CN106320192A - Beam section replacement reinforcement method for large-span concrete continuous beam bridge - Google Patents

Abstract

The invention discloses a beam section replacement and reinforcement method for a long-span concrete continuous beam bridge, which comprises the following steps: cutting and lifting the replaced concrete beam section from the concrete continuous beam's span to be reinforced; Two fixed sections are formed, steel-concrete joints are arranged on the cutting end faces of the two fixed sections; steel beams are hoisted between the two steel-concrete joints and connected with the steel-concrete joints. By replacing the damaged concrete beam sections with steel beams, it can completely solve the mid-span deflection, cracking and other diseases, improve the alignment of the bridge deck, and also improve the overall bearing capacity of the concrete continuous beam bridge; it is safe, reliable, and easy to operate. With the advantages of good performance and strong practicability, it can be used for maintenance and reinforcement of long-span concrete continuous beam (rigid frame) bridges.

Description

A Beam Segment Replacement Reinforcement Method for Long-span Concrete Continuous Beam Bridge

technical field

The invention relates to the reinforcement technology of concrete bridges, in particular to a beam section replacement reinforcement method for long-span concrete continuous beam bridges.

Background technique

The construction of long-span concrete continuous beam (rigid frame) bridges began in the 1970s in China. Because of its good adaptability and economy, it quickly became the most competitive bridge type within the range of 60m to 300m, and was widely used. Large highway bridges and municipal viaducts. Due to the imperfection of bridge structure design and material theory at that time, the increasing traffic volume, the limitation of maintenance management and the harsh natural conditions in recent years, various problems and structural diseases of some bridges have been caused, mainly manifested as cracking (" web cracking", "bottom plate cracking", "roof cracking") and "mid-span deflection", the light ones will affect the durability and aesthetics of the structure, and the severe ones will limit the normal use of the bridge or cause the structure to lose its bearing capacity. The reinforcement and maintenance of old and dangerous bridges has attracted worldwide attention.

At present, there are mainly three types of bridge reinforcement technologies. The first is to increase the dead load reinforcement method, which increases the bearing capacity and increases the dead load of the structure at the same time. It mainly includes the method of pasting steel plates and the method of increasing the section. Most of them are passive reinforcement methods, and the reinforcement efficiency is low. The second is to basically maintain the constant load reinforcement method, such as changing the structural system reinforcement method, external prestressing reinforcement method, etc., which are active reinforcement methods. Theoretically, the reinforcement effect is better, but the durability and reliability need to be improved. The third is to reduce the dead load reinforcement method, which mainly includes reducing bridge deck pavement and replacing light guardrails. It is an active reinforcement method, but because most of it is to reduce the weight of auxiliary structures, the reinforcement effect is limited.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned technical deficiencies, and propose a beam segment replacement and reinforcement method for long-span concrete continuous beam bridges, which can not only actively reinforce and reduce dead loads, but also start with the method of changing the structural system, thoroughly Solve problems such as mid-span deflection and beam segment cracking.

In order to achieve the above object, the technical solution of the present invention provides a beam segment replacement and reinforcement method for long-span concrete continuous beam bridges, comprising the following steps:

S1. Cut and lift the replacement concrete beam section from the span of the concrete continuous beam to be reinforced;

Said step S1 comprises:

S11. Remove the bridge deck pavement and ancillary facilities for the replacement concrete beam section, partially reinforce the concrete continuous beam, and set up a supporting system and a hoisting system connected to the supporting system on the two fixed sections, and pass the hoisting system Lift and fix the replacement concrete beam section;

S12. The two ends of the replacement concrete beam section are cut symmetrically in a figure-eight shape, and the side-span beam body is protected by temporary external prestressing or active stress support under the bridge to ensure the safety of the demolition process of the middle beam section;

S13. After the cutting is completed, control the hoisting system to hoist and lower the cut replacement concrete beam section to the corresponding placement platform.

S2. Two fixed sections are formed after the reinforced span is cut, and steel-concrete joints are arranged on the cut end faces of the two fixed sections;

S3. Lift the steel beam between the two steel-concrete joints and connect with the steel-concrete joints.

According to the above scheme, the local reinforcement in step S11 includes: stretching the external prestress on the two adjacent spans of the span to be reinforced, pouring a diaphragm in the box girder of the fixed section, and placing a diaphragm near the cut end surface of the fixed section Drill holes to the prestressed tendons, and grout the prestressed tendons.

According to the above scheme, the step S12 also includes setting an anti-impact cantilever on the cutting end surface of the fixed section when cutting to a set thickness, and setting a hydraulic device at the front end of the anti-impact cantilever, and one end of the hydraulic device abuts the replacement concrete beam section cutting end face.

According to the above scheme, the step S13 also includes monitoring the relative heights of the four corners of the replaced concrete beam section during the hoisting and lowering process, so that the vertical relative height between any two corners of the replaced concrete beam section is less than 10 mm.

According to the above scheme, the step S2 includes:

S21. Chisel away the concrete within 1m of the fixed section close to its cut end face, and reshape, chisel, clean, cut and shear the beam end of the fixed section after the concrete has been chiseled out, and retain the original supporting steel bars and prestressed tendon;

S22. Hoist the steel-concrete joint to the installation position, and fix it with the concrete chiseled end of the fixed section;

S23. Concrete is poured and cured at the connection between the steel-concrete joint and the fixed section, and the prestress is stretched after the concrete reaches the set strength.

The steel-concrete joint is composed of the concrete beam section of the steel-concrete joint and the steel box beam section of the steel-concrete joint. The steel structure of the steel-concrete joint is placed vertically first, the filling concrete is poured, and then the steel-concrete joint is placed horizontally. Ship to the bridge site, and finally the top plate, bottom plate and web at the end of the steel box girder are made into double wall plates, and the filled concrete and the top plate, bottom plate and web of the adjacent concrete box girder section are passed through the PBL shear plate, prefabricated Stressed steel bars are connected with ordinary steel bars and extended forward to connect them with concrete diaphragms, prestressed short beams are anchored to concrete diaphragms and steel box diaphragms, and prestressed long beams are anchored to concrete diaphragms On the tooth blocks of the top plate and the bottom plate of the rear beam section.

According to the above scheme, the step S3 includes:

S31, making a steel beam matching the two steel-concrete joints, transporting the steel beam to the bottom of the steel-concrete joint and hoisting it between the two steel-concrete joints;

S32. Fixing one end of the steel beam to one of the steel-concrete joints through high-strength bolts and then welding, and then fixing the other end of the steel beam to the other steel-concrete joint through high-strength bolts and then welding.

S33. Tension steel beam prestressed.

According to the above scheme, in the step S33, the two ends of the steel bundle used for the tension and prestressing of the steel beam are respectively anchored at a position 10 m away from one end of the steel beam.

Compared with the prior art, the present invention substitutes steel girders for the replaced concrete girder sections that have already suffered from diseases, so as to completely solve the problems of mid-span deflection, cracking, etc., improve the alignment of the bridge deck, and also improve the performance of the concrete continuous girder bridge. Overall carrying capacity. The utility model has the advantages of safety and reliability, strong operability, low reinforcement cost and strong practicability.

Description of drawings

Fig. 1 is a schematic diagram of dismantling a replaced concrete beam section of the present invention.

Fig. 2 is a schematic diagram of the installation of the steel-concrete joint of the present invention.

Fig. 3 is a schematic diagram of steel beam installation of the present invention.

Fig. 4 is a structural schematic diagram of the steel-concrete joint of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

As shown in Figure 1, Figure 2, and Figure 3, the embodiment of the present invention takes a concrete continuous beam bridge with a middle span of 98m and two adjacent side spans 3 of 65m as an example, and the corresponding middle two are set as main piers 2. The two near the edge are side piers 1, the middle span is between two main piers 2, and the side span 3 is between side piers 1 and main piers 2. Wherein, the middle part of the mid-span is damaged. In this embodiment, the damaged middle beam section of the mid-span is selected as the replacement concrete beam section 4 and replaced with a steel beam 9 . The middle beam section needs to have sufficient self-supporting capacity, and the two ends are in the area with small bending moment. The concrete of this beam section can be demolished by lowering the entire section, or it can be removed in sections. The figure shows that the whole section is lowered tear down.

Referring to Fig. 1, it is the dismantling schematic diagram of the replacement concrete beam section 4 of the present embodiment, and its specific replacement steps are as follows:

S1, cutting and lifting the replacement concrete beam section 4 from the span to be reinforced of the concrete continuous beam;

It should be noted that the span to be reinforced in this embodiment is the above-mentioned middle span, and the replacement concrete beam section 4 is the damaged concrete middle beam section.

The specific cutting and lifting steps are as follows:

S11. Remove and replace the bridge deck pavement of the concrete beam section 4 and its auxiliary facilities, partially reinforce the concrete continuous beam, and set the support system 5 and the hoisting system 6 connected to the support system 5 on the two fixed sections correspondingly, And the replacement concrete beam section 4 is hoisted and fixed by the hoisting system 6;

Before cutting, it is first necessary to disassemble the bridge deck pavement of the replacement concrete beam section 4 and its auxiliary settings, such as railings and the like. After dismantling, stretch the external prestress on the two adjacent spans of the span to be reinforced, that is, stretch the prestress on the two side spans 3, specifically by setting the prestressed steel tendons 10 on the two side spans 3. At the same time, since the support system 5 and the hoisting system 6 need to be installed on the fixed section to facilitate the hoisting of the replaced concrete beam section 4 and steel beam 9, due to the relatively large gravity of the replaced concrete beam section 4 and steel beam 9, it is easy to give weight during the hoisting process. The pressure of the fixed section is relatively large, so in this embodiment, the transverse diaphragm 11 is poured in the box girder at the position of the fixed section for carrying the support system 5 to increase the bearing capacity of the box girder in the fixed section; Drill holes on the upper and lower sides of one end face to the prestressed tendons, and grout the prestressed tendons. Specifically, the prestressed channels are drilled in sections within a range of about 5m from the fixed section to the cut end face, and the inside of the drilled holes The prestressed rib bellows are used for secondary grouting to enhance the fullness of prestressed channel grouting.

After reinforcement, the support system 5 and the hoisting system 6 can be assembled on site. The support system 5 and the hoisting system 6 of this embodiment are all existing conventional equipment, which are simple, convenient, safe and able to meet the needs. After the assembly is completed, Can carry out trial lifting, and monitor the stress change of the fixed section and the stress change of the support system 5 and the hoisting system 6, which can easily ensure the safety of the box girder structure and construction of the concrete continuous girder bridge.

S12, the two ends of the replacement concrete beam section 4 are symmetrically cut in a figure-eight shape;

During specific cutting, first use two hoisting systems 6 to hang the two ends of the replacement concrete beam section 4, and then cut, adopt a figure-eight cut during cutting. When cutting to the set thickness, generally when cutting to one-half to one-third of the thickness of the replacement concrete beam section 4, an anti-impact cantilever is set on the cutting end face of the fixed section, and a hydraulic pressure is set at the front end of the anti-impact cantilever. One end of the hydraulic device abuts the cutting end face of the replacement concrete beam section 4. The hydraulic device can use a conventional jack, and the force between the cutting end face of the fixed section and the cutting end face of the replacement concrete beam section 4 can be adjusted by the jack during cutting. Prevent sudden uneven subsidence and impact of the replacement concrete beam section 4.

Moreover, the other end should be cut after one end of the replacement concrete beam section 4 is cut first. After both ends of the replacement concrete beam section 4 are cut, the impact force during cutting can be slowly released by adjusting the jacking force of the jack.

Wherein, when the replacement concrete beam section 4 is longer, the lower section can be cut in sections. For example, the middle beam section replacement concrete beam section 4 can be cut to 19m in the middle first, and then sectionally symmetrically cut to the side span. The specific section can be two sections. One 3m, two 3m, two 3m, two 2m. The specific cutting can be carried out according to actual needs, which is not limited here.

S13. After the cutting is completed, the hoisting system 6 is controlled to hoist and lower the cut replacement concrete beam section 4 to the corresponding placement platform 7 .

During the specific hoisting and lowering process, it is necessary to monitor the relative heights of the four corners of the replacement concrete beam section 4 in real time to ensure that the vertical relative height between any two corners of the replacement concrete beam section 4 is less than 10mm, and the smaller the vertical relative height, the higher the height. Well, it is especially good that the replacement concrete beam section 4 is in a horizontal state.

As shown in Figure 2, it is a schematic diagram of the installation of the steel-concrete joint 8 of this embodiment, and its installation steps are as follows:

S2. Two fixed sections are formed after the reinforced span is cut, and steel-concrete joints 8 are arranged on the cutting end faces of the two fixed sections; The length of the part is 2.5m, and the length of the inner concrete part 8.1 is 1.5m. A 50mm bearing plate 8.3 is set on the joint surface, and the top plate of the connecting steel box girder part 8.2 adopts a stiffening plate, which corresponds to the stiffening plate (PBL) in the concrete part; first Place the steel structure of the steel-concrete joint vertically, pour the filling concrete, and then place the steel-concrete joint horizontally.

The specific installation process of steel concrete joint 8 is as follows

S21. Chisel off the concrete of the fixed section close to its cutting end face, and chisel off along the length direction of the fixed section, the chiseled length is about 1m, and shape, chisel, clean and cut the beam end of the fixed section after the concrete is chiseled The shear force is strong, and the original supporting steel bars and prestressed tendons in the fixed section are retained;

And before step S21, it is necessary to move the support system 5 and the hoisting system 6 to the side span for a certain distance;

S22. Hoist the steel-concrete joint 8 to the installation position, make the top plate, bottom plate and web plate at the end of the steel box girder into double wall plates, pass the filled concrete and the top plate, bottom plate and web plate of the adjacent concrete box girder section through the PBL Shear plate 8.4, prestressed steel bars and ordinary steel bars are well connected, and then extended slightly forward to connect it with concrete diaphragm 8.5, and prestressed short beams are anchored to the concrete diaphragm and steel box diaphragm Above, the prestressed long-beam steel bars are anchored on the top plate and bottom plate tooth blocks of the rear beam section of the concrete diaphragm. In order to ensure the accuracy of installation, the steel-concrete joint 8 needs to be precisely positioned. terminal fixed connection;

S23. Concrete is poured and cured at the connection between the steel-concrete joint 8 and the fixed section, and the prestress is stretched after the concrete reaches a set strength. After tensioning and prestressing, the steel-concrete joint 8 is protected and painted in a conventional manner.

As shown in Figure 3, it is the installation schematic diagram of the steel beam 9 of the present embodiment, and its installation steps are as follows:

S3. Lift the steel beam 9 between the two steel-concrete joints 8 and connect with the steel-concrete joint 8 .

S31, making a steel beam 9 matching the two steel-concrete joints 8, transporting the steel beam 9 below the steel-concrete joint 8 and hoisting it between the two steel-concrete joints 8;

The steel girder 9 can be manufactured in a factory or at a set location. The length of the steel girder 9 should be set according to the distance between the steel-concrete joints 8. The steel girder 9 of this embodiment is 45m. The steel girder 9 is manufactured under the stress-free state on the overall tire frame, and is calculated and analyzed according to the actual load of the concrete continuous girder bridge, and the pre-camber of the steel girder 9 is set according to the calculated and analyzed data.

Before the steel girder 9 is hoisted, it is necessary for the steel girder 9 to correspond precisely to the two steel-concrete joints 8, that is, the steel girder 9 needs to be positioned at the position 7 to prevent the platform, so as to ensure that the steel girder 9 is vertically hoisted up and connected to the two steel-concrete joints 8. Connector 8 matches. Moreover, during the hoisting process, the vertical height difference between any two corners of the four corners of the steel beam 9 should be less than 10mm, which can be monitored in real time by the monitoring system to ensure the stability of the steel beam 9 during the hoisting process.

S32. Fix one end of the steel beam 9 to one of the steel-concrete joints 8 through high-strength bolts and weld them, and then fix the other end of the steel beam 9 to the other steel-concrete joint 8 through high-strength bolts and weld them.

After hoisting and positioning the steel beam 9, first temporarily fix one end of the steel beam 9 with the steel-concrete joint 8 through high-strength bolts, and then perform permanent fixation by welding, and finally connect the other end of the steel beam 9 through high-strength bolts, adjust the position after connection and then perform welding .

S33. Prestressing the tensioned steel beam 9, the two ends of the steel bundle used for the tensioning and prestressing of the steel beam 9 are respectively anchored to the position 10m away from one end of the steel beam 9.

After the steel girder 9 is prestressed and stretched, the steel girder 9 bridge deck pavement and the installation of its ancillary facilities can be carried out.

The specific embodiments of the present invention described above do not constitute a limitation to the protection scope of the present invention. Any other corresponding changes and modifications made according to the technical concept of the present invention are included in the protection scope of the claims of the present invention.

Claims (7)

1. the beam section replacing and reinforcing method for large span concrete continuous beam bridge, it is characterised in that comprise the steps:

S1, by displacement Concrete Beam Segment from concrete continuous beam treat reinforcing step up cutting and handling；Specifically include:

S11, the deck paving removing displacement Concrete Beam Segment and affiliated facility thereof, carry out local stiffening to concrete continuous beam, And on two canned paragraphs, be all correspondingly arranged support system and the Lift-on/Lift-off System being connected with support system, and incited somebody to action by Lift-on/Lift-off System Displacement Concrete Beam Segment lifting is fixing；

S12, it is the cutting of splayed symmetry at the two ends of displacement Concrete Beam Segment, and uses under interim external prestressing or bridge actively Stress support protection end bay beam body, it is ensured that middle beam section demolishing process safety；

S13, cut after, control Lift-on/Lift-off System will cutting after displacement Concrete Beam Segment lifting transfer to corresponding placement Platform.

S2, wait reinforce across cutting after formed two canned paragraphs, the cutting end face of two canned paragraphs is respectively provided with steel concrete joint；

S3, winch to girder steel be connected between two steel concrete joints and with steel concrete joint.

Beam section replacing and reinforcing method the most according to claim 1, it is characterised in that local stiffening bag in described step S11 Include: wait to reinforce across adjacent two step up stretch-draw external prestressing, in the box beam of canned paragraph, pour diaphragm plate, and at canned paragraph Punching to Prestress tendon near top and bottom of its cutting end face one end, and Prestress tendon is carried out grouting pour.

Beam section replacing and reinforcing method the most according to claim 1 and 2, it is characterised in that described step S12 is additionally included in cuts Cutting to when setting thickness, arrange protecting against shock outrigger on the cutting end face of canned paragraph, the front end of protecting against shock outrigger arranges hydraulic pressure dress Putting, hydraulic means one end abuts the cutting end face of displacement Concrete Beam Segment.

Beam section replacing and reinforcing method the most according to claim 3, it is characterised in that described step S13 is additionally included in lifting The relative altitude at decentralization process monitoring displacement four angles of Concrete Beam Segment, makes erecting between displacement Concrete Beam Segment any two angle Straight relative altitude is less than 10mm.

Beam section replacing and reinforcing method the most according to claim 4, it is characterised in that described step S2 includes:

S21, cut canned paragraph concrete in the 1m of its cutting end face, and by the beam-ends cut after concrete of canned paragraph Shaping, dabbing, clean, cut shearing and be good for, and original spacer bar and presstressed reinforcing steel in retaining canned paragraph；

S22, steel concrete joint is winched to installation site, and fixing with the concrete chisel removal end of canned paragraph be connected；

S23, in steel concrete joint and canned paragraph junction casting concrete maintenance, reach to set intensity post-stretching to concrete pre- Stress.

Steel concrete joint is made up of steel concrete joint Concrete Beam Segment and steel concrete joint steel box-girder section, uses side board-like after filling concrete Formula, the most vertical placement steel concrete joint steel construction, pour fill concrete, then horizontal steel concrete joint, transport to bridge location by shipping, After top board, base plate and the web of steel box-girder end made double ancient piece of jade, round, flat and with a hole in its centre plate, by the concrete box beam section of the concrete filled with next-door neighbour Top board, negative and web connect by PBL shear plate, deformed bar and regular reinforcement, and extend itself and coagulation forward Soil diaphragm plate connect, prestressing force short bundle Bar Anchorage on concrete diaphragm plate and steel case diaphragm plate, prestressing force long bundle reinforcing bar anchor Gu after concrete diaphragm plate on the tooth block of the top board of beam section, base plate.

Beam section replacing and reinforcing method the most according to claim 5, it is characterised in that described step S3 includes:

The girder steel that S31, making match with two steel concrete joints, is transported to girder steel below steel concrete joint and winches to two steel concretes and connect Between Tou；

S32, girder steel one end is fixed by high-strength bolt and one of them steel concrete joint after weld, then the girder steel other end is led to Cross after high-strength bolt is fixed with another steel concrete joint and weld.

S33, stretch-draw girder steel prestressing force.

Beam section replacing and reinforcing method the most according to claim 6, it is characterised in that open for girder steel in described step S33 Prestressed steel bundle two ends are drawn to be anchored in girder steel respectively from 10m position, its one end.