WO2024082720A1 - Prefabricated thin-walled hollow pier construction method based on steel bar post-installation - Google Patents

Abstract

A prefabricated thin-walled hollow pier construction method based on steel bar post-installation, comprising: dividing a pier column into a plurality of prefabricated sections, the plurality of sections being divided into two types of sections, i.e., I-type sections and II-type sections, wherein each I-type section is divided into two straight-plate modules and two U-shaped modules in the longitudinal direction, and each II-type section is divided into four L-shaped modules in the longitudinal direction; providing a main steel bar channel in the main steel bar position of each module, and providing a hoop steel bar channel in the hoop steel bar position of each of some of the modules of each section; installing the I-type sections and the II-type sections alternately at a pier position, during installation of each section, a hoop steel bar being inserted in each hoop steel bar channel and being connected to a preset hoop steel bar by means of a threaded sleeve, and main steel bars being inserted into main steel bar channels of upper and lower sections and being connected by means of threaded sleeves. The present invention greatly reduces the weight of each section of pier column, thereby facilitating transportation and installation, and the connection between the sections is firm, so that shear resistance is high.

Description

A post-reinforcement prefabricated assembly type thin-walled hollow pier construction method

The present invention claims the priority of the Chinese patent application with application number 202211297039.5 filed with the State Intellectual Property Office of China on October 21, 2022, and invention name “A construction method for prefabricated and assembled thin-walled hollow piers by post-reinforcement method”, the entire contents of which are incorporated by reference into this application.

Technical Field

The invention belongs to the technical field of bridge construction, relates to the construction of bridge piers, and specifically relates to a post-reinforcement method for assembling prefabricated thin-walled hollow piers.

Background technique

The pier is the load-bearing system of the bridge structure, and its construction quality directly affects the safety performance of the bridge structure. Traditional piers are mostly cast-in-place, which is inefficient and affected by the on-site construction and maintenance environment, and there are many uncontrollable factors in quality.

With the development of prefabrication and assembly technology, prefabricated piers are gradually being used in bridge construction. Prefabricated piers can be prefabricated in factories and in a standardized manner, and have the advantages of controlled quality, fast construction speed, and no influence from the construction environment.

At present, prefabricated piers are all based on sleeve connection technology, that is, a connection sleeve is preset in the prefabricated pier, and embedded steel bars are set on the top surface of the pedestal. When the prefabricated pier is installed on the pedestal, the embedded steel bars on the pedestal are inserted into the sleeve, and then the sleeve is grouted to ensure the connection between the steel bars and the sleeve. Although this method avoids some shortcomings of cast-in-place construction to a certain extent, it also has some shortcomings: on the one hand, the density of grouting in the sleeve is difficult to control and there is a lack of effective detection means, so the quality of steel bar installation is uncontrollable; on the other hand, the sleeve material is generally cast steel, which is brittle and has poor seismic resistance, so it is difficult to promote in high-intensity earthquake areas; third, due to the need for steel bar insertion and grouting, as well as its own mechanical properties, the sleeve needs to have a larger inner cavity size and thickness, and its outer diameter is much larger than the steel bar diameter. If the pier structure size is not increased, the sleeve will affect the thickness of the protective layer. In order to ensure the thickness of the protective layer, the pier structure size must be increased, resulting in an increase in the cost of prefabricated piers.

In view of the existence of the above-mentioned problems, most of the prefabricated piers are currently built with one column to the top, which results in a large volume and weight of the prefabricated piers. Large equipment is needed for transportation and installation, and high requirements are placed on the hardening of the site, which in turn pushes up the overall construction cost. This is especially true for mountainous areas with poor traffic conditions, where it is difficult to transport large components and bring large equipment to the site. This limits the application of prefabricated piers in mountain bridges. Currently, there are no cases of prefabricated pier construction for mountain bridges.

In addition, for prefabricated thin-walled hollow piers, the extrusion of the inner formwork after concrete pouring makes it difficult to demould the inner formwork, which increases the difficulty of prefabrication of the pier column.

Summary of the invention

The purpose of the present invention is to provide a post-reinforcement method for thin-walled hollow pier construction in response to the above-mentioned problems existing in existing prefabricated assembled pier columns, thereby reducing the construction cost of prefabricated assembled pier columns while ensuring the construction quality of the pier columns, and promoting the popularization and application of assembled pier column construction methods.

The technical solution of the present invention is as follows:

A post-reinforcement prefabricated assembled thin-wall hollow pier construction method, characterized by:

(1) Pier segment design: The thin-walled hollow pier is divided into multiple prefabricated segments, which are further divided into two types: type I segments and type II segments. Type I segments are divided into four modules along the longitudinal direction, including two straight modules and two U-shaped modules, and type II segments are divided into four L-shaped modules along the longitudinal direction.

Each module has two side end surfaces and upper and lower end surfaces respectively provided with tenon or tenon groove structures that can match each other;

(2) Pier column main reinforcement and stirrup layout design: According to the designed bearing capacity of the pier column structure, the main reinforcement and stirrup layout of the pier column is carried out, and a layout diagram is drawn as the basis for the layout of the main reinforcement and stirrups of all prefabricated modules;

(3) Module prefabrication: Each module is prefabricated in the prefabrication yard. During prefabrication, when tying the steel bar skeleton, the main bars of all modules are not installed first. Main bar holes are reserved at the designed position of each main bar, and:

For straight plate modules, a threaded sleeve is screwed to both ends of each circumferential stirrup, and one half of each threaded sleeve is screwed to the stirrup, and the other half is reserved for connection with the rear stirrup of the U-shaped module;

For the U-shaped module, the stirrups at both ends are not installed first, and stirrup channels are reserved at the design position of each stirrup at both ends;

For L-shaped modules, the hoop reinforcement at one end is not installed first, and a hoop reinforcement channel is reserved at the design position of each hoop reinforcement at this end; a threaded sleeve is screwed to the end of each hoop reinforcement facing the module end face at the other end, and one half of the threaded sleeve is screwed to the hoop reinforcement, and the other half is reserved for connection with the post-installed hoop reinforcement of another L-shaped module;

After the reinforcement skeleton of each module is tied, the formwork is erected and concrete is poured. When the concrete reaches a certain strength, the formwork is removed to complete the module prefabrication.

After all modules are prefabricated, they are transported to the pier construction site and wait for installation;

(3) Cap construction: When pouring the cap, a threaded sleeve is embedded in the top surface of the cap according to the main reinforcement layout of the pier column, corresponding to each main reinforcement position, and the top surface of the threaded sleeve is flush with the top surface of the cap; the top surface of the cap is provided with a tenon or tenon groove matching the bottom of the pier column segment;

(4) Pier column installation: The pier column segments are installed in a staggered manner using type I segments and type II segments. When installing the first segment, the four modules of the segment are sequentially hoisted onto the pedestal, and the tenons and grooves between the modules fit together, and the bottom of each module is It fits with the tenon and mortise on the top surface of the pedestal;

Insert stirrups into each stirrup hole, and screw one end of the stirrup to the other half of the threaded sleeve opposite to it, and anchor the other end with a nut;

Insert a main reinforcement into each main reinforcement hole, screw the lower end of the main reinforcement to the threaded sleeve pre-buried on the cap, screw the upper end of the main reinforcement to another threaded sleeve, and screw one half of the threaded sleeve to the main reinforcement;

Grouting is performed in the stirrup channels and main reinforcement channels to complete the installation of the first segment pier column;

Hang the four modules of the segment that is different from the first segment onto the first segment, adjust the tenons and mortises between the modules and between the modules and the first segment, and then install the stirrups and main bars in the same way as the first segment;

The above method is used to stagger the subsequent segments to complete the installation of the prefabricated pier.

Compared with the existing prefabricated piers, this method has the following advantages:

The pier column is divided into multiple sections, and each section is divided into multiple modules, which greatly reduces the weight of each section of the pier column, making it easier to transport and hoist, and is conducive to its promotion and application in mountainous areas and areas with inconvenient transportation;

Each section of the pier is divided into multiple plate unit modules, which are convenient for erecting and dismantling the molds during prefabrication, greatly reducing the difficulty of prefabrication and facilitating rapid factory prefabrication;

The main reinforcement between segments is connected by threaded sleeves, which ensures reliable force bearing. The mortise and tenon structure between the upper and lower segments and between the modules of each segment can also increase the shear resistance of the structure, making the seismic effect of the prefabricated assembled piers no different from that of the cast-in-place piers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the modular segmentation of type I segments;

FIG2 is a schematic diagram of the modular segmentation of type II segments;

Figure 3 is a schematic diagram of the layout of the main reinforcement and hoop reinforcement of the pier column;

FIG4 is a schematic diagram of the planar structure of a straight module of an I-type segment;

FIG5 is an elevation view of a straight module of an I-type segment;

FIG6 is a plan view of a U-shaped module of an I-shaped segment;

FIG7 is an elevation view of a U-shaped module of an I-shaped segment;

Fig. 8 is a plan view of an L-shaped module of a type II segment;

FIG9 is a schematic diagram of the connection structure between the threaded sleeve and the main reinforcement and the annular stirrups;

FIG10 is a schematic diagram of the elevation structure of the platform;

11 is a schematic diagram of the structure of type I segments and type II segments staggered installation on the platform;

FIG12 is a schematic diagram of a method of inserting stirrups into stirrups of an I-type segment;

FIG13 is a schematic diagram of the planar structure after the I-type segment is installed;

FIG14 is a schematic diagram of the state of the stirrups being installed, anchored and grouted in the stirrup duct;

FIG15 is a detailed view of the installation structure of the stirrup anchor nut in FIG14;

FIG16 is a schematic diagram of a state where a main reinforcement is inserted into a main reinforcement hole;

FIG. 17 is a schematic diagram of the planar structure after the Type II segment is installed.

Detailed ways

The specific implementation methods of the present invention are as follows:

(1) Pier column segment design: As shown in FIGS. 1 and 2 , the thin-walled hollow pier is divided into a plurality of prefabricated segments, and the plurality of segments are further divided into two types: type I segments 10 and type II segments 20 . The type I segment 1 is longitudinally divided into four modules, including two straight-plate modules 101 and two U-shaped modules 102 , and the type II segment is longitudinally divided into four L-shaped modules 201 ;

Each module has two side end surfaces and upper and lower end surfaces respectively provided with tenon 1 and tenon groove 2 structures that can match each other;

(2) Layout design of main reinforcement and stirrups of pier columns: As shown in Figure 3, the main reinforcement 3 and stirrups 4 of the pier columns are laid out according to the designed bearing capacity of the pier column structure, and a layout diagram is drawn as the basis for the layout of the main reinforcement and stirrups of all pier column prefabricated modules;

(3) Module prefabrication: As shown in Figures 4 to 8, each module is prefabricated in a prefabrication yard. During prefabrication, when tying the steel bar skeleton, the main bars of all modules are not installed first, and a main bar channel 5 is reserved at the designed position of each main bar, and:

For the straight plate module 101, a threaded sleeve 6 is screwed to both ends of each annular stirrup 4, and one half of each threaded sleeve is screwed to the stirrup, and the other half is reserved for connection with the rear stirrup of the U-shaped module;

For the U-shaped module 102, the stirrups at both ends are not installed first, and stirrup channels 7 are reserved at the design positions of each stirrup at both ends;

For the L-shaped module 201, the circumferential stirrups at one end are not installed first, and a stirrup channel 7 is reserved at the design position of each stirrup at this end; each circumferential stirrup 4 at the other end is screwed with a threaded sleeve 6 at one end facing the module end face, and one half of the threaded sleeve is screwed with the stirrup, and the other half is reserved for connection with the later installed stirrups of another L-shaped module;

All the above-mentioned reserved main reinforcement holes 5 and annular stirrup reinforcement holes 7 can be formed by PVC pipes, and the PVC pipes are tied and fixed to the steel frame.

The threaded sleeve 6 and its connection structure with the stirrup 4 are shown in FIG9 , and its reserved end is set as a groove structure, which can guide the later installed stirrups when they are inserted and connected. The threaded sleeve installed on the pedestal and the threaded sleeve connected to the later installed main reinforcement are both set with this groove structure.

After the reinforcement skeleton of each module is tied, the formwork is erected and concrete is poured. When the concrete reaches a certain strength, the formwork is removed to complete the module prefabrication.

After all modules are prefabricated, they are transported to the pier construction site and wait for installation.

(3) Cap construction: As shown in Figure 10, when pouring the cap 30, the top surface of the cap is aligned with the main reinforcement layout of the pier column. A threaded sleeve 6 should be embedded in advance at each main reinforcement position, and the top surface of the threaded sleeve should be flush with the top surface of the cap; the top surface of the cap should be provided with a tenon or tenon groove matching the bottom of the pier column segment;

(4) Pier column installation: As shown in FIG. 11 , the pier column segments are installed in an alternating manner using type I segments 10 and type II segments 20. In the embodiment shown in FIG. 11 , the first segment is installed with a type I segment, the second segment is installed with a type II segment, and the third segment is installed with a type I segment. Alternatively, the first segment may be installed with a type II segment, and the second segment may be installed with a type I segment, and the installation may be repeated in this manner.

As shown in FIGS. 12 and 13 , the four modules of the I-type segment 10 are sequentially suspended on the cap, the tenons and tenons between the modules fit together, and the tenons and tenons at the bottom of each module fit together with the tenons and tenons at the top of the cap;

Insert the annular reinforcement 4 into each stirrup hole 7, and screw one end of the inserted stirrup to the other half of the threaded sleeve 6 on the module opposite to it, and anchor the other end with a nut;

As shown in Figures 14 and 15, in order to facilitate the installation of the anchor nut 8, when each module is prefabricated, an annular groove is provided around the end of the annular stirrup channel facing the outer wall of the module to accommodate and install the anchor nut; when each segment is installed, after the stirrups are inserted into the stirrup channel 7 of one module and connected with the threaded sleeve 6 of another module, the stirrups are tensioned, and the anchor nut 8 is screwed on the end of the stirrup facing the outer wall of the module, and the anchor nut is screwed into the annular groove, and the annular groove is sealed and repaired with concrete at a later stage.

As shown in FIG16 , a main reinforcement 3 is inserted into each main reinforcement hole 5, the lower end of the main reinforcement is screwed to the threaded sleeve 6 pre-buried on the cap, and the upper end of the main reinforcement is screwed to another threaded sleeve 6, and one half of the threaded sleeve is screwed to the main reinforcement;

Grouting is performed in the stirrup channels and main reinforcement channels to complete the installation of the first section pier.

Grouting can be done by pressure-free grouting, filling the hole with self-compacting, non-shrinkage cement slurry.

As shown in Figure 17, the four modules of the II-type segment are hoisted onto the first segment, the tenons and mortises between the modules and between the modules and the first segment are adjusted, and then the stirrups and main bars are installed in the same way as the first segment;

The above method is used to install subsequent segments in turn to complete the installation construction of the prefabricated pier.

In order to increase the firmness of the connection between segments, adhesive material is applied to the four end faces of each module when each segment is installed.

During the specific implementation of the present invention, when each module is prefabricated and the steel frame is tied, 2-4 vertical hangers can be symmetrically arranged on the steel frame. The arrangement of the hangers is shown in Figures 4 to 8, and the upper end of each hanger 9 is higher than the height of the module; when the module is transported and installed, it can be lifted by connecting the sling through the hanger 9; when the pier segment is installed, after each module is lifted, the exposed end of the hanger is cut off.

Claims (7)

1. A post-reinforcement prefabricated assembled thin-wall hollow pier construction method, characterized by:

   (1) Pier segment design: The thin-walled hollow pier is divided into multiple prefabricated segments, which are further divided into two types: type I segments and type II segments. Type I segments are divided into four modules along the longitudinal direction, including two straight modules and two U-shaped modules, and type II segments are divided into four L-shaped modules along the longitudinal direction.

   Each module has two side end surfaces and upper and lower end surfaces respectively provided with tenon or tenon groove structures that can match each other;

   (2) Pier column main reinforcement and stirrup layout design: According to the designed bearing capacity of the pier column structure, the main reinforcement and stirrup layout of the pier column is carried out, and a layout diagram is drawn as the basis for the layout of the main reinforcement and stirrups of all prefabricated modules;

   (3) Module prefabrication: Each module is prefabricated in the prefabrication yard. During prefabrication, when tying the steel bar skeleton, the main bars of all modules are not installed first. Main bar holes are reserved at the designed position of each main bar, and:

   For straight plate modules, a threaded sleeve is screwed to both ends of each circumferential stirrup, and one half of each threaded sleeve is screwed to the stirrup, and the other half is reserved for connection with the rear stirrup of the U-shaped module;

   For the U-shaped module, the stirrups at both ends are not installed first, and stirrup channels are reserved at the design position of each stirrup at both ends;

   For L-shaped modules, the hoop reinforcement at one end is not installed first, and a hoop reinforcement channel is reserved at the design position of each hoop reinforcement at this end; a threaded sleeve is screwed to the end of each hoop reinforcement facing the module end face at the other end, and one half of the threaded sleeve is screwed to the hoop reinforcement, and the other half is reserved for connection with the post-installed hoop reinforcement of another L-shaped module;

   After the reinforcement skeleton of each module is tied, the formwork is erected and concrete is poured. When the concrete reaches a certain strength, the formwork is removed to complete the module prefabrication.

   After all modules are prefabricated, they are transported to the pier construction site and wait for installation;

   (3) Cap construction: When pouring the cap, a threaded sleeve is embedded in the top surface of the cap according to the main reinforcement layout of the pier column, corresponding to each main reinforcement position, and the top surface of the threaded sleeve is flush with the top surface of the cap; the top surface of the cap is provided with a tenon or tenon groove matching the bottom of the pier column segment;

   (4) Pier column installation: The pier column segments are installed in a staggered manner using type I segments and type II segments. When installing the first segment, the four modules of the segment are sequentially hoisted onto the cap. The tenons and tenons between the modules fit in with each other, and the tenons and tenons between the bottom of each module and the top of the cap fit in with each other.

   Insert stirrups into each stirrup hole, and screw one end of the stirrup to the other half of the threaded sleeve opposite to it, and anchor the other end with a nut;

   Insert a main reinforcement into each main reinforcement hole, screw the lower end of the main reinforcement to the threaded sleeve pre-buried on the cap, screw the upper end of the main reinforcement to another threaded sleeve, and screw half of the threaded sleeve to the main reinforcement;

   Grouting is performed in the stirrup channels and main reinforcement channels to complete the installation of the first segment pier column;

   Hang the four modules of the segment that is different from the first segment onto the first segment, adjust the tenons and mortises between the modules and between the modules and the first segment, and then install the stirrups and main bars in the same way as the first segment;

   The above method is used to stagger the subsequent segments to complete the installation of the prefabricated pier.
2. According to the post-reinforcement prefabricated assembled thin-walled hollow pier construction method described in claim 1, it is characterized in that: when each module is prefabricated, 2-4 vertical hangers are symmetrically arranged on the steel skeleton when the steel skeleton is tied, and the upper end of each hanger is higher than the height of the module; when the module is transported and installed, it is lifted by connecting the hanger to the hoist; after each module is installed, the exposed end of the hanger is cut off.
3. According to the post-reinforcement prefabricated assembled thin-walled hollow pier construction method described in claim 1, it is characterized in that: when each module is prefabricated, an annular groove is provided around one end of the annular stirrup channel facing the module outer wall, for accommodating and installing anchor nuts; when each segment is installed, after the stirrups are inserted into the stirrup channel of one module and connected to the threaded sleeve of another module, the stirrups are tensioned, and the anchor nuts are screwed on the end of the stirrups facing the module outer wall, and the anchor nuts are screwed into the annular groove, and the annular notch is sealed and repaired with concrete at a later stage.
4. The post-reinforcement prefabricated assembled thin-walled hollow pier construction method according to claim 1 is characterized in that when tying the steel reinforcement skeleton of each module, all reserved main reinforcement channels and annular stirrup reinforcement channels are formed by PVC pipes.
5. The post-reinforcement prefabricated assembled thin-walled hollow pier construction method according to claim 1 is characterized in that the main reinforcement holes and stirrup reinforcement holes are grouting by using a pressure-free grouting method to fill the holes with self-compacting non-shrinkage cement slurry.
6. The post-reinforcement prefabricated assembled thin-walled hollow pier construction method according to claim 1 is characterized in that the ports of all threaded sleeves adopt a bevel structure to facilitate the connection with the main reinforcement or stirrups of other modules when the module is installed.
7. The post-reinforcement prefabricated assembled thin-walled hollow pier construction method according to claim 1 is characterized in that when each segment is installed, bonding material is applied to the four end faces of each module.