A post-tensioned, loosely bonded, co-tensioned prestressed concrete frame structure system with UHPC connection and its design and construction method.

Abstract

This invention discloses a post-tensioned, loosely bonded co-tensioned prestressed concrete frame structure system with UHPC (Ultra-High-Pressure Polymer) connection, comprising precast concrete upper columns, precast concrete lower columns, post-tensioned, loosely bonded co-tensioned prestressed concrete composite beams, UHPC node core areas, and composite slabs. The upper longitudinal main reinforcement, lower longitudinal main reinforcement, ordinary steel bars, and pre-tensioned prestressing tendons are all directly anchored or bent and anchored within the UHPC node core area. This structural system not only facilitates and speeds on-site construction, improving component installation efficiency, but also significantly reduces the anchorage length of steel bars, greatly reduces the amount of stirrups in the node core area, avoids steel bar congestion, reduces the component cross-sectional height, lightens the self-weight, and improves the crack resistance and self-healing performance of the components, thereby improving the overall seismic performance of the frame structure. Simultaneously, pre-tensioning prestressing allows for construction of precast beams with minimal or no support, and the post-tensioned, loosely bonded tendons have good durability and are easy to construct, solving the problem of incomplete grouting in post-tensioned bonding.

Description

Technical Field

[0001] This invention relates to the field of precast prestressed prefabricated building construction technology, and more specifically, to a post-tensioned, loosely bonded co-tensioned precast prestressed concrete frame structure system with UHPC connection, and its design and construction methods. Background Technology

[0002] Cast-in-place structures suffer from numerous limitations, including low construction efficiency and high energy consumption, making them increasingly unsuitable for the demands of industrialized building development. Precast concrete structures, with their advantages of rapid construction, factory-produced components, reduced on-site wet work, and reduced environmental pollution, have become the future direction of industrialized building development. After years of development and promotion, precast concrete structures have been widely researched and used.

[0003] Precast concrete frame structures refer to structures where beams and columns are prefabricated in a prefabrication plant and transported to the construction site for connection to form an integral structure. Compared with cast-in-place concrete structures, they offer advantages such as faster construction speed, easier assurance of component quality, higher overall quality, less environmental pollution, reduced labor costs, and savings in formwork and supports, making them a structural form with a very broad prospect. For wet-connection precast concrete frame structures, easy-to-construct and effectively integrity-ensuring joint construction methods are key to their widespread application. However, past earthquake disasters have shown that precast structures suffer more severe damage in earthquakes, making it difficult to achieve the same seismic performance as cast-in-place structures. To improve the integrity and reliability of joint connections in precast concrete frames and achieve or even surpass the seismic performance of cast-in-place concrete structures, prestressed technology and UHPC (Ultra High Performance Concrete) materials have been introduced into precast structures.

[0004] Post-tensioned and bonded prestressed precast concrete structures are formed by assembling precast ordinary concrete members and precast pre-tensioned prestressed members together using tensioned prestressing tendons. They combine the characteristics of pre-tensioned prestressed concrete structures, post-tensioned and bonded prestressed concrete structures, and precast structures. The internal stress generated by prestressing in the concrete section can partially or completely offset the stress on the section under service loads, delaying crack initiation and improving the stiffness of the members. During unloading, cracks can partially or completely close, demonstrating good elastic recovery performance. Simultaneously, prestressed concrete can fully utilize the material strength of the prestressing tendons and concrete, reducing the structure's self-weight. Furthermore, the application of prestressing contributes to improved performance and overall integrity of precast structures, promoting their application in large-span, heavy-load structures.

[0005] UHPC possesses excellent bonding properties, significantly reducing the anchorage length of reinforcing bars and strands. Its high strength reduces the amount of stirrups required in the joint core area. Using UHPC in the joint core area simplifies the construction and improves the overall frame integrity. Prestressed structures exhibit excellent load-bearing performance; applying UHPC to the joint core area creates a precast prestressed frame structure. In-depth research on this structure will facilitate the further promotion and application of precast prestressed concrete frame structures. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies and, by leveraging the superior performance of UHPC (Ultra-High-Pressure Concrete), propose a post-tensioned, loosely bonded, co-tensioned prestressed concrete frame structure system with UHPC connections, along with its design and construction methods. This system combines three traditional structural elements: pre-tensioned prestressed structures, post-tensioned, loosely bonded prestressed structures, and prefabricated and composite structures. Furthermore, it utilizes high-performance UHPC materials to improve the seismic performance of prefabricated precast concrete frame structures.

[0007] The advantages of this invention are mainly reflected in two aspects: the connection technology of precast prestressed concrete beam-column members and the rebar connection technology between the members. Regarding the member connection technology, beam-column members are connected through high-performance UHPC (unstressed high-pressure concrete) to form a UHPC node core area, making it easier to meet the seismic fortification requirements of strong nodes and weak members, thereby improving the ductility of the beam-column nodes and thus improving the seismic performance of the overall frame structure. Regarding the rebar connection technology, the rebar between beam-column members only requires simple lap splices with very short lap lengths, significantly saving the fabrication time of precast members and on-site installation time. Therefore, the UHPC-connected post-tensioned, slowly bonded co-tensioned precast prestressed concrete frame structure system and its design and construction methods proposed in this invention are in line with my country's green development strategy for building industrialization.

[0008] The technical problem solved by this invention can be achieved by the following technical solutions:

[0009] A UHPC-connected post-tensioned and loosely bonded co-tensioned prestressed concrete frame structure system includes a precast concrete upper column, a precast concrete lower column, a post-tensioned and loosely bonded co-tensioned prestressed concrete composite beam, a UHPC node core area, and a composite slab.

[0010] The precast concrete upper column is provided with upper longitudinal main reinforcement, and the precast concrete lower column is provided with lower longitudinal main reinforcement. The post-tensioned and slowly bonded co-tensioned prestressed concrete composite beam is provided with precast pre-tensioned prestressed concrete beam, beam composite layer and post-tensioned and slowly bonded prestressing tendons. The precast pre-tensioned prestressed concrete beam is provided with ordinary steel bars and pre-tensioned prestressing tendons. The beam composite layer is provided with top continuous steel bars. The composite slab is composed of a precast concrete slab and a slab composite layer cast on the slab.

[0011] The upper longitudinal main reinforcement extends out of the bottom surface of the precast upper column and is directly anchored in the core area of ​​the UHPC node; the lower longitudinal main reinforcement extends out of the top surface of the precast lower column and is directly anchored in the core area of ​​the UHPC node; and the ordinary steel bars and prestressed tendons extend out of the end face of the precast prestressed concrete beam and are directly anchored in the core area of ​​the UHPC node.

[0012] The pre-tensioned prestressing tendons include straight or polygonal tendons, and the post-tensioned loosely bonded prestressing tendons include straight, polygonal, and curved tendons;

[0013] The post-tensioned and slowly bonded co-tensioned prestressed concrete composite beam can also be a fully prestressed beam;

[0014] The post-tensioned bonded prestressing tendons in the core area of ​​the node can be bonded, partially bonded, unbonded, or unbonded.

[0015] The post-tensioned, loosely bonded co-tensioned prestressed concrete composite beam is constructed and verified as a pre-tensioned prestressed concrete simply supported beam before the pouring of the beam composite layer, slab composite layer, and UHPC node core area. After the pouring of the node core area, beam composite layer, and slab composite layer, when the concrete strength of the node and composite layer reaches the design requirements, the loosely bonded prestressing tendons are tensioned. After tensioning, the construction stage verification is performed as a frame beam. After the prestress is established, the post-tensioned, loosely bonded prestressing tendons are calculated based on the effective prestress during construction verification. For the bonded and unbonded portions of the node core area, the calculation is based on the effective prestress under the serviceability limit state. Under the ultimate bearing limit state, the stress increment of the unbonded tendons is considered. Under seismic loads, the recovery performance provided by the unbonded tendons is considered.

[0016] Furthermore, the post-tensioned and slowly bonded co-tensioned prestressed concrete composite beam consists of a pre-tensioned prestressed concrete beam, a beam composite layer, and post-tensioned and slowly bonded prestressing tendons.

[0017] Furthermore, the post-tensioned and loosely bonded prestressing tendons are pre-embedded in the precast pre-tensioned prestressed concrete beam members according to the design position, and pass through the core area of ​​the UHPC node with both ends extending outside the core area of ​​the UHPC node. Clamps and anchors are fixedly installed at both ends, with one end set on the outside of the column and the other end set in the beam composite layer.

[0018] Furthermore, recessed grooves are provided on the bottom surface of the precast concrete upper column, the top surface of the precast concrete lower column, and the end face of the post-tensioned and slowly bonded co-tensioned prestressed concrete composite beam (U-shaped grooves can also be provided at the beam end, and structural shear reinforcement can be provided if necessary).

[0019] Furthermore, the precast concrete upper column is fixed in the corresponding position using reliable supports.

[0020] Furthermore, the stirrups in the precast concrete upper column, precast concrete lower column, and post-tensioned, loosely bonded co-tensioned prestressed concrete composite beam are divided into a dense zone and a non-dense zone. The stirrups in the core area of ​​the UHPC node are arranged according to design requirements. The shear bearing capacity of the core area is calculated using a diagonal compression bar model, and the steel fibers in the UHPC are considered to be equivalent to horizontal stirrups and vertical longitudinal bars, taking into account their contribution to the shear resistance of the core area of ​​the node. At the same time, the beneficial contribution of the loosely bonded prestressed tendons to the shear resistance of the node is also considered.

[0021] Furthermore, the top surface of the precast prestressed concrete beam and the precast concrete slab is provided with a rough surface layer.

[0022] This invention also provides a design method for the system, comprising the following steps:

[0023] Step 1: Design beams and columns according to existing specifications and invention patents;

[0024] Step 2: The seismic design of the joints should be carried out according to the following method, calculating the horizontal shear capacity V of the joints. jh :

[0025] The shear capacity of frame beam-column joints shall meet the following requirements:

[0026]

[0027] V jh =υ jh ·b j ·h c +V fh +0.4N pe

[0028] υ jh =α t ·β t ·η t ·λ t (JI) 0.15 (BI) 0.30 (f c ) 0.75

[0029]

[0030] λ t =1.31

[0031] V fh =ηλ f h b b c

[0032]

[0033] In the formula: eb —Beam offset distance;

[0034] h c —Column height;

[0035] ρ b —Total longitudinal reinforcement ratio of the beam section;

[0036] f yb —Design value of yield strength of longitudinal reinforcement in beams;

[0037] ρ j —Stirrup ratio in the core area of ​​the node;

[0038] f yj —Design value of the yield strength of the stirrups in the core area of ​​the node;

[0039] N pe —The effective prestressing resultant force of the post-tensioned prestressing tendons acting in the core area of ​​the node;

[0040] b c —Column width;

[0041] b b —Liang Kuan;

[0042] h b —Liang Gao;

[0043] f c —Design value of axial compressive strength of concrete;

[0044] η—Effective coefficient of UHPC steel fiber;

[0045] l—Length of UHPC steel fibers;

[0046] d—Diameter of UHPC steel fibers;

[0047] V f —UHPC steel fiber volume content;

[0048] Step 3: At the intermediate nodes of the frame's intermediate floors, the upper longitudinal reinforcement of the frame beams should penetrate through the intermediate nodes; the diameter of each longitudinal reinforcement beam penetrating the central column, for seismic grades I, II, and III, when the column has a rectangular cross-section, should not exceed the smaller of 1 / 18 of the column's cross-sectional dimension in that direction and x; x is calculated using the following formula:

[0049]

[0050] A post-tensioned, loosely bonded, co-tensioned prestressed concrete frame structure system with UHPC (Ultra-High-Pressure Polymer) connection includes the following steps:

[0051] Step 1: Fabricate precast concrete lower columns, precast concrete upper columns, precast prestressed concrete beams, and precast concrete slabs; among them, the longitudinal reinforcement of the precast concrete lower columns and precast concrete upper columns needs to be anchored into the core area of ​​the node with sufficient anchorage length; when precasting prestressed concrete beams, the prestressed tendons are tensioned on the platform first, and the post-tensioned and slowly bonded prestressed tendons are embedded in the beam according to the design position, with sufficient length reserved on both sides, and then the concrete is poured. After the concrete has cured to sufficient strength, the prestressed tendons are released and sufficient anchorage length is reserved at the beam end;

[0052] Step 2: After the precast components have cured, hoist the precast concrete lower column and install it on the foundation, and then install an appropriate number of stirrups on the extended longitudinal main bars;

[0053] Step 3: Hoist the precast prestressed concrete beam to the top surface of the precast concrete lower column, making the bottom surface of the precast prestressed concrete beam flush with the top surface of the precast concrete lower column. Place the end of the precast prestressed concrete beam on the precast concrete lower column and fix it with supports. Since the beam already has prestressing effect, supports are not required. The ordinary steel bars and prestressed tendons extending from the prestressed concrete beams on both sides should be reasonably avoided in the core area of ​​the joint and directly anchored or bent and anchored according to the structural requirements.

[0054] Step 4: Hoist the precast concrete upper column to the top of the precast concrete lower column, and fix the precast concrete upper column in the corresponding position with reliable supports. At this time, tie the stirrups installed in Step 2 to the column longitudinal reinforcement. The longitudinal reinforcements extending from the precast concrete upper and lower columns should be reasonably avoided in the core area of ​​the node and directly anchored.

[0055] Step 5: Pass the top continuous steel bar through the stirrups reserved in the beam composite layer area and the node core area and tie them. Then tie the pre-embedded and extended loosely bonded prestressed tendons in the pre-tensioned prestressed concrete beam in the node core area according to the design position. For the unbonded part of the node, sleeves need to be put on the loosely bonded tendons. Then pour the UHPC node core area and set the formwork so that the UHPC will not enter the beam composite layer.

[0056] Step 6: After the core area of ​​the UHPC node has cured to a sufficient strength, the precast concrete slab, composite slab, double T slab or secondary beam is hoisted onto the precast prestressed concrete beam and fixed.

[0057] Step 7: Pour the beam composite layer and slab composite layer;

[0058] Step 8: After the composite concrete of the beam and slab layers has cured to sufficient strength, tension the slow-bonding prestressing tendons.

[0059] Step 9: Repeat the above production process to complete the tensioned and bonded prestressed concrete frame structure system.

[0060] Compared with the prior art, the advantages of the present invention are as follows:

[0061] 1. This invention combines precast concrete structures, prestressed prestressing, and post-tensioned, loosely bonded prestressed structures. Leveraging the advantages of precast structures—convenient and rapid construction, high-quality build quality, energy efficiency, and environmental friendliness—the combination of pre-tensioned, loosely bonded prestressed structures improves structural performance, reduces component cross-sectional height, lightens self-weight, enhances component crack resistance, and improves self-healing capabilities, thereby improving the overall seismic performance of the frame structure. Prestressed prestressing allows for construction of precast beams with minimal or no support, while the post-tensioned, loosely bonded reinforcement offers good durability, ease of construction, and solves the problem of insufficient compaction during post-tensioned bonding grouting.

[0062] 2. This invention uses UHPC material with excellent performance. Applying it to the core area of ​​the node can achieve reliable connection of precast beam and column components. It can not only improve the load-bearing capacity and seismic performance of the node, but also significantly reduce the anchorage length of steel bars and steel strands, and significantly reduce the amount of stirrups used in the core area of ​​the node. This avoids the congestion of steel bars in the core area of ​​the node, and greatly improves the efficiency of the production, transportation and installation of precast beam and column components. Attached Figure Description

[0063] Figure 1 This is a structural schematic diagram of the precast prestressed concrete frame structure system based on UHPC of the present invention.

[0064] Figure 2 This is a schematic diagram of the reinforcement of a two-span frame structure according to the present invention.

[0065] Figure 3 This is a schematic diagram of the material of a two-span frame structure according to the present invention.

[0066] Figure 4 Detailed construction diagram of the intermediate layer frame edge node of the present invention

[0067] Figure 5 Isometric view of the edge node of the intermediate layer frame of the present invention

[0068] Figure 6 Detailed diagram of node construction in the intermediate layer framework of this invention.

[0069] Figure 7 Axonometric view of the nodes in the intermediate layer frame of this invention. Detailed Implementation

[0070] To make the features, objectives and advantages of the present invention easier to understand, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0071] like Figure 1-7 As shown, the UHPC-connected post-tensioned and loosely bonded co-tensioned prestressed concrete frame structure system of the present invention includes a precast concrete upper column (1), a precast concrete lower column (2), a post-tensioned and loosely bonded co-tensioned prestressed concrete composite beam (3), a UHPC node core area (4), and a composite slab (18).

[0072] The precast concrete upper column (1) is provided with upper longitudinal main reinforcement (5), the precast concrete lower column (2) is provided with lower longitudinal main reinforcement (6), the post-tensioned and slowly bonded co-tensioned prestressed concrete composite beam (3) is provided with precast pre-tensioned prestressed concrete beam (7) and beam composite layer (8) and post-tensioned and slowly bonded prestressing tendons (9), the precast pre-tensioned prestressed concrete beam (7) is provided with ordinary steel bars (10) and pre-tensioned prestressing tendons (17), the beam composite layer (8) is provided with top continuous steel bars (11), and the composite slab (18) is composed of a precast concrete slab (19) and a slab composite layer (20) cast on the slab.

[0073] The upper longitudinal main reinforcement (5) extends out of the bottom surface of the precast upper column (1) and is directly anchored in the core area (4) of the UHPC node. The lower longitudinal main reinforcement (6) extends out of the top surface of the precast lower column (2) and is directly anchored in the core area (4) of the UHPC node. The ordinary steel reinforcement (10) and the prestressed tendon (17) extend out of the end face of the precast prestressed concrete beam (7) and are directly anchored in the core area (4) of the UHPC node.

[0074] The pre-tensioned prestressing tendons (17) include straight or broken line tendons, and the post-tensioned loosely bonded prestressing tendons (9) include straight, broken line, and curved tendons;

[0075] The post-tensioned bonded prestressed tendon (9) in the core area of ​​the node can be bonded, partially bonded, unbonded, or unbonded;

[0076] The post-tensioned, loosely bonded co-tensioned prestressed concrete composite beam (3) is constructed and verified as a pre-tensioned prestressed concrete simply supported beam before the pouring of the beam composite layer (8), slab composite layer (20) and UHPC node core area (4). After the pouring of the node core area (4), beam composite layer (8), and slab composite layer (20), when the concrete strength of the node and composite layer reaches the design requirements, the loosely bonded prestressing tendons (9) are tensioned. After tensioning, the construction stage verification is performed as a frame beam. After the prestress is established, the post-tensioned, loosely bonded prestressing tendons (9) are calculated based on the effective prestress during construction verification. For the part of the node core area that is bonded and unbonded, the calculation is based on the effective prestress under the normal serviceability limit state. Under the ultimate bearing limit state, the stress increment of the unbonded tendons is considered. Under seismic load, the recovery performance provided by the unbonded tendons is considered.

[0077] The post-tensioned and slowly bonded co-tensioned prestressed concrete composite beam (3) consists of a pre-tensioned prestressed concrete beam (7), a beam composite layer (8), and post-tensioned and slowly bonded prestressing tendons (9); the composite slab (18) consists of a precast concrete slab (19) and a slab composite layer (20) cast on the slab.

[0078] The post-tensioned and slowly bonded prestressed tendons (9) are pre-embedded in the precast pre-tensioned prestressed concrete beam (7) component according to the design position, and pass through the core area (4) of the UHPC node and extend beyond the core area (4) of the UHPC node at both ends. Clamps (15) and anchors (16) are fixedly installed at both ends respectively, with one end set on the outside of the column and the other end set in the beam composite layer.

[0079] The bottom surface of the precast concrete upper column (1), the top surface of the precast concrete lower column (2), and the end face of the post-tensioned and slowly bonded precast prestressed concrete composite beam (3) are all provided with recessed grooves (U-shaped grooves can also be provided at the beam ends, and structural shear reinforcement can be provided if necessary).

[0080] The precast concrete upper column (1) is fixed in the corresponding position by a reliable support (12).

[0081] The stirrups (13) in the precast concrete upper column (1), precast concrete lower column (2), and post-tensioned and loosely bonded co-tensioned precast prestressed concrete composite beam (3) are divided into a dense zone and a non-dense zone. The stirrups (14) in the core area (4) of the UHPC node are arranged according to the design requirements. The shear bearing capacity of the core area is calculated according to the inclined compression bar model. The steel fibers in the UHPC are considered to be equivalent to horizontal stirrups and vertical longitudinal bars, and their contribution to the shear resistance of the core area of ​​the node is considered. At the same time, the beneficial contribution of the loosely bonded prestressed tendons to the shear resistance of the node is also considered.

[0082] The top surfaces of the precast prestressed concrete beam (7) and the precast concrete slab (19) are provided with a rough surface layer.

[0083] The seismic design of this system includes the following steps:

[0084] Step 1: Design beams and columns according to existing specifications and invention patents;

[0085] Step 2: The seismic design of its nodes should be carried out according to the following method: Calculate the horizontal shear capacity V of the node. jh ;

[0086] Step 3: The diameter of each longitudinal steel bar in the beam that runs through the central column should not be greater than the smaller of 1 / 18 of the column's cross-sectional dimension in that direction and x.

[0087] A post-tensioned, loosely bonded, co-tensioned prestressed concrete frame structure system with UHPC (Ultra-High-Pressure Concrete) connection, characterized by the following steps:

[0088] Step 1: Construct precast concrete lower column (2), precast concrete upper column (1), precast prestressed concrete beam (7), and precast concrete slab (19); among them, the precast concrete lower column (2) and precast concrete upper column (1) need to reserve sufficient anchorage length for the longitudinal reinforcement extending into the core area (4) of the node; when precasting the prestressed concrete beam (7), the prestressed tendons (17) are first tensioned on the platform, and the post-tensioned and slowly bonded prestressed tendons (9) are pre-embedded in the beam according to the design position, and sufficient length is reserved on both sides, and then the concrete is poured. When the concrete is cured to sufficient strength, the prestressed tendons (17) are released and sufficient anchorage length is reserved at the beam end;

[0089] Step 2: After the precast components have been cured, hoist the precast concrete lower column (2) and install it on the foundation, and then install an appropriate number of stirrups (14) on the extended longitudinal main reinforcement (6);

[0090] Step 3: Hoist the precast prestressed concrete beam (7) to the top surface of the precast concrete lower column (2), so that the bottom surface of the precast prestressed concrete beam (7) is flush with the top surface of the precast concrete lower column (2), and place the end of the precast prestressed concrete beam (7) on the precast concrete lower column (2) and fix it with a support. Since the beam already has prestressing effect, it can be without support. Among them, the ordinary steel bars (10) and prestressed tendons (17) extending from the prestressed concrete beams (7) on both sides should be reasonably avoided in the core area of ​​the node and directly anchored or bent and anchored according to the structural requirements.

[0091] Step 4: Hoist the precast concrete upper column (1) directly above the precast concrete lower column (2), and fix the precast concrete upper column (1) in the corresponding position with a reliable support (12). At this time, tie the stirrups (14) installed in step 2 together with the column longitudinal reinforcement. The longitudinal reinforcements extending from the precast concrete upper and lower columns are reasonably avoided in the core area of ​​the node and are directly anchored.

[0092] Step 5: Pass the top continuous steel bar (11) through the stirrup (13) reserved in the beam composite layer area and the node core area (4) and tie it. Then tie the pre-embedded and extended slow-bonded prestressed tendons (9) in the pre-tensioned prestressed concrete beam (7) in the node core area according to the design position. For the unbonded part of the node, a sleeve needs to be put on the slow-bonded tendon. Then pour the UHPC node core area (4) and set the template so that the UHPC will not enter the beam composite layer (8) part.

[0093] Step 6: After the core area (4) of the UHPC node has been cured to a sufficient strength, the precast concrete slab, composite slab, double T slab or secondary beam is hoisted onto the precast prestressed concrete beam (7) and fixed.

[0094] Step 7: Pour the beam composite layer (8) and slab composite layer (20);

[0095] Step 8: After the concrete of the beam composite layer (8) and slab composite layer (20) has been cured to sufficient strength, the slow-bonding prestressing tendons (9) are tensioned.

[0096] Step 9: Repeat the above production process to complete the tensioned and bonded prestressed concrete frame structure system.

[0097] The above description is merely an exemplary description of the present invention. Obviously, the specific implementation of the present invention is not limited to the above-described manner. That is, the description is not restrictive. Without departing from the inventive concept and technical solution of the present invention, the present invention can be easily improved, changed or replaced in various ways, and all such improvements and changes fall within the protection scope of the present invention.

Claims

1. A UHPC-connected post-tensioned and loosely bonded co-tensioned prestressed concrete frame structure system, comprising a precast concrete upper column (1), a precast concrete lower column (2), a post-tensioned and loosely bonded co-tensioned prestressed concrete composite beam (3), a UHPC node core area (4), and a composite slab (18). Its features are, The precast concrete upper column (1) is provided with upper longitudinal main reinforcement (5), the precast concrete lower column (2) is provided with lower longitudinal main reinforcement (6), the post-tensioned and slowly bonded co-tensioned prestressed concrete composite beam (3) is provided with precast pre-tensioned prestressed concrete beam (7), beam composite layer (8) and post-tensioned and slowly bonded prestressing tendons, the precast pre-tensioned prestressed concrete beam (7) is provided with ordinary steel bars (10) and pre-tensioned prestressing tendons, the beam composite layer (8) is provided with top continuous steel bars (11), the composite slab (18) is composed of precast concrete slab (19) and slab composite layer (20) cast on the slab; The upper longitudinal main reinforcement (5) extends out of the bottom surface of the precast upper column (1) and is directly anchored in the core area (4) of the UHPC node; the lower longitudinal main reinforcement (6) extends out of the top surface of the precast lower column (2) and is directly anchored in the core area (4) of the UHPC node; the ordinary steel reinforcement (10) and the prestressed tendon extend out of the end face of the precast prestressed concrete beam (7) and are directly anchored in the core area (4) of the UHPC node; The pre-tensioned prestressing tendons include straight or polygonal tendons, and the post-tensioned loosely bonded prestressing tendons include straight, polygonal, and curved tendons; The post-tensioned bonded prestressing tendons in the core area of ​​the node can be bonded, partially bonded, unbonded, or unbonded. The post-tensioned and loosely bonded co-tensioned prestressed concrete composite beam (3) is constructed and verified as a pre-tensioned prestressed concrete simply supported beam before the beam composite layer (8), slab composite layer (20) and UHPC node core area (4) are poured. After the node core area (4) and beam composite layer (8) and slab composite layer (20) are poured, when the concrete strength of the node and composite layer reaches the design requirements, the loosely bonded prestressing tendons are tensioned. After the tensioning is completed, the construction stage verification is performed as a frame beam. After the prestress is established, the post-tensioned and loosely bonded prestressing tendons are calculated based on the effective prestress during construction verification. For the part of the node core area that is bonded and unbonded, the calculation is based on the effective prestress under the normal serviceability limit state. Under the ultimate bearing limit state, the stress increment of the unbonded tendons is considered. Under seismic load, the recovery performance provided by the unbonded tendons is considered. The post-tensioned and slowly bonded prestressed tendons are pre-embedded in the precast pre-tensioned prestressed concrete beam (7) component according to the design position, and pass through the core area (4) of the UHPC node and extend beyond the core area (4) of the UHPC node at both ends. Clamps (15) and anchors (16) are fixedly installed at both ends respectively, with one end set on the outside of the column and the other end set in the beam composite layer. The core areas of the edge nodes, middle nodes and corner nodes of the co-tensioned prestressed concrete frame structure system are all UHPC node core areas (4); The stirrups in the core area (4) of the UHPC node are arranged according to the design requirements. The shear bearing capacity calculation of the core area considers the steel fibers in the UHPC as equivalent to horizontal stirrups and vertical longitudinal bars, and considers their contribution to the shear resistance of the core area of ​​the node. At the same time, the beneficial contribution of the loosely bonded prestressed tendons to the shear resistance of the node is also considered. The construction method of the co-tensioned prestressed concrete frame structure system includes: The end of the precast prestressed concrete beam (7) is placed on the precast concrete lower column (2), and the precast concrete upper column (1) is hoisted to the top of the precast concrete lower column (2). The area enclosed between the precast prestressed concrete beam and the precast concrete lower and upper columns is the core area of ​​the UHPC node.

2. The UHPC-connected post-tensioned and loosely bonded co-tensioned prestressed concrete frame structure system according to claim 1, characterized in that, The post-tensioned and slowly bonded co-tensioned prestressed concrete composite beam (3) consists of a pre-tensioned prestressed concrete beam (7), a beam composite layer (8), and post-tensioned and slowly bonded prestressing tendons; the composite slab (18) consists of a precast concrete slab (19) and a slab composite layer (20) cast on the slab.

3. The UHPC-connected post-tensioned, loosely bonded co-tensioned prestressed concrete frame structure system according to claim 1, characterized in that, The bottom surface of the precast concrete upper column (1), the top surface of the precast concrete lower column (2), and the end face of the post-tensioned and slowly bonded precast prestressed concrete composite beam (3) are all provided with recessed grooves or U-shaped grooves.

4. The UHPC-connected post-tensioned and loosely bonded co-tensioned prestressed concrete frame structure system according to claim 1, characterized in that, The stirrups in the precast concrete upper column (1), precast concrete lower column (2), and post-tensioned and slowly bonded co-tensioned prestressed concrete composite beam (3) are divided into a dense zone and a non-dense zone.

5. The UHPC-connected post-tensioned and slowly bonded co-tensioned prestressed concrete frame structure system according to claim 1, characterized in that, The top surfaces of the precast prestressed concrete beam (7) and the precast concrete slab (19) are provided with a rough surface layer.

6. The construction method of the post-tensioned, loosely bonded, co-tensioned prestressed concrete frame structure system with UHPC connection according to any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Construct precast concrete lower column (2), precast concrete upper column (1), precast prestressed concrete beam (7), and precast concrete slab (19); among them, the precast concrete lower column (2) and precast concrete upper column (1) need to reserve sufficient anchorage length for the longitudinal reinforcement extending into the core area (4) of the node; when precasting prestressed concrete beam (7), the prestressing tendons are first tensioned on the platform, and the post-tensioned and slowly bonded prestressing tendons are pre-embedded in the beam according to the design position, and sufficient length is reserved on both sides, and then the concrete is poured. When the concrete is cured to sufficient strength, the prestressing tendons are released and sufficient anchorage length is reserved at the beam end; Step 2: After the precast components have been cured, hoist the precast concrete lower column (2) and install it on the foundation, and then install an appropriate number of stirrups on the extended longitudinal main reinforcement (6); Step 3: Hoist the precast prestressed concrete beam (7) to the top surface of the precast concrete lower column (2), so that the bottom surface of the precast prestressed concrete beam (7) is flush with the top surface of the precast concrete lower column (2), and place the end of the precast prestressed concrete beam (7) on the precast concrete lower column (2) and fix it with a support. Since the beam already has prestressing effect, it can be without support. Among them, the ordinary steel bars (10) and prestressing tendons extending from the prestressed concrete beams (7) on both sides should be reasonably avoided in the core area of ​​the node and directly anchored or bent and anchored according to the structural requirements. Step 4: Hoist the precast concrete upper column (1) directly above the precast concrete lower column (2), and fix the precast concrete upper column (1) in the corresponding position with a reliable support (12). At this time, tie the stirrups installed in step 2 together with the column longitudinal reinforcement. The longitudinal reinforcements extending from the precast concrete upper and lower columns should be reasonably avoided in the core area of ​​the node and directly anchored. Step 5: Pass the top continuous steel bar (11) through the stirrups reserved in the beam composite layer area and the node core area (4) and tie it. Then tie the pre-embedded and extended slow-bonded prestressed tendons in the pre-tensioned prestressed concrete beam (7) in the node core area according to the design position. For the unbonded part of the node, a sleeve needs to be put on the slow-bonded tendon. Then pour the UHPC node core area (4) and set the template so that the UHPC will not enter the beam composite layer (8) part. Step 6: After the core area (4) of the UHPC node has been cured to a sufficient strength, the precast concrete slab, composite slab, double T slab or secondary beam is hoisted onto the precast prestressed concrete beam (7) and fixed. Step 7: Pour the beam composite layer (8) and slab composite layer (20); Step 8: After the concrete of the beam composite layer (8) and slab composite layer (20) has been cured to sufficient strength, the bonded prestressing tendons are tensioned. Step 9: Repeat the above production process to complete the tensioned and bonded prestressed concrete frame structure system.

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