CN106958208A - A kind of novel reinforced method of double curvature arched bridge - Google Patents

Abstract

The invention discloses a new reinforcement method for a double-curved arch bridge, which comprises the following steps: 1) closing the traffic on the bridge deck, dismantling the bridge deck and auxiliary facilities on the bridge deck, and clearing the filler on the arch; 2) corresponding to the original arch rib above the arch back 3) Cut rough at the bottom of the rectangular trough, implant shear steel bars, then set up a formwork on the arch back of the top of the rectangular trough, bind the steel bars, and pour concrete to form a new arch protruding from the arch back The height of the new arch rib is the same as that of the arch back; 4) To repair the transverse wall, chisel the arch back and the new arch rib on both sides of the transverse wall along the bridge direction. Planting bars, building formwork, and pouring concrete; 5) Gouging the top of the transverse wall, implanting vertical steel bars, and building new columns to support the bridge deck; 6) Newly building the bridge deck. The invention has the advantages of less weight increase of the bridge structure, good integrity of old and new structures, low reinforcement cost, good adaptability, no restriction of the environment under the bridge, no change of the appearance of the original bridge, good operability, and good application prospects.

Description

A New Strengthening Method for Double Curved Arch Bridge

technical field

The invention relates to the technical field of bridge maintenance and reinforcement, in particular to a novel reinforcement method for double-curved arch bridges.

Background technique

The double-curved arch bridge is an original structural form in my country. It was mostly built in the 1970s and 1980s. It is generally composed of the main arch ring and the arch building, as shown in Figure 1. The main arch ring is composed of several parts such as arch ribs, arch waves, arch back or arch slabs, and horizontal connections. Arch structures are generally composed of transverse walls or columns, abdominal arch rings, arch fillers, and bridge deck systems. , because its shape is arc-shaped in both vertical and horizontal directions, it is called a double-curved arch bridge. The specific structure is shown in Figure 1.

Due to the characteristics of material saving, low cost, simple construction and beautiful appearance, the double-curved arch bridge has been widely promoted and applied nationwide. However, due to the lower design load standard and less steel used in the structure, this type of bridge has obvious congenital defects. In recent years, due to the impact of various factors such as the huge increase in traffic volume, natural erosion, and material aging, the structure has suffered from various degrees of disease, and there are serious safety hazards. Nevertheless, the double-curvature arch bridge has a certain load-bearing capacity, as long as the cause of the disease is found and a reasonable reinforcement method is adopted, its load-bearing potential can be fully utilized and improved.

The main arch ring is the most important upper load-bearing member in the double-curved arch bridge, and it is also the member with the most diseases. Therefore, the main direction of our research is to repair and strengthen the main arch ring. Commonly used reinforcement methods for the main arch ring of double-curved arch bridges include arch rib outsourcing concrete reinforcement method, pasting steel plate or carbon fiber reinforcement method, shotcrete anchor reinforcement method, and enhanced transverse connection reinforcement method. These reinforcement methods basically start from the lower part of the arch ring. (soffits) for reinforcement. Although the method of strengthening from the soffit has many advantages, it has the disadvantages of inconvenient construction and difficult guarantee of construction quality. This method needs to build a large number of construction supports under the bridge. When the bridge crosses valleys, rivers, roads, railways, etc. In the area, the construction is often difficult, the reinforcement cost is high, and the traffic under the bridge will be seriously affected. Moreover, the previous reinforcement methods will cause a large change in the appearance of the bridge, and will cause irreparable damage to some bridges with cultural relic value.

At present, there are patents that improve the strength of the entire arch ring by modifying the structure of the main arch ring, so as to enhance the stability of the entire bridge. The Chinese invention patent of "Arch Sleeve Reinforcement Method", which introduces a reinforcement method to increase the strength of the main arch ring by increasing the cross-section of the main arch ring. A plurality of arch-shaped concrete reinforcements with the same length as the main arch ring are poured, and the structural strength of the main arch ring is enhanced by a plurality of reinforcement ribs arranged at intervals protruding from the back of the arch. The method of this patent can greatly enhance the structural strength of the entire main arch ring, but this reinforcement method has two shortcomings: one is that the newly added concrete is too heavy, which increases the load-bearing burden of the main arch ring, and the original There are many diseases in the main arch ring itself, which may cause secondary damage to the original main arch ring and its substructure; second, the construction process is complicated, the material consumption is large, and the reinforcement cost is high.

There are also papers that increase the strength of the main arch ring by thickening the arch, which is called the method of increasing the cross section of the arch. The method of increasing the cross-section of the arch back is divided into equal thickness reinforcement and variable thickness reinforcement. Equal thickness reinforcement means that the thickness of the newly added concrete is the same, and variable thickness reinforcement means that the thickness of the newly added concrete is different. For example, in the paper titled "Zhang Lili. Finite element analysis of the main arch ring reinforcement method of double-curved arch bridge [D]. Northeast Forestry University, 2014", the method of increasing the cross-section of the arch back is equal-thickness reinforcement. This method is on the arch back. Arrange a certain number of steel bars within a certain range from the arch foot to the vault top and cast in-situ concrete of equal thickness to increase the section of the arch ring, increase its section height and the ability to resist negative bending moments, thereby improving the bearing capacity of the double-arch bridge. The paper titled "Wang Xuefeng. Research and application of double-curvature arch bridge reinforcement with arched back enlarged section method [D]. Wuhan University of Technology, 2012" mentioned that the arched back enlarged section method is variable thickness reinforcement. The only difference of the thickness reinforcement method is that the thickness of the cast-in-place concrete decreases sequentially from the arch foot to the vault top. Compared with the equal thickness reinforcement method, this method seems to reduce the self-weight of the newly added concrete, but in fact it does not. Through limited The meta-modeling analysis shows that the constant-thickness reinforcement method is better than the variable-thickness reinforcement method when the same amount of concrete is consumed, so we should give priority to equal-thickness reinforcement in future reinforcement schemes. The above two reinforcement methods derived from the method of increasing the cross-section of the arched back have two shortcomings. One is that the self-weight of the newly added concrete mentioned above is too large, which increases the load-bearing burden of the old bridge; After the structure is cracked, the shear stress of the old and new concrete joint surface is mainly borne by the passive shear friction force generated by the shear reinforcement passing through the joint surface. The shear resistance capacity of the joint surface is limited, and it is easy to cause cross-bridge slippage or misalignment.

It can be seen that there are three main problems in the reinforcement of double-curved arch bridges at this stage: first, how to reduce the self-weight of newly added concrete, that is, the self-weight of newly added concrete in general reinforcement methods is too large, which increases the load-bearing burden of the old bridge and cannot be maximized to improve the bearing capacity of the bridge; secondly, how to maximize the shear capacity of the joint surface of old and new concrete, so as to more effectively improve the integrity of the reinforced structure and ensure the effective transfer of stress at the joint surface; thirdly, how to simplify construction Process, reduce reinforcement costs, in order to obtain maximum economic benefits with minimum cost. At present, there is no effective reinforcement method that can solve these three major problems.

Contents of the invention

One of the objectives of the present invention is to provide a novel double-curved arch bridge reinforcement method for the deficiencies of the prior art.

A novel reinforcement method for a double-curvature arch bridge, characterized in that it comprises the following steps:

1) Close the traffic on the bridge deck, remove the bridge deck and auxiliary facilities on the bridge deck, and remove the filler on the arch;

2) Excavate a rectangular groove along the direction of the bridge at the position corresponding to the original arch rib above the arch back. The rectangular groove extends from the arch foot to the top of the arch. Extend to the end of the rectangular groove notch, and when encountering the obstruction of the transverse wall, use high-pressure water jet technology to cut through the transverse wall, so that the rectangular groove runs through all the transverse walls along the direction of the bridge;

3) Gouging rough at the bottom of the rectangular groove, implanting shear steel bars, then setting up a formwork on the arch back of the rectangular groove top, binding the steel bars, pouring concrete to form a new arch rib protruding from the arch back, and the poured new arch rib runs through each For a transverse wall, the height of the new arch ribs relative to the arch back is the same;

4) To repair the transverse wall, chisel the arch back and the new arch rib along the bridge to both sides of the transverse wall, plant reinforcement on the chiseled arch back and the new arch rib, build a formwork, and pour concrete into the formwork to repair the transverse wall. At the damaged part of the wall, newly poured concrete wraps the damaged part of the lower part of the transverse wall, and also wraps a part of the new arch rib, which enhances the stability of the entire structure;

5) Chisel the top of the transverse wall, implant vertical steel bars, and build new columns to support the bridge deck;

6) To build a new bridge deck, after the bridge deck is completed, install bridge deck ancillary facilities of the same shape and size as the original bridge.

A further solution is: the width of the new arch rib is the same as that of the rectangular groove.

A further solution is: the new arch rib and the original main arch ring are connected in a nested manner.

A further solution is: when excavating the rectangular groove, it is excavated by high-pressure water jet technology.

A further solution is: the new arch rib and the rectangular groove run through each transverse wall.

A further solution is: when repairing the transverse wall, the transverse wall is repaired by outsourcing concrete.

The present invention has the advantages of less weight increase of the bridge structure, good integrity of the old and new structures, low reinforcement cost, good adaptability, no restriction of the environment under the bridge, no change of the appearance of the original bridge, good operability, and good application prospects, etc. The specific description is as follows :

(1) Less weight increase of the structure: Compared with the original structure, the weight of the structure strengthened by this method increases less. Only the part of the new arch rib relative to the arch back is the real new concrete, and the cross-sectional size of the new arch rib is relatively small , so the self-weight of the reinforced bridge structure increases less, which can maximize the bridge's bearing capacity;

(2) The integrity of the new and old structures is good: this reinforcement method not only improves the integrity of the reinforced structure by setting shear reinforcement on the joint surface of the new and old structures, but also prevents the transverse bridge direction of the newly added arch ribs through the two walls of the notch. Sliding or misalignment enhances the shear resistance of the joint surface, thereby improving the integrity of the reinforced structure;

(3) Low reinforcement cost: The construction process of this reinforcement method is relatively simple, the material consumption is less, the amount of newly poured concrete is small, and most of the work can be completed above the arch back, no support is required during the construction process, and the reinforcement cost is low;

(4) Good adaptability: This reinforcement method can be applied to the reinforcement and reconstruction of double-curved arch bridges with various spans and layout forms, and can also be applied to the reinforcement of reinforced concrete slab-arch bridges; In the case of damage, the range of notch excavation can be adjusted appropriately according to the needs, thereby greatly improving the bearing capacity, mechanical performance and safety reserve of the main arch ring;

(5) Not constrained by the environment under the bridge: most of the work of this reinforcement method is completed above the arch back, and there is no need to erect construction supports under the bridge during the construction process. It is convenient for bridge construction across rivers, highways, and railways, and does not affect the traffic under the bridge. Small social impact;

(6) Do not change the appearance of the original bridge: This reinforcement method retains as much of the original structure as possible, and all exposed main components can be retained as needed. The newly added structures are all located in the closed space composed of the main arch ring, bridge deck and side walls , not visible from the outside. This method can ensure that the bridge maintains its original historical appearance;

(7) Good operability: This reinforcement method first removes most of the arched buildings, and the work space is not limited when the new arch ribs are built, and the construction safety and quality are more guaranteed. The new notches on the original arch back can be implemented with ultra-high pressure water jet crushing technology. The construction precision is high, and the original structure to be preserved will not be damaged during the process. A large amount of concrete crushing work is done by machinery, which greatly reduces labor intensity;

(8) Good application prospects: There are a large number of double-curvature arch bridges in operation in China, most of which need to be reinforced. The reinforcement method of adding arch ribs to the original arch back can greatly improve the mechanical performance of double-curvature arch bridges in service and improve bridge performance. This method does not change the appearance of the bridge and is of great significance to the double-curved arch bridge with cultural relics and historical value.

Description of drawings

Figure 1 Schematic diagram of the original double-curved arch bridge;

Fig. 2 Schematic diagram of the combined structure of the new arch rib and the original main arch ring (a is the elevation view, b is the section view);

Fig. 3 Schematic diagram of the reinforced double-curved arch bridge;

Among them: 1—main arch ring; 1.1—original arch rib; 1.2—arch back; 1.3—transverse wall; 1.4—abdominal arch ring; 1.5—filling on arch; 1.6— Bridge deck; 1.7—Auxiliary facilities of bridge deck; 2—New arch rib; 3—New column.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific engineering examples.

As shown in Figures 2 and 3, this project example increases the structural strength of the entire main arch ring by adding arch ribs to the arch back, thereby improving the bearing capacity of the entire double-curved arch bridge.

The construction steps of this project example are as follows:

(1) To close the traffic on the bridge deck, first remove the auxiliary structures such as railings, sidewalk slabs, lamp posts, etc., then manually cooperate with small machinery such as pneumatic picks to break and remove the bridge deck pavement, and then use manual cooperation with ultra-high pressure water jets to remove the filler on the arch ;

(2) Use high-pressure water jet technology or other equipment to excavate rectangular grooves along the direction of the bridge at the positions corresponding to the original arch ribs on the arch back. The specific excavation range of rectangular grooves is the hollow section of the main arch ring shown in Figure 3 (for the For the solid belly section, because the filler on the arch is thicker, it has a good distribution effect on the wheel load, and it is difficult to see cracks in the main arch ring of this section in actual use, so the reinforcement of the main arch ring of this section may not be considered; for For the solid belly section of the vault, the bending moment of the vault can be "transferred" by strengthening the arch foot, so the reinforcement of this section is not considered). JTG/TJ22-2008 ) stipulates that for beams and compression members, the minimum thickness of the new concrete layer should not be less than 15cm), according to field work experience, the width of the rectangular groove is generally about 1.5 times the width of the original arch rib. The arch feet on both sides start to be excavated symmetrically, and extend together to the end of the rectangular groove. When encountering the obstruction of the transverse wall, use high-pressure water jet technology to cut through the transverse wall, so that the rectangular groove runs through all the transverse walls along the direction of the bridge;

(3) Chiseling at the bottom of the notch, implanting shearing steel bars, then setting up a formwork on the arch back of the top of the rectangular slot, binding the steel bars, pouring concrete to form a new arch rib protruding from the arch back, and the poured new arch rib runs through For each horizontal wall, the height of the new arch rib relative to the arch back is the same; according to previous reinforcement experience, the height of the new arch rib relative to the arch back is generally 20cm~40cm, as shown in Figure 2;

(4) To repair the transverse wall, chisel the arch back and the new arch rib on both sides of the transverse wall along the bridge, plant reinforcement on the chiseled arch back and the new arch rib, build a formwork, and pour concrete into the formwork for repair At the damaged part of the transverse wall, the newly poured concrete will wrap the damaged part of the lower part of the transverse wall, and also wrap part of the new arch rib, which enhances the stability of the whole structure;

(5) Chisel rough at the top of the transverse wall, implant vertical steel bars, and build new columns to support the bridge deck. The original bridge deck is supported by fillers. The weight of the fillers is too large, so that the main arch circle bears huge pressure, and columns are used instead. Finally, the pressure on the main arch ring is reduced, and the stability of the bridge structure is enhanced;

(6) For the new bridge deck, after the bridge deck is completed, install sidewalk slabs, railings and other ancillary facilities of the same shape and size as the original bridge. The reinforced double-curved arch bridge structure is shown in Figure 3.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above-mentioned engineering examples, and what is described in the above-mentioned engineering examples and the description only illustrates the principle of the present invention, and the present invention also has various aspects without departing from the spirit and scope of the present invention Variations and improvements, these changes and improvements will fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (5)

1. a kind of double-curvature arch bridge novel reinforcement method is characterized in that: comprise the following steps: 1) Close the traffic on the bridge deck, remove the bridge deck and auxiliary facilities on the bridge deck, and remove the filler on the arch; 2) Excavate a rectangular groove along the direction of the bridge at the position corresponding to the original arch rib above the arch back. The rectangular groove extends from the arch foot to the top of the arch. Extend to the end of the rectangular groove notch, and when encountering the obstruction of the transverse wall, use high-pressure water jet technology to cut through the transverse wall, so that the rectangular groove runs through all the transverse walls along the direction of the bridge; 3) Gouging rough at the bottom of the rectangular groove, implanting shear steel bars, then setting up a formwork on the arch back of the rectangular groove top, binding the steel bars, pouring concrete to form a new arch rib protruding from the arch back, and the poured new arch rib runs through each For a transverse wall, the height of the new arch ribs relative to the arch back is the same; 4) To repair the transverse wall, chisel the arch back and the new arch rib along the bridge to both sides of the transverse wall, plant reinforcement on the chiseled arch back and the new arch rib, build a formwork, and pour concrete into the formwork to repair the transverse wall. At the damaged part of the wall, newly poured concrete wraps the damaged part of the lower part of the transverse wall, and also wraps a part of the new arch rib, which enhances the stability of the entire structure; 5) Chisel the top of the transverse wall, implant vertical steel bars, and build new columns to support the bridge deck; 6) To build a new bridge deck, after the bridge deck is completed, install bridge deck ancillary facilities of the same shape and size as the original bridge. 2. The new reinforcement method for double-curved arch bridges according to claim 1, characterized in that: the width of the new arch rib is the same as that of the rectangular groove. 3. The new reinforcement method for double-curved arch bridge according to claim 1, characterized in that: the new arch rib and the original main arch ring are connected in a nested manner. 4. According to claim 1, the novel reinforcement method for double-curved arch bridges is characterized in that: when digging rectangular grooves, high-pressure water jet technology is used for digging. 5. According to claim 1, the new reinforcement method for the double-curvature arch bridge is characterized in that: when repairing the transverse wall, the transverse wall is repaired by outsourcing concrete.