A method for producing pier columns with shear keys

Abstract

This invention discloses a method for producing pier columns with shear keys, belonging to the field of building construction. The method includes the following steps: selecting multiple standard section side molds and shear key side molds of different heights according to the required length of the precast pier column; horizontally binding the reinforcing cage using a reinforcing cage binding jig; horizontally assembling the standard section side molds and shear key side molds of one long-width face, then vertically assembling the section templates of the two short-width faces, then hoisting in the reinforcing cage; finally assembling the section templates of the other long-width face and the bottom mold; inserting a reinforcing steel positioning sleeve from the top to assemble the pier column mold and insert the reinforcing cage into the mold; flipping the pier column mold, then placing the pier column mold into the production platform, and fixing the bottom mold with bolts and a steel base; pouring concrete to complete the production of the precast pier column. This invention reasonably solves the problem of shared molds, saving costs and reducing the stagnation of molds on site.

Description

Technical Field

[0001] This invention belongs to the field of building construction, and in particular to a method for producing pier columns containing shear keys. Background Technology

[0002] Piers are load-bearing structures in civil engineering used to support the superstructure, and are mostly cast-in-place concrete structures. With the development of the prefabricated construction industry, precast piers have become a trend. The connection between precast piers and the substructure is often achieved using grouting sleeves. However, this method has drawbacks such as incomplete grouting and high cost. Therefore, socket-type precast piers have become the preferred design choice. However, socket-type precast piers have shear keys on their sides, and their formwork differs significantly from existing technologies where the side molds only have planes with grout inlet and outlet holes for the grouting sleeves and rubber plugs to fix the sleeves in the bottom mold. Existing formwork types can no longer meet the needs of current pier production. Furthermore, traditional precast piers, due to their large demand and relatively uniform component dimensions, require a large quantity of formwork with limited variety. In contrast, municipal projects are smaller in scale, with more varied component dimensions, requiring fewer but more diverse formwork types, necessitating a higher formwork reuse rate.

[0003] See appendix Figure 7 The shear keys on the side of the pier are matched with the shear keys in the bearing socket of the pier cap, and caulking material is filled between them to increase the strength of the bond. In order to improve shear resistance without reducing the structural strength of the pier itself, the protruding part of the shear key is 2cm higher than the side of the pier, and the concave surface of the shear key is flush with the side of the pier. This is different from the existing concave shear key setting, which increases the difficulty of formwork manufacturing. At the same time, the presence of the shear key also increases the difficulty of sharing formwork.

[0004] Meanwhile, traditional precast piers can ensure the protective layer of the bottom side reinforcement through grouting sleeves, while the protective layer of the reinforcement at the shear key of socket-type precast piers is more difficult to guarantee. In addition, during the reinforcement binding process, traditional precast piers can use grouting sleeves as a controller for the sinking of the reinforcement cage, while the sinking of the vertical main reinforcement of socket-type piers is more difficult to control. Summary of the Invention

[0005] To overcome the above-mentioned technical defects, the present invention provides a method for producing pier columns with shear keys, so as to solve the problems involved in the background art.

[0006] This invention provides a method for producing a pier column containing shear keys, comprising:

[0007] Step 1: Select multiple standard section side molds and side molds with shear keys of different heights according to the height requirements of the precast piers to be produced;

[0008] Step 2: Tie the steel cage horizontally according to the steel cage tying jig; and after the steel cage is tied into shape, tie a ring of concrete pads around the outside of the steel cage.

[0009] Step 3: Horizontally assemble the standard section of the side formwork and the section of the side formwork with shear keys on one long and wide face. Then, vertically assemble the section of the formwork on both short and wide faces. Then, hoist the steel cage in. Finally, assemble the section of the formwork and the bottom formwork on the other long and wide face. Insert the steel positioning sleeve from the top to realize the assembly of the pier column formwork and the insertion of the steel cage into the formwork.

[0010] Step 4: Flip the pier column template, then move the pier column template into the production platform, and connect and fix the bottom formwork with bolts and steel base;

[0011] Step 5: Pour concrete to complete the production of precast pier columns.

[0012] Preferably or optionally, the side formwork with shear key is made of 32mm steel plate, the shear key is chiseled out according to the design requirements of the pier column, and a chamfer of R150 is made at the bends on both ends.

[0013] The short width surface of the side formwork with shear key is made of 32mm steel plate, and the dimensions of the shear key are chiseled out according to the design requirements of the pier column.

[0014] Preferably or optionally, each of the four sides of the standard section side mold and the shear key side mold is provided with a connecting frame; and a positioning hole is provided on the connecting frame.

[0015] Preferably or optionally, the standard section side mold and the reinforcing back rib of the shear key side mold are located on the same plane.

[0016] Preferably or optionally, the horizontal binding method for the reinforcing cage includes the following steps:

[0017] The steel cage binding jig is assembled according to the design.

[0018] Place the transverse stirrups and longitudinal main bars of the steel cage, and weld a 2cm steel bar end to the bottom of every two transverse stirrups of the longitudinal main bars as a support for the steel cage;

[0019] The longitudinal reinforcement is tied to the longitudinal main reinforcement, and the steel cage tying jig is removed to form a steel cage.

[0020] Preferably or optionally, the method for binding the reinforcing cage further includes the following steps:

[0021] After the reinforcing cage is tied and formed, a 2.5cm thick high-strength concrete pad is tied around the outside of the reinforcing cage in a quincunx pattern; at the same time, a 4.5cm thick high-strength concrete pad is tied around the shear key position, and all the high-strength concrete pads are placed in the recess of the shear key template.

[0022] Preferably or optionally, the method for flipping the pier column formwork includes the following steps:

[0023] First, a gantry crane is used to lift and rotate the formwork and reinforcing bars as a whole. When the latter half of the formwork is about to stand upright, a buffer hydraulic cylinder is used to rotate the platform to bear the force, and the gantry crane is used to slowly rotate and stand the formwork upright.

[0024] Preferably or optionally, the tilting platform needs to be welded and fixed to the ground embedded parts, and the tilting platform needs to be sunk 400mm below the ground.

[0025] Preferably or optionally, a single pier prefabrication platform is provided with 9 embedded steel plates as a steel base; during pier casting, the pier bottom formwork is fixed to the steel base by bolts.

[0026] Preferably or optionally, the standard section side mold includes:

[0027] One standard section side mold with a height of 4m and a cross-section of 1.6m*1.8m, one standard section side mold with a height of 3m and a cross-section of 1.6m*1.8m, one standard section side mold with a height of 2m and a cross-section of 1.6m*1.8m, and one standard section side mold with a height of 1m and a cross-section of 1.6m*1.8m; wherein, the R150mm chamfer is made on the side with a width of 1.8m.

[0028] Two adjusting sections each with a height of 4m and a width of 0.4m, a height of 3m and a width of 0.4m, a height of 2m and a width of 0.4m, and a height of 1m and a width of 0.4m.

[0029] The side mold with shear key includes:

[0030] One 1.7m high, 1.6m x 1.8m side mold with shear keys, wherein the R150mm chamfer is made on the 1.8m wide side.

[0031] Two adjusting sections with shear keys, each 1.7m high and 0.4m wide, and one side mold adjusting section with shear keys, each 0.15m high. The R150mm chamfer is made on the side with a width of 1.8m.

[0032] This invention relates to a method for producing pier columns with shear keys, which has the following advantages compared to the prior art: This invention selects multiple standard section side molds and shear key side molds of different heights according to the length requirements of the precast pier columns to be produced, thus rationally solving the problem of shared templates, saving costs and reducing on-site template stagnation; it also solves the problem of template fabrication when the shear key protrudes from the side of the precast pier column; by binding high-strength concrete pads to the outside of the reinforcing cage after it is tied and formed, the problems of controlling the protective layer thickness at the shear key and controlling the settlement of the reinforcing cage are solved, greatly improving production efficiency and ensuring construction quality. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the pier mold in this invention.

[0034] Figure 2 This is a schematic diagram of the cross-section of the pier column with dimensions of 1.6m * 1.8m in this invention.

[0035] Figure 3 This is a cross-sectional schematic diagram of a pier column with cross-sectional dimensions of 1.8m * 2.0m in this invention.

[0036] Figure 4 This is a schematic diagram of the template structure with a width of 1.8m in this invention.

[0037] Figure 5 This is a schematic diagram of the structure of the flipping platform of the present invention.

[0038] Figure 6 This is a schematic diagram of the production method of the present invention.

[0039] Figure 7 This is a schematic diagram of the installation structure of the shear key and the bearing platform and slot in the prior art.

[0040] The attached figures are labeled as follows: 10, standard section side formwork; 20, side formwork with shear key; 30, bottom formwork; 40, steel base; 11, connecting frame; 12, hoisting ear plate; 50, tilting platform; 60, precast pier column; 61, shear key; 70, pier cap slot. Detailed Implementation

[0041] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0042] See appendix Figure 6 A method for producing a pier column containing shear keys includes the following steps:

[0043] Step 1: Select multiple standard section side molds 10 and side molds with shear keys of different heights according to the length requirements of the precast piers to be produced;

[0044] Specifically, the molds for producing precast pier columns mainly include: side molds, bottom molds 30, and rebar positioning fixtures. In this embodiment, the above-mentioned pier column molds can produce precast pier columns with two different cross-sections: 1.6m*1.8m and 1.8m*2.0m, but the precast construction process used is the same. The standard section side mold 10 and the side mold with shear keys 20 include four sides, specifically two long-width sides and two short-width sides.

[0045] Specifically, the standard section side mold 10 and the side mold with shear key 20 mainly include: 1.7m (height) side mold with shear key 201 sections, 4m (height) standard section side mold 101 sections, 3m (height) standard section side mold 101 sections, 2m (height) standard section side mold 101 sections, and 1m (height) standard section side mold 101 sections, all with a cross-sectional dimension of 1.6m*1.8m; 1 adjustment section with shear key 20 and a cross-sectional dimension of 1.8m*2.0m; and 2 adjustment sections each of 1.7m, 4m, 3m, 2m, and 1m in the 0.4m (1.6m direction) adjustment sections, with a R150mm chamfer on the 1.8m width.

[0046] It is worth noting that "section" is defined as the four sides of the mold, meaning "1 section" includes templates on all four sides; "unit" is defined as one side, meaning "2 units" includes templates on only two sides.

[0047] Different standard sections can be combined to form standard section side molds 10 and side molds with shear keys of different heights. See appendix. Figure 1 The production of pier columns with a height of 11700mm and a cross-sectional dimension of 1.6m*1.8m can be achieved by combining one 1.7m (height) standard side formwork section (20 sections), one 4m (height) standard side formwork section (101 sections), one 3m (height) standard side formwork section (101 sections), one 2m (height) standard side formwork section (101 sections), one 1m (height) standard side formwork section (101 sections), a bottom formwork section (30 sections), and a steel base section (40 sections). See also the appendix. Figure 2 Appendix Figure 3 , attached Figure 2 This is a schematic diagram of the cross-section of a pier column with dimensions of 1.6m x 1.8m. Figure 3This diagram shows the cross-section of a pier column with dimensions of 1.8m x 2.0m. By adding 0.4m and 0.15m adjusting sections, pier column formwork with different cross-sectional dimensions can be assembled. Specifically, the shear key height for a pier column with a cross-section of 1.6m x 1.8m is 1.7m; the shear key height for a pier column with a cross-section of 1.8m x 2.0m is 1.85m. This combination of formwork effectively saves on pier column mold costs, increases mold turnover, and reduces mold waste; it also solves the problem of shared formwork, saving costs and reducing on-site formwork stagnation.

[0048] The long and wide sides of the shear key side formwork 20 are made of 32mm steel plate, with the shear key dimensions chiseled out according to the pier design requirements. The depth is generally around 2cm, and a 150mm chamfer is applied at the bends on both ends. The short side of the shear key side formwork 20 is also made of 32mm steel plate, with the shear key dimensions chiseled out according to the pier design requirements. There are no welds at the shear key locations, resulting in better overall formwork integrity.

[0049] The panel of the standard section side formwork 10 is made of 12mm steel plate. The longitudinal ribs of the standard section side formwork 10 and the side formwork 20 with shear keys are made of 200*100*8mm rectangular tubes. The connecting frame 11 of the standard section side formwork 10 and the side formwork 20 with shear keys is made of 16mm steel plate. At the same time, the reinforcing back ribs of the formwork section with shear keys and other formwork sections are aligned on the same plane, making the structure more stable and easier to reinforce. In addition, lifting ear plates 12 are welded to the sides of the standard section side formwork 10 and the side formwork 20 with shear keys. The lifting ear plates 12 welded on the side formwork are used for the overall lifting of the pier column side formwork and the lifting of individual formwork pieces. The pier column formwork is also flipped over by the lifting ear plates 12.

[0050] Step 2: Tie the steel cage horizontally according to the steel cage tying jig; and after the steel cage is tied into shape, tie a ring of concrete pads around the outside of the steel cage.

[0051] Specifically, the pier reinforcement bars are tied horizontally. The reinforcement jig is provided by the formwork manufacturer. The design length of the pier reinforcement bar tying jig is 11m. The jig is designed to be used for both types of piers with different cross-sections. The positioning steel plate is replaced with the corresponding one for each type of pier. The side formwork positioning steel plate has elongated holes. Before lifting the reinforcement bars, the side formwork positioning steel plate is pulled back. The net spacing between the columns of the reinforcement bar tying platform is 1900mm. When tying the reinforcement bars for both types of piers with different cross-sections, the bottom surface is used as the tying surface. The bottom surface is also used as the 1.8m wide surface when flipping the pier formwork.

[0052] In this embodiment, a method for horizontally binding a reinforcing cage is provided, comprising the following steps: assembling the reinforcing cage binding jig according to the design, wherein the reinforcing cage binding jig is provided by the template manufacturer; placing the transverse stirrups and longitudinal main bars of the reinforcing cage as required, and welding a 2cm steel bar end at every two transverse stirrups at the bottom of the longitudinal main bars as a support for the reinforcing cage; binding the longitudinal bars and the longitudinal main bars, and removing the reinforcing cage binding jig to form the reinforcing cage.

[0053] Traditional precast piers can use grouting sleeves as a controller for the sinking of the reinforcing cage, while the sinking of the vertical main reinforcement bars in socket-type piers is more difficult to control. Therefore, using grouting sleeves as a controller for the sinking of the reinforcing cage in traditional precast piers, while the sinking of the vertical main reinforcement bars in socket-type piers is more difficult to control, can effectively prevent the sinking of the reinforcing cage.

[0054] Furthermore, after the reinforcing cage is tied and formed, a ring of 2.5cm thick high-strength concrete spacers (C60) is tied around the outside of the reinforcing cage in a quincunx pattern, with no less than 4 spacers per m. 2 Simultaneously, a ring of 4.5cm high-strength concrete spacers was tied around the shear key locations. All spacers were placed in the recessed areas of the shear key formwork to ensure the required concrete cover thickness for the reinforcement at the protruding parts of the shear key formwork. This solved the problems of controlling the concrete cover thickness at the shear key locations and controlling the settlement of the reinforcement cage, greatly improving production efficiency and ensuring construction quality.

[0055] Step 3: Horizontally assemble the standard section side formwork 10 and the section formwork 20 with shear keys on one long and wide face. Then, vertically assemble the section formwork on both short and wide faces. Then, hoist in the steel cage. Finally, assemble the section formwork and bottom formwork 30 on the other long and wide face. Insert the steel positioning sleeve from the top to realize the assembly of the pier column formwork and the insertion of the steel cage into the formwork.

[0056] Specifically, taking the production of precast piers with a cross-section of 1.6m*1.8m as an example, the formwork sections for the 1.8m width are assembled according to the required length of the precast pier. Next, the formwork sections for the 1.6m width on both sides are assembled. Then, the reinforcing cage is hoisted in, and finally, the 1.8m width side formwork and bottom formwork are assembled. Reinforcing steel positioning sleeves are inserted from the top, completing the pier mold assembly and reinforcing cage placement. For the 1.8*2.0m pier side formwork, a modular formwork is considered. The addition of 400mm adjusting sections allows for the assembly of a 1.8*2.0m pier, with a 150mm adjusting section considered at the lower shear key.

[0057] Each of the four sides of the standard section side formwork 10 and the shear key side formwork 20 is provided with a connecting frame 11; and a positioning hole is provided on the connecting frame 11. Positioning and fixing are achieved by passing a positioning sleeve through the positioning hole; the positioning sleeve is made of φ60*5mm seamless pipe, the positioning sleeve height is 400mm, and the circumference of the positioning fixture is 5mm smaller than the cross-section of the positioning hole of the pier column; the positioning sleeves for steel bars with a diameter of 32mm-40mm are all made of φ60*5mm seamless pipe.

[0058] Step 4: Flip the pier column template, then move the pier column template into the production platform, and connect and fix the bottom mold 30 to the steel base 40 with bolts;

[0059] Specifically, see Appendix Figure 5 First, a gantry crane is used to lift and rotate the formwork and reinforcing bars as a whole. When the rear half of the formwork is about to stand upright, the buffer cylinder is stressed, and the gantry crane slowly rotates the formwork upright. Then, the pier mold is placed into the production platform. Each pier prefabrication platform has nine embedded steel plates as steel bases 40. During pier casting, the pier bottom formwork 30 is bolted to the steel bases 40. The rotating platform 50 needs to be welded to the ground embedded parts, and the rotating platform 50 needs to be sunk 400mm below the ground; the user needs to ensure proper drainage.

[0060] Step 5: Pour concrete to complete the production of precast pier columns.

[0061] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A method for producing a pier column containing shear keys, characterized in that, include: Step 1: Select multiple standard section side molds and side molds with shear keys of different heights according to the length requirements of the precast piers to be produced; The long and short width surfaces of the shear key side mold are chiseled to form the shear key template recess; Step 2: Assemble the rebar cage binding jig according to the design, place the transverse stirrups and longitudinal main bars of the rebar cage, and weld a 2cm rebar end to every two transverse stirrups at the bottom of the longitudinal main bars as a support for the rebar cage. Tie the transverse stirrups to the longitudinal main bars. After the rebar cage is bound, tie a 2.5cm thick high-strength concrete pad around the outside of the rebar cage in a quincunx pattern. At the same time, tie a 4.5cm thick high-strength concrete pad around the shear key position, and all the high-strength concrete pads are placed in the recess of the shear key template. Step 3: Horizontally assemble the standard section of the side formwork and the section of the side formwork with shear keys on one long and wide face. Then, vertically assemble the section of the formwork on both short and wide faces. Then, hoist the steel cage in. Finally, assemble the section of the formwork and the bottom formwork on the other long and wide face. Insert the steel positioning sleeve from the top to realize the assembly of the pier column formwork and the insertion of the steel cage into the formwork. Step 4: Flip the pier column template, then move the pier column template into the production platform, and connect and fix the bottom formwork with bolts and steel base; Step 5: Pour concrete to complete the production of precast pier columns.

2. The method for producing a pier column with shear keys according to claim 1, characterized in that, The long and wide sides of the side formwork with shear keys are made of 32mm steel plates, and the dimensions of the shear keys are chiseled out according to the design requirements of the pier column, with R150mm chamfers bent on both end faces; the short and wide sides of the side formwork with shear keys are made of 32mm steel plates, and the dimensions of the shear keys are chiseled out according to the design requirements of the pier column.

3. The method for producing a pier column with shear keys according to claim 1, characterized in that, Each of the standard section side mold and the side mold with shear key has a connecting frame on all four sides; and a positioning hole is provided on the connecting frame.

4. The method for producing a pier column containing a shear key according to claim 1, characterized in that, The standard section side mold and the reinforcing back rib of the side mold with shear key are located on the same plane.

5. The method for producing a pier column with a shear key according to claim 1, characterized in that, The method for flipping the pier column formwork includes the following steps: First, a gantry crane is used to lift and rotate the formwork and reinforcing bars as a whole. When the latter half of the formwork is about to stand upright, a buffer hydraulic cylinder is used to rotate the platform to bear the force, and the gantry crane is used to slowly rotate and stand the formwork upright.

6. The method for producing a pier column containing a shear key according to claim 5, characterized in that, The tilting platform needs to be welded and fixed to the ground embedded parts, and the tilting platform needs to be sunk 400mm below the ground.

7. The method for producing a pier column with a shear key according to claim 1, characterized in that, Nine precast steel plates are set on the precast platform of a single pier column as a steel base; when the pier column is poured, the bottom formwork of the pier column is fixed to the steel base by bolts.

8. The method for producing a pier column with shear keys according to claim 1, characterized in that, The standard section side mold includes: One standard section side mold with a height of 4m and a cross-section of 1.6m*1.8m, one standard section side mold with a height of 3m and a cross-section of 1.6m*1.8m, one standard section side mold with a height of 2m and a cross-section of 1.6m*1.8m, and one standard section side mold with a height of 1m and a cross-section of 1.6m*1.8m; wherein, a chamfer of R150mm is made on the side with a width of 1.8m; Two adjusting sections each with a height of 4m and a width of 0.4m, a height of 3m and a width of 0.4m, a height of 2m and a width of 0.4m, and a height of 1m and a width of 0.4m. The shear key side mold includes: one section of shear key side mold with a height of 1.7m and a width of 1.6m and a height of 1.8m, wherein a chamfer of R150mm is made on the side surface with a width of 1.8m; Two adjusting sections with shear keys, each 1.7m high and 0.4m wide, and one side mold adjusting section with shear keys, each 0.15m high. The R150mm chamfer is made on the side with a width of 1.8m.

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