A UHPC connected post-tensioned unbonded shared-tension prefabricated prestressed concrete opening beam frame structure and a design and construction method thereof

Abstract

The application discloses a UHPC connected post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole beam frame structure system, which comprises a prefabricated concrete upper column, a prefabricated concrete lower column, a post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam, a UHPC node core area and a composite slab. The structure system is not only convenient and fast in on-site construction and improves component installation efficiency, but also can greatly reduce the anchoring length of steel bars, greatly reduce the amount of stirrups in the node core area, avoid the congestion of steel bars in the node core area, reduce the component section height, reduce the self weight, improve the component crack resistance and self-recovery performance, thereby improving the seismic performance of the overall frame structure. The pre-tensioned prestressed steel bars can be less supported or free of support during the construction of the prefabricated beam, thereby reducing the construction cost, and the post-tensioned unbonding can enhance the integrity of the frame, so that the structure has a certain self-resetting capacity and structural toughness in the earthquake, and the post-earthquake repair cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of prefabricated prestressed assembly type building construction, in particular to a UHPC connected post-tensioned unbonded shared tension prefabricated prestressed concrete open hole beam frame structure and its design and construction method. BACKGROUND

[0002] The construction efficiency of cast-in-place structure is low, and the energy loss is high, and many limitations, which gradually cannot meet the development requirements of building industrialization. Prefabricated assembly type building has become the development direction of building industrialization because of its fast construction speed, factory production of components, reduction of on-site wet work and reduction of environmental pollution. After years of development and promotion, prefabricated assembly type concrete structure has been widely researched and used.

[0003] The prefabricated assembly type concrete frame structure refers to the structure that the beam-column components are prefabricated in the prefabrication plant and transported to the construction site for connection to form the overall structure. Compared with the cast-in-place concrete structure, it has the advantages of fast construction speed, easy guarantee of component quality, good quality, small environmental pollution, saving of labor cost, and saving of a large amount of formwork and support, etc., and is a structure form with very broad prospects. For wet connection assembly type concrete frame structure, the node construction form which is easy to construct and effectively guarantees the integrity is the key to its popularization and application. However, from the past earthquake disasters, the assembly type structure is seriously damaged in the earthquake, and it is difficult to achieve the same seismic performance as the cast-in-place structure. In order to improve the integrity and reliability of the assembly type concrete frame node connection and achieve or even exceed the seismic performance of the cast-in-place concrete structure, the prestressed technology and UHPC (Ultra High Performance Concrete, ultra high performance concrete) material are introduced into the assembly type structure.

[0004] The post-tensioned unbonded shared tension prestressed assembly type concrete structure is formed by assembling the prefabricated ordinary concrete components and the prefabricated pretensioned prestressed components together to work together through tensioning the prestressed reinforcement, which has the characteristics of pretensioned prestressed, post-tensioned unbonded prestressed concrete structure and assembly type structure. The internal stress generated by the prestress in the concrete section can partially or completely offset the stress in the section under the use load, delay the occurrence of cracks and improve the stiffness of the component. When unloaded, the cracks can be partially or completely closed, and the elastic recovery performance of the structure is good. At the same time, the prestressed concrete can fully utilize the material strength of the prestressed reinforcement and the concrete, and reduce the self weight of the structure. And the application of prestress helps to improve the performance and integrity of the assembly type structure, and promotes the application of assembly type structure in large-span and heavy-load structures.

[0005] UHPC has excellent bonding performance, which can greatly reduce the anchorage length of steel bars and steel strands in it; it has high strength, which can reduce the amount of stirrups in the core area of the joint, and using UHPC in the core area of the joint can make the structure simple and the overall framework good. The prestressed structure has excellent stress performance, and the application of UHPC in the core area of the joint forms a prefabricated prestressed framework structure. Further research on this structure is beneficial to the further promotion and application of prefabricated prestressed concrete frame structure. SUMMARY

[0006] The purpose of the present application is to overcome the shortcomings of the prior art, combined with the excellent performance of UHPC, a UHPC connected post-tensioned non-bonding co-tension prefabricated prestressed concrete open hole beam framework structure and its design and construction method are proposed. It combines three traditional structures of pre-tensioned prestressed structure, post-tensioned non-bonding prestressed structure and assembly structure and composite structure, and uses UHPC high-performance materials, so as to improve the seismic performance of prefabricated assembly concrete frame structure.

[0007] The advantages of the present application mainly lie in the connection technology of prefabricated pre-tensioned prestressed concrete open hole beam column components and the steel bar connection technology between components. In the component connection technology, the beam column components are connected by UHPC with excellent performance to form the UHPC joint core area, which is more easily to realize the seismic fortification requirement of strong node and weak component, thereby improving the ductility of beam column joint and improving the seismic performance of the overall framework structure. In the steel bar connection technology, the steel bars between the beam column components only need to be simply overlapped, and the overlap length is very small, thereby greatly saving the production time of prefabricated components and the on-site installation time. Therefore, the UHPC connected post-tensioned non-bonding co-tension prefabricated prestressed concrete open hole beam framework structure system and its design and construction method proposed by the present application meet the green development strategy of China's building industrialization.

[0008] The technical problems solved by the present application can be realized by using the following technical solutions:

[0009] A UHPC connected post-tensioned non-bonding co-tension prefabricated prestressed concrete open hole beam framework structure, comprising a prefabricated concrete upper column, a prefabricated concrete lower column, a post-tensioned non-bonding co-tension prefabricated prestressed concrete open hole composite beam, a UHPC joint core area and a composite slab;

[0010] The prefabricated concrete upper column is provided with upper longitudinal main reinforcement, the prefabricated concrete lower column is provided with lower longitudinal main reinforcement, the post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam is provided with prefabricated pre-tensioned prestressed concrete open-hole beam, beam composite layer and post-tensioned unbonded prestressed reinforcement, the prefabricated pre-tensioned prestressed concrete open-hole beam is provided with ordinary reinforcement and pre-tensioned prestressed reinforcement, and a hanging reinforcement or a steel mesh sheet can be arranged around the hole opening if necessary, and the steel mesh sheet can also be a welded steel mesh, the beam composite layer is provided with top longitudinal reinforcement, and the composite slab is composed of a prefabricated concrete slab and a slab composite layer poured on the slab;

[0011] The upper longitudinal main reinforcement extends out of the bottom surface of the prefabricated upper column and is directly anchored in the UHPC node core area, the lower longitudinal main reinforcement extends out of the top surface of the prefabricated lower column and is directly anchored in the UHPC node core area, and the ordinary reinforcement and the pre-tensioned prestressed reinforcement extend out of the end surface of the prefabricated pre-tensioned prestressed concrete open-hole beam and are directly anchored in the UHPC node core area.

[0012] The pre-tensioned prestressed reinforcement includes straight-line and folded-line-shaped reinforcement, and the post-tensioned unbonded prestressed reinforcement includes straight-line, folded-line and curved-line-shaped reinforcement.

[0013] The post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam is constructed according to the pre-tensioned prestressed concrete open-hole simply supported beam before pouring the beam composite layer, the slab composite layer and the UHPC node core area, after pouring the node core area and the beam composite layer and the slab composite layer, when the strength of the node and the composite layer reaches the design requirement, the post-tensioned unbonded prestressed reinforcement is tensioned, after the tensioning is completed, the construction stage calculation is performed according to the frame beam; the post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam is different in the cross section of the upper chord at the hole opening and in the stress state before and after pouring, and the prefabricated pre-tensioned prestressed concrete open-hole beam hole opening upper and lower chord should be calculated; after the pre-tensioning is established, the construction calculation and the normal use limit state calculation are performed according to the effective pre-tensioning, and the stress increment should be considered in the bearing capacity limit state calculation; under the seismic load, the recovery performance of the unbonded prestressed reinforcement to the node is considered.

[0014] Further, the post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam is composed of the prefabricated pre-tensioned prestressed concrete open-hole beam, the beam composite layer and the post-tensioned unbonded prestressed reinforcement; the composite slab is composed of the prefabricated concrete slab and the slab composite layer poured on the slab.

[0015] Further, the post-tensioned unbonded prestressed reinforcement is embedded in the prefabricated pre-tensioned prestressed concrete open-hole beam component, passes through the UHPC node core area and extends out of the UHPC node core area at both ends, and clamps and anchors are respectively arranged at both ends, one end is arranged outside the column, and the other end is arranged in the beam composite layer.

[0016] Further, the bottom surface of the prefabricated concrete upper column, the top surface of the prefabricated concrete lower column, and the end surface of the post-tensioned unbonded and shared-tension prefabricated prestressed concrete open-hole composite beam are all provided with recessed grooves.

[0017] Further, the prefabricated concrete upper column is fixed in the corresponding position by reliable support.

[0018] Further, the stirrups in the prefabricated concrete upper column, the prefabricated concrete lower column, and the post-tensioned unbonded and shared-tension prefabricated prestressed concrete open-hole composite beam are divided into an encryption area and a non-encryption area, the stirrups in the UHPC node core area are arranged according to design requirements, the shear bearing capacity of the core area is calculated according to the softened strut-and-tie model, and the steel fibers in the UHPC are equivalent to horizontal stirrups and vertical longitudinal reinforcement, and the contribution of the steel fibers to the shear resistance of the node core area is considered, and the beneficial contribution of the unbonded prestressed reinforcement to the shear resistance of the node is also considered.

[0019] Further, the prefabricated prestressed concrete open-hole beam and the top surface of the prefabricated concrete slab are provided with a rough surface layer.

[0020] The application also provides a design method of the system, which comprises the following steps:

[0021] Step 1: The beam and column are designed according to existing specifications and invention patents.

[0022] Step 2: The strength of the upper and lower chord bars at the hole opening of the prefabricated prestressed concrete open-hole beam is calculated before the pouring of the beam composite layer, the slab composite layer and the UHPC node core area of the post-tensioned unbonded and shared-tension prefabricated prestressed concrete open-hole composite beam.

[0023] Step 3: The hole opening position in the post-tensioned unbonded and shared-tension prefabricated prestressed concrete open-hole composite beam should be located as far as possible in the 1 / 3 section of the span, and when located in the 1 / 3 section of the beam end, the distance from the edge of the hole near the node to the inner edge of the node should be greater than 1.5 times the beam height.

[0024] A UHPC connected post-tensioned unbonded and shared-tension prefabricated prestressed concrete open-hole beam frame structure, comprising the following steps:

[0025] Step 1: prefabricated concrete lower column, prefabricated concrete upper column, prefabricated prestressed concrete open-hole beam, prefabricated concrete slab are made; wherein the prefabricated concrete lower column and the prefabricated concrete upper column are anchored into the node core area by extending longitudinal reinforcement with sufficient anchoring length; when prefabricating the prefabricated prestressed concrete open-hole beam, the prestressed reinforcement is first tensioned on the pedestal, the post-tensioned unbonded prestressed reinforcement is pre-buried in the beam according to the design position, and sufficient structural length is reserved at both ends, then the concrete is poured, and when the concrete is cured to sufficient strength, the prestressed reinforcement is released and sufficient anchoring length is reserved at the beam end;

[0026] Step 2: After the maintenance of the prefabricated component is completed, the prefabricated concrete lower column is hoisted and installed on the foundation, and then a proper number of stirrups are installed on the protruding longitudinal main reinforcement;

[0027] Step 3: The prefabricated pretensioned prestressed concrete hole beam is hoisted to the top surface of the prefabricated concrete lower column, the bottom surface of the prefabricated pretensioned prestressed concrete hole beam is flush with the top surface of the prefabricated concrete lower column, the end of the prefabricated pretensioned prestressed concrete hole beam is placed on the prefabricated concrete lower column, and is fixed by a support, and since the pretensioned prestressed force in the beam is also available, the support can be omitted; wherein the ordinary steel bars and the pretensioned prestressed bars protruding from the two side pretensioned prestressed concrete hole beams are reasonably avoided and directly anchored or bent and anchored in the node core area according to the construction requirements;

[0028] Step 4: The prefabricated concrete upper column is hoisted to directly above the prefabricated concrete lower column, and the prefabricated concrete upper column is fixed in the corresponding position by a reliable support, at this time, the stirrups installed in step 2 are bound together with the column longitudinal reinforcement; wherein the longitudinal reinforcement protruding from the prefabricated concrete upper and lower columns is reasonably avoided and directly anchored in the node core area;

[0029] Step 5: The top longitudinal steel bars are passed through the stirrups reserved in the beam composite layer area and the node core area and are bound well, then the unbonded prestressed bars embedded and protruding from the pretensioned prestressed concrete hole beam are bound well in the node core area according to the designed position, and then the UHPC node core area is poured, and the formwork is arranged so that the UHPC does not enter the beam composite layer part;

[0030] Step 6: After the UHPC node core area is maintained to sufficient strength, the prefabricated concrete flat plate (or composite plate, double T plate, secondary beam) is hoisted to the prefabricated prestressed concrete beam and is fixed;

[0031] Step 7: The beam composite layer and the plate composite layer are poured;

[0032] Step 8: After the beam composite layer and the plate composite layer are maintained to sufficient strength, the prestressed bars are tensioned;

[0033] Step 9: The above manufacturing process is repeated to complete the post-tensioned unbonded shared-tension prefabricated prestressed concrete hole beam frame structure system.

[0034] Compared with the prior art, the advantages of the present application are that:

[0035] 1.The present application combines prefabricated assembly concrete structure, pre-tensioned prestressed structure and post-tensioned unbonded prestressed structure together, uses the advantages of prefabricated assembly structure, such as convenient and fast construction, good construction quality, energy saving and environmental protection, and combines post-tensioned unbonded shared tension prestressed structure to improve the structural performance, reduce the cross-section height of the component, reduce the self weight, improve the crack resistance and self-recovery of the component, thereby improving the seismic performance of the overall frame structure. The pre-tensioned prestressed reinforcement makes the prefabricated beam less supported or free supported during construction, reduces the construction cost, and the post-tensioned unbonded structure can enhance the overall integrity of the frame, so that the structure has certain self-resetting capacity and structural toughness in the earthquake, and reduces the repair cost after the earthquake.

[0036] 2.The present application uses UHPC material with excellent performance, which is applied in the node core area, can realize reliable connection of prefabricated beam column components, not only can improve the bearing capacity and seismic performance of the node, but also can greatly reduce the anchoring length of the steel bar and steel strand, and can significantly reduce the amount of stirrup in the node core area, thereby avoiding the congestion of steel bars in the node core area, and greatly improving the production, transportation and installation efficiency of prefabricated beam column components. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The structural schematic diagram of the prefabricated prestressed concrete open beam frame structure system based on UHPC of the present application

[0038] Figure 2 The reinforcement schematic diagram of a two-span frame structure of the present application

[0039] Figure 3 The material schematic diagram of a two-span frame structure of the present application

[0040] Figure 4 The detailed structure diagram of the edge node of the intermediate layer frame of the present application

[0041] Figure 5 The axonometric view of the edge node of the intermediate layer frame of the present application

[0042] Figure 6 The detailed structure diagram of the middle node of the intermediate layer frame of the present application

[0043] Figure 7 The axonometric view of the middle node of the intermediate layer frame of the present application DETAILED DESCRIPTION

[0044] In order to better understand the features, objects and advantages of the present application, the present application is further described below in combination with the drawings and specific embodiments.

[0045] As Figures 1-7The UHPC connected post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole beam frame structure system comprises a prefabricated concrete upper column (1), a prefabricated concrete lower column (2), a post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam (3), a UHPC node core area (4), and a composite slab (18).

[0046] The prefabricated concrete upper column (1) is internally provided with upper longitudinal main reinforcement (5), the prefabricated concrete lower column (2) is internally provided with lower longitudinal main reinforcement (6), the post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam (3) is internally provided with a prefabricated pre-tensioned prestressed concrete open-hole beam (7) and a beam composite layer (8) and a post-tensioned unbonded prestressed reinforcement (9), the prefabricated pre-tensioned prestressed concrete open-hole beam (7) is provided with ordinary reinforcement (10) and pre-tensioned prestressed reinforcement (17), the beam composite layer (8) is internally provided with top longitudinal reinforcement (11), and the composite slab (18) is composed of a prefabricated concrete slab (19) and a slab composite layer (20) poured on the slab.

[0047] The upper longitudinal main reinforcement (5) extends out of the bottom surface of the prefabricated upper column (1) and is directly anchored in the UHPC node core area (4), the lower longitudinal main reinforcement (6) extends out of the top surface of the prefabricated lower column (2) and is directly anchored in the UHPC node core area (4), and the ordinary reinforcement (10) and the pre-tensioned prestressed reinforcement (17) extend out of the end surface of the prefabricated pre-tensioned prestressed concrete open-hole beam (7) and are directly anchored in the UHPC node core area (4).

[0048] The pre-tensioned prestressed reinforcement (17) comprises straight and folded line-shaped reinforcement, and the post-tensioned unbonded prestressed reinforcement (9) comprises straight, folded, and curved line-shaped reinforcement.

[0049] The post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam (3) is calculated and verified according to the pre-tensioned prestressed concrete open-hole simply supported beam before pouring the beam composite layer (8), the slab composite layer (20), and the UHPC node core area (4), after pouring the node core area (4) and the beam composite layer (8) and the slab composite layer (20), and when the strength of the node and the composite layer concrete reaches the design requirement, the post-tensioned unbonded prestressed reinforcement (9) is tensioned, and after the tensioning is completed, the construction stage is calculated and verified according to the frame beam; the post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam is different in cross-section and stress state at the hole opening before and after pouring the beam composite layer, the slab composite layer, and the UHPC node core area, and the prefabricated pre-tensioned prestressed concrete open-hole beam hole opening upper and lower chord bars should be calculated and verified; after the pre-tensioning is established, the post-tensioned unbonded prestressed reinforcement (9) is calculated and verified according to the effective pre-tensioning in the construction and normal use limit state, and the stress increment should be considered in the bearing capacity limit state; under the seismic load, the recovery performance of the unbonded prestressed reinforcement (9) to the node is considered.

[0050] The post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam (3) is composed of a prefabricated pre-tensioned prestressed concrete open-hole beam (7), a beam composite layer (8), and a post-tensioned unbonded prestressed tendon (9); the composite slab (18) is composed of a prefabricated concrete slab (19) and a slab composite layer (20) poured on the slab;

[0051] The post-tensioned unbonded prestressed tendon (9) is embedded in the prefabricated pre-tensioned prestressed concrete open-hole beam (7) component, passes through the UHPC node core area (4) and extends out of the UHPC node core area (4), and the two ends are respectively fixedly provided with clamps (15) and anchors (16), one end is arranged outside the column, and the other end is arranged in the beam composite layer;

[0052] The bottom surface of the prefabricated concrete upper column (1), the top surface of the prefabricated concrete lower column (2), and the end surface of the post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam (3) are provided with recesses;

[0053] The prefabricated concrete upper column (1) is fixed in the corresponding position by reliable support (12);

[0054] The stirrups (13) in the prefabricated concrete upper column (1), the prefabricated concrete lower column (2), and the post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam (3) are divided into dense areas and non-dense areas, the stirrups (14) in the UHPC node core area (4) are arranged according to design requirements, the shear capacity of the core area is calculated according to the softened strut-and-tie model, and the steel fibers in the UHPC are equivalent to horizontal stirrups and vertical longitudinal reinforcement, and their contribution to the shear resistance of the node core area is considered, and the beneficial contribution of the unbonded prestressed tendon to the shear resistance of the node is also considered;

[0055] The top surface of the prefabricated pre-tensioned prestressed concrete open-hole beam (7) and the prefabricated concrete slab (19) is provided with a rough surface layer.

[0056] The seismic design of the system includes the following steps:

[0057] Step 1: The beam and column are designed according to existing specifications and invention patents;

[0058] Step 2: Check the strength of the upper and lower chord bars at the hole of the prefabricated pre-tensioned prestressed concrete open-hole beam before pouring the beam composite layer, the slab composite layer, and the UHPC node core area of the post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam;

[0059] Step 3: The hole position in the post-tensioned unbonded co-tension prefabricated prestressed concrete open-hole composite beam should be located as close to the middle 1 / 3 section as possible, and when located in the 1 / 3 section of the beam end, the distance from the edge of the hole near the node to the inner edge of the node should be greater than 1.5 times the beam height.

[0060] A UHPC connected post-tensioned unbonded co-tension prefabricated prestressed concrete opening beam frame structure is characterized by comprising the following steps:

[0061] Step 1: prefabricated concrete lower column (2), prefabricated concrete upper column (1), prefabricated pre-tensioned prestressed concrete opening beam (7), prefabricated concrete slab (19) are made; wherein the prefabricated concrete lower column (2), the prefabricated concrete upper column (1) is anchored into the node core area (4) with sufficient anchoring length; when prefabricating the pre-tensioned prestressed concrete opening beam (7), the pre-tensioned prestressed steel bars (17) are pre-tensioned on the pedestal, the post-tensioned unbonded prestressed steel bars (9) are pre-embedded in the beam according to the design position, and sufficient structural length is reserved at both ends, then the concrete is poured, and when the concrete is cured to sufficient strength, the pre-tensioned prestressed steel bars (17) are released and sufficient anchoring length is reserved at the beam end;

[0062] Step 2: after the prefabricated components are cured, the prefabricated concrete lower column (2) is hoisted and installed on the foundation, then a proper number of stirrups (14) are installed on the extended longitudinal reinforcement (6);

[0063] Step 3: the prefabricated pre-tensioned prestressed concrete opening beam (7) is hoisted to the top surface of the prefabricated concrete lower column (2), the bottom surface of the prefabricated pre-tensioned prestressed concrete opening beam (7) is flush with the top surface of the prefabricated concrete lower column (2), the end of the prefabricated pre-tensioned prestressed concrete opening beam (7) is placed on the prefabricated concrete lower column (2), and is fixed with support, and since the beam has pre-tensioned prestressed effect, support can be omitted; wherein the ordinary steel bars (10) and pre-tensioned prestressed steel bars (17) of the pre-tensioned prestressed concrete opening beam (7) on both sides are reasonably avoided and directly anchored or bent and anchored in the node core area according to the structural requirements;

[0064] Step 4: the prefabricated concrete upper column (1) is hoisted to directly above the prefabricated concrete lower column (2), and the prefabricated concrete upper column (1) is fixed in the corresponding position with reliable support (12), at this time the stirrups (14) installed in step 2 are tied together with the column longitudinal reinforcement; wherein the longitudinal reinforcement of the prefabricated concrete upper and lower columns is reasonably avoided and directly anchored in the node core area;

[0065] Step 5: the top longitudinal steel bars (11) are passed through the stirrups (13) reserved in the beam composite layer area and the node core area (4) and are tied well, then the unbonded prestressed steel bars (9) pre-embedded and extended in the pre-tensioned prestressed concrete opening beam (7) are tied well in the node core area according to the design position, and then the UHPC node core area (4) is poured and the formwork is set so that the UHPC does not enter the beam composite layer (8) part;

[0066] Step 6: After the UHPC node core area (4) is cured to sufficient strength, the prefabricated concrete slab (or composite slab, double T slab, secondary beam) (19) is hoisted to the prefabricated prestressed concrete beam (7) and fixed;

[0067] Step 7: Pouring the beam composite layer (8) and the slab composite layer (20);

[0068] Step 8: After the beam composite layer (8) and the slab composite layer (20) are cured to sufficient strength, the prestressed tendon (9) is tensioned;

[0069] Step 9: Repeat the above manufacturing process to complete the post-tensioned unbonded shared-tension prefabricated prestressed concrete open-hole beam frame structure system.

[0070] The above is only an exemplary description of the present application, and it is obvious that the specific implementation of the present application is not limited by the above method. That is, the description is not limiting, and the present application can be easily improved, changed or replaced without departing from the method concept and technical solution of the present application. These improvements and changes are within the scope of protection of the present application.

Claims

1. A UHPC connected post-tensioned unbonded co-tensioned precast prestressed concrete open-hole beam frame structure system, comprising a precast concrete upper column (1), a precast concrete lower column (2), a post-tensioned unbonded co-tensioned precast prestressed concrete open-hole composite beam (3), a UHPC node core area (4) and a composite slab (18) ; characterized in that The precast concrete upper column (1) is provided with an upper longitudinal main reinforcement (5), the precast concrete lower column (2) is provided with a lower longitudinal main reinforcement (6), the post-tensioned unbonded co-tensioned precast prestressed concrete open-hole composite beam (3) is provided with a precast pre-tensioned prestressed concrete open-hole beam (7), a beam composite layer (8) and a post-tensioned unbonded prestressed reinforcement (9), the precast pre-tensioned prestressed concrete open-hole beam (7) is provided with ordinary reinforcement (10) and pre-tensioned prestressed reinforcement (17), and a hanging reinforcement (21) or a steel mesh (22) is arranged around the hole, the steel mesh is a welded steel mesh, the beam composite layer (8) is provided with a top longitudinal reinforcement (11), and the composite slab (18) is composed of a precast concrete slab (19) and a slab composite layer (20) poured 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 UHPC node core area (4), the lower longitudinal main reinforcement (6) extends out of the top surface of the precast lower column (2) and is directly anchored in the UHPC node core area (4), and the ordinary reinforcement (10) and the pre-tensioned prestressed reinforcement (17) extend out of the end surface of the precast pre-tensioned prestressed concrete open-hole beam (7) and are directly anchored in the UHPC node core area (4) ; The pre-tensioned prestressed reinforcement (17) comprises straight and folded line reinforcements, and the post-tensioned unbonded prestressed reinforcement (9) comprises straight, folded and curved line reinforcements; The post-tensioned unbonded co-tensioned precast prestressed concrete open-hole composite beam (3) is calculated according to the pre-tensioned prestressed concrete open-hole simply supported beam before pouring the beam composite layer (8), the slab composite layer (20) and the UHPC node core area (4), after pouring the node core area (4) and the beam composite layer (8) and the slab composite layer (20), when the strength of the node and the composite layer concrete reaches the design requirement, the post-tensioned unbonded prestressed reinforcement (9) is tensioned, and after the tensioning is completed, the construction stage calculation is carried out according to the frame beam; the post-tensioned unbonded co-tensioned precast prestressed concrete open-hole composite beam is different in cross section of the upper chord at the hole and in stress state before and after pouring the beam composite layer, the slab composite layer and the UHPC node core area, and the precast pre-tensioned prestressed concrete open-hole beam hole upper and lower chord should be calculated; after the pre-tensioning is established, the post-tensioned unbonded prestressed reinforcement (9) is calculated according to the effective pre-tensioning in the construction calculation, the normal use limit state calculation, and the stress increment should be considered in the bearing capacity limit state calculation; under the seismic load, the recovery performance of the post-tensioned unbonded prestressed reinforcement (9) to the node is considered. The post-tensioned unbonded prestressed tendon (9) is embedded in the prefabricated pre-tensioned prestressed concrete open-hole beam (7) component, passes through the UHPC node core area (4) and extends out of the UHPC node core area (4), and the two ends are respectively fixedly provided with clamps (15) and anchorage devices (16), one end is arranged outside the column, and the other end is arranged in the beam composite layer; The edge node, the middle node and the corner node core area of the post-tensioned unbonded shared-tension prefabricated prestressed concrete open-hole beam frame structure system are all UHPC node core areas (4); The stirrups in the UHPC node core area (4) are arranged according to design requirements, and the calculation of the shear bearing capacity of the core area considers that the steel fibers in the UHPC are equivalent to horizontal stirrups and vertical longitudinal reinforcement, and considers the contribution of the steel fibers to the shear resistance of the node core area, and also considers the beneficial contribution of the unbonded prestressed tendon to the shear resistance of the node; The construction method of the post-tensioned unbonded shared-tension prefabricated prestressed concrete open-hole beam frame structure system comprises: The end of the prefabricated pre-tensioned prestressed concrete open-hole beam (7) is placed on the prefabricated concrete lower column (2), the prefabricated concrete upper column (1) is hoisted to directly above the prefabricated concrete lower column (2), and the area enclosed between the prefabricated pre-tensioned prestressed concrete open-hole beam and the prefabricated concrete lower column and upper column is the UHPC node core area.

2. The UHPC connected post-tensioned un-bonded co-tensioned precast prestressed concrete open-web beam framed structural system according to claim 1, characterized in that, The post-tensioned unbonded shared-tension prefabricated prestressed concrete open-hole composite beam (3) is composed of a prefabricated pre-tensioned prestressed concrete open-hole beam (7), a beam composite layer (8) and a post-tensioned unbonded prestressed tendon (9); and the composite slab (18) is composed of a prefabricated concrete slab (19) and a slab composite layer (20) poured on the slab.

3. The UHPC connected post-tensioned un-bonded co-tensioned precast prestressed concrete open-web beam framed structural system according to claim 1, characterized in that, The bottom surface of the prefabricated concrete upper column (1), the top surface of the prefabricated concrete lower column (2) and the end surface of the post-tensioned unbonded shared-tension prefabricated prestressed concrete open-hole composite beam (3) are all provided with recessed grooves.

4. The UHPC connected post-tensioned un-bonded co-tensioned precast prestressed concrete open-web beam framed structural system according to claim 1, characterized in that, The stirrups in the prefabricated concrete upper column (1), the prefabricated concrete lower column (2) and the post-tensioned unbonded shared-tension prefabricated prestressed concrete open-hole composite beam (3) are divided into dense areas and non-dense areas.

5. The UHPC connected post-tensioned un-bonded co-tensioned precast prestressed concrete open-web beam framing structural system according to claim 1, wherein, The top surface of the prefabricated pre-tensioned prestressed concrete open-hole beam (7) and the prefabricated concrete slab (19) is provided with a rough surface layer.

6. A design method of the UHPC connected post-tensioned un-bonded co-tensioned precast prestressed concrete open-web beam frame structural system according to claim 1, characterized in that: The hole position in the beam should be located as far as possible in the 1 / 3 section of the span, and when located in the 1 / 3 section of the beam end, the distance from the edge of the hole near the node to the inner edge of the node should be greater than 1.5 times the height of the beam.

7. The construction method of the UHPC connected post-tensioned un-bonded and co-tensioned precast prestressed concrete open-web beam frame structure according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: Step 1: prefabricate a prefabricated concrete lower column (2), a prefabricated concrete upper column (1), a prefabricated pre-tensioned prestressed concrete open-hole beam (7) and a prefabricated concrete slab (19); wherein the prefabricated concrete lower column (2) and the prefabricated concrete upper column (1) need to reserve sufficient anchoring length for the anchoring of longitudinal reinforcement into the node core area (4); when prefabricating the pre-tensioned prestressed concrete open-hole beam (7), first tension the pre-tensioned prestressed tendon (17) on the pedestal, embed the post-tensioned unbonded prestressed tendon (9) in the beam according to the design position, and reserve sufficient structural length at both ends, then pour concrete, and when the concrete is cured to sufficient strength, release the pre-tensioned prestressed tendon (17) and reserve sufficient anchoring length at the beam end; Step 2: After the curing of the precast component is completed, hoist the precast concrete lower column (2) and install it on the foundation, and then install a proper number of stirrups on the protruding longitudinal main reinforcement (6); Step 3: Hoist the precast pretensioned prestressed concrete hole beam (7) to the top surface of the precast concrete lower column (2), make the bottom surface of the precast pretensioned prestressed concrete hole beam (7) flush with the top surface of the precast concrete lower column (2), make the end of the precast pretensioned prestressed concrete hole beam (7) rest on the precast concrete lower column (2), and fix it with a support, and since there is a pretensioning effect in the beam, the support can be omitted; wherein the ordinary steel bars (10) and pretensioning reinforcement (17) protruding from the pretensioned prestressed concrete hole beams (7) on both sides are reasonably avoided and directly anchored or bent and anchored in the node core area according to the construction requirements; Step 4: Hoist the precast concrete upper column (1) to 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, the stirrups installed in step 2 are tied together with the column longitudinal reinforcement; wherein the longitudinal reinforcement protruding from the precast concrete upper and lower columns is reasonably avoided and directly anchored in the node core area; Step 5: Pass the top longitudinal steel bars (11) through the stirrups reserved in the beam composite layer area and the node core area (4) and tie them well, then tie the unbonded prestressed reinforcement (9) embedded and protruding from the pretensioned prestressed concrete hole beam (7) in the node core area according to the designed position, and then pour the UHPC node core area (4) and set the formwork so that the UHPC does not enter the beam composite layer (8) part; Step 6: After the UHPC node core area (4) is cured to sufficient strength, hoist the precast concrete slabs, composite slabs, double T slabs or secondary beams to the precast prestressed concrete beams and fix them; Step 7: Pour the beam composite layer (8) and the slab composite layer (20); Step 8: After the beam composite layer (8) and the slab composite layer (20) are cured to sufficient strength, tension the prestressed reinforcement (9); Step 9: Repeat the above manufacturing process to complete the post-tensioned unbonded co-tensioned precast prestressed concrete hole beam frame structure system.

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