CN103938546B - Simply supported non-uniform construction method - Google Patents

Abstract

The invention discloses a simply-supported variable continuous construction method, which is specifically as follows: pouring bridge piers, and setting mounting supports on the top of the bridge piers; hoisting prefabricated inverted T-shaped cover beams on the mounting supports; hoisting small box girders and putting them on hold On the flange of the prefabricated inverted T-shaped cover beam, make it into a simply supported state; pour concrete into the gap between the web of the prefabricated inverted T-shaped cover beam and the small box girders on both sides to form a wet joint, At the same time, the threading and tensioning of the negative moment steel tendons between the upper part of the web and the top plates of the small box girders on both sides are completed. The simply supported variable continuous structure of the present invention is also formed through the above construction method. The invention has the advantages of reliable structure and good durability of common simply supported variable continuous structure, and can also improve the bridge landscape, greatly reduce the structural height from the bridge deck to the bottom of the girder, save the clearance under the bridge, and simplify the construction steps , a simply supported variable continuous construction method and its structure that shortens the construction period.

Description

Simply supported variable continuous construction method

technical field

The invention relates to the technical field of bridge structure and construction, in particular to a simply supported variable continuous construction method.

Background technique

The simply supported beam structure system with continuous bridge deck is often at a disadvantage in the competition with the continuous beam structure system due to the disadvantages of easy cracking of the bridge deck. At the same time, due to the complex and cumbersome construction of cast-in-place concrete continuous beams, people have always hoped to combine the batch prefabrication of simply supported beams with the superior performance of continuous beams, and to speed up the construction of continuous beams by means of mass prefabrication of beams or slabs. The cumbersome formwork process is omitted, resulting in the "simply supported first and then continuous" construction method of prefabricating the entire span beam and slab, erecting it in place, pouring concrete at the end and stretching the prestress to make it continuous. The system is called "simply supported first and then continuous structural system". At present, the simple-supported-to-continuous structure accounts for a large proportion of the porous medium-span bridges in the bridges of high-grade highways (especially expressways).

Combining the two structural systems of continuous bridge deck and simply supported variable continuous structure, the comparison of the advantages and disadvantages of the schemes is shown in the following table:

It can be seen from the above table that the simply supported variable continuous structure system is slightly inferior to the bridge deck continuous scheme in terms of construction speed and project cost, and is superior to bridge decks in terms of structural stiffness, durability, bridge landscape, and engineering applications. Continuity program. The bridge on the expressway is a road section with many heavy vehicles, which has higher requirements on the reliability and durability of the structure. To sum up, the simply supported variable continuous small box girder is a better structural solution.

The construction process of the common simply supported variable continuous structure is generally simple supported first and then continuous bridge construction. The specific process is as follows:

① The prefabrication of the main girder adopts factory production. When the concrete strength of the girder and slab reaches 100% of the design strength, the prestressed steel strands in the positive bending moment area are stretched, and the tunnel grouting is performed after the stretching is completed.

②Before the steel strands in the negative bending moment area are stretched, set up temporary supports, and install the beams and slabs on the temporary supports hole by hole to make it a simply supported state, and install the permanent supports in place at the same time.

③ Connect the steel bars in the joint section, set the joint steel bundle bellows and pass the steel strands in the bellows, and pour concrete when the daily temperature is ≤ 15°C. When the strength of the concrete reaches 100% of the design strength, the strands in the negative bending moment area are stretched and grouted.

④Remove the temporary support to complete the transition from simple support to continuous system.

The simply supported variable continuous structure formed according to the above process has the following advantages:

①It has the advantages of high rigidity, small deformation, less expansion joints, comfortable driving, and good structural durability.

②The prestressed steel tendons of simply supported beams are stretched in the factory, while the layout and tension of prestressed steel tendons in the negative moment area are all carried out on the main beam. Only hoisting equipment is needed to lift the main beam, which reduces construction equipment and It can avoid obstacles on the ground caused by tensioning the prestressed steel strands.

③Prefabricated beams can use standard components for factory unified production and management, which is beneficial to technical operations, saves construction time, shortens the construction period, and improves economic benefits.

The currently applied small box girder simply supported variable continuous structure system has obvious advantages in terms of structural rigidity, durability, and engineering application, but there are also problems such as excessive cover beam height and relatively long construction period. The conventional simply supported variable continuous structure still has the following deficiencies:

① It is necessary to design a large cover beam. If a rectangular cover beam is used, the calculated cover beam height will be about 3.8m. In order to meet the clearance under the bridge, the scheme requires the bridge deck elevation to be raised by about 2m; moreover, the cover beam is bulky and oppressive. Strong sense, poor landscape effect.

② Generally, the system conversion of the support is required, and the construction is relatively troublesome.

③ The workload of steel bar binding and concrete pouring of the beam is relatively large, which will cause the extension of the construction period.

4. There is also another kind of uncapped beam on the top of the pier, the prefabricated small box girder is first supported on the temporary support, and the method of removing the support after the beam (under the support) is poured. However, this construction method has high requirements for the stability of the support, and the construction and removal of the temporary support is labor-intensive and material-intensive. The construction will also seriously affect the traffic.

Therefore, for the current simply supported variable continuous construction method and its structure, it is necessary to carry out research and improvement for further optimization. Those skilled in the art have been devoting themselves to the development of a simple-support variable-continuous construction method and its structure, which can overcome the above-mentioned deficiencies, and not only have the advantages of the common simple-support variable-continuous structure, such as reliable structure and good durability, but also improve the bridge landscape, The height of the structure from the bridge deck to the bottom of the cap beam is greatly reduced, the clearance under the bridge is saved, the construction steps are simplified, and the construction period is shortened.

Contents of the invention

In view of the deficiencies of the above-mentioned prior art, the present invention proposes a simple-supported variable continuous structure that has the advantages of reliable structure and good durability, and can also improve the bridge landscape and greatly reduce the structural height from the bridge deck to the bottom of the girder. , save the clearance under the bridge, simplify the construction steps, and shorten the construction period of the simply supported variable continuous construction method and its structure.

In order to achieve the above object, the present invention provides a simple-support variable continuous construction method, which is as follows: pouring bridge piers, and setting mounting supports on the top of the bridge piers; hoisting the prefabricated inverted T-shaped cover beams on the mounting supports; Put the small box girder hoist on the wing plate of the prefabricated inverted T-shaped cover beam to make it a simply supported state; pour the gap between the web of the prefabricated inverted T-shaped Concrete forms wet joints, and at the same time completes the penetration and tensioning of the negative moment steel tendons between the upper part of the web and the top plates of the small box girders on both sides.

As a further improvement of the present invention, after the prefabricated inverted T-shaped cover beam is hoisted to the installation support, the first batch of prestressed steel tendons is stretched along the length direction of the web.

As a further improvement of the present invention, after the small box girder is hoisted and placed on the flange of the prefabricated inverted T-shaped cover girder, the second batch of prestressed steel tendons is stretched along the length direction of the web.

As a further improvement of the present invention, after the negative moment steel tendons are threaded and stretched, the third batch of prestressed steel tendons is stretched in the wet joint.

As a further improvement of the present invention, after the tensioning of the third batch of prestressed steel beams is completed, a reinforced concrete pavement layer, a waterproof layer and an asphalt concrete pavement layer are sequentially laid on the upper surface of the small box girder from bottom to top .

The present invention also proposes a simply supported variable continuous structure, which includes: bridge pier, installation support, small box girder and prefabricated inverted T-shaped cover beam, the installation support is arranged on the top of the bridge pier, and the prefabricated inverted T shaped cover beam is arranged on the installation support, and the small box girder rests on the wing plates of the prefabricated inverted T-shaped cover beams on two adjacent piers, and the small box girder and the prefabricated inverted T-shaped cover beam They are connected as a whole by cast-in-place concrete, and negative moment steel beams are stretched between the upper web of the prefabricated inverted T-shaped cover beam and the top plates of the small box girders on both sides.

As a further improvement of the present invention, prestressed steel beams are stretched along the length direction of the web in the prefabricated inverted T-shaped cap beam.

As a further improvement of the present invention, prestressed steel beams are stretched in the concrete filled between the web of the prefabricated inverted T-shaped cover beam and the small box girders on both sides.

As a further improvement of the present invention, the upper surface of the small box girder is successively laid with a reinforced concrete pavement layer, a waterproof layer and an asphalt concrete pavement layer.

As a further improvement of the present invention, a rubber strip is provided between the small box girder and the wing plate of the prefabricated inverted T-shaped cover girder.

The beneficial effects of simply supported variable continuous structure and construction method thereof of the present invention are as follows:

1. The structure of the present invention is reliable and durable, and the cover beam adopted by the simply supported variable continuous structure is a prefabricated inverted T-shaped cover beam, which greatly reduces the structural height from the bridge deck to the bottom of the cover beam, saves the clearance under the bridge, and improves The bridge landscape is clear, and the construction method of the present invention is adopted, the construction period is short, the construction steps are simple and effective, and the labor intensity is small.

2. The cover beam of the present invention is prefabricated in a factory, and the way of on-site hoisting and installation will minimize the negative impact of the cover beam construction on ground traffic and avoid adverse effects on ground traffic. At the same time, the amount of concrete pouring required in the construction process is small, so the workload can be further effectively reduced and the construction period can be shortened.

3. In the present invention, negative moment steel strands and prestressed steel strands are inserted between the small box girder and the prefabricated inverted T-shaped cover beam, which further improves the reliability of the present invention.

The idea, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings, so as to fully understand the purpose, features and effects of the present invention.

Description of drawings

Fig. 1 is the construction evolution diagram of the simply supported variable continuous construction method in this embodiment.

Fig. 2 is a structural schematic diagram of the simply supported variable continuous structure in this embodiment.

FIG. 3 is a partial enlarged view of A in FIG. 2 .

detailed description

Fig. 1 is the construction evolution diagram of the simply supported variable continuous structure construction method in this embodiment. This embodiment proposes a simple-support variable-continuous construction method, combined with that shown in Figure 1, the specific construction process is as follows:

Step 1: pouring the bridge pier 1, setting the installation support 3 on the top of the bridge pier 1; hoisting the prefabricated inverted T-shaped cover beam 2 on the installation support 3.

Step 2: hoisting and placing the small box girder 4 on the wing plate 22 of the prefabricated inverted T-shaped cover beam 2 to make it a simply supported state.

Step 3: Pour concrete into the gap between the web 21 of the prefabricated inverted T-shaped cover beam 2 and the small box girders 4 on both sides to form a wet joint 6, and at the same time complete the joint between the upper part of the web 21 and the top plates of the small box girders on both sides. Threading and tensioning of negative moment steel beam 5.

Through the above three steps, the simply supported variable continuous construction can be completed. It can be seen that this construction method simplifies the construction steps and greatly shortens the construction period.

As a further implementation of this embodiment, after the prefabricated inverted T-shaped cover beam 2 in the first step is hoisted onto the mounting support 3, the first batch of prestressed steel beams 8 are tensioned along the length direction of the web 21. pull. Exemplarily, as shown in FIG. 1 , the first batch of prestressed steel tendons 8 is arranged in two vertical rows, and each vertical row includes three prestressed steel tendons.

As a further implementation of this embodiment, after the small box girder 4 in the second step is hoisted and placed on the wing plate 22 of the prefabricated inverted T-shaped cover beam 2, the second batch of prestressed steel tendons is carried out along the length direction of the web plate 21. 7 tensegrity. Exemplarily, as shown in FIG. 1 , the second batch of prestressed steel tendons 7 is three prestressed steel tendons arranged in a vertical row between the two vertical rows of the first batch of prestressed steel tendons 8 .

As a further implementation of this embodiment, after the completion of the threading and tensioning of the negative moment steel tendons 5 in the step 3, the third batch of prestressed steel tendons 9 is stretched in the wet joint 6 . Exemplarily, as shown in FIG. 1 , the third batch of prestressed steel tendons 9 is divided into two vertical rows, and each vertical row includes three prestressed steel tendons, and each of the left and right wet joints 6 is provided with a corresponding vertical row. Then proceed to step 4: laying a reinforced concrete pavement layer, a waterproof layer and an asphalt concrete pavement layer sequentially on the upper surface of the small box girder 4 from bottom to top. Of course, in other specific embodiments, the construction of other auxiliary facilities can also be carried out on the small box girder 4 according to the construction design needs, such as the construction of expansion joints or other construction bridge auxiliary facilities, which is a general prior art in the art. Those skilled in the art can easily construct the structure, and details will not be repeated here.

According to the above construction method, this embodiment also proposes a simply supported variable continuous structure, as shown in Figure 2 and Figure 3, the simply supported variable continuous structure of this embodiment includes: pier 1, mounting support 3, small box girder 4 and the prefabricated inverted T-shaped cover beam 2, the installation support 3 is set on the top of the bridge pier 1, the prefabricated inverted T-shaped cover beam 2 is set on the installation support 3, and the small box girder 4 is placed on the prefabricated inverted structure of two adjacent bridge piers 1 On the wing plate 22 of the T-shaped cover beam 2, the small box girder 4 and the prefabricated inverted T-shaped cover beam 2 are connected as a whole through cast-in-place concrete, and the upper part of the web 21 of the prefabricated inverted T-shaped Negative bending moment steel beams 5 are stretched between the top plates of beams 4 .

As a further implementation of this embodiment, the prefabricated inverted T-shaped cover girder 2 is stretched with prestressed steel tendons along the length direction of the web 21 . Exemplarily, in the web 21 of the prefabricated inverted T-shaped cover beam 2 of this embodiment, the first batch of prestressed steel tendons 8 and the second batch of prestressed steel tendons 7 are stretched to form three rows and three rows of prestressed steel tendons. bundle.

As a further implementation of this embodiment, prestressed steel tendons are stretched in the concrete filled between the web 21 of the prefabricated inverted T-shaped cover beam 2 and the small box girders 4 on both sides. The prestressed steel tendons here refer to the third batch of prestressed steel tendons 9 arranged in the wet joint 6 .

As a further implementation of this embodiment, a rubber strip is provided between the small box girder 4 and the wing plate 22 of the prefabricated inverted T-shaped cover girder 2 .

As a further implementation of this embodiment, the upper surface of the small box girder 4 is successively laid with a reinforced concrete pavement layer, a waterproof layer and an asphalt concrete pavement layer from bottom to top. Of course, in other specific embodiments, the construction of other auxiliary facilities can also be carried out on the small box girder 4 according to the construction design needs, such as the construction of expansion joints or other construction bridge auxiliary facilities, which is a general prior art in the art. Those skilled in the art can easily construct the structure, and details will not be repeated here.

The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make many modifications and changes according to the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art shall be within the scope of protection defined by the claims.

Claims (5)

1. a Simply supported non-uniform construction method, is characterized in that:

Build bridge pier, erection support is set at described pier coping portion;

Prefabricated inverted T-shaped bent cap is lifted on described erection support;

Small box girder lifting is shelved on the wing plate of described prefabricated inverted T-shaped bent cap, makes it to become simply-supported state;

Gap concreting between the web and both sides small box girder of described prefabricated inverted T-shaped bent cap forms wet seam, completes wearing and stretch-draw of the hogging moment steel bundle between described web top and both sides small box girder top board simultaneously.

2. Simply supported non-uniform construction method as claimed in claim 1, is characterized in that: described prefabricated inverted T-shaped bent cap is lifting after to described erection support, and the length direction along web carries out the stretch-draw of first prestressed strand.

3. Simply supported non-uniform construction method as claimed in claim 2, is characterized in that: after small box girder lifting is shelved on the wing plate of described prefabricated inverted T-shaped bent cap, the length direction along web carries out the stretch-draw of second batch prestressed strand.

4. Simply supported non-uniform construction method as claimed in claim 3, is characterized in that: complete hogging moment steel bundle wear with stretch-draw after, in described wet seam, carry out the stretch-draw of the 3rd batch of prestressed strand.

5. Simply supported non-uniform construction method as claimed in claim 4, it is characterized in that: after the stretch-draw completing the 3rd batch of prestressed strand, lay reinforced concrete pavement layer, waterproofing course and asphalt concrete pavement layer successively from lower to upper at the upper surface of described small box girder.