A precast pier sleeve made of UHPC and SMA composite materials and its construction method

Abstract

This invention relates to a precast pier sleeve made of UHPC and SMA composite materials and its construction method, comprising a UHPC sleeve, SMA wire, ECC grouting material, pre-drilled holes, a grouting port, and a grout outlet. The precast sleeve is located at the connection between the pier and the abutment. The inner diameter of the precast sleeve is adapted to the outer diameter of the pier. The precast sleeve is composed of two UHPC plates with semi-circular cross-sections. Holes are evenly distributed along the height direction on both sides of the UHPC plates for the SMA wire to pass through. The SMA wire connects the two UHPC plates. The recovery stress generated by the SMA as the temperature rises enhances the impact resistance and collision resistance of the precast sleeve. A grouting hole is provided at the lower end of the precast sleeve, and a grout outlet is provided at the upper end. The gap between the precast sleeve and the pier is filled with ECC grouting material through the grouting port, making the connection between the pier and the precast sleeve tighter and more reliable. The sleeve can effectively restrain the ECC grout, enhance the bonding and anchoring effect at the joint surface, and ensure the sleeve's force transmission capacity.

Description

Technical Field

[0001] This invention relates to the field of bridge technology, and in particular to a precast pier sleeve and construction method using composite UHPC and SMA materials. Background Technology

[0002] When bridge structures are built in water, the piers are prone to collisions and friction with mud, sand, and rocks in the water. Landslides, falling rocks, and even ship traffic can also impact the piers, generating significant impacts and posing major safety hazards, making them vulnerable parts. Traditional pier protection devices primarily serve to resist impacts, offering little improvement to the structure's mechanical properties and relatively poor durability. To improve the safety of bridge operations, a UHPC precast sleeve can be installed around the pier, using SMA wire composite. SMA possesses shape memory effect and superelastic properties, which not only protects the pier and substructure but also accelerates construction progress, making on-site construction more convenient and efficient.

[0003] In my country, the construction of bridge piers for the substructure of most bridges adopts the cast-in-place construction method. This construction method has a long construction period and cannot guarantee the construction quality, making it difficult to meet the needs of today's rapidly developing economy. However, if prefabricated concrete structures are used, the connection strength between the existing bridge piers and the abutments is insufficient, resulting in poor impact resistance. Summary of the Invention

[0004] To address the aforementioned issues, this invention discloses a precast pier sleeve made of composite UHPC and SMA materials, which is reinforced by casting during on-site construction and installation. This not only improves the strength and impact resistance of the substructure but also ensures construction progress and enhances practicality.

[0005] Precast pier sleeves using composite UHPC and SMA materials include ultra-high performance concrete (UHPC) sleeves, shape memory alloy (SMA) wires, fiber cementitious composite (ECC) materials, pre-drilled holes, grouting ports, and grout outlets.

[0006] Furthermore, the UHPC sleeve has a grouting port at the bottom and a grout outlet at the top.

[0007] A construction method for precast pier sleeves using UHPC and SMA composite materials is characterized by the following steps: Step 1: Install prefabricated UHPC sleeves at the connection between the lower part of the pier and the abutment. The size of the UHPC sleeve during prefabrication should be determined according to the diameter of the pier, and the inner diameter of the UHPC sleeve should be slightly larger than the diameter of the pier to ensure dimensional fit and smooth subsequent grouting. Step 2: Pass the SMA wire with residual strain through the pre-drilled holes in the UHPC board, connect the two UHPC boards, and fix the SMA wire. Step 3: Pour the ECC grout into the gap between the UHPC sleeve and the pier through the grouting port, ensuring that the ECC grout fully fills the gap between the UHPC sleeve and the pier; Step 4: After the grout has cured, heat the SMA wire and use the large recovery stress generated by it to reinforce the UHPC sleeve.

[0008] Furthermore, the prefabricated sleeve is located at the connection between the pier and the abutment. The UHPC sleeve is composed of two UHPC plates with a semi-circular cross section, which are prefabricated in the factory and then assembled on site.

[0009] Furthermore, the UHPC board has holes evenly distributed along the height direction on both sides for SMA wires to pass through. After the prefabricated sleeve is installed, the SMA wires with residual strain are passed through the holes reserved on the UHPC board to connect the two UHPC boards and fix the SMA wires.

[0010] Furthermore, the SMA wire can be pre-treated at low temperature to give it residual strain. After the SMA wire connects the two UHPC boards, the recovery stress generated by the SMA as the temperature rises enhances the anti-collision and impact resistance of the prefabricated sleeve.

[0011] Furthermore, the precast sleeve is provided with a grouting port at the lower end and a grout outlet at the upper end, using a single-point grouting method. The gap between the precast sleeve and the pier is filled with ECC grout from the grouting port. The use of ECC grouting makes the connection between the pier and the precast sleeve tighter and more reliable. The sleeve can effectively restrain the ECC grout, enhance the bonding and anchoring effect at the joint surface, and ensure the force transmission capacity of the sleeve.

[0012] When the SMA wire heats up and generates recovery stress, the stress is transmitted from point to line and from line to surface through the SMA wire-sleeve connection and the ECC grout-sleeve interface, thereby improving the anti-collision performance and durability of the bridge pier.

[0013] The beneficial effects of this invention are: In this invention, by setting up UHPC precast pier sleeves, SMA wires are used as pretensioners to connect the steel plates on both sides, providing horizontal strength and stiffness; the UHPC steel plates will improve the shear strength and ductile energy dissipation capacity of the pier, thereby improving the pier's resistance to collapse.

[0014] ECC aggregate grouting effectively increases the stability of the connection between the precast sleeve and the pier, enhances the bonding and anchoring effect at the joint surface, ensures the force transmission capacity of the sleeve, greatly reduces the cracking and damage of the pier, and improves the corrosion resistance and long-term impact safety of the pier.

[0015] 3. This invention adopts a method that combines prefabrication and cast-in-place construction. The process is simple, effectively shortens the construction period, ensures construction quality, speeds up construction progress, and also improves the rigidity and strength of the substructure, as well as the corrosion resistance and impact resistance of the bridge piers. It has good application and promotion prospects. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the prefabricated pier sleeve using composite materials of UHPC and SMA proposed in this invention. Figure 2 This is a side view of the prefabricated pier sleeve using UHPC and SMA composite materials proposed in this invention. Figure 3 This is a top view of the prefabricated pier sleeve using UHPC and SMA composite materials proposed in this invention. List of reference numerals in the attached diagram: 1. UHPC sleeve; 2. SMA wire; 3. ECC grout; 4. Pre-drilled hole; 5. Grouting port; 6. Grout outlet. Detailed Implementation

[0017] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, and the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0018] like Figure 1 As shown, a precast pier sleeve using UHPC and SMA composite materials and its construction method are described, including UHPC sleeve 1, SMA wire 2, ECC grouting material 3, reserved hole 4, grouting port 5 and grout outlet 6.

[0019] First, a prefabricated UHPC sleeve 1 is installed at the connection between the lower part of the pier and the abutment. The sleeve diameter should be determined according to the pier diameter during prefabrication, and the sleeve diameter should be slightly larger than the pier diameter to ensure dimensional compatibility and smooth subsequent grouting. The sleeve is composed of two UHPC plates with a semi-circular cross-section, which are prefabricated in the factory and then assembled on site. The UHPC plates have evenly distributed holes along the height direction on both sides for SMA wires 2 to pass through.

[0020] Secondly, after the prefabricated sleeve is installed, the SMA wire 2 with residual strain is passed through the reserved hole 4 on the UHPC board to connect the two UHPC boards and fix the SMA wire 2.

[0021] SMA wire 2 can be pre-treated at low temperature to give it residual strain. After the SMA wire 2 connects the two UHPC plates 1, the recovery stress generated by the SMA as the temperature rises enhances the anti-collision and impact resistance of the prefabricated sleeve.

[0022] ECC grout 3 is injected into the gap between UHPC sleeve 1 and bridge pier through the grouting port, ensuring that ECC grout 3 fully fills the gap between UHPC sleeve and bridge pier. The sleeve can effectively restrain the ECC grout, enhance the bonding and anchoring effect at the joint surface, and ensure the force transmission capacity of the sleeve.

[0023] After the grout has cured, the SMA wire 2 is heated, and the large recovery stress generated by it is used to reinforce the UHPC sleeve 1. When the SMA wire 2 heats up and generates recovery stress, the stress is transferred from point to line and from line to surface through the connection between the SMA wire 2 and the sleeve and the ECC grout 3 and the sleeve, thereby improving the impact resistance and durability of the bridge pier.

[0024] The invention adopts a method that combines prefabrication and cast-in-place construction. The process is simple, effectively shortens the construction period, ensures construction quality, and improves the rigidity and strength of the substructure, as well as the corrosion resistance and impact resistance of the bridge piers. It has good prospects for application and promotion.

[0025] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims

1. A precast pier sleeve made of composite UHPC and SMA materials, characterized in that: It includes a UHPC sleeve (1), SMA wire (2), ECC grout (3) and reserved holes (4); the UHPC sleeve (1) is made of two UHPC plates with a semi-circular cross section. Each semi-circular UHPC plate has several reserved holes (4) evenly arranged on both sides along the height direction for the SMA wire (2) to pass through; the SMA wire (2) connects the two semi-circular UHPC plates; the gap between the UHPC sleeve (1) and the pier is filled with ECC grout (3).

2. The precast pier sleeve using UHPC and SMA composite materials as described in claim 1, characterized in that: The UHPC sleeve (1) has a grouting port (5) at the bottom and a grout outlet (6) at the top.

3. A construction method for a precast pier sleeve using UHPC and SMA composite materials, based on the precast pier sleeve using UHPC and SMA composite materials as described in any one of claims 1-2, characterized in that: Includes the following steps: Step 1: Install the prefabricated UHPC sleeve at the connection between the lower part of the pier and the abutment. The UHPC sleeve (1) should be prefabricated according to the diameter of the pier. The inner diameter of the UHPC sleeve should be slightly larger than the diameter of the pier. Step 2: Pass the SMA wire with residual strain through the pre-drilled holes in the UHPC board, connect the two UHPC boards, and fix the SMA wire. Step 3: Pour the ECC grout into the gap between the UHPC sleeve and the pier through the grouting port, ensuring that the ECC grout fully fills the gap between the UHPC sleeve and the pier; Step 4: After the grout has cured, heat the SMA wire and use the large recovery stress generated by it to reinforce the UHPC sleeve.

4. The construction method for prefabricated pier sleeves using UHPC and SMA composite materials according to claim 3, characterized in that: The precast sleeve is located at the connection between the pier and the abutment. The UHPC sleeve is made of two UHPC plates with a semi-circular cross section, which are prefabricated in the factory and then assembled on site.

5. The construction method for prefabricated pier sleeves using UHPC and SMA composite materials according to claim 3, characterized in that: The UHPC board has holes evenly distributed along the height direction on both sides for SMA wires to pass through. After the prefabricated sleeve is installed, the SMA wire with residual strain is passed through the reserved holes on the UHPC board to connect the two UHPC boards and fix the SMA wire.

6. The construction method for the precast pier sleeve using UHPC and SMA composite materials according to claim 3, characterized in that: The SMA wires are pre-treated at low temperatures to give them residual strain. After the SMA wires connect the two UHPC boards, the recovery stress generated by the SMA as the temperature rises enhances the anti-collision and impact resistance of the prefabricated sleeve.

7. The construction method for the precast pier sleeve using UHPC and SMA composite materials according to claim 3, characterized in that: The precast sleeve is provided with a grouting port at the lower end and a grout outlet at the upper end. The gap between the precast sleeve and the pier is filled with ECC grout from the grouting port. Using ECC grouting makes the connection between the pier and the precast sleeve tighter and more reliable.

Images