CN203174594U - Bridge lower portion structure prevented from being corroded by high-concentration saline solution - Google Patents

Abstract

The utility model discloses a bridge substructure for preventing high-concentration salt solution corrosion, which comprises a pier column and a cap, and a prefabricated concrete sheath is arranged on the outside of the cast-in-situ pile at the lower part of the cap, and the net distance between the prefabricated concrete sheath and the cast-in-place pile is the same. Exceeding 1.0cm, the bottom edge of the precast concrete sheath is located below the high-concentration salt solution corrosion area, and the top edge is flush with the top of the cast-in-situ pile; the outer surface of the precast concrete sheath is coated with anti-corrosion materials. The utility model uses the prefabricated concrete sheath as the anti-corrosion protection component of the pouring pile, which prolongs the service life of the bridge substructure and reduces the difficulty of later maintenance; the anti-corrosion coating can further increase the anti-corrosion life of the prefabricated concrete sheath, and the comprehensive cost is low ; The precast concrete sheath is separated from the cast-in-situ pile, so the mechanical performance of the bridge substructure will not be changed; the construction difficulty is small, and the precast concrete sheath is a prefabricated component, which can be purchased in batches by the factory.

Description

Bridge Substructures Protected Against Corrosion by High Concentration Salt Solutions

technical field

The utility model relates to a bridge structure, in particular to an anti-corrosion structure for the lower part of the bridge.

Background technique

"Technical Specifications for Anti-corrosion of Concrete Structures in Highway Engineering (JTG/T B07-01-2006)" clearly stipulates that "the anti-corrosion durability of highway concrete structures shall be Design. When different components in the same structure and different parts of the same component have different local environments, they should be treated differently. The durability design of concrete structure anti-corrosion should ensure the application of the structure in its long-term service life In order to meet the needs of reliability, repairability and safety, maintenance and inspection requirements during use must be put forward." At the same time, the "General Specifications for Design of Highway Bridges and Culverts" proposes that the basic design principles of bridges are "advanced technology, safe and reliable, applicable and durable, and economical and reasonable. ", so the durable and anti-corrosion design of highway bridge components is an indispensable design link.

According to the different design reference periods, service environment categories and environmental action levels of bridge components, the specification puts forward specific requirements for the corrosion resistance durability design of bridge components. Class F) components, additional anti-corrosion measures may be taken for durability design.

The substructure of the bridge is located below the surface, which is a concealed project. It is not easy to be found after being damaged by corrosion, and the inspection and maintenance work is extremely difficult. challenge. The corrosion level of the substructure of the bridge under the corrosive environment of high-concentration salt solution is relatively high, generally above D level. In addition to meeting the basic structural requirements and material durability requirements of the code, necessary additional anti-corrosion measures must be taken to reduce the maintenance workload in the later stage, improve the durability of the bridge substructure, and ensure the safety of the bridge substructure components.

Conventional anti-corrosion measures for the substructure of bridges are to put forward durability design requirements for concrete materials, and to meet the design requirements by putting forward durability design indicators for concrete strength grade, maximum water-cement ratio, minimum amount of cementitious materials and concrete admixtures. According to the requirements of "Technical Specification for Corrosion Protection of Concrete Structures in Highway Engineering JTG/T B07-01-2006", for structural parts in important projects that are severely affected by the environment (D, E and F grades), the durability of the material meets the design requirements. On the other hand, it is necessary to take other necessary measures to ensure the safety and reliability of the main structure.

Utility model content

The utility model aims to solve the technical problem of high anti-corrosion and durability requirements for the bridge substructure under the corrosion environment of high-concentration salt solution, and provides a bridge substructure that prevents high-concentration saline solution corrosion, which can improve the durability of the bridge substructure Reliability, while reducing the difficulty of construction and the difficulty of later maintenance.

In order to solve the above technical problems, the utility model is realized through the following technical solutions:

A bridge substructure for preventing high-concentration salt solution corrosion, including pier columns and caps, the cast-in-place piles at the lower part of the caps are provided with prefabricated concrete sheaths, and the net distance between the prefabricated concrete sheaths and the cast-in-situ piles is No more than 1.0 cm, the bottom edge of the prefabricated concrete sheath is located below the high-concentration salt solution corrosion area, and the top edge is flush with the top of the cast-in-place pile.

The outer surface of the prefabricated concrete sheath is coated with anti-corrosion materials.

The anti-corrosion material is silicone rubber emulsion, polyurea elastomer or fluorocarbon resin coating.

The wall thickness of the prefabricated concrete sheath is 20cm-35cm.

The beneficial effects of the utility model are:

(1) The utility model uses the prefabricated concrete sheath as the anti-corrosion protection component of the cast-in-situ pile, which isolates the high-concentration salt solution from corroding the cast-in-situ pile, prolongs the service life of the bridge substructure, and reduces the difficulty of later maintenance of the bridge substructure;

(2) The prefabricated concrete sheath of the present utility model is a prefabricated concrete structure, which can ensure the processing quality. At the same time, its outer surface is coated with anti-corrosion materials, which can effectively improve the anti-corrosion life of the pre-cast concrete sheath, further increase the anti-corrosion effect, and the overall cost lower;

(3) The prefabricated concrete sheath of the utility model can control its anti-corrosion life through the design of the thickness, which can not only achieve the effect of permanent protection within the service life of the bridge substructure, but also avoid waste of materials, and the anti-corrosion effect is highly reliable;

(4) The prefabricated concrete sheath and cast-in-situ piles of the utility model are separated from each other, so the mechanical performance of the bridge substructure will not be changed, but the friction force of the cast-in-situ pile within the range of the precast concrete sheath will not be calculated;

(5) The construction difficulty of the utility model is small, and the prefabricated concrete sheath is a prefabricated component, which can be purchased in batches by the factory.

Description of drawings

Fig. 1 is the structural representation of the bridge substructure provided by the utility model;

Fig. 2 is the sectional view of cast-in-place pile;

Figure 3 is a cross-sectional view of a precast concrete sheath.

In the figure: 1: cast-in-place pile; 2: precast concrete sheath; 3: cap; 4: pier column.

Detailed ways

As shown in Figures 1 to 3, this embodiment discloses a bridge substructure for preventing high-concentration salt solution corrosion, including pier columns 4 and caps 3, and the cast-in-place pile 1 at the lower part of the caps 3 is provided with precast concrete protection. Cover 2, the net distance between the prefabricated concrete sheath 2 and the outer surface of the cast-in-place pile 1 is 0.01m, and its wall thickness is 0.25m. The prefabricated concrete sheath 2 is a cylindrical prefabricated concrete structure, and its height extends from the corrosion area of the high-concentration salt solution to the top of the cast-in-situ pile 1 , thereby serving as an anti-corrosion barrier for the cast-in-place pile 1 . Usually, the clear distance between the precast concrete sheath 2 and the cast-in-place pile 1 does not exceed 1.0 cm, and the precast concrete sheath 2 does not participate in the stress of the bridge substructure. The wall thickness of the prefabricated concrete sheath 2 is in the range of 20cm to 35cm, and the specific wall thickness is controlled by the design anticorrosion period.

The outer surface of the prefabricated concrete sheath 2 can also be coated with anti-corrosion materials. The anti-corrosion materials can be selected from silicone rubber emulsion, polyurea elastomer, fluorocarbon resin coating, etc. Any anti-corrosion material with good alkali resistance, adhesion and corrosion resistance All can be used in the utility model. The anti-corrosion coating can effectively increase the anti-corrosion life of the precast concrete sheath, further increase the anti-corrosion effect, and the overall cost is low.

The construction method of the bridge substructure for preventing the corrosion of the high-concentration salt solution is as follows:

The cast-in-place pile 1 is subjected to stress analysis and cross-section reinforcement according to the conventional pile foundation. At the same time, the concrete of cast-in-place pile 1 is made of high-performance durable concrete, and the thickness of the steel bar protection layer is selected according to the requirements of the anti-corrosion design code. The prefabricated concrete sheath 2 does not participate in the structural force;

Determine the corrosion range of the cast-in-situ pile 1 according to the geological report, determine the length of the precast concrete sheath 2 according to the corrosion range of the cast-in-situ pile 1; determine the wall thickness of the precast concrete sheath 2 according to the structural design reference period of the pile foundation;

According to the determined length and wall thickness of the prefabricated concrete sheath 2, the prefabricated concrete sheath 2 is prefabricated according to the reinforced concrete member, and the inner wall of the prefabricated concrete sheath 2 and the cast-in-place pile 1 have a clear distance of 0.01m;

The reverse circulation drill with drill bit diameter Φ=D+2h+0.02 is used to carry out the expansion drilling construction in the range of the precast concrete sheath 2 on the top of the cast-in-place pile 1; where D is the diameter of the cast-in-place pile 1, and h is the wall thickness of the precast concrete sheath 2 ;

The drilling construction of the lower part of the cast-in-situ pile 1 is carried out after secondary centering with reverse circulation drilling with a drill bit diameter Φ=D; wherein D is the diameter of the cast-in-place pile 1;

After drilling and clearing the bottom, hoist the precast concrete sheath 2 and sink it into place until the top edge of the precast concrete sheath 2 is flush with the design elevation of the cast-in-place pile 1;

A temporary anchoring and locking device is arranged on the top of the precast concrete sheath 2 to prevent the precast concrete sheath 2 from sinking, and to jack up the precast concrete sheath 2 when pouring underwater concrete;

Lift the cast-in-place pile 1 and put the reinforcement cage in place, and set up the reinforcement protection layer within the range of the precast concrete sheath 2 to ensure that the thickness of the reinforcement protection layer within the range of the precast concrete sheath 2 is uniform;

Pouring underwater concrete and completing the construction of cast-in-place pile 1;

Carry out the construction of caps 3 and pier columns 4 sequentially according to conventional methods.

Although the preferred embodiment of the utility model has been described above in conjunction with the accompanying drawings, the utility model is not limited to the above-mentioned specific implementation, and the above-mentioned specific implementation is only illustrative and not restrictive. Under the enlightenment of the utility model, those of ordinary skill can also make many specific transformations without departing from the spirit of the invention and the protection scope of the claims, and these all belong to the protection scope of the utility model.

Claims (4)

1. A bridge substructure for preventing high-concentration salt solution corrosion, comprising pier columns and caps, is characterized in that, the cast-in-place pile at the bottom of the cap is provided with a prefabricated concrete sheath outside, and the prefabricated concrete sheath and the cap are The net distance of the cast-in-place piles is not more than 1.0 cm, the bottom edge of the prefabricated concrete sheath is located below the high-concentration salt solution corrosion area, and the top edge is flush with the top of the cast-in-place piles. 2. A bridge substructure for preventing high-concentration salt solution corrosion according to claim 1, wherein the outer surface of the precast concrete sheath is coated with an anti-corrosion material. 3. A bridge substructure for preventing high-concentration salt solution corrosion according to claim 2, wherein the anti-corrosion material is silicone rubber emulsion, polyurea elastomer or fluorocarbon resin coating. 4 . The bridge substructure for preventing high-concentration salt solution corrosion according to claim 1 , wherein the wall thickness of the prefabricated concrete sheath is 20 cm to 35 cm.

Images