CN110374014B

CN110374014B - Construction method of long-span continuous beam UHPC column

Info

Publication number: CN110374014B
Application number: CN201910733636.XA
Authority: CN
Inventors: 杨纪; 怀臣子; 徐世俊; 张阳; 冯仲林; 陈阳阳; 杨磊; 宋银平; 黄毅; 余方亮; 魏星; 黄泰鑫; 赵海增; 郭坤领; 熊东; 张铎; 王睿; 管曼羽; 张小涛; 高香玉
Original assignee: Yellow River Engineering Consulting Co Ltd
Current assignee: Yellow River Engineering Consulting Co Ltd
Priority date: 2019-08-09
Filing date: 2019-08-09
Publication date: 2021-06-25
Anticipated expiration: 2039-08-09
Also published as: CN110374014A

Abstract

The invention discloses a construction method of a large-span continuous beam UHPC column, which comprises the steps of prefabricating UHPC column sections, installing 0-section UHPC column sections on a main pier bracket, pouring common concrete, tensioning prestressed bundles, assembling a hanging basket, installing 1-section UHPC column sections on a hanging basket template, positioning the 1-section UHPC column sections through U-shaped positioning steel plates of the 0-section UHPC column sections, forming a rhombic pouring cavity by a cast-in-place joint surface structure and the U-shaped positioning steel plates which are opposite to each other, casting RPC into the rhombic pouring cavity, pouring 1-section common concrete, tensioning the prestressed bundles, moving and assembling the hanging basket, constructing other concrete sections with UHPC columns, constructing other common prestressed concrete sections and folding sections, and completing construction. The invention has the advantages of ingenious structure, convenient operation and convenient implementation, reduces the interference of secondary vertical molds, ensures the effective combination of the UHPC precast column and the post-cast joint, and solves the problem of continuous increase of deformation of the large-span prestressed concrete continuous beam structure caused by shrinkage and creep.

Description

Construction method of long-span continuous beam UHPC column

Technical Field

The invention relates to the technical field of bridge construction, in particular to a construction method of a long-span continuous beam UHPC column.

Background

The continuous span deflection of a long-span continuous beam (continuous rigid frame) caused by the shrinkage and creep of concrete in the operation process is a common problem in bridge engineering. UHPC (Ultra-High Performance Concrete) is an Ultra-High Performance Concrete material, has Ultra-High compressive strength, flexural strength and toughness, and compared with common Concrete, the UHPC has the characteristics of extremely low shrinkage Performance and small creep coefficient after being subjected to thermal curing due to the addition of active powder in the preparation process. Based on the characteristics, researchers assume that UHPC columns are arranged in a compression area of the continuous beam so as to solve the problem that the deformation of a large-span prestressed concrete continuous beam structure is continuously increased due to shrinkage and creep. However, how to design a bridge structure, simplify construction steps and reduce construction cost becomes a difficult problem to be solved urgently when the UHPC is applied to the construction of the long-span continuous beam.

Disclosure of Invention

In order to solve the problems, the invention provides a construction method of a long-span continuous beam UHPC column, which can adopt the following technical scheme:

the invention relates to a construction method of a long-span continuous beam UHPC column, which comprises the following steps:

prefabricating a UHPC column segment, wherein longitudinal steel bars are arranged in the UHPC column segment, cast-in-place joint surface structures are arranged at two ends of the UHPC column segment, a U-shaped positioning steel plate used for connecting adjacent UHPC column segments is coated at one end of the UHPC column segment, and shear nails are welded at the inner side and the outer side of a bottom plate, a left side plate and a right side plate of the U-shaped positioning steel plate;

secondly, erecting a bracket beside the main pier, then installing a No. 0 section of UHPC column segment on the template near the bottom, pouring No. 0 section of common concrete, stretching a No. 0 section of prestressed bundles after the strength of the concrete meets the design requirement, and assembling a hanging basket for symmetrical cantilever construction;

thirdly, installing a No. 1 section of UHPC column segment on the hanging basket template, positioning the No. 1 section of UHPC column segment through a U-shaped positioning steel plate of a No. 0 section of UHPC column segment, and forming a rhombic casting cavity by a cast-in-place joint surface structure and the U-shaped positioning steel plate which are opposite to each other;

fourthly, pouring RPC in a rhombic pouring cavity in the third step, pouring 1 section of common concrete, stretching 1 section of prestressed bundles after the strength of the concrete meets the design requirement, and moving and assembling the hanging basket for symmetrical cantilever construction;

fifthly, according to the method of the third step and the fourth step, the rest concrete segments designed with UHPC columns are constructed in sequence;

and sixthly, constructing other common prestressed concrete sections and closure sections in sequence according to a conventional construction method to finish bridge construction.

The total length of the concrete segment designed with UHPC columns in each span is 1/4-1/5 of the main span.

The concrete segment designed with the UHPC columns is provided with 1-10 UHPC column segments in parallel along the bridge width direction.

The invention has the advantages of ingenious structure, convenient operation and convenient implementation, can effectively reduce the interference of secondary vertical molds, ensure the effective combination of the UHPC precast column and the post-cast joint, can solve the problem of continuous deformation increase of the large-span prestressed concrete continuous beam structure caused by shrinkage and creep, and provides technical support for the construction of the large-span continuous beam with the UHPC column.

Drawings

FIGS. 1-7 are schematic illustrations of the construction steps of the present invention.

Fig. 8 is an enlarged view of a portion a in fig. 2.

Fig. 9 is a cross-sectional view taken along line I-I of fig. 8.

Detailed Description

The construction method of the long-span continuous beam UHPC column according to the invention is described in the following by specific examples.

As shown in fig. 1 to 7, the construction method includes the steps of:

firstly, prefabricating UHPC column sections 1, as shown in figures 8 and 9, wherein each UHPC column section 1 is internally provided with a longitudinal steel bar 1.1, two ends of each UHPC column section 1 are provided with cast-in-place joint surface structures 1.2 with concave middle parts, one end of each UHPC column section 1 is coated with a U-shaped positioning steel plate 1.3 for connecting adjacent UHPC column sections, and the inner side and the outer side of a bottom plate, a left side plate and a right side plate of each U-shaped positioning steel plate 1.3 are welded with shear nails 1.4;

secondly, erecting a bracket beside the main pier, prepressing the bracket, then installing a No. 0 UHPC column segment on the template close to the bottom, pouring No. 0 common concrete, tensioning a No. 0 prestressed bundle after the strength of the concrete reaches 90% of the design strength, and assembling a symmetrical hanging basket 2 for cantilever construction on the No. 0 segment; typically, according to design, the UHPC column segments are arranged 1-10 side by side in the bridge width direction.

Thirdly, installing a No. 1 section of UHPC column segment on the hanging basket template, positioning the No. 1 section through a U-shaped positioning steel plate 1.3 of a No. 0 section of UHPC column segment, and forming a rhombic casting cavity 1.5 (see figure 8) by a cast-in-place joint surface structure 1.2 and the U-shaped positioning steel plate 1.3 which are opposite to each other;

fourthly, pouring RPC (reactive powder concrete) into the rhombic casting cavity 1.5 in the third step in a cast-in-place mode to integrally connect the two UHPC column sections, then casting the common concrete of the section 1, tensioning the prestressed bundles of the section 1 after the strength of the concrete reaches 90% of the design strength, and moving and assembling the hanging basket 2 for symmetrical cantilever construction;

fifthly, according to the method of the third step and the fourth step, the rest concrete segments designed with UHPC columns are constructed in sequence; generally, the total length of each concrete section designed with UHPC columns in the bridge is 1/4-1/5 of the main span of the bridge, and the concrete section designed with UHPC columns in the embodiment is 0-8 sections.

Specifically, for the common prestressed concrete segments, common concrete is poured firstly, after the strength of the concrete reaches 90% of the designed strength, the segment prestressed tendons are tensioned, then the hanging baskets 2 for symmetrical cantilever construction are moved and assembled, the operations are repeated, and all the common prestressed concrete segments are constructed in sequence.

When the folding section construction is carried out, firstly, a support beside the side pier is erected, a construction side span beam section is poured on the support, and then the folding section is constructed in sequence according to the design folding sequence.

And finally, dismantling the support, and constructing a bridge deck system, traffic engineering and other auxiliary facilities to complete bridge construction.

Compared with the common large-span continuous beam, the large-span continuous beam constructed by the invention has the advantages that the mid-span vertical displacement caused by 10-year shrinkage and creep is reduced by about 40-50%, the structure corner in the negative moment area is reduced by about 40%, the problem of continuous increase of the structure deformation caused by shrinkage and creep can be fully solved, and the service life of the large-span prestressed concrete continuous beam is effectively prolonged.

Claims

1. A construction method of a long-span continuous beam UHPC column is characterized by comprising the following steps: the method comprises the following steps:

sixthly, constructing other common prestressed concrete sections and closure sections in sequence according to a conventional construction method to finish bridge construction;

the total length of the concrete segment designed with the UHPC column in each span is 1/4-1/5 of the main span;