CN103758031A - Method for manufacturing assembled type bridge pier by utilizing steel fiber reinforced self-compacting concrete - Google Patents

Abstract

The invention discloses a method for manufacturing an assembled type bridge pier by utilizing steel fiber reinforced self-compacting concrete. The method comprises the steps of preparing the concrete, prefabricating bridge pier segments, assembling the bridge pier segments, fixing the bridge pier segments and the like. By the adoption of the assembled type bridge pier manufactured through the method, construction and pouring quality can be guaranteed, the construction efficiency of a bridge is enhanced, and the seismic performance of the bridge pier can also be improved. The assembled type bridge pier is made of certain steel fiber reinforced self-compacting concrete, the comprehensive power performance of the segments is superior, and seismic performance of connector parts is 2-3 times that of existing common concrete prefabricated segments under the condition that structures and sizes are equal. The bridge pier segments in the structure are assembled in the mode that a shear key is connected with a short reinforcing steel bar in an inserted mode, the shock resistance, pier energy consumption, post-earthquake restoration in potential plastic hinge areas between the segments and other seismic-area dynamic properties are superior, and the method can be applicable to construction of the bridge pier. By the adoption of the steel fiber reinforced self-compacting concrete, concrete on the surface of a finished bridge pier is not prone to cracking, and therefore durability is good.

Description

A method for preparing assembled bridge piers using steel fiber self-compacting concrete

technical field

The invention relates to the field of bridge building construction, and particularly designs a method for preparing assembled bridge piers by using steel fiber self-compacting concrete.

Background technique

At present, the piers used in the substructure of bridges mostly adopt ordinary reinforced concrete structures, which are composed of ordinary concrete and steel bars. During construction, it is necessary to bind steel bars on site, set formwork, pour commercial concrete, and meet the use requirements after maintenance. On-site operations require large sites to place materials and formwork. When pouring concrete, manual vibration is required to ensure compactness. The pouring of densely reinforced joints is often not dense, and the finished steel-concrete structure piers are prone to cracking when subjected to bending moments. , resulting in a decrease in the durability of the pier column.

In order to solve this problem, the segmental prefabricated pier structure system has been adopted at home and abroad. The structural system of the segmental prefabricated piers is completely processed in the prefabrication field, and the dry (glue joint) or wet joints are used on site to connect, and the prestressed tension is carried out after assembly to form the overall structure of the pier column, which minimizes on-site welding And on-site concrete pouring workload, which is beneficial to quality control, speeds up the construction progress, reduces the impact on traffic and surrounding environment, and conforms to the theme of economic growth mode of environmental protection, energy saving and low carbon.

However, theoretical calculations and experiments have proved that if ordinary concrete is used to assemble piers with dry joint segments, if the joints only use concave-convex shear keys, under the action of earthquake force, the following shortcomings will appear: 1. The joints of pier segments are prone to impact 2. The overall impact resistance of the bridge pier, the energy consumption of the pier body, and the post-earthquake repair of the potential plastic hinge area between segments are not good, so it is not suitable for use in earthquake-prone areas; 3. The finished product The concrete on the surface of the piers is easy to crack, and the durability needs to be improved.

Aiming at the above-mentioned shortcomings, the present invention provides a method for preparing assembled bridge piers by using some kind of steel fiber self-compacting concrete, so that it can overcome the above-mentioned technical defects.

Contents of the invention

In view of this, the purpose of the present invention is to provide a method for preparing assembled bridge pier columns using steel fiber self-compacting concrete, using self-developed special steel fiber self-compacting concrete, and using shear keys and short bridges between segmental joints The steel bars, the obtained prefabricated segments and the assembled pier body have good dynamic performance and good energy dissipation capacity, which can delay the cracking of concrete in the potential plastic hinge area between segments, and significantly improve the crack resistance and durability of components. It can better protect the safety of segmental components and pier bodies, and can meet the design requirements of segmental prefabricated piers in special geographical environments such as earthquake-prone areas.

The object of the present invention is solved by following technical means: a kind of method utilizing steel fiber self-compacting concrete to prepare assembled type bridge pier column comprises the following steps:

A, configure concrete, the specific process is:

a. Prepare concrete raw materials according to the following proportions by weight: 300-350 parts of cement, 190-205 parts of Class I fly ash, 765-775 parts of medium sand with a fineness modulus of 2.3-3, continuously graded gravel 900-910 parts, 8-9 parts of water reducing agent, 39-40 parts of water-soluble steel fiber, 180-185 parts of water;

b. Preparation of self-compacting steel fiber concrete: After mixing the crushed stone and medium sand obtained in a., add cement and Class I fly ash, after mixing evenly, gradually add water to the mixture, and add two After one-half of the water, add the water reducer, and then gradually add the remaining half of the water until the mixture is uniform; finally, add steel fiber and mix evenly;

B. Prefabricated pier segment: Bind the reinforcement cage on the platform, and prepare the first pier segment by pouring vertical formwork. When pouring self-compacting steel fiber concrete, vibrating machines are not allowed to avoid the directionality of the steel fiber, and then Prefabricated pier segments are maintained to the design strength; and so on, other segments are poured and marked with numbers;

C. On-site assembly: pour the cap at the predetermined position, install the pier segments on the cap in accordance with the pre-marked order, and form the integral pier column with tension and prestress. If there is a cover beam, it can be combined with the cap and pier body Tension and anchor together.

Further, the volume ratio of the water-soluble steel fiber is 0.3%-0.6%, the equivalent diameter of the steel fiber is 0.1-0.3mm, the aspect ratio is 40-70, and the tensile strength of the steel fiber is not less than 1000MPa.

Further, in step a, prepare concrete raw materials according to the following proportions by weight: 330 parts of cement, 200 parts of Class I fly ash, 768 parts of medium sand with a fineness modulus of 2.3-3, and 902 parts of continuously graded gravel parts, 8.46 parts of water reducer, 39.25 parts of water-soluble steel fiber, and 181.5 parts of water.

Further, the pier segment includes a pier segment body, the top of the pier segment body is provided with short steel bars along the circumference, and the bottom is provided with a reserved hole for the short steel bar to be inserted into the limit along the circumference, and the reserved hole The diameter of the hole is greater than the diameter of the short steel bar; one end of the pier segment body is provided with a shear key, and the other end is provided with a shear key groove; the pier segment body is provided with a plurality of axially penetrating prestressed tendon holes along the circumference.

Further, in step C, pre-embed short steel bars and shear key grooves on the cap base, then put the shear key at the bottom of the first pier segment into the grooves, and insert the pre-embedded short steel bars into the reserved holes, And so on; after all are in place, pass the prestressed tendon through the prestressed tendon hole for prestressed tension and anchorage. If there is a cover beam, only a single short steel bar can be inserted between the cover beam and adjacent pier segments.

Further, the height of the shear key is the same as the depth of the groove of the shear key, and the butt fit is good after being placed.

Further, the pier segment body is a hollow structure.

Further, in step B, in order to facilitate the positioning of shear keys and short reinforcement holes, the top surface of the second segment can be poured as a template for the first segment, and the rest can be analogized.

Further, in step B, during the multi-segment preparation process, the poured pier segments can be hoisted away, and only adjacent segments can be reserved as pouring support platforms.

Beneficial effects of the present invention: the present invention provides a method for preparing an assembled bridge pier by using steel fiber self-compacting concrete. The pier can not only ensure the quality of construction pouring, but also reduce labor and significantly improve the seismic performance of the bridge. After actual verification, the effect is remarkable: 1. Using self-developed special steel fiber concrete, through the analysis of bridge pier mechanics and stress structure, combined with repeated experiments, adjusting the ratio of various raw materials, the comprehensive mechanical properties of the assembled pier segments prepared by it are superior, Under the condition of the same structure and the same size, the seismic performance of the joint is 2-3 times that of the existing ordinary concrete prefabricated section; Assembled with the joint method, the overall impact resistance of the bridge pier, the energy consumption of the pier body, the post-earthquake repair of the potential plastic hinge area between the segments, etc. are superior in dynamic performance in the earthquake area, and can be used for the construction of bridge pier columns in the earthquake area; 3. Adopt this kind of steel Fiber concrete, the concrete on the surface of the finished pier column is not easy to crack and has good durability.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is the assembled structure schematic diagram of adjacent bridge pier section of the present invention;

Fig. 2 is a top view structural schematic diagram of the pier section of the present invention;

Fig. 3 is a schematic bottom view of the bridge pier segment according to the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with accompanying drawing:

Embodiment 1, a kind of method utilizing steel fiber self-compacting concrete to prepare assembled bridge pier column, comprises the following steps:

A, configure concrete, the specific process is:

a. Prepare concrete raw materials according to the following proportions by weight: 300kg of cement, 205kg of Class I fly ash, 765kg of medium sand with a fineness modulus of 2.3, and 910kg of continuously graded crushed stone; the particle size of the continuously graded crushed stone The diameter is determined according to the gap between steel bars, and the value can be taken according to the specification; 9kg of water reducing agent, 39kg of water-soluble steel fiber, and 185kg of water; among them, the volume ratio of the water-soluble steel fiber is 0.3%-0.6%, the volume ratio of the steel fiber, etc. The effective diameter is 0.1-0.3mm, the aspect ratio is 40-70, and the tensile strength of the steel fiber is not less than 1000MPa.

b. Preparation of self-compacting steel fiber concrete: After mixing the crushed stone and medium sand obtained in a., add cement and Class I fly ash, after mixing evenly, gradually add water to the mixture, and add two After one-half of the water, add the water reducer, and then gradually add the remaining half of the water until the mixture is uniform; finally, add steel fiber and mix evenly;

B. Prefabricated pier segment: Bind the reinforcement cage on the platform, and prepare the first pier segment by pouring vertical formwork. When pouring self-compacting steel fiber concrete, vibrating machines are not allowed to avoid the directionality of the steel fiber, and then Prefabricated pier segments are maintained to the design strength; and so on, other segments are poured and marked with numbers;

C. On-site assembly: pour the cap at the predetermined position, install the pier segments on the cap in accordance with the pre-marked order, and form the integral pier column with tension and prestress. If there is a cover beam, it can be combined with the cap and pier body Just stretch and anchor together.

The structure of the pier segment described in step B includes a pier segment body 1, the top of the pier segment body is provided with a short steel bar 2 along the circumference, and the bottom is provided with a reserved hole for inserting the short steel bar 2 along the circumference 3. The diameter of the reserved hole is larger than the diameter of the short steel bar; one end of the pier segment body is provided with a shear key 4, and the other end is provided with a shear key groove 5; the pier segment body is provided with multiple Axially penetrated prestressed tendon holes 6;

In step C, pre-embed short steel bars and shear key grooves on the cap base, then put the shear key at the bottom of the first pier segment into the grooves, insert short pre-embedded steel bars into the reserved holes, and so on ; After all are in place, pass the prestressed tendon 7 through the prestressed tendon hole 6 for prestressed tension and anchoring; sometimes according to the stress requirements, when the short steel bar runs through several segments, it is necessary to reserve a passage in the segment After the insertion of short steel bars is completed, the reserved holes are filled with grout.

If there is a cover beam, only a single short steel bar can be inserted between the cover beam and adjacent pier segments.

As a preferred solution, the height of the shear key 4 is preferably the same as the depth of the shear key groove 5, and the butt joint fits well after being put in. The pier segment body 1 is a hollow structure, which can reduce segment weight and save materials, while ensuring its compressive strength. In step B, in order to facilitate the positioning of shear keys and short reinforcement holes, the top surface of the second segment can be poured as a template for the first segment, and the rest can be analogized. In step B, during the multi-segment preparation process, the pier segments that have been cast can be lifted away, and only the adjacent segments can be reserved as the pouring support platform; this method can reduce the prefabricated construction height and reduce the difficulty of construction , which is conducive to ensuring the quality of the pier segment, ensuring the tight combination of two adjacent pier segments and the verticality of the pier body.

The difference between Example 2 and Example 1 is that in step a, the concrete raw materials are prepared according to the following proportions by weight: 350kg of cement, 190kg of grade I fly ash, 775kg of medium sand with a fineness modulus of 3, and continuous gradation 900kg of gravel, 8kg of water reducer, 40kg of water-soluble steel fiber, and 180kg of water;

Example 3, as the optimal implementation, differs from Example 1 in that: in step a, concrete raw materials are prepared according to the following proportions by weight: 330 kg of cement, 200 kg of grade I fly ash, and a fineness modulus of 2.3-3 768kg of medium sand, 902kg of continuously graded gravel, 8.46kg of water reducing agent, 39.25kg of water-soluble steel fiber, and 181.5kg of water.

Different from the assembled pier structure mentioned in the background technology, the pier segment includes the pier segment body 1, the short steel bar and the shear key groove vertically arranged on the top of the pier segment body, and the adjacent pier segment Reserved short reinforcement holes and shear keys axially arranged at the bottom of the body; the short reinforcements and shear keys are arranged along the circumference of the cross-section of the pier segment; the hole diameter of the reserved short reinforcement holes is larger than that of the short reinforcement Diameter, to ensure the comprehensive mechanical properties of the potential plastic hinge area between segments. When assembling, pre-embed short steel bars and shear key grooves on the cap base, then put the shear key at the bottom of the first pier segment into the grooves, insert short pre-embedded steel bars into the reserved holes, and so on. If there is a cover beam, only short steel bars can be inserted between the cover beam and adjacent pier segments. After all are in place, prestress tension and anchorage are carried out to avoid excessive horizontal displacement between segments when the earthquake force acts, and the reliability is good; the overall impact resistance of the pier, the energy consumption of the pier body, and the potential plastic hinge between the segments The dynamic performance such as regional post-earthquake repair is superior, and it is suitable for bridge construction in earthquake-prone areas.

The assembled bridge pier column prepared by using the special steel fiber self-compacting concrete of the invention can not only ensure the quality of construction and pouring, but also reduce labor force, and can obviously improve the seismic performance of the bridge. Using the special ratio of raw materials and special preparation process, the comprehensive mechanical properties of the assembled bridge pier segments are superior. Through the analysis of bridge pier mechanics and stress structure, under the same structure and the same size, the seismic performance of the joints is better than that of existing ordinary concrete prefabricated 2-3 times that of the section; the pier section of this structure is limited by shear keys, especially assembled by inserting short steel bars, the overall impact resistance of the pier, the energy consumption of the pier body, and the potential The post-earthquake repair of the plastic hinge area has superior dynamic performance in the earthquake area, and can be used for the construction of bridge piers in the earthquake area; the concrete on the surface of the finished pier column is not easy to crack and has good durability.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements without departing from the spirit and scope of the technical solution of the present invention shall be covered by the claims of the present invention.

Claims (9)

1. a method utilizing steel fiber self-compacting concrete to prepare assembled bridge piers, is characterized in that: comprise the following steps: A, configure concrete, the specific process is: a. Prepare concrete raw materials according to the following proportions by weight: 300-350 parts of cement, 190-205 parts of Class I fly ash, 765-775 parts of medium sand with a fineness modulus of 2.3-3, continuously graded gravel 900-910 parts, 8-9 parts of water reducing agent, 39-40 parts of water-soluble steel fiber, 180-185 parts of water; b. Preparation of self-compacting steel fiber concrete: After mixing the crushed stone and medium sand obtained in a., add cement and Class I fly ash, after mixing evenly, gradually add water to the mixture, and add two After one-half of the water, add the water reducer, and then gradually add the remaining half of the water until the mixture is uniform; finally, add steel fiber and mix evenly; B. Prefabricated pier segment: Bind the reinforcement cage on the platform, and prepare the first pier segment by pouring vertical formwork. When pouring self-compacting steel fiber concrete, vibrating machines are not allowed to avoid the directionality of the steel fiber, and then Prefabricated pier segments are maintained to the design strength; and so on, other segments are poured and marked with numbers; C. On-site assembly: pour caps at predetermined positions, install bridge pier segments on the caps in a pre-marked order, and tension and prestress to form a whole pier column. 2. The preparation method according to claim 1, characterized in that: the volume ratio of the water-soluble steel fiber is 0.3%-0.6%, the equivalent diameter of the steel fiber is 0.1-0.3mm, and the aspect ratio is 40- 70. The tensile strength of steel fiber is not less than 1000MPa. 3. The preparation method according to claim 1, characterized in that: in step a, the concrete raw materials are prepared according to the following proportions by weight: 330 parts of cement, 200 parts of Class I fly ash, and the fineness modulus is 2.3-3 768 parts of medium sand, 902 parts of continuously graded gravel, 8.46 parts of water reducing agent, 39.25 parts of water-soluble steel fiber, and 181.5 parts of water. 4. The preparation method according to claim 1, characterized in that: the pier segment includes a pier segment body (1), the top of the pier segment body is provided with short steel bars (2) along the circumference, and the bottom is along the circumference A reserved hole (3) is provided for inserting a short steel bar (2), the diameter of the reserved hole is larger than the diameter of the short steel bar; one end of the pier segment body is provided with a shear key (4), and the other A shear key groove (5) is provided at one end; a plurality of axially penetrating prestressed tendon holes (6) are provided along the circumference of the pier segment body. 5. The preparation method according to claim 4, characterized in that: in step C, short steel bars and shear key grooves are pre-embedded on the cap base, and then the shear key at the bottom of the first pier segment is placed In the groove, the pre-embedded short steel bars are inserted into the reserved holes, and so on; after all are in place, the prestressed tendons (7) are passed through the prestressed tendon holes (6) for prestressed tensioning and anchoring. 6. The preparation method according to claim 4, characterized in that: the height of the shear key (4) is the same as the depth of the groove (5) of the shear key, and the butt joint fits well after being put in. 7. The preparation method according to claim 4, characterized in that: the pier segment body (1) is a hollow structure. 8. The preparation method according to claim 1, characterized in that: in step B, in order to facilitate the positioning of shear keys and short reinforcement holes, the second segment can be poured with the top surface of the first segment as a template, and the rest can be analogized. 9. The preparation method according to claim 1, characterized in that: in step B, during the multi-segment preparation process, the pier segments that have been poured can be hoisted away, and only adjacent segments are reserved as pouring Just support the platform.

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