Joint structure of superposed beam and column with uhpc reinforcing block and construction method thereof

Abstract

A composite beam-column joint structure with UHPC reinforcing blocks and its construction method are disclosed, comprising a precast column, a composite beam, UHPC reinforcing blocks, high-strength fiber-reinforced non-shrink grout, and post-tensioned prestressing tendons. The precast column has a first duct; the precast beam has a second duct; a notch is provided at the bottom of the precast beam near the precast column; a raised strip is provided on the top edge of the notch; the UHPC reinforcing block is located at the notch; a first groove is provided on the end face of the UHPC reinforcing block near the precast column; the high-strength fiber-reinforced non-shrink grout is filled in the gap between the UHPC reinforcing block and the precast column; a third duct is provided within the UHPC reinforcing block; post-tensioned prestressing tendons are correspondingly inserted into the first, second, and third ducts; a second groove is provided in the middle of the top surface of the UHPC reinforcing block along the width direction of the beam; the raised strip is inserted into one side of the second groove. This invention solves the technical problem of the risk of concrete crushing at the beam end in traditional prestressed beam-column joints.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering structures, and in particular, it relates to a construction method for a connection node between a post-tensioned prestressed concrete composite beam and a column with a precast ultra-high performance concrete reinforcing block at the bottom of the beam end and no reinforcement at the beam end. Background Technology

[0002] In areas with high seismic fortification intensity, the concrete at the bottom of beam ends is prone to crushing under strong earthquakes, and the reinforcing bars at the bottom of beam ends are prone to breakage. Post-earthquake damage to the reinforcing bars and concrete at the bottom of beam ends is difficult to repair and costly. Invention patent ZL201611022936.X, "A Column-Through Prestressed Concrete Frame System and Its Construction Method," proposes a novel post-tensioned prestressed concrete frame system with no reinforcement at the beam ends. This eliminates ordinary reinforcing bars at the bottom of the beam ends, using only unbonded prestressed tendons to connect to the column, thus avoiding the breakage of the reinforcing bars at the bottom of the beam ends under strong earthquakes and reducing damage to the concrete at the beam ends. The book "Theoretical Experimental Research, Construction Guidelines and Engineering Cases of a New Prestressed Precast Frame System (PPEFF System)" reports the experimental results and engineering applications of the above-mentioned novel prestressed beam-column joint, achieving good results. However, the experimental results also show that when the inter-story drift angle exceeds 1 / 50, the concrete at the beam ends still poses a risk of crushing. Summary of the Invention

[0003] The purpose of this invention is to provide a composite beam-column joint structure with UHPC reinforcing blocks and its construction method, in order to solve the technical problem that the concrete at the beam end of the traditional prestressed beam-column joint is still at risk of crushing when the displacement angle is large.

[0004] To achieve the above objectives, the present invention adopts the following technical solution.

[0005] A composite beam and column joint structure with UHPC reinforcing blocks includes a precast column and a composite beam; the composite beam includes a precast beam portion, a cast-in-place composite layer portion and energy-dissipating steel bars at the top of the beam, and the precast beam portion and the cast-in-place composite layer portion are made of ordinary concrete; the joint structure also includes UHPC reinforcing blocks, fiber-reinforced high-strength non-shrink grouting material and post-tensioned prestressing tendons;

[0006] A first channel is provided inside the precast column at the lower position corresponding to the composite beam to be connected; the precast beam is located on one side of the precast column, and a gap is left between the precast beam and the precast column; a second channel is provided inside the precast beam at the position corresponding to the first channel; a notch is provided at the bottom of the end of the precast beam near the precast column; a raised strip is provided on the top edge of the notch along the width direction of the beam; the UHPC reinforcing block is a cuboid block made of ultra-high performance concrete; the UHPC reinforcing block is located at the notch of the precast beam, and UH... A horizontal connecting steel bar connects the PC reinforcing block and the precast beam; the end face of the UHPC reinforcing block near the precast column extends beyond the end face of the precast beam, and a gap is left between the UHPC reinforcing block and the precast column; a first groove is provided in the middle of the end face of the UHPC reinforcing block near the precast column, along the width direction of the beam; the fiber-reinforced high-strength non-shrink grout is injected into the gap between the UHPC reinforcing block and the precast column; a third channel is provided inside the UHPC reinforcing block at the position corresponding to the second channel; the end of the third channel near the precast column extends beyond the UHPC... The end face corresponding to the C-reinforcing block is spliced ​​and connected to the first duct; the post-tensioned prestressing tendons are correspondingly inserted into the first, second, and third ducts, connecting the precast column and precast beam portions to the UHPC reinforcing block; a second groove is provided in the middle of the top surface of the UHPC reinforcing block along the width direction of the beam; the protruding strip is inserted into one side of the second groove; the cast-in-place composite layer is cast on the upper part of the precast beam portion and between the precast beam portion and the precast column, and vertical connecting steel bars are connected between the cast-in-place composite layer portion and the UHPC reinforcing block; the beam top energy dissipation steel bars have one set The precast columns are spaced apart within the cast-in-place composite layer above the precast beam section; a first column anchor bar is provided within the precast column at the position corresponding to the energy-dissipating steel bar at the top of the beam, and the first column anchor bar is connected to the corresponding energy-dissipating steel bar at the top of the beam through a first steel bar connector embedded in the side of the precast column; a second column anchor bar is embedded within the precast column below the first column anchor bar; beam end shear reinforcement is provided in the cast-in-place composite layer at the end of the precast beam section; the second column anchor bar is connected to the beam end shear reinforcement through a second steel bar connector embedded in the side of the precast column.

[0007] Preferably, additional stirrups are provided at intervals above the UHPC reinforcing block; there is a set of additional stirrups, which are arranged at intervals along the longitudinal direction.

[0008] Preferably, the length of the UHPC reinforcing block does not exceed the height of the precast beam portion, the height of the UHPC reinforcing block does not exceed half the cross-sectional height of the precast beam portion, and the width of the UHPC reinforcing block is the same as the cross-sectional width of the precast beam portion; the concrete strength of the UHPC reinforcing block is not less than twice the concrete strength of the precast beam portion.

[0009] Preferably, the longitudinal cross-sectional width of the first groove gradually decreases from the groove opening to the groove bottom; the horizontal cross-sectional width of the second groove gradually decreases from the groove opening to the groove bottom; and the end face of the precast beam portion near the precast column is vertically aligned with the horizontal axis of the second groove.

[0010] Preferably, the fiber volume content in the UHPC reinforcing block is not less than 0.8% of the UHPC reinforcing block volume, and the fiber is metal fiber, polymer fiber, or a mixture of metal fiber and polymer fiber.

[0011] Preferably, the lower part of the precast beam section is pre-embedded with bottom reinforcing bars as specified in the design requirements. The ends of the bottom reinforcing bars do not extend beyond the ends of the beam and are bent upward near both ends to form bent-up anchorage sections. Beam stirrups are arranged longitudinally at intervals within the precast beam section. The beam stirrups are fitted onto the bottom reinforcing bars, and the upper ends of the beam stirrups extend beyond the top of the precast beam section and into the cast-in-place composite layer.

[0012] Preferably, there is one set of vertical connecting steel bars, which are arranged longitudinally at intervals in the UHPC reinforcing block; there is one set of horizontal connecting steel bars, which are arranged vertically at intervals in the UHPC reinforcing block; both the vertical connecting steel bars and the horizontal connecting steel bars are U-shaped.

[0013] A construction method for a node structure includes the following steps.

[0014] Step 1: Fabrication of UHPC Reinforcing Blocks: In the prefabrication plant, tie the horizontal and vertical connecting steel bars inside the UHPC reinforcing blocks and fix the third duct. Embed the horizontal and vertical connecting steel bars and the third duct into the mold and fix them. Pour UHPC concrete containing fibers and vibrate it. Then, finish the surface, let it stand, cure, demold, and enter the room temperature curing stage to complete the fabrication of the UHPC reinforcing blocks.

[0015] Step 2: Fabricate the precast beam section in the factory: First, tie the bottom steel bars and stirrups of the beam body to form a steel cage. Then, place the steel cage and the precast UHPC reinforcing blocks into the beam formwork for fixation and pour the beam body concrete. Next, cure the beam body concrete, demold, and complete the fabrication of the precast beam section with UHPC reinforcing blocks.

[0016] Step 3: Transport the precast beam section with UHPC reinforcing blocks to the construction site and hoist it onto the construction support brackets of the precast columns to which it is connected.

[0017] Step 4: Lay the post-tensioned prestressing tendons that run through the precast beams and columns, align and seal the prestressing connection ducts between the precast beams and the precast columns; inject fiber-reinforced high-strength non-shrink grout at the joint between the UHPC reinforcing block and the precast column.

[0018] Step 5: After the high-strength, non-shrink fiber grout reaches the specified strength, the post-tensioned prestressing tendons are tensioned to the specified strength; simultaneously, the energy-dissipating steel bars at the top of the beam are connected to the anchor bars in the first column using the first steel bar connector, and the anchor bars in the second column are connected to the shear steel bars at the beam end using the second steel bar connector.

[0019] Step six: Check whether the post-tensioned prestressing tendons are tensioned in place, and finally pour the concrete for the cast-in-place composite layer as a whole.

[0020] Preferably, when additional stirrups are provided above the UHPC reinforcing block, during construction step five, the additional stirrups are tied and welded to the corresponding vertical connecting steel bars.

[0021] Preferably, the energy-dissipating reinforcement at the top of the beam and the shear reinforcement at the ends of the beam are subjected to local unbonded and weakened treatment before construction.

[0022] Compared with the prior art, the present invention has the following features and beneficial effects.

[0023] 1. This invention is mainly suitable for areas with high seismic fortification intensity and for unbonded post-tensioned prestressed press-fit assembled frames with high requirements for controlling the degree of concrete damage at the bottom of the beam end under strong earthquake. This joint structure has the advantages of excellent seismic performance, good fire resistance, quick construction and low construction cost.

[0024] 2. This invention addresses the issue of concentrating beam-column joint damage under strong earthquakes at the beam-column connection point. It proposes a method of locally reinforcing the bottom of the beam end using ultra-high performance concrete (UHPC). This ensures that the lower concrete of the beam end remains undamaged or suffers only minor damage during strong earthquakes, while the damage is concentrated in the ordinary concrete and reinforcing steel at the upper part of the beam end. This damage is easily repairable and inexpensive after an earthquake. The key to this invention is its structural design, which facilitates factory prefabrication and on-site installation while ensuring a good connection between the UHPC and the beam-column concrete and reinforcing steel, reducing damage under earthquakes. Simultaneously, it provides measures to ensure the beam-column joint has sufficient fire resistance time (at least 3 hours) for escape, guaranteeing the joint's structural safety.

[0025] 3. The post-tensioned prestressed concrete composite beam-column connection node reinforced by UHPC in this invention has better seismic performance, less beam end damage under strong earthquakes, easier repair, and lower repair cost. In addition, it uses less UHPC material, making construction faster, lower in cost, easier to guarantee quality, and better in fire resistance. Attached Figure Description

[0026] The present invention will now be described in further detail with reference to the accompanying drawings.

[0027] Figure 1 This is a schematic diagram of the elevation of the joint structure of the composite beam and column with UHPC reinforcing blocks provided in an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the elevation structure of the connection between the UHPC reinforcing block and the prefabricated part of the composite beam in this invention.

[0029] Figure 3 This is a schematic diagram of the elevation and connecting steel bars of the UHPC reinforcing block in this invention.

[0030] Figure 4 This is a three-dimensional structural diagram of the connection between the UHPC reinforcing block and the prefabricated part of the composite beam in this invention.

[0031] Figure 5 This is a three-dimensional structural diagram of the UHPC reinforcing block in this invention.

[0032] Figure 6 This is a schematic diagram of a precast beam in this invention with a notch at the bottom of the end near the precast column.

[0033] Figure reference numerals: 1 - Precast column, 2 - Composite beam, 2.1 - Precast beam portion, 2.2 - Cast-in-place composite layer portion, 2.3 - Energy-dissipating reinforcement at the top of the beam, 2.4 - Additional stirrups, 2.5 - Bottom reinforcement of the beam, 2.6 - Beam stirrups, 2.7 - U-shaped reinforcing bars, 3 - UHPC reinforcing block, 4 - Fiber-reinforced high-strength non-shrink grout, 5 - Post-tensioned prestressing tendon, 6 - First duct, 7 - Second duct, 8 - Notch, 9 - Protrusion, 10 - Horizontal connecting reinforcement, 11 - First groove, 12 - Third duct, 13 - Second groove, 14 - Vertical connecting reinforcement, 15 - Anchoring reinforcement inside the first column, 16 - Anchoring reinforcement inside the second column, 17 - Shear reinforcement at the beam end, 18 - First reinforcement connector, 19 - Second reinforcement connector. Detailed Implementation

[0034] like Figure 1-6 As shown, this composite beam-column joint structure with UHPC reinforcing blocks includes a precast column 1 and a composite beam 2; the composite beam 2 includes a precast beam portion 2.1, a cast-in-place composite layer portion 2.2, and energy-dissipating steel bars 2.3 at the top of the beam, and the precast beam portion 2.1 and the cast-in-place composite layer portion 2.2 are made of ordinary concrete; the joint structure also includes UHPC reinforcing blocks 3, fiber-reinforced high-strength non-shrink grouting material 4, and post-tensioned prestressing tendons 5;

[0035] A first channel 6 is provided inside the precast column 1 at the lower position corresponding to the composite beam 2 to be connected; the precast beam portion 2.1 is located on one side of the precast column 1, and a gap is left between the precast beam portion 2.1 and the precast column 1; a second channel 7 is provided inside the precast beam portion 2.1 at the position corresponding to the first channel 6; a notch 8 is provided at the bottom of the end of the precast beam portion 2.1 near the precast column 1; a protruding strip 9 is provided on the top edge of the notch 8 along the width direction of the beam; the UHPC reinforcing block 3 is a cuboid block made of ultra-high performance concrete; the UHPC reinforcing block 3 is located at the notch 8 of the precast beam portion 2.1, and a horizontal connection is provided between the UHPC reinforcing block 3 and the precast beam portion 2.1. The UHPC reinforcing block 3 extends beyond the end face of the precast beam portion 2.1 on the side near the precast column 1, and a gap is left between the UHPC reinforcing block 3 and the precast column 1; a first groove 11 is provided in the middle of the end face of the UHPC reinforcing block 3 near the precast column 1, along the width direction of the beam; the fiber high-strength non-shrink grout 4 is injected into the gap between the UHPC reinforcing block 3 and the precast column 1; a third channel 12 is provided in the UHPC reinforcing block 3 at the position corresponding to the second channel 7; the end of the third channel 12 near the precast column 1 extends beyond the end face of the UHPC reinforcing block 3 and is spliced ​​and connected to the first channel 6; the post-tensioned prestressing tendon 5 is correspondingly inserted through the first channel 6 and the second channel 7. Within the third duct 12, the precast column 1, the precast beam portion 2.1, and the UHPC reinforcing block 3 are connected; the post-tensioned prestressing tendon 5 is anchored to the side of the precast column 1 away from the composite beam 2; a second groove 13 is provided in the middle of the top surface of the UHPC reinforcing block 3 along the width direction of the beam; the protruding strip 9 is inserted into one side of the second groove 13; the cast-in-place composite layer portion 2.2 is cast on the upper part of the precast beam portion 2.1 and between the precast beam portion 2.1 and the precast column 1, and a vertical connecting steel bar 14 is connected between the cast-in-place composite layer portion 2.2 and the UHPC reinforcing block 3; a set of energy-dissipating steel bars 2.3 at the top of the beam is spaced apart in the cast-in-place composite layer portion 2.2 above the precast beam portion 2.1; the precast column A first column anchor bar 15 is provided at the position corresponding to the energy-dissipating steel bar 2.3 at the top of the beam, and the first column anchor bar 15 and the corresponding energy-dissipating steel bar 2.3 at the top of the beam are connected by a first steel bar connector 18 pre-embedded on the side of the precast column 1; in this embodiment, the other end of the first column anchor bar 15 is bent downward to form a bent anchor section to increase the connection force with the precast column 1; a second column anchor bar 16 is pre-embedded in the precast column 1 below the first column anchor bar 15; a beam end shear steel bar 17 is provided in the cast-in-place composite layer 2.2 at the end of the precast beam part 2.1; the second column anchor bar 16 and the beam end shear steel bar 17 are connected by a second steel bar connector 19 pre-embedded on the side of the precast column 1.

[0036] In this embodiment, additional stirrups 2.4 are provided at intervals above the UHPC reinforcing block 3; there is a set of additional stirrups 2.4, which are arranged at intervals along the longitudinal direction, and the additional stirrups 2.4 are welded to the vertical connecting steel bars 14 at the position of the vertical connecting steel bars 14.

[0037] In this embodiment, the length of the UHPC reinforcing block 3 does not exceed the height of the precast beam portion 2.1, the height of the UHPC reinforcing block 3 does not exceed half the cross-sectional height of the precast beam portion 2.1, and the width of the UHPC reinforcing block 3 is the same as the cross-sectional width of the precast beam portion 2.1; the concrete strength of the UHPC reinforcing block 3 is not less than twice the concrete strength of the precast beam portion 2.1.

[0038] In this embodiment, the longitudinal cross-sectional width of the first groove 11 gradually decreases from the groove opening to the groove bottom; the horizontal cross-sectional width of the second groove 13 gradually decreases from the groove opening to the groove bottom; the end face of the precast beam portion 2.1 near the precast column 1 is vertically aligned with the horizontal axis of the second groove 13; the side of the protrusion 9 that contacts the second groove 13 is an inclined surface.

[0039] In this embodiment, the fiber volume content in the UHPC reinforcing block 3 is not less than 0.8% of the volume of the UHPC reinforcing block 3, and the fiber is metal fiber, polymer material fiber, or a mixture of metal fiber and polymer material fiber; the concrete in the precast beam part 2.1 is ordinary concrete without fiber. The UHPC reinforcing block 3 is first made separately and cured under high temperature steam or hot water conditions for more than 24 hours to reach the specified strength, and then tied to the steel cage and corrugated pipe of the precast beam part 2.1, with additional connecting steel reinforcement. After the steel reinforcement is tied and fixed in the formwork, the UHPC reinforcing block 3 and the concrete of the precast beam part 2.1 are cast together in the factory and cured to the specified strength; the second channel 7 in the precast beam part 2.1 is formed by the pre-embedded corrugated pipe, and the third channel 12 in the UHPC reinforcing block 3 is formed by the pre-embedded corrugated pipe.

[0040] In this embodiment, the thickness of the high-strength, non-shrink fiber grout 4 is 20~40mm.

[0041] In this embodiment, the lower part of the precast beam section 2.1 is pre-embedded with bottom reinforcing bars 2.5 as specified in the design requirements. The ends of the bottom reinforcing bars 2.5 do not extend beyond the ends of the beam and are bent upward near both ends to form bent-up anchorage sections. Beam stirrups 2.6 are arranged longitudinally at intervals within the precast beam section 2.1. The beam stirrups 2.6 are fitted onto the bottom reinforcing bars 2.5, and the upper ends of the beam stirrups 2.6 extend beyond the top of the precast beam section 2.1 and into the cast-in-place composite layer section 2.2.

[0042] In this embodiment, there is one set of vertical connecting steel bars 14, which are arranged longitudinally at intervals in the UHPC reinforcing block 3; there is one set of horizontal connecting steel bars 10, which are arranged vertically at intervals in the UHPC reinforcing block 3; both the vertical connecting steel bars 14 and the horizontal connecting steel bars 10 are U-shaped.

[0043] The construction method for this node structure includes the following steps.

[0044] Step 1, fabrication of UHPC reinforcing block 3: In the prefabrication plant, tie the horizontal connecting steel bars 10 and vertical connecting steel bars 14 inside the UHPC reinforcing block 3, and fix the third duct 12. Embed the horizontal connecting steel bars 10, vertical connecting steel bars 14 and the third duct 12 into the mold and fix them. Pour UHPC concrete containing fibers and vibrate it. Then, let it stand for curing, demold it, and enter the normal temperature curing stage to complete the fabrication of UHPC reinforcing block 3. The curing conditions are to cure under high temperature steam or hot water for more than 24 hours to reach the specified strength before demolding.

[0045] Step 2, fabricating the precast beam section 2.1 in the factory: First, tie the bottom steel bars 2.5 and the stirrups 2.6 of the beam body to form a steel cage. Then, place the steel cage and the precast UHPC reinforcing block 3 into the beam formwork for fixation and pour the beam body concrete. Then, cure the beam body concrete, demold, and complete the fabrication of the precast beam section 2.1 with UHPC reinforcing block 3.

[0046] Step 3: Transport the precast beam portion 2.1 with UHPC reinforcing block 3 to the construction site and hoist it onto the construction support bracket connected to the precast column 1.

[0047] Step 4: Lay the post-tensioned prestressing tendons 5 that run through the precast beam and column, align and close the prestressing connection ducts between the precast beam part 2.1 and the precast column 1; inject fiber-reinforced high-strength non-shrink grout 4 into the joint between the UHPC reinforcing block 3 and the precast column 1.

[0048] Step 5: After the high-strength, non-shrink fiber grout 4 reaches the specified strength, the post-tensioned prestressed tendons 5 are tensioned to the specified strength; simultaneously, the energy-dissipating steel bars 2.3 at the top of the beam are connected to the anchor bars 15 in the first column using the first steel bar connector 18, and the anchor bars 16 in the second column are connected to the shear bars 17 at the beam end using the second steel bar connector 19.

[0049] Step six: Check whether the post-tensioned prestressing tendon 5 is tensioned in place, and finally pour the concrete of the cast-in-place composite layer 2.2 as a whole.

[0050] In this embodiment, when an additional stirrup 2.4 is provided above the UHPC reinforcing block 3, during the construction in step five, the additional stirrup 2.4 is tied and welded to the vertical connecting steel bar 14.

[0051] In this embodiment, the energy-dissipating steel bar 2.3 at the top of the beam and the shear-resistant steel bar 17 at the end of the beam are partially unbonded and weakened before construction.

[0052] In this embodiment, the bottom surface of the UHPC reinforcing block 3 is flush with the bottom surface of the precast beam portion 2.1, and half of the second groove 13 on the top of the UHPC reinforcing block 3 is located at the bottom of the protrusion 9, and the other half is located at the bottom of the cast-in-place composite layer portion 2.2.

[0053] In this embodiment, a U-shaped reinforcing bar 2.7 is provided above the notch 8 in the precast beam part 2.1; the groove of the U-shaped reinforcing bar 2.7 is horizontally arranged, and the ends of the U-shaped reinforcing bar 2.7 are respectively connected to the stirrups inside the precast beam part 2.1.

[0054] The above embodiments are not exhaustive examples of specific implementation methods, and other embodiments are also possible. The purpose of the above embodiments is to illustrate the present invention, rather than to limit the scope of protection of the present invention. All applications derived from simple variations of the present invention fall within the scope of protection of the present invention.

Claims

1. A joint structure of composite beam and column with UHPC reinforcing blocks, comprising a precast column (1) and a composite beam (2); the composite beam (2) comprises a precast beam portion (2.1), a cast-in-place composite layer portion (2.2), and energy-dissipating steel bars at the top of the beam (2.3), wherein the precast beam portion (2.1) and the cast-in-place composite layer portion (2.2) are made of ordinary concrete; characterized in that: The node structure also includes a UHPC reinforcing block (3), fiber high-strength non-shrink grout (4), and post-tensioned prestressing tendons (5); a first channel (6) is provided in the precast column (1) at the lower position corresponding to the composite beam (2) to be connected; the precast beam part (2.1) is located on one side of the precast column (1), and a gap is left between the precast beam part (2.1) and the precast column (1); a second channel (7) is provided in the precast beam part (2.1) at the position corresponding to the first channel (6); a notch (8) is provided at the bottom of the precast beam part (2.1) near the precast column (1); a protrusion (9) is provided on the top edge of the notch (8) along the width direction of the beam; the UHPC reinforcing block (3) is a cuboid block made of ultra-high performance concrete; the UHPC reinforcing block (3) is located at the notch (8) of the precast beam part (2.1), and the UHPC A horizontal connecting steel bar (10) is connected between the reinforcing block (3) and the precast beam part (2.1); the end face of the UHPC reinforcing block (3) near the precast column (1) extends beyond the end face of the precast beam part (2.1), and a gap is left between the UHPC reinforcing block (3) and the precast column (1); a first groove (11) is provided in the middle of the end face of the UHPC reinforcing block (3) near the precast column (1) along the width direction of the beam; the fiber high-strength non-shrink grout (4) is injected into the gap between the UHPC reinforcing block (3) and the precast column (1); a third channel (12) is provided in the UHPC reinforcing block (3) at the position corresponding to the second channel (7); the end of the third channel (12) near the precast column (1) extends beyond the UHPC The end face corresponding to the reinforcing block (3) is spliced ​​and connected to the first duct (6); the post-tensioned prestressing tendon (5) is correspondingly inserted into the first duct (6), the second duct (7) and the third duct (12) to connect the precast column (1), the precast beam part (2.1) and the UHPC reinforcing block (3); the UHPC A second groove (13) is provided in the middle of the top surface of the reinforcing block (3) along the width direction of the beam; the protruding strip (9) is inserted into one side of the second groove (13); the cast-in-place composite layer (2.2) is cast on the upper part of the precast beam part (2.1) and between the precast beam part (2.1) and the precast column (1), and a vertical connecting steel bar (14) is connected between the cast-in-place composite layer (2.2) and the UHPC reinforcing block (3); there is a set of energy-dissipating steel bars (2.3) at the top of the beam, which are spaced apart in the cast-in-place composite layer (2.2) above the precast beam part (2.1); a first column anchor bar (15) is provided in the precast column (1) at the position corresponding to the energy-dissipating steel bar (2.3) at the top of the beam, and the first column anchor bar (15) is connected to the corresponding energy-dissipating steel bar (2.3) at the top of the beam.3) The precast columns (1) are connected by a first steel connector (18) embedded in the side of the precast column (1); a second internal anchor bar (16) is embedded in the precast column (1) below the first internal anchor bar (15); a beam end shear reinforcement bar (17) is provided in the cast-in-place composite layer (2.2) at the end of the precast beam (2.1); the second internal anchor bar (16) and the beam end shear reinforcement bar (17) are connected by a second steel connector (19) embedded in the side of the precast column (1).

2. The composite beam-column joint structure with UHPC reinforcing blocks according to claim 1, characterized in that: Additional stirrups (2.4) are provided at intervals above the UHPC reinforcing block (3); there is a set of additional stirrups (2.4) arranged at intervals along the longitudinal direction.

3. The composite beam-column joint structure with UHPC reinforcing blocks according to claim 1, characterized in that: The length of the UHPC reinforcing block (3) does not exceed the height of the precast beam part (2.1), the height of the UHPC reinforcing block (3) does not exceed half the cross-sectional height of the precast beam part (2.1), and the width of the UHPC reinforcing block (3) is the same as the cross-sectional width of the precast beam part (2.1); the concrete strength of the UHPC reinforcing block (3) is not less than twice the concrete strength of the precast beam part (2.1).

4. The composite beam-column joint structure with UHPC reinforcing blocks according to claim 1, characterized in that: The longitudinal cross-sectional width of the first groove (11) gradually decreases from the groove opening to the groove bottom; the horizontal cross-sectional width of the second groove (13) gradually decreases from the groove opening to the groove bottom; the end face of the precast beam part (2.1) near the precast column (1) is vertically aligned with the horizontal axis of the second groove (13).

5. The composite beam-column joint structure with UHPC reinforcing blocks according to claim 1, characterized in that: The fiber volume content in the UHPC reinforcing block (3) is not less than 0.8% of the volume of the UHPC reinforcing block (3), and the fiber is metal fiber, polymer fiber, or a mixture of metal fiber and polymer fiber.

6. The composite beam-column joint structure with UHPC reinforcing blocks according to claim 1, characterized in that: The precast beam section (2.1) has pre-embedded bottom steel bars (2.5) as specified in the design requirements at the bottom. The ends of the bottom steel bars (2.5) do not extend beyond the ends of the beam and are bent upward near both ends to form bent-up anchorage sections. Beam stirrups (2.6) are arranged longitudinally and at intervals within the precast beam section (2.1). The beam stirrups (2.6) are fitted onto the bottom steel bars (2.5), and the upper ends of the beam stirrups (2.6) extend beyond the top of the precast beam section (2.1) and into the cast-in-place composite layer section (2.2).

7. The composite beam-column joint structure with UHPC reinforcing blocks according to claim 1, characterized in that: There is one set of vertical connecting steel bars (14), which are arranged longitudinally at intervals in the UHPC reinforcing block (3); there is one set of horizontal connecting steel bars (10), which are arranged vertically at intervals in the UHPC reinforcing block (3); both the vertical connecting steel bars (14) and the horizontal connecting steel bars (10) are U-shaped.

8. A construction method for a node structure according to any one of claims 1-7, characterized in that, The steps include the following: Step 1, making UHPC reinforcing block (3): Bind the horizontal connecting steel bars (10) and vertical connecting steel bars (14) inside the UHPC reinforcing block (3) in the prefabrication plant, and fix the third duct (12). Embed the horizontal connecting steel bars (10), vertical connecting steel bars (14) and the third duct (12) into the mold and fix them. Pour UHPC concrete containing fiber and vibrate it. Then, let it stand for curing, demold it, and enter the normal temperature curing stage to complete the production of UHPC reinforcing block (3). Step 2, fabricate the precast beam section in the factory (2.1): First, tie the bottom steel bars (2.5) and stirrups (2.6) of the beam body to form a steel cage. Then, place the steel cage and the precast UHPC reinforcing block (3) into the beam formwork for fixing and pour the beam body concrete. Then, cure the beam body concrete, demold, and complete the fabrication of the precast beam section (2.1) with UHPC reinforcing block (3). Step 3: Transport the precast beam section (2.1) with UHPC reinforcing block (3) to the construction site and hoist it onto the construction support bracket connected to the precast column (1); Step 4: Lay the post-tensioned prestressing tendons (5) that run through the precast beam and column, align and close the prestressing connection ducts between the precast beam (2.1) and the precast column (1); inject fiber-reinforced high-strength non-shrink grout (4) into the joint between the UHPC reinforcing block (3) and the precast column (1). Step 5: After the fiber high-strength non-shrink grout (4) reaches the specified strength, the post-tensioned prestressed tendons (5) are tensioned to the specified strength; at the same time, the energy-dissipating steel bars (2.3) at the top of the beam are connected to the anchor bars (15) in the first column using the first steel bar connector (18), and the anchor bars (16) in the second column are connected to the shear bars (17) at the beam end using the second steel bar connector (19); Step 6: Check whether the post-tensioned prestressing tendons (5) are tensioned in place, and finally pour the concrete of the cast-in-place composite layer (2.2) as a whole.

9. The construction method according to claim 8, characterized in that: When additional stirrups (2.4) are provided above the UHPC reinforcing block (3), during the construction in step five, the additional stirrups (2.4) are tied and welded to the vertical connecting steel bars (14).

10. The construction method according to claim 8, characterized in that: Before construction, the energy-dissipating steel bars (2.3) at the top of the beam and the shear-resistant steel bars (17) at the end of the beam are subjected to local unbonded and weakened treatment.

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