provided between the stirrups 33 arranged in the wall panels 12 and the wheels 62 to prevent collisions between the stirrups 33 and the wheels 62 during transport. When designing the reinforcement protruding upwards from the deck panels 14, for example, lattice girders 15, the rolling path of the wheels 62 on the deck panels 14 must be taken into account.

[0156] Once the transfer carriage 61 has reached its designated installation location, a lowering device 64 is installed as shown in Fig. 29. The lowering device 64 consists of a steel structure with steel supports 58 and steel beams 59, as well as two hydraulic presses 63. The four steel supports 58 are placed next to the crossbeams 3 on the wall panels 12. The steel beams 59 and the hydraulic presses 63 are then mounted. It would also be possible to lift the lowering device 64 into its designated position in one piece using a crane.

[0157] In the next step, the weight of the roadway slab element 2 is transferred to the two hydraulic presses 63, and the roadway slab element 2 is raised, for example, by 50 mm. The transfer carriage 61 can then be moved away from the installation location of the roadway slab element 2 to collect the next roadway slab element 2. As soon as the transfer carriage 61 has left the installation location, the roadway slab element 2 can be lowered and placed onto the longitudinal beams 11.

[0158] The use of a transfer carriage 61 and a lowering device 64 enables the application of the method according to the invention in situations where a mobile crane cannot be used at all or only with great effort to place the roadway slab elements 2 onto the longitudinal beams 11.

[0159] An advantageous embodiment for installing the longitudinal reinforcement 32 and the transverse reinforcement 34 of the upper reinforcement layers of the roadway slab 1 is shown in Figures 30 to 33. As shown in Figure 30, part of the upper transverse reinforcement 34 was already installed in the roadway slab element 2 at the precast plant. As shown in Figure 31, the longitudinal reinforcement 32, which is arranged above and near the longitudinal beams 11, is installed in the next step. Subsequently, as shown in Figure 32, the remaining part of the transverse reinforcement 34 is installed. Finally, as shown in Figure 33, the remaining part of the longitudinal reinforcement 32 is installed. The procedure shown in the drawings Fig. 30 to Fig. 33 for installing the longitudinal reinforcement 32 and the transverse reinforcement 34 of the upper reinforcement layers of the roadway slab 1 is advantageous because part of the upper transverse reinforcement 34 can already be installed in the precast plant in this way.This reduces the effort required to lay the reinforcement on the construction site.

[0160] For a roadway slab 1, which, as in the first embodiment, is manufactured over longitudinal girders 11 arranged side by side and parallel to the longitudinal axis of the bridge, a portion of the upper transverse reinforcement 34, which is arranged between the longitudinal girders 11 after the roadway slab elements 2 have been placed, can already be incorporated into the roadway slab elements 2 at the precast plant. If, in such an example, the roadway slab elements 2 are transported on the longitudinal girders 11, it is advantageous to use two lifting trolleys 61 and two lowering devices 64.

[0161] The production of the roadway slab elements 2 and the longitudinal beams 11 in a precast plant can also be replaced by production on or near the construction site. With on-site production, the transport distances from the production site to the installation site of the roadway slab elements 2 and the longitudinal beams 11 are shorter than with production in a precast plant.

[0162] A third embodiment of the inventive method for producing a prestressed bridge 21 is shown in Figures 34 to 39. This embodiment demonstrates that a further acceleration of the construction progress can be achieved by carrying out the construction work simultaneously at several points on the bridge 21.

[0163] In the first step, as shown in Fig. 34, two longitudinal beams 11 are assembled from four segments 18. Manufacturing and transporting segments 18 instead of longitudinal beams 11 is advantageous because the segments 18 are shorter and lighter than the longitudinal beams 11. In the embodiment shown in Fig. 34, one longitudinal beam 11 is assembled from two segments 18. It would also be possible to assemble a longitudinal beam from, for example, three segments 18. However, the number of segments 18 from which a longitudinal beam 11 is composed should be chosen to be as small as possible in order to reduce the number of joints 24. In the embodiment shown in Fig. 34, there is a joint 24 in each longitudinal beam 11, which is filled with a grout. After the grout has hardened, the segments 18 are joined together to form a longitudinal beam 11 by applying longitudinal prestress.The joining of the four segments 18 to form two longitudinal beams 11 can take place simultaneously with the completion of the construction work on the piers 22 and the abutments 19.

[0164] The actual assembly of the superstructure of bridge 21 begins with the lifting of the longitudinal girders 11 using two mobile cranes, which are not shown in Fig. 35 for clarity. On the same day, the end crossbeam 28 can also be manufactured, and three deck slab elements 2 can be placed on the longitudinal girders 11. Simultaneously, the longitudinal girders 11 can be assembled from segments 18 for the second span of bridge 21.

[0165] The construction work for the following day is shown in Fig. 36. The longitudinal girders 11 in the central span of the bridge 21 are installed using two mobile cranes. Subsequently, the connecting reinforcements 31 are installed and the deflection points 40 are constructed. The recesses 16 on the top of the longitudinal girders 11 are crucial for the rapid construction of the deflection points 40. The formwork, reinforcement, and concrete are transported through the recesses 16 into the cavities 17 of the longitudinal girders 11. The construction workers have direct access to the deflection points 40 through the recesses 16. Without the recesses 16, the construction materials and formwork would have to be transported through the openings 60 in the end crossbeams 28 to the deflection points 40, which would be very detrimental to rapid construction progress. Simultaneously with the production of the deflection points 40, the longitudinal beams 11 can be assembled from segments 18 for the third span of the bridge 21.

[0166] The construction work for the following day is shown in Fig. 37. The longitudinal girders 11 in the third span of bridge 21 are installed using two mobile cranes. Subsequently, the deflection points 40 and the crossbeam 27 are constructed. After the concrete of the deflection points 40, constructed the previous day, has partially hardened, the longitudinal girders 11 installed in the first and second spans of bridge 21 are rigidly connected to each other. This allows six more deck slab elements 2 to be placed on the longitudinal girders 11. The transverse joints between the deck slab elements 2 and the longitudinal joints between the deck slab elements 2 and the longitudinal girders 11 can then be sealed. Finally, the longitudinal reinforcement 32 and the transverse reinforcement 34, which form the upper reinforcement of the deck slab 1, can be laid on the deck slab elements 2.

[0167] The construction work for the following day is shown in Fig. 38. The second end crossbeam 28 is manufactured. Six further deck slab elements 2 are placed on the longitudinal girders 11, followed by sealing the transverse and longitudinal joints and laying the reinforcement on the deck slab elements 2. After the end crossbeam 28 has been manufactured, the external tendons 36 can be installed. The external tendons 36 extend over the entire length of the bridge 21 and are anchored in the end crossbeams. After the concrete of the end crossbeams 28 has partially hardened, partial prestressing is applied to the external tendons 36.

[0168] The following day, as shown in Fig. 39, the remaining roadway slab elements 2 are laid on the longitudinal beams. After completion of the work to install the reinforcement of the roadway slab 2, the topping concrete 9 can be applied to the roadway slab elements 2 and the cover plates 14 of the longitudinal beams. It would also be possible to apply the topping concrete in several stages. For example, the topping concrete 9 could be applied earlier to the roadway slab elements 2 shown in Fig. 38.

[0169] A fourth embodiment of the method according to the invention is shown in Figures 40 to 42.

[0170] In this embodiment, the longitudinal beams are installed using the incremental sliding method.

[0171] Figure 40 shows a construction stage in which four longitudinal beams 11 are already installed in their final position and three longitudinal beams 11 are being inserted using the incremental launching method. To reduce the bending stresses in the longitudinal beams 11 during the insertion process, a launching nose 56 is mounted on the longitudinal beam 11 located at the front in the launching direction.

[0172] Joints 24 are arranged between the longitudinal girders 11. During the insertion of the longitudinal girders 11, the joints 24 between the adjacent longitudinal girders 11 are compressed by an approximately centric prestressing force. Recesses 16 are arranged on the upper and lower surfaces in the area of ​​the joints 24 between the adjacent longitudinal girders 11. The recesses 16 are advantageous for the installation of the bridge bearings 29 and the creation of the deflection points 40 above the piers 22 after the longitudinal girders 11 have been installed using the incremental launching method.

[0173] The arrangement of the tendons 36 for the approximately centric prestressing of the longitudinal beams 11 during the insertion process is also shown schematically in Fig. 40. The internal post-tensioned tendons 36 are arranged in the base plates 13 and in the cover plates 14 of the longitudinal beams 11. Each tendon 36 has a prestressing anchorage 37 and an end anchorage 39. For anchoring the tendons 36, pilasters are required, which are not shown in Figs. 40 to 42 for the sake of clarity. The tendons 36 are joined by a lap splice in the area of ​​the joints 24 or connected to each other by tendon couplers.

[0174] After the longitudinal girders 11 have been installed using the incremental launching method, the bridge bearings 29 are installed centrally beneath the longitudinal girders 11, and the temporary support structures 41 required for the launching process are removed. Subsequently, the deflection points 40 are constructed in the area of ​​the piers 22 and in the spans. Constructing the deflection points 40 in the final position of the longitudinal girders 11 is advantageous because it reduces the self-weight of the longitudinal girders 11 during the launching process. Minimizing this self-weight during the launching process is crucial for dimensioning the tendons 36 for the approximately centric prestressing of the longitudinal girders 11.

[0175] Figure 41 shows a construction stage after the installation of the longitudinal girders 11 in their final position, after the application of a layer 10 of reinforced concrete to the base slabs 13, after the construction of crossbeams 27 between the longitudinal girders 11 in the area of ​​the piers 22, after the application of partial prestressing to the three external tendons 36, and after the placement of three deck slab elements 2 on the longitudinal girders 11. The deck slab elements 2 have an approximately trapezoidal shape in plan view because the bridge 21 has the shape of a circular arc in plan view.

[0176] After the roadway slab elements 2 have been laid, the upper longitudinal reinforcement 32 and the upper transverse reinforcement 34 can be placed on the roadway slab elements 2 and the cover plates 14 of the longitudinal beams 11. In a final step, the topping concrete 9 is then applied to the roadway slab elements 2 and the cover plates 14 of the longitudinal beams 11.

[0177] Figure 42 shows a cross-section through a longitudinal beam 11 during the insertion of the longitudinal beams 11. The longitudinal beam 11 consists of two wall plates 12, a base plate 13 and a top plate 14. The internal tendons for the approximately centric prestressing of the longitudinal beams 11 are installed laterally next to the recesses 16 in the base plate 13 and in the top plate 14.

[0178] A fifth embodiment of the method according to the invention is shown in Figures 43 and 44.

[0179] Fig. 43 shows a longitudinal section through a longitudinal beam 11 at the deflection point 40 above the pier 22. In this embodiment, the parts of the deflection point 40 that do not contain connecting reinforcement 31 are already installed in the longitudinal beams 11 at the precast plant. Fig. 43 shows that in the area of ​​the joint 24 between the two adjacent longitudinal beams 11, connecting reinforcement 31 with reinforcement connections 46 is force-fitted to the longitudinal reinforcement 32 installed in the longitudinal beams 11. The connecting reinforcement 31 is installed approximately in the longitudinal direction of the bridge 21. The longitudinal reinforcement 32 installed in the wall panels 13 has two bends within the precast part of the deflection point 40. Fig. 44 shows that the connecting reinforcement 31 is butted in the part of the deflection point 40 produced after the installation of the longitudinal beams 11.The lap splice of the connecting reinforcement 31 is located next to the wall panels 12 of the longitudinal beams 11. In the part of the deflection point 40 produced after the installation of the longitudinal beams 11, the sheathing tubes of the external tendons 36 are also coupled.

[0180] Installing the parts of the deflection points 40, which do not contain connecting reinforcement 40, before installing the longitudinal beams 11 is advantageous because it speeds up the construction work on the construction site.

[0181] The exemplary embodiments show the production of prestressed bridges 21 with three and four spans. The method according to the invention can also be used for the production of bridges 21 with two and with more than four spans, wherein the length of the bridge 21 depends on the achievable length of the external tendons 36.

[0182] List of reference symbols: Roadway slab, Roadway slab element, Crossbeam, Slab, Concrete topping layer, Layer, Longitudinal beam, Wall slab, Base slab, Cover slab, Lattice girder, Recess, Cavity, Segment, Abutment, Bridge, Pier, Joint, Crossbeam, End crossbeam, Bridge bearing, Connecting reinforcement, Longitudinal reinforcement, Stirrup, Transverse reinforcement, Cotter pin, Tensioning link, Tensioning anchorage, End anchorage, Deflection point, Support structure, Bearing base, Elastomeric bearing, Steel plate, Concrete joint, Reinforcement connection, Lifting point, Lifting beam, Tension member

[0183] loop

[0184] round steel

[0185] Tilting bar, front nose, sheet steel

[0186] steel support

[0187] steel beam

[0188] Passage opening for transfer trolley

[0189] Wheel hydraulic press, lowering device, pressure rod

[0190] Tension bar

[0191] Zero rod

Claims

Patent claims 1. Method for producing a prestressed bridge (21) made of reinforced concrete - with a roadway slab (1) which has at least one cantilever; - with at least two longitudinal beams (11) arranged one behind the other under the roadway slab (1), wherein the at least two longitudinal beams (11) are arranged approximately parallel to the longitudinal axis or in the longitudinal axis of the bridge (21) and a joint (24) is formed between each pair of adjacent longitudinal beams (11); - with the static system of a continuous beam with at least two spans or a frame with at least two spans; wherein the method comprises the following steps: a. Providing roadway slab elements (2), - wherein a roadway slab element (2) has at least two slabs (5) and at least one crossbeam (3) and preferably two crossbeams (3); - wherein the slabs (5) are made of reinforced concrete or prestressed concrete; - wherein at least one crossbeam (3) is made of reinforced concrete, prestressed concrete, structural steel, lattice girders (15) or reinforcing bars; - wherein the slabs (5) are formed in plan view with four corner points; - wherein at least two plates (5) are connected by the at least one crossbeam (3); - wherein at least one crossbeam (3) is arranged in plan view at an angle of 80° to 90° to the longitudinal axis of the bridge (21); - wherein at least one crossbeam (3) is arranged above the plates (5); - wherein two opposite edges of a plate (5) are arranged at an angle of 80° to 90° to the longitudinal axis of the bridge (21); - wherein the two remaining opposite edges of each plate (5) are arranged at an angle of 0° to 10° to the longitudinal axis of the bridge (21); and - wherein an edge of a first plate (5) and an edge of a second plate (5) are spaced apart from each other at a distance approximately corresponding to the width at the top of a longitudinal beam (11), the edges being arranged at an angle of 0° to 10° to the longitudinal axis of the bridge (21); b. providing at least two prefabricated, thin-walled longitudinal beams (11) made of reinforced or prestressed concrete, having a single-cell, box-shaped cross-section along their longitudinal extent, wherein the length of a longitudinal beam (11) is at least twice the width of the longitudinal beam (11); characterized in that - the at least two longitudinal beams (11) with a width of less than 3.51 m are manufactured; - at least one longitudinal beam (11) is manufactured with a recess (16) in the base plate (13) and / or with a recess (16) in the top plate (14) at at least one end; - the recess (16) is produced with a length of 0.1 m to 3.0 m measured in the longitudinal direction of the bridge (21), and preferably with a length of 0.5 m to 1.0 m; and - the recess (16) is produced with a width of 0.2 m to 3.0 m measured in the transverse direction of the bridge (21), and preferably with a width of 0.5 m to 2.4 m; c. Installing the at least two longitudinal girders (11) with at least one crane, with at least one lifting device, or with the incremental launching method, - wherein in the completed bridge (21) the joint (24) between the at least two adjacent longitudinal beams (11) above a pier (22) is formed and - wherein the at least two adjacent longitudinal beams (11) are supported on the pier (22) by means of temporary support structures (41); d. installation of connecting reinforcement (31) in an area next to the joint (24) between the at least two longitudinal beams (11), - wherein the connecting reinforcement (31) is installed approximately in the longitudinal direction of the bridge (21), - wherein the connecting reinforcement (31) is butted and / or force-fit connected to the longitudinal reinforcement (32) installed in the adjacent longitudinal beams (11) and - wherein, when using the incremental launching method for installing the longitudinal beams (11), the connecting reinforcement (31) can optionally be installed before the longitudinal beams (11) are inserted; e. creating a deflection point (40) made of reinforced concrete in the area of ​​the joint (24) between the at least two longitudinal beams (11), wherein the connecting reinforcement (32) installed in step d is arranged in the deflection point (40); f. installing external tendons (36) in the cavity (17) formed by the wall panels (12), the base panels (13) and the cover panels (14) in the at least two longitudinal beams (11), - wherein the external tendons (36) extend over the entire length of the bridge (21); - wherein each external tendon (36) has at least one anchorage (37) and - wherein in the completed bridge (21) in a cross-section through a longitudinal girder (11) above a pier (22) the sum of the prestressing forces in the external tendons (36), which extend over the entire length of the bridge (21) extend, amounting to at least 20% of the total prestressing force present in this cross-section, acting in the longitudinal direction of the bridge (21); g. optionally, applying partial prestressing to the external tendons (36); h. placing the deck slab elements (2) on the at least two longitudinal girders (11), optionally starting the placement of the deck slab elements (2) as soon as all longitudinal girders (11) have been installed in at least one span of the bridge (21); i. optionally, applying further partial prestressing to the external tendons (36); j. placing reinforcement, preferably longitudinal reinforcement (32) and transverse reinforcement (34), on the deck slab elements (2) and over the deck slabs (14) of the at least two longitudinal girders (11), optionally starting the placement of the reinforcement as soon as at least one deck slab element (2) has been placed on the longitudinal girders (11); k.optionally applying a further partial prestress to the external tendons (36); l. applying the topping concrete (9) to the roadway slab elements (2) and over the deck slabs (14) of the at least two longitudinal girders (11) to produce the roadway slab (1), optionally starting the application of the topping concrete (9) as soon as the reinforcement has been laid on at least one roadway slab element (2); and m. applying the final prestress to the external tendons (36).

2. Method according to claim 1, characterized in that the at least one external tendon (36) is manufactured from two sections, each having a tension anchor (37) and an end anchor (39), an overlap splice for the two sections is made in a deflection point (40) with the two end anchors (39) and the two sections are anchored with tension anchors (37) in the end crossbeams (28) of the bridge (21).

3. Method according to claim 1 or 2, characterized in that a longitudinal beam (11) is assembled on the construction site from segments (18) which are connected to each other by a longitudinal prestressing.

4. Method according to one of claims 1 to 3, characterized in that a layer (10) of concrete is applied on at least a part of the base plate (13) on the construction site before or after the installation of a longitudinal beam (11).

5. Method according to one of claims 1 to 4, characterized in that the central axis of the support structures (41) is arranged at a distance of at most 200 mm in the longitudinal direction of the bridge (21) from the central plane of the pier (22) and preferably in the central plane of the pier (22).

6. Method according to one of claims 1 to 5, characterized in that a support structure (41) is produced with at least one steel plate (44) and with at least one elastomer bearing (43).

7. Method according to one of claims 1 to 6, characterized in that the transport of the roadway slab elements (2) is carried out with a transfer trolley (61), - wherein the transfer carriage (61) is moved on at least one longitudinal beam (11) in the longitudinal direction of the bridge; - the wheels (62) of the transfer carriage (61) roll on the cover plate (14) of the at least one longitudinal beam (11) during transport; and - at least one roadway slab element (2) is transported to the installation site.

8. Method according to any one of claims 1 to 7, characterized in that - two loops (53) with sufficient anchoring lengths are installed in a wall plate (12); - the loops (53) protrude from the wall panels (12) on the top of the longitudinal beam (11); - the loops (53) are arranged approximately normal to the mid-plane of the cover plate (14) of the longitudinal beam (11); - the loops (53) in the upper area have a constant radius of curvature; - in the loops (53) in the areas which have a constant radius of curvature, a round steel bar (54) is installed; and - a tension member (52) is attached to the round steel (54) approximately in the middle between two loops (53).

9. Method according to any one of claims 1 to 8, characterized in that - the concrete topping (9) is applied in two layers (10); - the first layer (10) of the topping concrete (9) is applied over the cover plates (14) of the at least two longitudinal beams (11) and, if applicable, over a part of the plates (5) of the roadway slab elements (2) adjacent to the at least two longitudinal beams (11); and - the thickness of the first layer (10) of the concrete topping (9) over the cover plates (14) of the at least two longitudinal beams (11) is at least 80 mm.

10. Method according to one of claims 1 to 9, characterized in that a part of the upper transverse reinforcement (34) is installed in the roadway slab elements (2) in the second layer from above and the remaining part of the transverse reinforcement (34) is installed on the construction site in the first layer from above.

11. Method according to one of claims 1 to 10, characterized in that at the upper end of at least two stirrups (33) and preferably of all stirrups (33) that project from the wall panels (12) on the upper side of the longitudinal beam (11), at least one cotter pin (35), the length of which is at least 20 mm shorter than the distance between two crossbeams (3) of the deck panel elements (2) measured in the longitudinal direction of the bridge (21), is installed inside the stirrups (33) before the deck panel elements (2) are placed on the at least two longitudinal beams (11), and in a subsequent step, at least one reinforcing bar of the longitudinal reinforcement (32), which has a length at least 1.0 m greater than the at least one cotter pin (35) and is arranged in the same reinforcement position as the at least one cotter pin (35), is installed next to the at least one cotter pin (35).

12. Method according to one of claims 1 to 11, characterized in that a part of a deflection point (40) which does not contain any connecting reinforcement (31) is installed in a longitudinal beam (11) before the longitudinal beam (11) is installed.

13. Method according to one of claims 1 to 12, characterized in that wall panels (12) are installed in at least one longitudinal beam (11) at at least one end, which have a higher concrete compressive strength than the wall panels (12) arranged in the middle area of ​​the longitudinal beam (11).

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