Combined pier column, centering mechanism for pier column construction, and pier column construction method

Abstract

The present invention discloses a composite pier, a centering mechanism for pier construction, and a pier construction method, belonging to the technical field of bridge engineering. The pier comprises a UHPC tube, a 'M' steel section, and waste fiber recycled concrete. The UHPC tube acts as a permanent mold and is arranged on the outer layer. The 'M' steel section is arranged inside the UHPC tube and is arranged concentrically with the UHPC tube. The waste fiber recycled concrete is poured in layers between the UHPC tube and the 'M' steel section to form a recycled concrete core. The UHPC tube, recycled concrete core, and 'M' steel section are connected as a whole. The UHPC tube comprises ordinary Portland cement, mineral admixtures, quartz sand, quartz powder, steel fiber, high-efficiency water reducer, and water. The mixing mass ratio of each component is: The UHPC tube comprises ordinary Portland cement, mineral admixtures, quartz sand, quartz powder, steel fiber, high-efficiency water reducer, and water. This technical solution is used to improve the compressive strength, tensile strength, toughness, durability, and other properties of the composite pier, thereby extending the service life of the composite pier.

Description

Technical Field

[0001] The present invention belongs to the technical field of bridge engineering, and in particular relates to a combined pier column, a centering mechanism for pier column construction, and a pier column construction method. Background Art

[0002] Due to the hoop effect of the steel tube on the concrete in the inner core area, the steel tube concrete composite pier column has the advantages of high compressive bearing capacity, good plasticity and toughness, high temperature resistance and corrosion resistance, and its structure is simple, construction is convenient, and it has high economic benefits. Therefore, the steel tube concrete composite pier column is widely used in high-rise main buildings, bridge engineering and other fields. However, the steel tube concrete composite pier column still has some shortcomings at this stage: (1) Due to the difference in elastic modulus and linear expansion coefficient of the two materials, the performance of the two at the interface is general and the structural integrity is poor; (2) Steel is generally prone to rust and has poor durability, requiring additional anti-rust coating, which increases the construction and maintenance costs of the structure; (3) The use of concrete not only has serious damage to the environment, but also concrete gradually deteriorates in nature, its mechanical properties decrease, its integrity is insufficient, and it may even break. Therefore, the construction industry urgently needs to find new materials and processes to replace it to meet the inevitable needs of sustainable development of the construction industry.

[0003] In recent years, with the advancement of urbanization in my country, a large number of new buildings have emerged, but at the same time, the demolition of old buildings and the disposal of construction waste are also facing serious problems. The disposal of these construction wastes not only consumes a lot of money and site resources, but also causes serious pollution to the environment. Therefore, maximizing the recycling and reuse of construction waste is an effective way to improve the above situation. At present, scholars at home and abroad generally use the abandoned building concrete in construction waste as recycled concrete aggregate by crushing it, partially or completely replacing natural aggregate, to obtain recycled concrete (RAC), making it a green and sustainable building material.

[0004] For example, the invention patent with publication number CN 108894432 A discloses an ultra-high-performance steel fiber concrete tube-constrained recycled block concrete column, the structure of which is mainly composed of UHPFRC tubes, recycled concrete, and ordinary concrete; the recycled concrete and ordinary concrete are mixed as required and then poured inside the UHPFRC tubes. The UHPFRC tubes and the internal concrete form a composite pier column. When subjected to upper loads, the UHPFRC tubes will have a hoop effect on the internal concrete, improving the bearing capacity of the pier column. Although the use of this composite pier column structure can save concrete and steel and enhance the compressive bearing capacity of the structure, due to defects such as recycled concrete aggregate defects and internal microcracks, the structure has problems such as low tensile strength and low toughness, and cannot meet the durability requirements of the structure in harsh environments.

[0005] In summary, the use of recycled concrete can effectively solve the problem of construction waste disposal. However, how to improve the compressive strength, tensile strength, toughness and other properties of the composite piers to meet the durability requirements of the structure and extend the service life of the composite piers has become a difficult problem that needs to be solved urgently. Summary of the Invention

[0006] In view of this, the object of the present invention is to provide a composite pier, a centering mechanism for pier construction, and a pier construction method, so as to improve the compressive strength, tensile strength, toughness and durability of the composite pier and extend the service life of the composite pier.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] The present invention discloses a composite pier column, comprising a UHPC tube, a 'M' steel, and waste fiber recycled concrete. The UHPC tube acts as a permanent mold and is arranged on the outer layer. The 'M' steel is arranged inside the UHPC tube and is arranged concentrically with the UHPC tube. The waste fiber recycled concrete is poured in layers between the UHPC tube and the 'M' steel to form a recycled concrete core. The UHPC tube, the recycled concrete core, and the 'M' steel are connected as a whole. The UHPC tube comprises ordinary Portland cement, mineral admixtures, quartz sand, quartz powder, steel fiber, high-efficiency water reducer, and water. The mixing mass ratio of each component is: m 水泥 ∶m 矿物掺和料 ∶m 石英砂 ∶m 石英粉 ∶m 钢纤维 ∶m 高效减水剂 ∶m 自来水 =1:0.2-0.4:1.1-1.3:0.24-0.26:0.14-0.16:0.024-0.026:0.17-0.19; the waste fiber recycled concrete includes cement, quartz sand, waste fiber, recycled coarse aggregate and tap water, and the mixing mass ratio between the components is: m 水泥 ∶m 石英砂 ∶m 废弃纤维 ∶m 再生粗骨料 ∶m 自来水 =1∶1.7-1.9∶0.001-0.002∶1.3-1.5∶0.4-0.6.

[0009] Furthermore, the UHPC tube is evenly arranged with longitudinal structural bars and spiral stirrups, and the longitudinal structural bars and spiral stirrups form a steel cage.

[0010] Furthermore, the cross-section of the UHPC tube is circular or square, and its thickness ranges from 2 cm to 12 cm.

[0011] Furthermore, an upper oblique groove and a lower oblique groove for splicing and positioning are respectively provided on both ends of the UHPC tube, and the connecting gap between the upper oblique groove and the lower oblique groove is filled with epoxy resin.

[0012] Furthermore, the mineral admixture includes fly ash, silica fume, slag powder and limestone powder; the steel fiber includes end hook-type steel fiber and corrugated steel fiber evenly distributed in the concrete; the high-efficiency water reducer is CX-8 polycarboxylic acid high-performance water reducer; the waste fiber in the waste fiber recycled concrete is a discarded polypropylene carpet segment, the length of the polypropylene carpet segment is 19 mm, and the recycled coarse aggregate in the waste fiber recycled concrete is an abandoned reinforced concrete building with a particle size of 5.5-25.5 mm, and the concrete grade is C40.

[0013] A centering mechanism for pier construction comprises a support column, wherein the support column is provided with a first support plate and a second support plate at intervals from top to bottom, a first through hole is opened in the middle of the upper surface of the first support plate, and at least three groups of first centering mechanisms are evenly distributed around the edge of the upper surface of the first support plate, the first centering mechanism comprises a first telescopic element fixed to the edge of the first support plate, the output end of the first telescopic element is arranged toward the center of the first support plate, an arc plate is provided on the output end of the first telescopic element, and at least three groups of second centering mechanisms are evenly distributed around the lower surface of the first support plate, the second centering mechanism comprises a second telescopic element fixed to the edge of the first support plate, the output end of the second telescopic element is arranged toward the center of the first support plate, and a wedge block is provided on the output end of the second telescopic element.

[0014] After the UHPC pipe is poured and cured, one end of it is hoisted and placed on the first pallet, and then it is pushed to the middle of the first pallet through the movement of the first centering mechanism. Similarly, the M-shaped steel is pushed to the middle of the second pallet through the second centering mechanism. Since the central axes of the first pallet and the second pallet coincide, the center lines of the M-shaped steel and the UHPC pipe are aligned at this time. It should be noted that the number of groups of the second centering mechanism is related to the number of M-shaped steel flange plates. For example, when there are six flange plates, three groups of second centering mechanisms are used. The wedge blocks are mainly clamped between adjacent flange plates, and each first telescopic element and each second telescopic element are controlled synchronously respectively.

[0015] The locking mechanism is fixedly mounted on the side panel and has a lockhole that is formed on the side panel that receives the locking cam of the locking cam, and a lockhole that is formed on the side panel that receives the locking cam.

[0016] When the M-shaped steel is hoisted onto the second pallet, the wedge block may not be aligned with the gap between the adjacent flange plates due to the incorrect angle, resulting in the inability to achieve centering. At the same time, the arc plate method is only suitable for column positioning. If used on the M-shaped steel, the contact area between the arc plate and the M-shaped steel flange plate is small and unstable, which will cause the M-shaped steel to rotate, resulting in poor centering effect. Therefore, the wedge block is used to push the M-shaped steel to the center.

[0017] When the M-shaped steel is placed on the third support plate, the third support plate will move downward under the action of its gravity. At this time, the mounting plate will contact the bottom surface of the M-shaped steel, that is, the retaining column is located between adjacent flange plates. At this time, it is only necessary to manually control the rotation of the rotating element to drive the M-shaped steel to rotate to the specified position matching the wedge block under the action of the retaining column. The setting of the reset spring is to prevent the flange plate from pressing the retaining column, causing damage to the retaining column or tipping over of the M-shaped steel.

[0018] Furthermore, a shock-absorbing spring is provided between the third support plate and the second support plate, and a lifting element is provided on one end of the retaining column located on the lower surface of the second support plate. The benefit is that it ensures the stability of the downward movement of the M-shaped steel and reduces its impact force. The lifting element can lift the M-shaped steel that has been aligned to the same plane as the end of the UHPC tube, which facilitates the fixation or pouring between the M-shaped steel and the UHPC tube.

[0019] Furthermore, a plurality of through holes are provided in the length direction of each flange plate of the M-shaped steel, and a traction rope is provided in the through hole, and the traction rope connects the through holes on each flange plate in series. The benefit is that, through this arrangement, after the waste fiber recycled concrete is poured, the traction rope is poured into the interior of the concrete, which can be understood as the traction rope being fixed in the recycled concrete core, that is, the connection effect between the M-shaped steel and the recycled concrete core is improved in a redirected manner, so that the contact surface between the M-shaped steel and the recycled concrete core is not easily separated when shaking or bending under stress; at the same time, this arrangement also improves the integrity of the pier column, so that the pier column is subjected to stress as a whole, thereby improving the stress effect of the pier column and further improving the toughness and ductility of the pier column. It is not difficult to understand that no matter whether the M-shaped steel or the recycled concrete core is subjected to bearing torque or bending torque, under the driving action of the traction rope (when one is subjected to stress, the traction rope will drive the other to be subjected to stress together), both will jointly bear lateral bending or vertical deformation.

[0020] Furthermore, an auxiliary centering mechanism is provided at the end of the UHPC tube, which includes an annular hoop, a wedge and an adjusting bolt. At least two groups of adjusting bolts are centrally symmetrically arranged on the annular hoop. The adjusting bolt is threadedly connected to the annular hoop, and one end of the wedge is fixed to the end of the adjusting bolt. The annular hoop is used to be fixed to the UHPC tube. The advantage is that by adjusting the position of the wedge to extend or retract, the wedge is clamped between the flange plates of the M-shaped steel, that is, the wedge can limit and guide the position of the M-shaped steel falling into the inside of the UHPC tube, ensuring the concentric arrangement of the M-shaped steel and the UHPC tube. Of course, it is not difficult to understand that the movement of the adjusting bolts arranged centrally and symmetrically should be consistent.

[0021] The present invention also discloses a construction method of a combined pier column, which specifically includes the following construction steps:

[0022] Step 1: Prefabricate the UHPC pipe. According to the design drawings, evenly arrange and tie several longitudinal structural bars and several spiral stirrups to form a steel cage. Cast the UHPC pipe in the steel cage according to the designed thickness and cure to the designed strength.

[0023] Step 2: Position and fix the steel sections. Prefabricate the steel sections in the factory or on-site according to the design drawings, and reserve holes in the steel sections to ensure that they meet the accuracy standards. After the steel sections are hoisted, perform multiple calibrations to ensure that the UHPC tubes and the M-shaped steel sections share the same center. Use bolts to fix the steel sections. After the bolts are installed, full weld the connection surfaces.

[0024] Step 3: Connect the ends of the UHPC pipe. Transport the prefabricated UHPC pipe to the construction site. After positioning and fixing the UHPC pipe, assemble the sections to make a permanent template. By rotating and adjusting, align the upper and lower oblique grooves of the UHPC pipe. After the splicing is completed, epoxy resin is used to fill and fix the concave and convex joints.

[0025] Step 4: Pour the recycled concrete core. Pour the mixed waste fiber recycled concrete between the UHPC pipe and the M-shaped steel. When the waste fiber recycled concrete reaches the required design strength, proceed to the next step.

[0026] The beneficial effects of the present invention are:

[0027] (1) Waste fibers generally come from discarded carpets (polypropylene carpets), which have low recycling costs and have the advantages of good acid and alkali resistance, light weight, and non-water absorption (i.e., they will not change the concrete mix ratio);

[0028] (2) Adding waste fibers to recycled concrete as reinforcing fibers can turn waste into treasure, improve the internal structure of recycled concrete, effectively improve the mechanical properties and ductility of recycled concrete, limit the development of cracks, and improve the durability of the structure;

[0029] (3) UHPC pipes and waste recycled concrete are very similar in elastic modulus, density and thermal expansion coefficient. Therefore, UHPC pipes have good performance at the interface with waste recycled concrete, better deformation coordination ability, better bearing capacity, toughness and ductility;

[0030] (4) The combination of M-shaped steel and concrete can effectively improve the bearing capacity and ductility of the structure;

[0031] (5) Use waste fiber recycled concrete to replace fresh concrete, realize the recycling and reuse of construction waste, save resources, be green and environmentally friendly, have high economic benefits, and meet the actual requirements of sustainable development;

[0032] (6) Using UHPC pipes instead of ordinary steel pipes to constrain the internal waste fiber recycled concrete, so that the core concrete is in a three-dimensional stress state, limiting its lateral deformation and the development of diagonal cracks; the internal configuration of the M-shaped steel can significantly improve the bearing capacity and ductility of the composite pier column;

[0033] (7) UHPC pipes have good impermeability and corrosion resistance, which can effectively protect the composite piers and meet the durability requirements of the structure in harsh environments;

[0034] (8) UHPC pipes act as permanent formwork, and there is no need to remove the formwork, which results in high construction efficiency and safety;

[0035] (9) UHPC pipes are prefabricated in the factory, transported to the construction site for end splicing, and finally poured with recycled concrete core to complete the construction. The UHPC pipe end connection method is simple and easy to operate, the construction process is convenient, which reduces the construction difficulty and saves time and cost.

[0036] (10) Compared with the traditional method of adding steel pipe to the internal pile core, the M-shaped steel has a larger contact area with the internal concrete and a better contact effect. At the same time, the setting of the traction rope further improves the contact and fixing effect between the two, making the contact surface of the two less likely to separate or slip during vibration or bending, thereby improving the anti-seismic and earthquake-proof effect of the pier column.

[0037] Other advantages, objectives and features of the present invention will be described in the following description and will be apparent to those skilled in the art to some extent, or those skilled in the art can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to make the purpose, technical solutions and beneficial effects of the present invention more clear, the present invention provides the following drawings for illustration:

[0039] Figure 1 This is a schematic diagram of the circular cross-section of a composite pier column composed of UHPC tube, waste fiber recycled concrete, and M-shaped steel. 1-1 is a horizontal cross-section, and 1-2 is a vertical cross-section.

[0040] Figure 2 This is a schematic diagram of the square section of a composite pier column made of UHPC tube, waste fiber recycled concrete, and M-shaped steel. 2-1 is a horizontal section view, and 2-2 is a vertical section view.

[0041] Figure 3 A three-dimensional schematic diagram of a composite pier column with a circular cross-section of UHPC tube, waste fiber recycled concrete, and M-shaped steel;

[0042] Figure 4 A three-dimensional schematic diagram of a square-section UHPC tube-waste fiber recycled concrete-M-shaped steel composite pier;

[0043] Figure 5 Schematic diagram of the epoxy resin end oblique groove connection used in the UHPC tube of the present invention, wherein 5-1 is a cross-sectional view of the end structure, and 5-2 is a cross-sectional view of the end splicing;

[0044] Figure 6 This is a three-dimensional schematic diagram of the traction rope installed on the M-shaped steel;

[0045] Figure 7 It is a schematic cross-sectional view of the traction rope acting on the M-shaped steel and the recycled concrete core;

[0046] Figure 8 This is a three-dimensional schematic diagram of the centering mechanism at work;

[0047] Figure 9 It is a three-dimensional schematic diagram of the centering mechanism;

[0048] Figure 10 Schematic diagram of a top view of the centering mechanism;

[0049] Figure 11 This is an exploded view of the centering mechanism;

[0050] Figure 12 This is a schematic diagram of the settings of components such as the retaining column and shock-absorbing spring.

[0051] The following are marked in the accompanying drawings:

[0052] UHPC pipe 1, upper oblique groove 1-1, lower oblique groove 1-2, epoxy resin 1-3, spiral stirrups 2, longitudinal structural reinforcement 3, M-shaped steel 4, waste fiber recycled concrete 5, traction rope 6, base 7, support column 8, second support plate 9, first support plate 10, arc plate 11, first telescopic element 12, second telescopic element 13, wedge block 14, first through hole 15, third support plate 16, sliding column 17, stop block 18, shock-absorbing spring 19, second through hole 20, mounting plate 21, stop column 22, return spring 23, output end 24, and rotary drive element 25. DETAILED DESCRIPTION

[0053] like Figures 1 to 12 As shown, the present invention provides a composite pier column, comprising a UHPC tube 1, a 'P-shaped steel' 4, and waste fiber recycled concrete 5. The UHPC tube 1 replaces the conventional steel tube in the prior art. The 'P-shaped steel' 4 is disposed within the UHPC tube 1. The waste fiber recycled concrete 5 is layered and poured between the UHPC tube 1 and the 'P-shaped steel' 4 to form a recycled concrete core. The UHPC tube 1 serves as a permanent formwork and is integrally connected to the core concrete. The UHPC tube 1 comprises ordinary Portland cement, mineral admixtures, quartz sand, quartz powder, steel fiber, a high-efficiency water reducer, and water. The mixing mass ratio of each component is: m 水泥 ∶m 矿物掺和料 ∶m 石英砂 ∶m 石英粉 ∶m 钢纤维 ∶m 高效减水剂 ∶m 自来水 =1∶0.2-0.4∶1.1-1.3∶0.24-0.26∶0.14-0.16∶0.024-0.026∶0.17-0.19; Waste fiber recycled concrete 5 includes cement, quartz sand, waste fiber, recycled coarse aggregate and tap water, and the mixing mass ratio between the components is: m 水泥 ∶m石英砂 ∶m 废弃纤维 ∶m 再生粗骨料 ∶m 自来水 =1∶1.7-1.9∶0.001-0.002∶1.3-1.5∶0.4-0.6.

[0054] Specifically, the UHPC tube 1 is evenly arranged with spiral stirrups 2 and longitudinal structural bars 3 to form a steel cage. The UHPC tube 1 adopts a circular or square cross-section with a thickness ranging from 2cm to 12cm. The concrete materials of the UHPC tube 1 include ordinary Portland cement, mineral admixtures, quartz sand, quartz powder, steel fiber, high-efficiency water reducer and water, preferably mixed in the following proportion: 水泥 ∶m 矿物掺和料 ∶m 石英砂 ∶m 石英粉 ∶m 钢纤维 ∶m 高效减水剂 ∶m 自来水 =1∶0.3∶1.2∶0.25∶0.15∶0.025∶0.18, where m represents mass.

[0055] Furthermore, the UHPC tube 1 acts as a construction template. A connection method that is convenient for construction is adopted. An upper oblique groove 1-1 and a lower oblique groove 1-2 are provided at the end assembly section of the UHPC tube 1 to serve as a connection and positioning function. After the oblique grooves are spliced, the connection gap is filled with epoxy resin 1-3 to serve as a connection and fixation function of the end.

[0056] Specifically, the M-shaped steel 4 is made of Q235 grade hot-rolled steel and is placed in the center of the core recycled concrete. The waste fiber recycled concrete 5 includes cement, quartz sand, waste fiber, recycled coarse aggregate and tap water, preferably using the following mix ratio: m cement: m quartz sand: m 废弃纤维 ∶m recycled coarse aggregate ∶m tap water = 1∶1.8∶0.001∶1.4∶0.5, where m represents mass. Since other raw materials are configured based on the mass of cement, the proportion of cement is maintained at 1.

[0057] like Figure 6 and Figure 7As shown, preferably, each flange of the cross-shaped steel 4 is provided with a plurality of through holes along its length, and a traction rope 6 is provided in each through hole. The traction rope 6 connects the through holes on each flange in series. With this arrangement, after the waste fiber recycled concrete 5 is poured, the traction rope 6 is poured into the interior of the concrete, which can be understood as the traction rope being fixed in the recycled concrete core. This improves the connection between the cross-shaped steel 4 and the recycled concrete core in a redirected manner, making the contact surface between the cross-shaped steel 4 and the recycled concrete core less likely to separate when shaken or bent under stress. At the same time, this arrangement also improves the integrity of the pier column, allowing the entire pier column to be subjected to stress together, improving the pier column's stress-bearing effect, and further enhancing the pier column's toughness and ductility. Preferably, the traction rope is an anti-corrosion treated steel wire rope or bent steel bar.

[0058] like Figures 8-12 As shown, a centering mechanism for pier construction includes at least three support columns 8 arranged on a base 7, and the support columns 8 are provided with a first support plate 10 and a second support plate 9 at intervals from top to bottom. A first through hole 15 is opened in the middle of the upper surface of the first support plate 10, and at least three groups of first centering mechanisms are evenly distributed on the circumference of the edge of the upper surface of the first support plate 10. The first centering mechanism includes a first telescopic element 12 fixed to the edge of the first support plate 10, and the output end 24 of the first telescopic element 12 is arranged toward the center of the first support plate 10, and an arc plate 11 is provided on the output end 24 of the first telescopic element 12. At least three groups of second centering mechanisms are evenly distributed on the circumference of the lower surface of the first support plate 10, and the second centering mechanism includes a second telescopic element 13 fixed to the edge of the first support plate 10, and the output end 24 of the second telescopic element 13 is arranged toward the center of the first support plate 10, and a wedge block 14 is provided on the output end 24 of the second telescopic element 13.

[0059] After the UHPC pipe is poured and cured, one end of it is hoisted and placed on the first support plate 10, and then it is pushed to the middle of the first support plate 10 through the movement of the first centering mechanism. Similarly, the M-shaped steel 4 is pushed to the middle of the second support plate 9 through the second centering mechanism. Since the central axes of the first support plate 10 and the second support plate 9 coincide with each other, the M-shaped steel 4 and the UHPC pipe are aligned in the center line at this time. It should be noted that the number of groups of the second centering mechanism is related to the number of flange plates of the M-shaped steel 4. For example, when there are six flange plates, three groups of second centering mechanisms are used. The wedge block 14 is mainly clamped between adjacent flange plates, and each first telescopic element 12 and each second telescopic element 13 are controlled synchronously respectively.

[0060] A third support plate 16 is provided in the middle of the first support plate 10, which matches the first through hole 15. The lower surface of the third support plate 16 is provided with at least two sliding posts 17. One end of the sliding post 17 is slidably connected to the second support plate 9, and the other end of the sliding post 17 is fixed to the third support plate 16. A stopper 18 is provided on the sliding post 17 to limit the sliding position of the sliding post 17. A second through hole 20 is opened in the middle of the third support plate 16, and a rotation positioning mechanism is provided below the second through hole 20. The rotation positioning mechanism includes a mounting plate 21 matching the second through hole 20. A plurality of stop posts 22 are provided on the mounting plate 21. The stop post 22 is vertically slidably connected to the mounting plate 21 and blocks a return spring 23 provided at one end below the mounting plate 21. The two ends of the return spring 23 are respectively fixed to the ends of the mounting plate 21 and the stop post 22. A rotation driving element 25 is provided below the stop post 22, and the output end 24 of the rotation driving element 25 is fixedly connected to the middle part of the mounting plate 21.

[0061] When the M-shaped steel 4 is hoisted onto the second supporting plate 9, there may be a problem that the wedge block 14 cannot be aligned with the gap between the adjacent flange plates due to the wrong angle, resulting in the inability to achieve the centering operation. At the same time, the arc plate 11 is only suitable for column positioning. If it is used on the M-shaped steel 4, the contact surface between the arc plate 11 and the flange plate of the M-shaped steel 4 is small and unstable, which will cause the M-shaped steel 4 to rotate, resulting in poor centering effect. Therefore, the wedge block 14 is used to push the M-shaped steel 4 to the center;

[0062] When the M-shaped steel 4 is placed on the third support plate 16, the third support plate 16 will move downward under the action of its gravity, that is, the mounting plate 21 is in contact with the bottom surface of the M-shaped steel 4, that is, the retaining column 22 is located between the adjacent flange plates. At this time, it is only necessary to manually control the rotation of the rotating element to drive the M-shaped steel 4 to rotate to the specified position matching the wedge block 14 under the action of the retaining column 22. The setting of the reset spring 23 is to avoid the flange plate just pressing the retaining column 22, causing damage to the retaining column 22 or the M-shaped steel 4 to fall over.

[0063] A shock-absorbing spring 19 is installed between the third support plate 16 and the second support plate 9. A lifting element is installed on one end of the stop column 22 located on the lower surface of the second support plate 9 to ensure the stability of the downward movement of the cross-shaped steel 4 and reduce its impact force. The lifting element can lift the aligned cross-shaped steel 4 to a level with the end of the UHPC tube, facilitating the fixation or casting of the cross-shaped steel 4 to the UHPC tube. It should be noted that the first telescopic element 12, the second telescopic element 13, and the lifting element can be hydraulic cylinders or linear motors, and the rotary drive element 25 can be a rotary motor. It should also be noted that after the alignment is completed and the UHPC tube 1 and cross-shaped steel 4 are fixed, the aligned UHPC tube 1 and cross-shaped steel 4 can be lifted by a crane, and the device can be removed. Connection to the pier and casting can then proceed. Preferably, the cross-shaped steel 4 in the assembled pier column is formed as a single unit, and the UHPC tube 1 is gradually spliced onto its outer side before casting.

[0064] Of course, in the above technical solution, only a simple deformation is required to first position the P-shaped steel 4 at the center of the pier base, and then fix it before positioning the UHPC tube 1. For example, the mechanism for rotating and adjusting the angle of the P-shaped steel 4 and the base 7 in this technical solution can be removed, and the first through hole 15 can be enlarged to place the UHPC tube 1 on the wedge block 14. After centering, the wedge block 14 is reset to allow the UHPC tube 1 to fall onto the pier base, thus achieving the centering operation. The device can be deformed according to the specific steps of pier construction. Of course, the second centering mechanism in this device can also be set to rotate to make the wedge block 14 match the position between adjacent flange plates. However, to avoid rotational interference, such a setting method will make the device too large. Therefore, the rotation setting method or the method of installing the plate 21 and the retaining column 22 can be determined according to actual operation.

[0065] The construction method of the above-mentioned UHPC pipe-waste fiber recycled concrete-M-shaped steel 4 composite pier column specifically adopts the following construction steps:

[0066] Step 1: Prefabricate UHPC tubes

[0067] According to the design drawings, several spiral stirrups 2 and several longitudinal structural bars 3 are evenly arranged, tied and spot welded to form a steel cage. UHPC pipes 1 are cast at the steel cage position according to the designed thickness and cured to the designed strength.

[0068] Step 2: Positioning and fixing the steel

[0069] According to the design drawings, the M-shaped steel 4 structure is prefabricated in the factory or construction site, and holes are reserved in the M-shaped steel 4 to ensure that its accuracy meets the standards. After the steel column 4 is hoisted, multiple adjustments are carried out to ensure that the UHPC tube 1 and the M-shaped steel 4 share the same center. Bolts are used to fix the steel. After the bolts are installed, the connection surface is fully welded.

[0070] Step 3: UHPC pipe end connection

[0071] The prefabricated UHPC tube 1 is transported to the construction site. After positioning and securing the tube, the tube is assembled in sections to create a permanent formwork. The oblique grooves of the upper assembly section 1-1 and the lower assembly section 1-2 of the UHPC tube are rotated and adjusted to align. After the grooves are joined, epoxy resin 1-3 is used to fill and secure the concave and convex joints.

[0072] Step 4: Casting the recycled concrete core

[0073] The mixed waste fiber recycled concrete 5 is poured between the UHPC pipe 1 and the M-shaped steel 4. When the waste fiber recycled concrete 5 reaches the required design strength, the next step is carried out.

[0074] For the composite piers provided above, the national standard "Code for Design of Concrete Structures" GB50010-2010 provides the formula for the compressive bearing capacity of the normal section as follows:

[0075]

[0076] Where N is the design value of axial pressure; φ is the stability coefficient of reinforced concrete components; f c1 is the design value of axial compressive strength of recycled concrete; f c2 is the design value of the axial compressive strength of UHPC pipe; f y ' is the design value of compressive yield strength of longitudinal ordinary steel bars; f s is the design value of the steel compressive strength; A1 is the cross-sectional area of the core concrete; A2 is the cross-sectional area of the UHPC pipe; A S ' is the cross-sectional area of all longitudinal ordinary steel bars; A S is the cross-sectional area of the steel section.

[0077] Table 1 lists the cross-sectional bearing capacity of a circular pier column constructed without reinforcement, consisting of a UHPC tube (1), recycled fiber concrete (5), and 4-shaped steel bars. The standard compressive strength values for the recycled fiber concrete (5), UHPC tube (1), and 4-shaped steel bars are 38.5 MPa, 136 MPa, and 235 MPa, respectively. The calculated length of the pier is designed to be 3 meters.

[0078] When calculating, the design value of compressive strength of waste fiber recycled concrete 5 is f c1 =26.5MPa, the design value of the compressive strength of UHPC pipe 1 is calculated by the conversion formula where η t Take 1.0, η f Take 0.85, γ c Take 1.45 to get f c2 =80MPa, the design value of compressive strength of M-shaped steel 4 is f s =170MPa.

[0079] In the symbols shown in the table, d is the cross-sectional design diameter of the circular composite pier, t is the design thickness of the UHPC tube, and φ is the stability factor of the reinforced concrete member.

[0080] A is the full cross-sectional area of the composite pier, which is mainly composed of three parts. The calculation expression is: A=A1+A2+A S ,in,

[0081] N1 is the bearing capacity of the composite pier column with UHPC tube 1, waste fiber recycled concrete 5 and M-shaped steel 4;

[0082] N2 is the normal section bearing capacity of ordinary concrete pier column, and the calculation expression is:

[0083] η is the load-bearing capacity improvement coefficient, and the calculation expression is: η = N1 / N2.

[0084] Table 1 Bearing capacity of normal section of circular column

[0085]

[0086]

[0087] Calculations from the table reveal that, when composite piers utilize the same cross-sectional area, the composite pier structure of UHPC tube 1, waste fiber recycled concrete 5, and M-shaped steel 4 exhibits a higher load-bearing capacity than conventional concrete piers. Increasing the thickness of the UHPC tube 1 or the cross-sectional area of the M-shaped steel 4 significantly improves load-bearing capacity. Therefore, once the design load value is determined, the composite piers provided by this patent can reduce cross-sectional dimensions compared to conventional concrete piers, saving concrete and achieving higher cross-sectional efficiency, resulting in better economic benefits.

[0088] Example 1:

[0089] In this embodiment, the composite pier column of UHPC pipe 1, waste fiber recycled concrete 5 and M-shaped steel 4 is as follows: Figure 1 、 Figure 3The UHPC tube 1 replaces the ordinary steel tube, and a M-shaped steel 4 is arranged inside the UHPC tube 1. Waste fiber recycled concrete 5 is poured in layers between the UHPC tube 1 and the M-shaped steel 4 to form a concrete pier. The UHPC tube 1 serves as a permanent formwork and is connected to the core concrete into one.

[0090] The composite pier column adopts a circular cross-section with a cross-section diameter of 300mm and a column height of 800mm. The UHPC tube 1 has a wall thickness of 30mm. The M-shaped steel 4 is designed as 6 flange plates. The flange plates are arranged outward and intersect at a point. The angle between two flange plates is 60°. Each flange plate is 12mm thick and 90mm long. The recycled concrete core 5 has a diameter of 240mm. The three are combined together to interact and jointly bear the external load.

[0091] The specific raw materials used are detailed below:

[0092] The UHPC tube 1 adopts symmetrical reinforcement. The spiral stirrups 2 adopt 8mm plain round steel bars with a stirrup spacing of 100mm. The longitudinal structural reinforcement 3 adopts 8mm plain round steel bars, 6 of which are arranged symmetrically in the annular direction and reinforced at the joints of the segment ends 1-1 and 1-2.

[0093] The concrete materials of the UHPC pipe 1 include cement, mineral admixtures, quartz sand, quartz powder, steel fiber, high-efficiency water reducer and tap water, and the proportions thereof are shown in the following table:

[0094] Table 2 UHPC mix ratio

[0095]

[0096]

[0097] Specifically, the cement used is P.O42.5 ordinary Portland cement; the mineral admixture is silica fume, with an SiO2 content ranging from 85% to 95%, a loss on ignition ranging from 1.5% to 6%, and a particle size ranging from 0.15μm to 0.35μm; the quartz sand particle size ranges from 0.2mm to 0.6mm; the quartz powder particle size ranges from 5μm to 50μm, with an SiO2 content of ≥95%; the steel fiber is a hook-end steel fiber with a single fiber density of 7.8g / cm 3 The diameter is approximately 0.25mm, the nominal length is 12mm, and the tensile strength ranges from 2200-2350MPa. The high-efficiency water reducer is CX-8 polycarboxylic acid high-performance water reducer, with a maximum water reduction rate of 30%. The M-shaped steel section 4 is made of Q235 hot-rolled steel and is placed in the center of the core recycled concrete.

[0098] Waste fiber recycled concrete 5 is mixed with cement, quartz sand, waste fiber, recycled coarse aggregate and tap water in the following proportions:

[0099] Table 3 Mix ratio of waste fiber recycled concrete

[0100]

[0101] Specifically, the cement used is P.O42.5 ordinary Portland cement; the quartz sand particle size ranges from 0.2mm to 0.6mm; the waste fiber comes from recycled discarded polypropylene carpets, which are manually cut into segments with a length of 19mm, and the single fiber density is 0.92g / cm 3 , the ultimate elongation is 1.69%, and the elastic modulus is 3.5×10 3 MPa, and the water absorption rate is generally less than 0.1%; the recycled coarse aggregate comes from the demolished abandoned reinforced concrete buildings, and its original concrete grade is C40. After artificial crushing, cleaning, screening and other processing steps, the particles with a particle size of 5.5-25.5mm are obtained, with good gradation and an apparent density of 2490kg / m 3 , water absorption rate is 4.18% and crushing index is 16%.

[0102] Example 2:

[0103] In this embodiment, the composite pier column of UHPC tube-waste fiber recycled concrete-M-shaped steel 4 is as follows Figure 2 、 Figure 4 The difference between this embodiment and embodiment 1 is that the cross section adopts a square cross section, the M-shaped steel 4 is designed as 8 flange plates, and the other practices are the same.

[0104] The composite pier column adopts a square cross-section with a side length of 300mm and a column height of 800mm. The UHPC tube 1 has a wall thickness of 30mm. The M-shaped steel 4 is designed as 8 flange plates. The flange plates are arranged outward and intersect at a point. The angle between two flange plates is 45°. Each flange plate is 12mm thick and 90mm long. The recycled concrete core 5 has a side length of 240mm. The three are combined together to interact with each other and jointly bear the external load.

[0105] The specific raw materials used are detailed below:

[0106] The UHPC tube 1 adopts symmetrical reinforcement. The spiral stirrups 2 adopt 8mm plain round steel bars with a stirrup spacing of 100mm. The longitudinal structural reinforcement 3 adopts 8mm plain round steel bars, 8 of which are arranged symmetrically in the annular direction and reinforced at the joints of the segment ends 1-1 and 1-2.

[0107] In this embodiment, the mix ratio of the UHPC pipe 1 and the waste fiber recycled concrete 5 is the same as that in Example 1.

[0108] Compared with Example 1, in this embodiment, the number of flange plates of the M-shaped steel 4 is increased, and the combination with the waste fiber recycled concrete 5 is closer, which further enhances the bearing capacity of the composite pier.

[0109] In summary, it can be seen that the present invention can significantly improve the bearing capacity of the pier column, has better tensile strength, toughness and durability, is simple to connect, is convenient to construct, and has high economic benefits and wide applicability.

[0110] In actual use, the present invention can be used alone or in combination with other known pier structures.

[0111] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A centering mechanism for composite pier column construction, used to realize centering construction of composite pier columns, characterized by: The composite pier column includes UHPC tube, M-shaped steel, and waste fiber recycled concrete. The UHPC tube acts as a permanent mold and is arranged on the outer layer. The M-shaped steel is arranged inside the UHPC tube and is arranged concentrically with the UHPC tube. The waste fiber recycled concrete is poured in layers between the UHPC tube and the M-shaped steel to form a recycled concrete core. The UHPC tube, recycled concrete core and M-shaped steel are connected into one. The UHPC tube includes ordinary Portland cement, mineral admixtures, quartz sand, quartz powder, steel fiber, high-efficiency water reducer and water. The mixing mass ratio of each component is: m 水泥 ∶m 矿物掺和料 ∶m 石英砂 ∶m 石英粉 ∶m 钢纤维 ∶m 高效减水剂 ∶m 自来水 =1:0.2-0.4:1.1-1.3:0.24-0.26:0.14-0.16:0.024-0.026:0.17-0.19; the waste fiber recycled concrete includes cement, quartz sand, waste fiber, recycled coarse aggregate and tap water, and the mixing mass ratio between the components is: m 水泥 ∶m 石英砂 ∶m 废弃纤维 ∶m 再生粗骨料 ∶m 自来水 =1:1.7-1.9:0.001-0.002:1.3-1.5:0.4-0.6; The centering mechanism for pier column construction comprises a support column, wherein the support column is provided with a first support plate and a second support plate at intervals from top to bottom, a first through hole is opened in the middle of the upper surface of the first support plate, and at least three groups of first centering mechanisms are evenly distributed around the circumference of the upper surface edge of the first support plate, the first centering mechanism comprises a first telescopic element fixed to the edge of the first support plate, the output end of the first telescopic element is arranged toward the center of the first support plate, an arc plate is provided on the output end of the first telescopic element, and at least three groups of second centering mechanisms are evenly distributed around the circumference of the lower surface of the first support plate, the second centering mechanism comprises a second telescopic element fixed to the edge of the first support plate, the output end of the second telescopic element is arranged toward the center of the first support plate, and a wedge block is provided on the output end of the second telescopic element; The cam is secured to the bottom of the second support plate and has a locking plate which is adapted to lock the cam and to position the locking plate so as to lock the locking plate in the locking position.

2. A centering mechanism for composite pier construction according to claim 1, characterized in that: The UHPC tube is evenly arranged with longitudinal structural reinforcements and spiral stirrups, which form a steel cage.

3. The centering mechanism for composite pier construction according to claim 1, characterized in that: The cross-section of the UHPC tube is circular or square, and its thickness ranges from 2 cm to 12 cm.

4. The centering mechanism for composite pier construction according to claim 1, characterized in that: The mineral admixtures include fly ash, silica fume, slag powder and limestone powder; the steel fibers include hook-end steel fibers and corrugated steel fibers evenly distributed in the concrete; the high-efficiency water reducer is CX-8 polycarboxylic acid high-performance water reducer; the waste fibers in the waste fiber recycled concrete are discarded polypropylene carpet segments, each of which has a length of 19 mm; the recycled coarse aggregate in the waste fiber recycled concrete is discarded reinforced concrete buildings with a particle size of 5.5-25.5 mm, and the concrete grade is C40.

5. The centering mechanism for composite pier construction according to claim 1, characterized in that: A plurality of through holes are provided in the length direction of each flange plate of the M-shaped steel. A traction rope is provided in the through hole, and the traction rope connects the through holes on each flange plate in series.

6. The centering mechanism for composite pier construction according to claim 1, characterized in that: A shock-absorbing spring is provided between the third supporting plate and the second supporting plate, and a lifting element is provided on one end of the blocking column located on the lower surface of the second supporting plate.

Images