CN115110435A - Construction method of orthotropic combined bridge deck - Google Patents

Abstract

The invention relates to a construction method of an orthotropic composite bridge deck, belonging to the technical field of bridge structures. The bridge deck includes U-shaped longitudinal rib, transverse rib, steel cover plate, and concrete plate. A support piece is welded on the surface of the steel cover board, and the support piece is connected with a shear connector, and the shear connector is embedded in the concrete. There are cavities between the supports. The invention uses I-beam to bend a small steel box with U-shaped longitudinal ribs, and the small steel box is transversely welded to form the main body of the bridge deck structure. The construction method makes the production modularized and speeds up the production progress; it avoids the fatigue pattern that occurs on the U-shaped longitudinal rib in the conventional orthotropic composite deck, and starts from the U-shaped longitudinal rib and the welding seam of the steel cover. It is beneficial to improve the life of the structure; the cavity reserved between the supports can improve the bending resistance of the bridge deck structure, and the material properties of the steel cover plate and the concrete slab can be fully exerted; pouring concrete into the supports of the same group can further improve the Orthotropic combination of deck stiffness and girder stiffness.

Description

A kind of construction method of orthotropic composite bridge deck

technical field

The invention relates to a construction method of a bridge deck, in particular to a construction method of an orthotropic composite bridge deck, and belongs to the technical field of bridge engineering.

Background technique

With the rapid development of my country's economy, a number of large-span river and sea-crossing highway bridges have been started successively, and have been completed and opened to traffic one after another. In the history of bridge construction in my country, there has been an unprecedented climax of building large-span bridges. The steel box girder has high torsional rigidity, reasonable bending stress diagram and small shear stress, and is especially suitable for large-span bridges, curved bridges and narrow-pier-column bridges. Considering light weight, prefabrication and economy, the long-span suspension bridges and cable-stayed bridges of highways basically choose streamlined steel box girders as stiffening girders. Steel box girders generally use orthotropic decks. The orthotropic bridge deck is composed of steel cover plate, longitudinal stiffeners and transverse stiffeners. Because of its different longitudinal stiffness and transverse stiffness perpendicular to it, it is called an orthotropic deck. With its advantages of large bearing capacity, light weight, fast construction and beautiful structure, it has solved the contradiction between the self-weight, load-bearing and span of the bridge, and has become the preferred bridge deck form for long-span steel bridges.

The orthotropic bridge deck has a complex structure and a large number of welds. It not only has to bear the wheel load of the vehicle repeatedly, but also participates in the overall stress of the steel box girder as a part of the main beam. The local stress cycles are too many, and it will cause inevitable stress concentration and welding defects during the welding process of the beam body, so that the bridge deck is prone to fatigue cracks after a period of operation. Once a long-span steel bridge has fatigue cracks, it is not only difficult and expensive to maintain, but also causes a catastrophic accident of sudden bridge failure.

How to avoid fatigue cracks and ensure the durability of orthotropic bridge decks has long been a difficult issue. At present, in the actual bridge design, the main measures to solve the fatigue problem of the bridge deck include: reasonably matching the dimensions of the longitudinal ribs, transverse ribs and the bridge deck, and constructing appropriate arc-shaped incision rulers; For the Seventh Yangtze River Bridge, the main girder is a composite girder structure, and the bridge deck is made of concrete deck; pavement layers can also be simply added, such as reinforced high-performance concrete, sandwich steel plate layer, polymer-modified concrete, epoxy resin asphalt Concrete, steel fiber reinforced concrete, etc. These measures either retarded the cracking only slightly, or there was no major increase in stiffness after a substantial increase in deck weight.

SUMMARY OF THE INVENTION

In order to overcome the deficiencies in the prior art, the present invention develops a construction method of an orthotropic composite bridge deck, which aims to reduce the fatigue cracks of the orthotropic bridge deck structure.

The technical solution proposed by the present invention is a construction method of an orthotropic composite bridge deck, the composite bridge deck comprises U-shaped longitudinal ribs, transverse ribs, steel cover plates, and concrete slabs, and is characterized in that: the upper surface of the steel cover plate is connected and supported The support is connected with a shear connector, the shear connector is embedded in concrete, and there is a cavity or foam between the supports.

Preferably, the support member is an angle steel, the end of one side is welded perpendicular to the steel cover plate, and the other side is parallel to the upper surface of the steel cover plate.

Preferably, the support member is channel steel, the web of the channel steel is perpendicular to the steel cover plate, and the two sides of one wing plate of the channel steel are connected to the upper surface of the steel cover plate through fillet welds; or the support member is I-beam, the web of the I-beam is perpendicular to the steel cover plate, and the two sides of a wing plate of the I-beam are connected to the upper surface of the steel cover plate through fillet welds.

Preferably, the support member is connected above the intersection line of the side plate of the U-shaped longitudinal rib and the steel cover plate.

Preferably, two support members are connected above the intersection line; the two support members are symmetrically arranged with respect to the intersection line to form a support member group.

Preferably, the space between the support member groups is a cavity or a foam body, and the space in the support member group is filled with concrete.

Preferably, the concrete slab is a prefabricated slab, and there are reserved grooves on the prefabricated slab, and the positions of the reserved slots correspond to the positions of the shear connectors; the prefabricated slabs are placed on the support members, and the shear connectors are The top is lower than the upper surface of the prefabricated board.

Preferably, the prefabricated panel includes a side panel and a middle panel, three sides of the side panel are protruded with reinforcing bars, and four sides of the center panel are protruded with reinforcing bars; the prefabricated panel is integrated by a cast-in-place concrete connecting belt; The connection strips correspond to the positions of the transverse ribs or transverse connection structures below them; the longitudinal connection strips are located on the support group, and the cast-in-place concrete enters the inner space of the support group.

A construction method for an orthotropic composite bridge deck, the construction comprising the following steps:

Step 1: In the steel component manufacturing workshop, the I-beam is bent and welded to form a small steel box with U-shaped longitudinal ribs and a top plate; a plurality of small steel boxes are connected side by side, and the top plate forms a steel cover plate;

Step 2 On the upper surface of the steel cover plate above the intersection line of the side plate of the U-shaped longitudinal rib and the steel cover plate, symmetrically weld two support members. The two supports form a support group; the shear connectors are welded on the top surface of the supports, and a plurality of shear connectors close to each other form a connector group;

Step 3: Assemble the bridge deck steel members produced in Step 2 together with other components of the steel box girder into steel box girder segments, and transport them to the bridge construction site;

Step 4: Plan to pour concrete in different zones, reserve post-pouring belts between the sub-areas, and set the longitudinal post-casting belts above the support group. In each partition, the support member groups are filled with plastic foam; the steel mesh is bound, concrete is poured in each partition, and maintained; then, the post-casting belt between each partition is poured and maintained.

A construction method for an orthotropic composite bridge deck, the construction comprising the following steps:

Step 1: In the steel component manufacturing workshop, the I-beam is bent and welded to form a small steel box with U-shaped longitudinal ribs and a top plate; a plurality of small steel boxes are connected side by side, and the top plate forms a steel cover plate;

Step 2 On the upper surface of the steel cover plate above the intersection line of the side plate of the U-shaped longitudinal rib and the steel cover plate, symmetrically weld two support members. The two supports form a support group; the shear connectors are welded on the top surface of the supports, and multiple shear connectors close to each other form a connector group; in the concrete precast field, each prefabricated slab is prefabricated with concrete ;

In step 3, the precast concrete slabs are transported to the construction site; the bridge deck steel members produced in step 2 are assembled into steel box girder segments together with other components of the steel box girder, and transported to the bridge construction site;

Step 4: On the horizontal cast-in-place edge of each installation zone of the planned prefabricated panel, weld the clapboard as a template; paste rubber strips along the longitudinal direction on the edges of the two supports of the support group to ensure that the interior of each support group after the prefabricated panel is installed Close the gap between the prefabricated slab and the outside; place the precast concrete slab; at the cast-in-place belt along the transverse direction of the bridge, seal the gap between the prefabricated slab and the formwork and between the prefabricated slab and the top surface of the connector with building sealant;

Step 5: Concrete is poured into the support group corresponding to the precast concrete slab through the reserved slot. The pouring sequence is from one end of the prefabricated slab to the other end along the longitudinal direction of the bridge. Concrete is discharged; then pour from the reserved groove that has just been discharged until concrete is discharged from the next adjacent reserved groove; this is the sequence of operations. After the reserved grooves are filled with concrete, the connecting belts between the prefabricated slabs are cast in place. The cast-in-place concrete is covered with plastic film and cured.

The beneficial effects of the present invention include the following aspects:

(1) Most of the fatigue cracks of the orthotropic bridge deck are related to the U-shaped longitudinal ribs, such as appearing on the U-shaped longitudinal ribs, and originating from the joints between the U-shaped longitudinal ribs and the steel cover plate, and the penetration of the U-shaped longitudinal ribs. Cracks at the cross-connection of transverse ribs and diaphragms, butt welds of U-shaped longitudinal ribs, etc. The invention uses I-beam to bend a small steel box with U-shaped longitudinal ribs, and the small steel box is transversely welded to form the main body of the bridge deck structure. This construction method cancels the connection weld between the U-shaped longitudinal rib and the steel cover plate, and greatly reduces the number of fatigue cracks that may occur here from the source. Although welds have been added to the steel cover, there are few reports of fatigue cracks occurring at the joints between the steel covers. The reason is that the stress is relatively small and the stress state is better at the top of the U-shaped longitudinal rib. ;

(2) Bend a small steel box with U-shaped longitudinal ribs from I-beam, and use section steel as a support. Section steel is used for the entire bridge deck steel structure. ;

(3) The reduction of cracks starting from the U-shaped longitudinal rib and the weld of the steel cover plate is conducive to improving the structural life;

(4) The reduction of cracks starting from the U-shaped longitudinal rib and the weld of the steel cover plate reduces the maintenance workload in the later period, because the cracks deep into the steel cover plate are not easy to find. Once found, the cracking degree is serious and repairing is difficult. Because repairs require interruption of traffic;

(5) Welding supports on the steel cover plate and installing precast concrete slabs on the supports can improve the bending resistance of the composite bridge deck structure;

(6) Concrete is poured into the space in the support group, which can further improve the stiffness of the orthotropic composite bridge deck and the stiffness of the main beam, and improve the stress state of the steel cover;

(7) The steel structure part in the present invention is made in the factory, and the prefabricated concrete slab is also made in the prefabrication field in advance, and assembled on site, which speeds up the construction progress and is conducive to rapid construction;

(8) Above the transverse rib and the diaphragm, there are cast-in-place concrete connecting belts, thereby enhancing the lateral stiffness of the bridge deck.

Description of drawings

Figure 1 is a schematic diagram of the process of making a small steel box from I-beam;

Figure 2 Schematic diagram of the steel bridge deck assembly assembled with small steel boxes;

Figure 3 Schematic diagram of the structure after welding shear nails;

Figure 4 is a schematic diagram of the structure after filling between the angle steel groups;

Figure 5 is a schematic diagram of the distribution of pouring pieces;

Figure 6 is a schematic cross-sectional view of the structure after the steel mesh is bound;

Figure 7 is a schematic diagram of the structure after the concrete is poured in pieces;

Figure 8 is a schematic cross-sectional view of the structure after installing the horizontal formwork;

9 is a schematic cross-sectional view of the composite bridge deck structure in Embodiment 1;

Figure 10 is a schematic diagram of the side plate of the precast concrete slab in Example 2;

Fig. 11 is the schematic diagram of the middle plate of the concrete precast slab in Example 2;

Figure 12 is a schematic diagram of the distribution planning of precast concrete slabs in Example 2;

Figure 13 is a schematic cross-sectional view of the structure through A-A in Figure 12;

Figure 14 is a schematic top view of the structure after the prefabricated panels are placed in Embodiment 2;

Figure 15 is a schematic plan view of the structure after pouring concrete in Example 2;

Figure 16 is a schematic cross-sectional view of the structure through B-B in Figure 15;

Figure 17 is a schematic cross-sectional view of the structure through C-C in Figure 15;

Figure 18 is a schematic view of the structure after the permanent base film is placed in Example 3;

Figure 19 is a schematic cross-sectional view of the structure after binding the steel mesh in Embodiment 3;

Figure 20 is a schematic cross-sectional view of the composite bridge deck structure in Embodiment 3;

Figure 21 is a schematic diagram of the distribution planning of precast concrete slabs in Example 4;

FIG. 22 is a schematic cross-sectional view of the structure corresponding to C-C in FIG. 15 in Embodiment 4. FIG.

In the picture: steel cover plate 1, U-shaped longitudinal rib 2, shear nail 3, transverse rib 4, prefabricated plate 5, steel bar 6, reserved groove 7, small partition 8, large partition 9, side plate 10, middle plate Plate 11, connecting belt 12, cast-in-place concrete 13, mould beam 14, small steel box 15, I-beam 16, angle steel 17, polypropylene foam board 18, steel mesh 19, corrugated board 20.

Detailed ways

Example 1

In this embodiment, a foam board is embedded in the composite bridge deck. The steel structure part of the composite bridge deck is shown in Figures 1-3. Figure 1 shows the process of making the small steel box 15 by using the I-beam 16. In the workshop of the steel structure manufacturing plant, the I-beam 16 is placed on the mold beam 14. , the die beam 14 is a steel beam and both ends are supported, and the two rows of punching heads hinged with the upper thrust rod are symmetrically pressed on the two ends of the web of the I-beam 16 from above, and the I-beam 16 is bent. Fold it to form a small steel box 15, and weld the seam in the middle. A plurality of small steel boxes 15 are welded side by side, the top plate of the small steel boxes 15 forms the steel cover plate 1 , and the web portion corresponding to the I-beam 16 becomes the U-shaped longitudinal rib 2 . Above the intersection line of the side plate of the U-shaped longitudinal rib 2 and the steel cover plate 1, the welded angle steel 17 is used as a support, and the two angle steels 17 are symmetrically arranged on the intersection line to form a support group. One end of the angle steel 17 is welded with the steel cover plate 1 , and the other side is parallel to the upper surface of the steel cover plate 1 . The shear nails 3 are welded on the angle steel 17 as a shear connector, and the four shear nails 3 at the same place are used as a connector group, see Figure 5. The fabricated bridge deck steel members and other components of the steel box girder are assembled into steel box girder segments and transported to the bridge construction site.

Steel box girder segments are erected on the site and welded into one. A polypropylene foam board 18 is placed between the sets of supports, see FIGS. 4 and 5 . The concrete bridge deck planned to be poured is divided into several areas, and post-pouring belts are left between the areas, mainly to avoid cracks in the concrete slab after large-scale pouring. Polypropylene foam panels 18 are installed between adjacent sets of support members in each zone. The longitudinal post-casting belt is arranged above the support group. The position of the transverse post-casting belt is set to correspond to the transverse rib or diaphragm below it; the reinforcement mesh 19 is bound, see Figure 6; the concrete is poured in each zone and cured, and the schematic diagram of the structure after the concrete is poured in pieces is shown in Figure 7; then, The connecting belts 12 between each subarea are poured and maintained, as shown in Figure 8. 9 is a schematic cross-sectional view of the composite bridge deck structure of Example 1 at positions other than transverse ribs and non-diaphragm plates. The cast-in-place concrete 13 fills the space inside each support group and forms the upper concrete bridge deck, so that the The various components in Figure 9 form an organic whole and become an orthotropic composite bridge deck.

Example 2

This embodiment is a modification of Embodiment 1, and the bridge deck adopts concrete prefabricated parts. The concrete slab is made of prefabricated slabs 5 assembled and cast-in-place joints. The prefabricated slab 5 has a reserved slot 7, and the position of the reserved slot 7 corresponds to the position of the connector group; the prefabricated slab 5 is divided into side slabs 10 and 7. There are two types of middle plate 11, see Figure 10 and Figure 11. Three sides of the side plate 10 have protruding steel bars 6, and four sides of the middle plate 11 are protruded with steel bars 6, and the extension length of the steel bars 6 is 200mm. After the prefabricated board 5 is placed on the support group, the connector group enters the reserved groove 7, and the top of the shear nail 3 is 20 mm lower than the upper surface of the prefabricated board 5; Bend horizontally in opposite directions to avoid mutual interference during installation. The width of the prefabricated panel 5 is such that the transverse seam is just below the position of the transverse rib or the transverse partition, and the longitudinal seam is located on the support group. Before placing the prefabricated panel 5, it is necessary to weld the small partition plate 8 and the large partition plate 9 at the transverse joint position as a template, as shown in Figure 12 and Figure 13. Small baffles 8 are welded before and after the connector group in the planned area of each prefabricated panel 5 . The tops of the small partition 8 and the large partition 9 are flush with the top surface of the angle steel 17 . Paste 2mm thick rubber strips along the longitudinal direction on the top edge of the two angle steels 17 of the support group to ensure that the interior and exterior of each support group are closed after installing the prefabricated panels 5; place the prefabricated panels 5, see Figure 14; At the horizontal cast-in-place belt, use building sealant to seal the gaps between the prefabricated plate 5 and the formwork, and between the prefabricated plate 5 and the top surface of the angle steel 17.

Concrete is poured into the support group corresponding to the precast concrete slab 5 through the reserved slot 7. The pouring sequence is from one end of the prefabricated slab 5 to the other end along the longitudinal direction of the bridge. Concrete is discharged from the retaining groove 7; and then poured from the reserved groove 7 where the concrete has just been discharged, until the next adjacent reserved groove 7 has concrete discharged; this is the sequence of operations. After the reserved groove 7 is filled with concrete, the connecting strips 12 between the prefabricated slabs are cast in place, as shown in Figure 15. The cast-in-place concrete is covered with plastic film and cured. The schematic cross-sectional view of the structure through B-B in FIG. 15 is shown in FIG. 16 , the schematic cross-sectional view of the structure through C-C in FIG. 15 is shown in FIG. 17 , and the transverse rib 4 can be seen in FIG. 17 . The transverse rib 4 is T-shaped steel, the web is on top, and it is welded on the lower surface of the steel cover plate 1 . Holes are dug in the web of the transverse rib 4 so that the U-shaped longitudinal rib 2 can pass through.

Example 3

This embodiment is a modification of Embodiment 1, and holes are arranged between the concrete slab and the steel cover plate 1, as shown in Figures 18-20. Fig. 18 is a schematic view of the structure after the permanent bottom film is placed. A corrugated plate 20 is placed between adjacent support member groups. The corrugated plate 20 is used as a permanent template and will not be removed after the bridge is formed. The corrugated plate 20 is made of a steel plate by fixing its two long sides and pressing its middle. The corrugated plate 20 is welded with the edge of the top surface of the angle steel 17 . Figure 19 shows a schematic cross-sectional view of the structure after binding the steel mesh 19. Still as in Example 1, the concrete is poured in different areas, and then the connecting belt 12 is poured. The cross-section of the finally obtained composite bridge deck structure is shown in Figure 20. The upper part of the steel cover plate 1 of the composite bridge deck is provided with holes, In the case of reducing its own weight, the bending resistance of the composite bridge deck is increased, and the bending resistance of the entire main beam is also increased, thereby reducing fatigue cracks.

Example 4

This embodiment is a modification of Embodiment 2, and concrete is poured into the support group. See Figures 21-22. The small partitions 8 are no longer provided before and after the connector group under each prefabricated board 5 . After the bridge is completed, the schematic cross-sectional view of the composite bridge deck is shown in Figure 22, which is not located at the position of the diaphragm, nor is the transverse rib set. After concrete is poured inside the support group, the stress area of the steel cover 1 when the vehicle load is transmitted to the steel cover 1 is increased, which can further improve the stress state of the steel cover 1 .

In the present invention, "above" includes directly above and obliquely above, and other similar positional relationships are also to be understood in the same way.

Claims (10)

1. An orthotropic composite bridge deck, comprising U-shaped longitudinal ribs, transverse ribs, steel cover plates, and concrete slabs, is characterized in that: the upper surface of the steel cover plate is connected to a support member, and the support member is connected to a shear connector, which is resistant to The shear connectors are embedded in concrete, with cavities or foam between the supports. 2 . The orthotropic composite bridge deck according to claim 1 , wherein the supporting member is an angle steel, the end of one side is vertically welded to the steel cover plate, and the other side is parallel to the upper surface of the steel cover plate. 3 . 3. The orthotropic composite bridge deck according to claim 1, characterized in that: the support member is channel steel, the web of the channel steel is perpendicular to the steel cover plate, and the two sides of a wing plate of the channel steel pass through The fillet weld is connected to the upper surface of the steel cover; or the support is an I-beam, the web of the I-beam is perpendicular to the steel cover, and the two sides of a wing plate of the I-beam are connected to the steel cover through fillet welds board surface. 4. The orthotropic composite bridge deck according to claim 1, wherein the supporting member is connected above the intersection line of the side plate of the U-shaped longitudinal rib and the steel cover plate. 5 . The orthotropic composite bridge deck according to claim 4 , wherein two support members are connected above the intersection line; the two support members are arranged symmetrically with respect to the intersection line to form a Support group. 6 . The orthotropic composite bridge deck according to claim 5 , wherein the supporting member groups are hollow or foamed, and the spaces in the supporting member groups are filled with concrete. 7 . 7. The orthotropic composite bridge deck according to claim 6, characterized in that: the concrete slab is a prefabricated slab, and the prefabricated slab has a reserved groove, and the position of the reserved groove is the same as that of the shear connector. The positions are corresponding; the prefabricated board is placed on the support, and the top of the shear connector is lower than the upper surface of the prefabricated board. 8. The orthotropic composite bridge deck according to claim 7, characterized in that: the prefabricated plate comprises a side plate and a middle plate, three sides of the side plate have protruding steel bars, and four sides of the middle plate are protruded with steel bars The prefabricated slabs are connected into one by the cast-in-place concrete; the horizontal connecting belt corresponds to the position of the transverse rib or the horizontal connecting structure below it; interior space. 9. A construction method for an orthotropic composite bridge deck, characterized in that: the construction comprises the following steps, Step 1: In the steel component manufacturing workshop, the I-beam is bent and welded to form a small steel box with U-shaped longitudinal ribs and a top plate; a plurality of small steel boxes are connected side by side, and the top plate forms a steel cover plate; Step 2 On the upper surface of the steel cover plate above the intersection line of the side plate of the U-shaped longitudinal rib and the steel cover plate, two support members are symmetrically welded; the two support members form a support member group; Surface welded shear connectors, and multiple shear connectors close to each other form a connector group; Step 3: Assemble the bridge deck steel members produced in Step 2 together with other components of the steel box girder into steel box girder segments, and transport them to the bridge construction site; Step 4: Plan to pour concrete in different zones, reserve post-pouring belts between the sub-sections, and set the longitudinal post-casting belts above the support member groups; in each zone, fill plastic foam between the support member groups; bind steel mesh, pour each Partition concrete, and cure; then, pour the post-pouring belt between each partition, and cure. 10. A construction method for an orthotropic composite bridge deck, characterized in that: the construction comprises the following steps, Step 1: In the steel component manufacturing workshop, the I-beam is bent and welded to form a small steel box with U-shaped longitudinal ribs and a top plate; a plurality of small steel boxes are connected side by side, and the top plate forms a steel cover plate; Step 2 On the upper surface of the steel cover plate above the intersection line of the side plate of the U-shaped longitudinal rib and the steel cover plate, two support members are symmetrically welded; the two support members form a support member group; Surface welded shear connectors, and multiple shear connectors close to each other form a connector group; in the concrete prefabrication field, each prefabricated slab is prefabricated with concrete; In step 3, the precast concrete slabs are transported to the construction site; the bridge deck steel members produced in step 2 are assembled into steel box girder segments together with other components of the steel box girder, and transported to the bridge construction site; Step 4: On the horizontal cast-in-place edge of each installation zone of the planned prefabricated panel, weld the clapboard as a template; paste rubber strips along the longitudinal direction on the edges of the two supports of the support group to ensure that the interior of each support group after the prefabricated panel is installed Close the gap between the prefabricated slab and the outside; place the precast concrete slab; at the cast-in-place belt along the transverse direction of the bridge, seal the gap between the prefabricated slab and the formwork and between the prefabricated slab and the top surface of the connector with building sealant; Step 5: Concrete is poured into the support group corresponding to the precast concrete slab through the reserved slot. The pouring sequence is from one end of the precast slab to the other end along the longitudinal direction of the bridge. Concrete is discharged; then pour from the reserved groove that has just been discharged until concrete is discharged from the next adjacent reserved groove; this is the sequence of operations. After the reserved grooves are filled with concrete, the connecting belts between the prefabricated slabs are cast in place. The cast-in-place concrete is covered with plastic film and cured.

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