A UHPC board and concrete combined frame slab bridge and construction method thereof

Abstract

The present invention discloses a UHPC plate and concrete combined frame slab bridge and a construction method thereof, wherein the structural part includes a plurality of piers arranged at equal intervals, cap beams are provided on the piers, UHPC plate girders are arranged between the cap beams, concrete is poured on the UHPC plate girders and connected to the cap beams by concrete, negative moment zone UHPC prefabricated plates are provided at the ends of the adjacent UHPC plate girders, and the two ends of the negative moment zone UHPC prefabricated plates are respectively connected to the concrete at the ends of the UHPC plate girders on both sides. The UHPC plate concrete combined continuous frame slab bridge designed by the present invention has better stress performance, better durability, more convenient construction process, and lower construction cost than cast-in-place ordinary concrete structures, and has very significant advantages, and has strong applicability for the construction of bridges in coastal splash zones.

Description

Technical Field

[0001] The present invention is applied to the technical field of structural engineering, and specifically is a UHPC board and concrete combined frame slab bridge and a construction method thereof. Background Art

[0002] Steel bridges and steel-concrete composite bridges are not suitable for bridge construction in coastal areas due to their outstanding durability problems. Therefore, most bridges in coastal areas are concrete bridges. However, the environmental conditions in coastal splash zones are harsh and the working conditions are complex. Therefore, the construction and maintenance of concrete bridges in coastal splash zones are seriously threatened, which is specifically manifested in the following aspects:

[0003] (1) Bearing performance: Bridges located in coastal splash zones are directly subjected to huge wave impacts. Excessive ocean dynamic impacts may even exceed the live load of the bridge, which will have an adverse effect on the structural stress and make it difficult for the beam body to meet the crack resistance requirements.

[0004] (2) Durability: Conventional concrete structures are prone to cracking under complex offshore working conditions. Harmful substances in the marine environment will corrode the cracked concrete structures, further accelerating the corrosion of internal steel bars, and the durability problem is worrying.

[0005] (3) Construction: Coastal bridges are located in areas with deep silt and mudflats, making it difficult to erect scaffolding. The cast-in-place construction of the bridge superstructure is complex, with high construction costs and a long construction period.

[0006] In summary, conventional concrete structures are difficult to meet the mechanical properties and durability requirements of bridges in the complex environmental conditions of coastal splash zones. Therefore, it is very necessary to propose a new type of bridge structure with reasonable force, good crack resistance and excellent durability, which is of great significance to promoting the development and construction of bridges in coastal splash zones.

[0007] Ultra High Performance Concrete (UHPC) is a new type of cement-based material, which is considered to be the most innovative material in the past thirty years. It has achieved innovative breakthroughs in the performance of civil engineering materials, and has ultra-high mechanical properties, ultra-high toughness and ultra-high durability. It is an ideal civil engineering material. Bridges built with all UHPC must have better mechanical properties and durability than conventional concrete structures. However, the current UHPC production and preparation process is complex and the unit price of the material is high, so it is unrealistic to widely and comprehensively apply UHPC to bridge structures. Therefore, how to combine UHPC with concrete to manufacture continuous frame slab bridges suitable for coastal splash zones has become a technical problem that needs to be solved urgently. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a UHPC board and concrete combined frame slab bridge and a construction method thereof in view of the deficiencies in the prior art.

[0009] In order to solve the above technical problems, a UHPC plate and concrete combined frame slab bridge of the present invention comprises a plurality of piers arranged at equal intervals, cap beams are provided on the piers, UHPC plate girders are built between the cap beams, concrete is poured on the UHPC plate girders and connected to the cap beams by concrete, negative bending moment zone UHPC prefabricated panels are correspondingly provided at the ends of adjacent UHPC plate girders, and the two ends of the negative bending moment zone UHPC prefabricated panels are respectively connected to the concrete at the ends of the UHPC plate girders on both sides.

[0010] As a possible implementation, further, the UHPC plate truss includes a prefabricated groove UHPC plate, on which steel truss stiffening ribs and angle steel connectors are arranged at intervals, and the steel truss stiffening ribs and angle steel connectors are fixedly connected to the prefabricated groove UHPC plate by anchor bolts.

[0011] As a possible implementation manner, further, the steel truss stiffening rib includes an upper chord and a lower chord arranged in parallel, a web member is arranged between the upper chord and the lower chord, and two ends of the web member are fixedly connected to the upper chord and the lower chord respectively through node plates.

[0012] As a possible implementation manner, further, the lower chord is evenly provided with reserved bolt holes for connection with anchor bolts.

[0013] As a possible implementation manner, further, the negative bending moment zone UHPC prefabricated panels arranged at the ends of each group of adjacent UHPC plate trusses are arranged in parallel in multiple groups, and one side of the negative bending moment zone UHPC prefabricated panels is provided with prefabricated panel connecting steel bars for inserting concrete poured on the UHPC plate trusses.

[0014] As a possible implementation manner, further, the cap beam is provided with a cap beam extending connecting steel bar for inserting into the cap beam for pouring concrete on the cap beam.

[0015] As a possible implementation manner, further, the angle steel connector is provided with bolt holes and structural holes.

[0016] A construction method of a UHPC board and concrete combined frame slab bridge specifically comprises the following steps:

[0017] S1. Complete the construction of bridge piers and cap beams on site, and reserve the cap beam extension connecting steel bars on the top of the cap beam;

[0018] S2. Prefabricate the trough UHPC panels and negative moment zone UHPC prefabricated panels in the factory, and weld the steel sections and steel plates to form steel truss stiffening ribs. Pre-embed anchor bolts in the trough UHPC panels, reserve bolt holes on the lower chord of the steel truss stiffening ribs, reserve bolt holes and structural holes on the angle steel connectors, and pre-embed the prefabricated panel connecting steel bars in the negative moment zone UHPC prefabricated panels.

[0019] S3. Assemble the prefabricated grooved UHPC panels and steel truss stiffening ribs together through anchor bolts to form UHPC plate trusses. Then anchor the angle steel connectors to the bottom of the UHPC plate trusses with anchor bolts. Then hoist the UHPC plate trusses as a single span and place them on the cap beams of adjacent bridge piers. Then use the UHPC plate trusses as permanent formwork without setting up brackets. Pour ordinary concrete in the UHPC plate trusses and connect the steel bars to the cap beams through the cap beams. At the same time, the UHPC plate trusses and the ordinary concrete inside them form a combined structure, which bears force together during operation.

[0020] S4. When the cast-in-place ordinary concrete of the main beam has not solidified, place multiple UHPC precast panels in the negative bending moment area of ​​the composite bridge and arrange them closely. Use external force to squeeze the UHPC precast panels in the negative bending moment area so that the connecting steel bars are inserted into the cast-in-place ordinary concrete of the main beam. Sufficiently vibrate to ensure that the UHPC precast panels in the negative bending moment area and the cast-in-place ordinary concrete of the main beam fit tightly without bubbles. After the cast-in-place ordinary concrete of the main beam solidifies and is fully cured, the entire bridge is formed into a whole and the construction is completed.

[0021] The present invention adopts the above technical solution and has the following beneficial effects:

[0022] (1) Good crack resistance and excellent stress-bearing performance: The key stress-bearing parts of the structure of the present invention are wrapped with UHPC of a certain thickness and participate in the joint stress of the structure. The crack resistance and mechanical properties of UHPC far exceed those of ordinary concrete, which can effectively enhance the crack resistance and mechanical properties of the entire structure.

[0023] (2) Strong durability: UHPC has a dense structure, which can effectively prevent external harmful substances from entering its matrix. The parts of the present invention that are prone to cracking due to stress are protected by UHPC, thereby effectively improving the overall durability of the structure.

[0024] (3) Strong structural integrity: UHPC and ordinary concrete (NC) have excellent bonding strength and anti-seepage durability. The angle steel connector is designed with structural holes, and the steel truss stiffening ribs are designed in the form of trusses, which are more reliable when combined with the cast-in-place ordinary concrete of the main beam. This can ensure that the UHPC layer and the NC structure work well together and avoid peeling damage.

[0025] (4) Convenient and fast construction: The present invention uses UHPC plate trusses as a non-disassembly formwork to cast ordinary concrete for the main beam, without the need to set up a bracket. The UHPC plate trusses can be hoisted as a single span and can participate in the overall stress of the structure without disassembly. The construction is very convenient and fast.

[0026] (5) Good economy: Although the unit price of the UHPC material used in the present invention is relatively high, the amount used is relatively small compared to the overall structure, so it has little impact on the cost of the overall structure. In addition, the construction method used in the present invention is convenient and does not require the erection of a scaffold. Therefore, it can greatly save the construction cost generated by the erection of the scaffold and the treatment of the soft soil foundation at the bottom of the scaffold. In general, the cost of the entire bridge project will be reduced.

[0027] In summary, the UHPC board designed in the present invention has better stress-bearing performance, better durability, more convenient construction process, and lower construction cost compared with the cast-in-place ordinary concrete structure and the concrete combined frame slab bridge. It has very significant advantages and is very suitable for the construction of bridges in coastal splash zones. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0029] Figure 1 It is a schematic plan view of a UHPC board and concrete combined frame slab bridge of the present invention;

[0030] Figure 2 It is a schematic elevation diagram of a UHPC board and concrete combined frame slab bridge of the present invention;

[0031] Figure 3 This is a large-scale drawing of the connection of the negative bending moment area at the top of the main beam pier of the present invention;

[0032] Figure 4 It is a schematic cross-sectional view of the main beam of the UHPC board and concrete combined frame slab bridge of the present invention;

[0033] Figure 5 This is a schematic diagram of the prefabricated grooved UHPC panel of the present invention;

[0034] Figure 6 This is a schematic elevation diagram of the steel truss stiffening rib of the present invention;

[0035] Figure 7 This is a schematic diagram of the cross section of the steel truss stiffening rib of the present invention;

[0036] Figure 8 It is a three-dimensional schematic diagram of the angle steel connecting piece of the present invention;

[0037] Fig. 9 This is a large elevation drawing of the joint between the grooved UHPC plate and the steel truss stiffening ribs of the present invention;

[0038] Fig.10 This is a large-scale drawing of the cross section of the joint between the grooved UHPC plate and the steel truss stiffening rib of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0040] like Figure 1 , 2 As shown in Figures 3 and 4, the UHPC plate and concrete combined frame slab bridge proposed in the present invention is composed of a prefabricated trough UHPC plate 1, a steel truss stiffening rib 8, an angle steel connector 11, a UHPC prefabricated plate 3 in a negative bending zone, a main beam cast-in-place ordinary concrete 2, a bridge pier 6 and a cap beam 5; wherein the bridge pier 6 and the cap beam 5 are ordinary concrete components, which are cast-in-place on site, and a cap beam extending connecting steel bar 7 is reserved at the top of the cap beam 5 for strengthening the connection between the main beam cast-in-place ordinary concrete 2 and the cap beam 5; the prefabricated trough UHPC plate 1, the steel truss stiffening rib 8 and the angle steel connector 11 are all prefabricated components, which are prefabricated in a factory; Figure 5 , 6 As shown in , 7, 8, 9, and 10, the prefabricated groove UHPC plate 1 consists of a bottom plate and a side plate. When prefabricated in the factory, anchor bolts 9 are embedded in the bottom plate to connect the steel truss stiffening rib 8 and the angle steel connector 11; the steel truss stiffening rib 8 is welded by an upper chord 12, a lower chord 13, a web member 14, and a node plate 15. When prefabricated in the factory, a series of bolt holes 10 are reserved on the lower chord. The prefabricated groove UHPC plate 1 and the steel truss stiffening rib 8 are assembled to form a UHPC plate truss through anchor bolts 9. When assembling, align the anchor bolts 9 with the bolt holes 10 reserved for the stiffening ribs and tighten the anchor bolts 9; bolt holes 17 and structural holes 16 are reserved on the angle steel connector 11, which are anchored and connected to the UHPC through anchor bolts 9. The bottom of the plate truss; the main beam cast-in-place ordinary concrete 2 is poured using the UHPC plate truss as a template, without the need for additional support. The UHPC plate truss is hoisted and installed as a single-span on the cap beam 5 of the adjacent pier 6. Then, after the steel bars are tied, the main beam is cast-in-place ordinary concrete 2 is poured inside the UHPC plate truss and on the top of the cap beam to form the main beam and consolidate the main beam to the lower structure as a whole; the UHPC precast slab 3 in the negative bending moment area is divided into multiple slabs in the transverse direction of the bridge. When prefabricated in the factory, precast slab connecting steel bars 4 are reserved on the slabs. The UHPC precast slab 3 in the negative bending moment area is to improve the crack resistance of the negative bending moment area of ​​the combined continuous frame slab bridge. The precast slab connecting steel bars 4 can make the interface bonding between the UHPC precast slab 3 in the negative bending moment area and the main beam cast-in-place ordinary concrete 2 more reliable.

[0041] The present invention further includes a construction method of a UHPC board and concrete combined frame slab bridge, referring to Figures 1 to 10The specific construction steps are as follows:

[0042] S1. Complete the construction of the bridge pier 6 and the cap beam 5 on site, and reserve the cap beam extending connecting steel bars 7 on the top of the cap beam 5.

[0043] S2. Prefabricate the groove UHPC plate 1 and the negative moment zone UHPC prefabricated plate 3 in the factory, weld the steel section and the steel plate to form the steel truss stiffening rib 8, embed anchor bolts 9 on the groove UHPC plate 1, reserve bolt holes 10 on the lower chord of the steel truss stiffening rib 8, reserve bolt holes 17 and structural holes 16 on the angle steel connector 11, and embed the prefabricated plate connecting steel bars 4 on the negative moment zone UHPC prefabricated plate 3.

[0044] S3. Assemble the prefabricated grooved UHPC plate 1 and the steel truss stiffening rib 8 together through the anchor bolts 9. During assembly, align the bolt holes 10 reserved on the steel truss stiffening rib 8 with the anchor bolts 9 on the grooved UHPC plate 1, and tighten the anchor bolts 9 to complete the assembly to form the UHPC plate truss. Then anchor the angle steel connector 11 to the bottom of the UHPC plate truss with the anchor bolts 9. The assembly method is the same as that of the steel truss stiffening rib. Then hoist the UHPC plate truss as a single span and place it on the cap beam of the adjacent pier. The lap length of the UHPC plate truss and the cap beam 5 is 10 to 20 cm. Then, use the UHPC plate truss as a permanent formwork without setting up a bracket. Pour ordinary concrete 2 in the UHPC plate truss and connect the steel bars 7 and the cap beam 5 through the cap beam extension to consolidate. At the same time, the UHPC plate truss and the ordinary concrete 2 therein form a combined structure, which bears force together during operation.

[0045] In step S3, when pouring the cast-in-place ordinary concrete 2 of the main beam, in order to ensure that the UHPC plate truss has sufficient bearing capacity and stability during the construction process, the cast-in-place ordinary concrete 2 of the main beam can be divided into two layers and poured in sequence, that is, first pour a layer of ordinary concrete of a certain thickness, and after this layer of concrete forms strength and the UHPC plate truss forms a combined structure, pour the second layer of ordinary concrete. This pouring method can prevent the UHPC plate truss from being damaged due to the excessive wet weight of ordinary concrete, and can effectively ensure the safety of the construction process.

[0046] S4. When the cast-in-place ordinary concrete 2 of the main beam has not yet solidified, the prefabricated UHPC prefabricated panels 3 are placed in the negative bending moment area of ​​the composite bridge and arranged closely. The UHPC prefabricated panels 3 in the negative bending moment area are squeezed by external force to make the connecting steel bars 4 inserted into the cast-in-place ordinary concrete 2 of the main beam, and they are fully vibrated to make the UHPC prefabricated panels 3 in the negative bending moment area and the cast-in-place ordinary concrete 2 of the main beam fit tightly without bubbles. After the cast-in-place ordinary concrete 2 of the main beam solidifies and is fully cured, the UHPC plate truss, the UHPC prefabricated panels 3 in the negative bending moment area, and the cap beam 5 are connected together through the cast-in-place ordinary concrete 2 of the main beam, and the whole bridge forms a whole, which jointly bears the external load and completes the construction.

[0047] The above are embodiments of the present invention. For ordinary technicians in this field, according to the teachings of the present invention, all equivalent changes, modifications, substitutions and variations made within the scope of the patent application of the present invention without departing from the principles and spirit of the present invention should fall within the scope of the present invention.

Claims

1. A UHPC board and concrete combined frame slab bridge, comprising a plurality of piers arranged at equal intervals, with cap beams provided on the piers, characterized in that: UHPC plate trusses are arranged between the cap beams, concrete is poured on the UHPC plate trusses and connected to the cap beams by concrete, and negative moment zone UHPC prefabricated panels are arranged at the ends of adjacent UHPC plate trusses, and both ends of the negative moment zone UHPC prefabricated panels are respectively connected to the concrete at the ends of the UHPC plate trusses on both sides; the UHPC plate trusses include prefabricated groove-type UHPC panels, and steel truss stiffening ribs and angle steel connectors are arranged on the prefabricated groove-type UHPC panels at intervals, and the prefabricated groove-type UHPC panels are composed of a bottom plate and a side plate, and anchor bolts are embedded in the bottom plate during prefabrication in the factory, and the steel truss stiffening ribs and angle steel connectors are fixedly connected to the prefabricated groove-type UHPC panels by anchor bolts.

2. The UHPC board and concrete combined frame slab bridge according to claim 1, characterized in that: The steel truss stiffening rib comprises an upper chord and a lower chord arranged in parallel, a web member is arranged between the upper chord and the lower chord, and two ends of the web member are respectively fixedly connected to the upper chord and the lower chord through node plates.

3. The UHPC board and concrete combined frame slab bridge according to claim 2, characterized in that: The lower chord is evenly provided with reserved bolt holes for connection with anchor bolts.

4. The UHPC board and concrete combined frame slab bridge according to claim 1, characterized in that: The negative bending moment zone UHPC prefabricated panels arranged at the ends of each group of adjacent UHPC plate trusses are arranged in multiple groups in parallel, and one side of the negative bending moment zone UHPC prefabricated panels is provided with prefabricated panel connecting steel bars for inserting concrete poured on the UHPC plate trusses.

5. The UHPC board and concrete combined frame slab bridge according to claim 1, characterized in that: The cap beam is provided with cap beam extending connecting steel bars for inserting into the cap beam for pouring concrete.

6. The UHPC board and concrete combined frame slab bridge according to claim 1, characterized in that: The angle steel connecting piece is provided with bolt holes and structural holes.

7. A construction method for a UHPC board and concrete combined frame slab bridge, characterized in that: The specific steps include: S1. Complete the construction of bridge piers and cap beams on site, and reserve the cap beam extension connecting steel bars on the top of the cap beam; S2. Prefabricate the trough UHPC panels and negative moment zone UHPC prefabricated panels in the factory, and weld the steel sections and steel plates to form steel truss stiffening ribs. Pre-embed anchor bolts in the trough UHPC panels, reserve bolt holes on the lower chord of the steel truss stiffening ribs, reserve bolt holes and structural holes on the angle steel connectors, and pre-embed the prefabricated panel connecting steel bars in the negative moment zone UHPC prefabricated panels. S3. Assemble the prefabricated grooved UHPC panels and steel truss stiffening ribs together through anchor bolts to form UHPC plate trusses. Then anchor the angle steel connectors to the bottom of the UHPC plate trusses with anchor bolts. Then hoist the UHPC plate trusses as a single span and place them on the cap beams of adjacent bridge piers. Then use the UHPC plate trusses as permanent formwork without setting up brackets. Pour ordinary concrete in the UHPC plate trusses and connect the steel bars to the cap beams through the cap beams. At the same time, the UHPC plate trusses and the ordinary concrete inside them form a combined structure, which bears force together during operation. S4. When the cast-in-place ordinary concrete of the main beam has not solidified, place multiple UHPC precast panels in the negative bending moment area of ​​the composite bridge and arrange them closely. Use external force to squeeze the UHPC precast panels in the negative bending moment area so that the connecting steel bars are inserted into the cast-in-place ordinary concrete of the main beam. Sufficiently vibrate to ensure that the UHPC precast panels in the negative bending moment area and the cast-in-place ordinary concrete of the main beam fit tightly without bubbles. After the cast-in-place ordinary concrete of the main beam solidifies and is fully cured, the entire bridge is formed into a whole and the construction is completed.

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