CN115538592A - UHPC connected post-tensioned unbonded co-tensioned precast prestressed concrete open-pore beam frame structure and design and construction method thereof - Google Patents

Abstract

The invention discloses a post-tensioned unbonded co-tensioned precast prestressed concrete open-pore beam frame structure connected by UHPC (ultra high performance concrete), which comprises a precast concrete upper column, a precast concrete lower column, a post-tensioned unbonded co-tensioned precast prestressed concrete open-pore superposed beam, an UHPC (ultra high performance concrete) node core area and a superposed slab. The upper longitudinal main reinforcement extends out of the bottom surface of the prefabricated upper column and is directly anchored in a 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, the common reinforcement and the pretensioned prestressed reinforcement extend out of the end surface of the prefabricated pretensioned prestressed concrete open pore beam and are directly anchored or bent and anchored in the UHPC node core area, the pretensioned unbonded prestressed reinforcement is pre-embedded in the prefabricated pretensioned prestressed concrete open pore beam component, penetrates through the UHPC node core area, extends out of the UHPC node core area at two ends, is fixedly provided with a clamp and an anchorage at two ends respectively, one end is arranged outside the column, and the other end is arranged in the beam superposed layer. The structure system is convenient and quick in site construction, improves the installation efficiency of the components, can greatly reduce the anchoring length of the reinforcing steel bars, greatly reduces the stirrup amount of the core area of the node, avoids the crowding of the reinforcing steel bars of the core area of the node, can reduce the section height of the components, reduces the dead weight, and improves the anti-cracking performance and the self-recovery performance of the components, thereby improving the anti-seismic performance of the whole frame structure. The pretensioned prestressed tendons enable the precast beam to be supported less or free of support during construction, construction cost is reduced, and the post-tensioned unbonded framework integrity can be enhanced, so that the structure has certain self-resetting capability and structural toughness in an earthquake, and the post-earthquake repair cost is reduced.

Description

Post-tensioned unbonded co-tensioned prefabricated prestressed concrete open-pore beam frame structure connected by UHPC (ultra high Performance concrete) and design and construction methods thereof

Technical Field

The invention relates to the technical field of prefabricated prestressed assembly type building construction, in particular to a UHPC (ultra high performance concrete) connected post-tensioned unbonded co-tensioned prefabricated prestressed concrete open-pore beam frame structure and a design and construction method thereof.

Background

The cast-in-place structure has the limitations of low construction efficiency, high energy consumption and the like, and is gradually difficult to adapt to the development requirement of building industrialization. The prefabricated building has become the development direction of building industrialization due to the advantages of high construction speed, industrialized production of components, reduction of field wet operation, reduction of environmental pollution and the like. Through years of development and popularization, prefabricated concrete structures have been widely researched and used.

The prefabricated assembly type concrete frame structure is a structure that beam column components are prefabricated in a prefabrication factory and transported to a construction site to be connected to form an integral structure. Compared with a cast-in-place concrete structure, the cast-in-place concrete structure has the advantages of high construction speed, easy guarantee of component quality, good quality, small environmental pollution, labor cost saving, large quantity of templates and supports saving and the like, and has a very wide prospect. For a wet connection assembly type concrete frame structure, a node construction form which is easy to construct and effectively ensures integrity is the key for popularization and application. However, from the conventional earthquake disaster, the assembled structure is seriously damaged in the earthquake, and the same earthquake-proof performance as that of the cast-in-place structure is difficult to achieve. In order to improve the integrity and reliability of the joint connection of the prefabricated Concrete frame and achieve or even exceed the seismic Performance of a cast-in-place Concrete structure, a prestress technology and an Ultra High Performance Concrete (UHPC) material are introduced into the prefabricated structure.

The post-tensioned unbonded prestressed prefabricated concrete structure is a structure formed by splicing a prefabricated common concrete member and a prefabricated pre-tensioned prestressed member together through tensioning prestressed tendons, and has the characteristics of a pre-tensioned prestressed concrete structure, a post-tensioned unbonded prestressed concrete structure and a prefabricated structure. The internal stress generated by the prestress on the concrete section can partially or completely offset the section stress under the use load, thereby delaying the occurrence of cracks and improving the rigidity of the member. When unloading, the crack can be partially or completely closed, and the elastic recovery performance of the structure is good. Meanwhile, the prestressed concrete can make full use of the material strength of the prestressed tendons and the concrete, and the self weight of the structure is reduced. And the application of the prestress contributes to the improvement of the service performance and the integrity of the assembled structure, and promotes the application of the assembled structure in a large-span and heavy-load structure.

The UHPC has excellent bonding performance, and can greatly reduce the anchoring length of a steel bar and a steel strand in the UHPC; the strength is high, the stirrup consumption in the node core area can be reduced, and the UHPC is used in the node core area, so that the structure is simple and the frame integrity is good. The prestressed structure has excellent stress performance, and the UHPC is applied to a node core area to form a prefabricated prestressed frame structure. The structure is deeply researched, and the prefabricated prestressed concrete frame structure is favorable for further popularization and application.

Disclosure of Invention

The invention aims to provide a post-tensioned unbonded co-tensioned precast prestressed concrete open-pore beam frame structure connected by UHPC (ultra high Performance concrete) and a design and construction method thereof by combining the excellent performance of the UHPC, aiming at the defects in the prior art. The prefabricated assembled concrete frame structure combines three traditional structures of a pre-tensioned prestressing structure, a post-tensioned unbonded prestressing structure, an assembled structure and a superposed structure, and adopts a UHPC high-performance material, so that the aim of improving the seismic performance of the prefabricated assembled concrete frame structure is fulfilled.

The invention has the advantages of two aspects of the connecting technology of the prefabricated prestressed concrete open-pore beam column components and the reinforcing steel bar connecting technology between the components. In the aspect of component connection technology, beam column components are connected through UHPC with excellent performance to form a UHPC node core area, and the requirement of seismic fortification of strong node weak components is more easily realized, so that the ductility of beam column nodes is improved, and the seismic performance of the whole frame structure is improved. In the aspect of the steel bar connection technology, steel bars between beam column components only need to be simply lapped, and the lapping length is very small, so that the manufacturing time and the field installation time of prefabricated components are greatly saved. Therefore, the UHPC-connected post-tensioned unbonded co-tensioned precast prestressed concrete open-pore beam frame structure system and the design and construction method thereof provided by the invention conform to the green development strategy of building industrialization in China.

The technical problem solved by the invention can be realized by adopting the following technical scheme:

a post-tensioned unbonded co-tensioned precast prestressed concrete open-pore beam frame structure connected by UHPC comprises a precast concrete upper column, a precast concrete lower column, a post-tensioned unbonded co-tensioned precast prestressed concrete open-pore superposed beam, an UHPC node core area and a superposed slab;

the prefabricated concrete upper column is internally provided with an upper longitudinal main rib, the prefabricated concrete lower column is internally provided with a lower longitudinal main rib, the post-tensioned unbonded co-tensioned prefabricated prestressed concrete open-pore superposed beam is internally provided with a prefabricated pre-tensioned prestressed concrete open-pore beam, a beam superposed layer and a post-tensioned unbonded prestressed rib, the prefabricated pre-tensioned prestressed concrete open-pore beam is provided with a common steel bar and a pre-tensioned prestressed rib, a hanging rib or a steel bar net piece can be arranged around an orifice if necessary, the steel bar net piece can also adopt a welded steel bar net, the beam superposed layer is internally provided with a top through long steel bar, and the laminated slab consists of a prefabricated concrete slab and a slab superposed layer poured on the slab;

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 common reinforcement and the pretensioned prestressed reinforcement extend out of the end surface of the prefabricated pretensioned prestressed concrete open-hole beam and are directly anchored in the UHPC node core area;

the pre-tensioned prestressed tendons comprise straight-line and fold-line-shaped tendons, and the post-tensioned unbonded prestressed tendons comprise straight-line, fold-line and curved-line tendons.

The post-tensioned unbonded co-tensioned precast prestressed concrete open-pore superposed beam is characterized in that construction check calculation is carried out on the pre-tensioned prestressed concrete open-pore simply supported beam before a beam superposed layer, a plate superposed layer and a UHPC node core area are poured, tensioning of unbonded prestressed ribs is carried out when the concrete strength of the node and the superposed layer reaches design requirements after the node core area, the beam superposed layer and the plate superposed layer are poured, and construction stage check calculation is carried out on the frame beam after tensioning is finished; the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore superposed beam has different sections of upper chords at the pore opening and different stress states before the beam superposed layer, the slab superposed layer and the UHPC node core area are poured and after the beam superposed layer, and the construction checking calculation is carried out on the upper chords and the lower chords at the pore opening of the precast pre-tensioned prestressed concrete open-pore beam; after the prestress of the post-tensioned unbonded prestressed tendon is established, the construction checking calculation and the checking calculation of the normal use limit state are carried out by effective prestress calculation, and the stress increment is considered when the checking calculation of the bearing capacity limit state is carried out; under the earthquake load, the recovery performance of the unbonded prestressed tendons to the nodes is considered.

Furthermore, the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore superposed beam consists of a precast pre-tensioned prestressed concrete open-pore beam, a beam superposed layer and post-tensioned unbonded prestressed tendons; the composite slab is composed of a precast concrete slab and a slab stacking layer poured on the slab.

Furthermore, the prestressed tendons without bonding of post-tensioning are pre-buried in the prefabricated prestressed concrete trompil roof beam component of stretching earlier to pass UHPC node core area and both ends stretch out outside UHPC node core area, its both ends are fixed respectively and are provided with anchor clamps and ground tackle, and one end sets up in the post outside, and one end sets up in the roof beam coincide layer.

Furthermore, the bottom surface of the precast concrete upper column, the top surface of the precast concrete lower column and the end surface of the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore superposed beam are provided with sunken grooves.

Further, the precast concrete upper column is fixed at a corresponding position by using a reliable support.

Furthermore, stirrups in the precast concrete upper column, the precast concrete lower column and the post-tensioned unbonded common-tensioned precast prestressed concrete open-hole superposed beam are divided into an encrypted area and a non-encrypted area, stirrups in a core area of the UHPC node are arranged according to design requirements, the shear resistance and bearing capacity of the core area are calculated according to a softened tension-compression rod model, steel fibers in the UHPC are considered to be equivalent to horizontal stirrups and vertical longitudinal reinforcements, the contribution of the horizontal stirrups and the vertical longitudinal reinforcements to the shearing resistance of the node core area is considered, and the contribution of unbonded prestressed reinforcements to the shearing resistance of the node is considered.

Furthermore, the top surfaces of the precast prestressed concrete open-pore beam and the precast concrete slab are provided with rough surface layers.

The invention also provides a design method of the system, which comprises the following steps:

step 1: the beam and the column are designed according to the existing standard and invention patent;

step 2: checking and calculating the strength of upper and lower chords at the opening of a prefabricated pre-tensioned prestressed concrete open-pore composite beam before a beam laminated layer, a plate laminated layer and a UHPC node core area of the poured post-tensioned unbonded co-tensioned prefabricated prestressed concrete open-pore composite beam;

and step 3: the open hole position in the post-tensioned unbonded co-tensioned precast prestressed concrete open-hole superposed beam is positioned in a midspan 1/3 section as far as possible, and when the open hole position is positioned in a beam end 1/3 section, the distance from the edge of the open hole close to the node to the inner edge of the node is larger than 1.5 times of the height of the beam.

A post-tensioned unbonded co-tensioned pre-stressed concrete open-pore beam frame structure connected by UHPC comprises the following steps:

step 1: manufacturing a precast concrete lower column, a precast concrete upper column, a precast pre-tensioned prestressed concrete open-hole beam and a precast concrete slab; wherein, enough anchoring length needs to be reserved in the core area of the anchoring node of the precast concrete lower column and the precast concrete upper column extending out of the longitudinal bar; when the pre-tensioned prestressed concrete open-hole beam is prefabricated, pre-tensioned prestressed tendons are firstly tensioned on a pedestal, the post-tensioned unbonded prestressed tendons are pre-embedded in the beam according to the designed position, sufficient constructional length is reserved at two ends respectively, then concrete is poured, the pre-tensioned prestressed tendons are released when the concrete is cured to sufficient strength, and sufficient anchoring length is reserved at the beam end;

step 2: after the maintenance of the prefabricated part is finished, hoisting the prefabricated concrete lower column and installing the prefabricated concrete lower column on the foundation, and then installing a proper number of stirrups on the extended longitudinal main reinforcement;

and 3, step 3: hoisting the prefabricated pre-tensioned prestressed concrete open pore beam to the top surface of the prefabricated concrete lower column, enabling the bottom surface of the prefabricated pre-tensioned prestressed concrete open pore beam to be flush with the top surface of the prefabricated concrete lower column, enabling the end part of the prefabricated pre-tensioned prestressed concrete open pore beam to be placed on the prefabricated concrete lower column and fixed by a support, wherein the support can be avoided due to the pre-tensioned prestressing effect in the beam; the common steel bars and the pretensioned prestressed tendons extending out of the prestressed concrete open-pore beam on the two sides are reasonably avoided and directly anchored or bent and anchored in a node core area according to the construction requirements;

and 4, step 4: hoisting the precast concrete upper column to be right above the precast concrete lower column, fixing the precast concrete upper column at a corresponding position by using a reliable support, and binding the stirrup installed in the step 2 and the column longitudinal bar together; wherein, the longitudinal bars extending out of the upper and lower precast concrete columns are reasonably avoided in the core area of the node and are directly anchored;

and 5: the top through long steel bar penetrates through a stirrup reserved in a beam overlapping layer area and a node core area and is bound, then unbonded prestressed tendons which are pre-embedded and extend out of a pre-tensioned prestressed concrete open-hole beam are bound in the node core area according to the designed position, then a UHPC node core area is poured, and a template is arranged to prevent UHPC from entering the beam overlapping layer;

and 6: after the core area of the UHPC node is maintained to be enough strength, hoisting the precast concrete flat plate (or the composite slab, the double T plate and the secondary beam) to the precast prestressed concrete beam and fixing;

and 7: pouring a beam laminated layer and a plate laminated layer;

and 8: after the concrete of the beam laminated layer and the plate laminated layer is maintained to be of sufficient strength, tensioning the prestressed tendons;

and step 9: and repeating the manufacturing process to finish the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore beam frame structure system.

Compared with the prior art, the invention has the advantages that:

1. the prefabricated concrete structure, the pre-tensioned prestressing force structure and the post-tensioned unbonded prestressing structure are combined together, and the advantages of structural use performance, member section height reduction, deadweight reduction, member crack resistance improvement and self-recovery are improved by combining the post-tensioned unbonded co-tensioned prestressing structure on the basis of utilizing the advantages of convenience and rapidness in construction, good construction quality, energy conservation and environmental protection of the prefabricated structure, so that the anti-seismic performance of the whole frame structure is improved. The pretensioned prestressed tendons enable the precast beam to be supported less or free of support during construction, construction cost is reduced, and the post-tensioned unbonded framework integrity can be enhanced, so that the structure has certain self-resetting capability and structural toughness in an earthquake, and the post-earthquake repair cost is reduced.

2. The UHPC material with excellent performance is adopted and applied to the node core area, so that the reliable connection of the prefabricated beam column member can be realized, the bearing capacity and the anti-seismic performance of the node can be improved, the anchoring length of the steel bars and the steel strands can be greatly reduced, and the stirrup dosage in the node core area can be obviously reduced, thereby avoiding the steel bar crowding in the node core area, and greatly improving the manufacturing, transporting and installing efficiency of the prefabricated beam column member.

Drawings

FIG. 1 is a schematic structural view of a frame structure system of a UHPC-based prefabricated prestressed concrete open-pore beam according to the present invention

FIG. 2 is a schematic view of reinforcement of a two-span frame structure

FIG. 3 is a schematic view of a two-span frame structure

FIG. 4 is a detailed view of the edge node structure of the middle layer frame of the present invention

FIG. 5 is an isometric view of an intermediate layer frame edge node of the present invention

FIG. 6 is a detailed view of the node structure in the middle layer frame of the present invention

FIG. 7 is an isometric view of a node in an intermediate layer frame of the present invention

Detailed Description

So that the manner in which the features, objects, and advantages of the invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.

As shown in fig. 1 to 11, the framework structure of the UHPC-connected post-tensioned unbonded co-tensioned precast prestressed concrete open-pore beam comprises a precast concrete upper column (1), a precast concrete lower column (2), a post-tensioned unbonded co-tensioned precast prestressed concrete open-pore superposed beam (3), a UHPC node core area (4) and a superposed slab (18);

an upper longitudinal main rib (5) is arranged in the precast concrete upper column (1), a lower longitudinal main rib (6) is arranged in the precast concrete lower column (2), a precast pre-tensioned prestressed concrete open-pore superposed beam (3) without binding is internally provided with a precast pre-tensioned prestressed concrete open-pore beam (7), a beam superposed layer (8) and a post-tensioned prestressed rib (9), a common steel bar (10) and a pre-tensioned prestressed rib (17) are arranged in the precast pre-tensioned prestressed concrete open-pore beam (7), a top through long steel bar (11) is arranged in the beam superposed layer (8), and a superposed slab (18) consists of a precast concrete slab (19) and a slab superposed layer (20) poured on the slab;

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 common reinforcement (10) and the pretensioned prestressed reinforcement (17) extend out of the end surface of the prefabricated pretensioned prestressed concrete open pore beam (7) and are directly anchored in the UHPC node core area (4);

the pre-tensioned prestressed tendons (17) comprise straight tendons and broken line tendons, and the post-tensioned unbonded prestressed tendons (9) comprise straight tendons, broken lines and curved tendons;

the post-tensioned unbonded common-tensioned precast prestressed concrete open-pore superposed beam (3) is subjected to construction checking calculation according to a pre-tensioned prestressed concrete open-pore simply-supported beam before a beam superposed layer (8), a plate superposed layer (20) and a UHPC node core area (4) are poured, tensioning of unbonded prestressed ribs (9) is performed after the node core area (4), the beam superposed layer (8) and the plate superposed layer (20) are poured and when the strength of the node and the superposed layer concrete reaches design requirements, and construction stage checking calculation is performed according to a frame beam after tensioning is completed; the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore superposed beam has different sections of upper chords at the pore opening and different stress states before the beam superposed layer, the slab superposed layer and the UHPC node core area are poured and after the beam superposed layer, and the construction checking calculation is carried out on the upper chords and the lower chords at the pore opening of the precast pre-tensioned prestressed concrete open-pore beam; after the prestress is established, the construction checking calculation and the checking calculation of the normal use limit state of the post-tensioned unbonded prestressed tendon (9) are calculated by effective prestress, and the stress increment is considered when the checking calculation of the bearing capacity limit state is carried out; under earthquake load, the recovery performance of the unbonded prestressed tendons (9) to the nodes is considered;

the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore superposed beam (3) consists of a precast pre-tensioned prestressed concrete open-pore beam (7), a beam superposed layer (8) and post-tensioned unbonded prestressed tendons (9); the laminated slab (18) consists of a precast concrete slab (19) and a slab laminated layer (20) poured on the slab;

the post-tensioning unbonded prestressed tendon (9) is pre-embedded in the prefabricated pre-tensioning prestressed concrete open-pore beam (7) component, penetrates through the UHPC node core area (4), and extends out of the UHPC node core area (4) from two ends, the two ends of the post-tensioning unbonded prestressed tendon are respectively and fixedly provided with a clamp (15) and an anchorage device (16), one end of the post-tensioning unbonded prestressed tendon is arranged outside the column, and the other end of the post-tensioning unbonded prestressed tendon is arranged in the beam superposed layer;

the bottom surface of the precast concrete upper column (1), the top surface of the precast concrete lower column (2) and the end surface of the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore superposed beam (3) are provided with inward-sunk grooves;

the precast concrete upper column (1) is characterized in that the precast concrete upper column (1) is fixed at a corresponding position by a reliable support (12);

the reinforcement stirrup (13) in the precast concrete upper column (1), the precast concrete lower column (2) and the post-tensioned unbonded common-tensioned precast prestressed concrete open-hole superposed beam (3) is divided into an encrypted area and a non-encrypted area, the reinforcement stirrup (14) in the UHPC node core area (4) is arranged according to design requirements, the shear-resistant bearing capacity of the core area is calculated according to a softened tension-compression rod model, the steel fiber in the UHPC is considered to be equivalent to a horizontal reinforcement stirrup and a vertical longitudinal reinforcement, the contribution of the horizontal reinforcement stirrup and the vertical longitudinal reinforcement to the shear resistance of the node core area is considered, and the contribution of the unbonded prestressed reinforcement to the shear resistance of the node is considered;

the top surfaces of the precast prestressed concrete open pore beam (7) and the precast concrete slab (19) are provided with rough surface layers.

The seismic design of the system comprises the following steps:

step 1: the beam and the column are designed according to the existing standard and invention patent;

step 2: checking and calculating the strength of upper and lower chords at the opening of a prefabricated pre-tensioned prestressed concrete open-pore composite beam before a beam laminated layer, a plate laminated layer and a UHPC node core area of the poured post-tensioned unbonded co-tensioned prefabricated prestressed concrete open-pore composite beam;

and step 3: the middle opening position of the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore composite beam is positioned in a midspan 1/3 section as much as possible, and when the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore composite beam is positioned in a beam end 1/3 section, the distance from the edge of the hole close to the node to the inner edge of the node is larger than 1.5 times of the height of the beam.

The utility model provides a post-tensioned unbonded co-tensioning precast prestressed concrete open-cell beam frame structure that UHPC connects which characterized in that includes the following steps:

step 1: manufacturing a precast concrete lower column (2), a precast concrete upper column (1), a precast pre-tensioned prestressed concrete open pore beam (7) and a precast concrete slab (19); wherein, enough anchoring length is reserved for anchoring the precast concrete lower column (2) and the precast concrete upper column (1) into the node core area (4) by extending out of the longitudinal ribs; when the pre-tensioned prestressed concrete open pore beam (7) is prefabricated, pre-tensioned prestressed tendons (17) are firstly tensioned on a pedestal, post-tensioned unbonded prestressed tendons (9) are pre-embedded in the beam according to the design position, sufficient structural lengths are reserved at two ends respectively, then concrete is poured, the pre-tensioned prestressed tendons (17) are released when the concrete is cured to sufficient strength, and sufficient anchoring lengths are reserved at the beam end;

step 2: after the maintenance of the prefabricated parts is finished, hoisting the prefabricated concrete lower column (2) and installing the prefabricated concrete lower column on the foundation, and then installing a proper number of stirrups (14) on the extended longitudinal main reinforcements (6);

and 3, step 3: hoisting the prefabricated pre-tensioned prestressed concrete open pore beam (7) to the top surface of the prefabricated concrete lower column (2), enabling the bottom surface of the prefabricated pre-tensioned prestressed concrete open pore beam (7) to be flush with the top surface of the prefabricated concrete lower column (2), enabling the end part of the prefabricated pre-tensioned prestressed concrete open pore beam (7) to be placed on the prefabricated concrete lower column (2) and fixed by using a support, wherein the support can be avoided due to the pre-tensioned prestressing effect in the beam; wherein, the common steel bars (10) and the pretensioned prestressed tendons (17) extending out of the prestressed concrete open-pore beam (7) at the two sides are reasonably avoided and directly anchored or bent and anchored in the node core area according to the construction requirements;

and 4, step 4: hoisting the precast concrete upper column (1) to be right above the precast concrete lower column (2), fixing the precast concrete upper column (1) at a corresponding position by using a reliable support (12), and binding the stirrup (14) and the column longitudinal bar which are installed in the step 2 together; wherein, the longitudinal bars extending out of the upper and lower precast concrete columns are reasonably avoided in the core area of the node and are directly anchored;

and 5: the top through long steel bar (11) penetrates through a stirrup (13) reserved in a beam overlapping layer area and a node core area (4) and is bound well, then an unbonded prestressed rib (9) which is pre-buried and extends out of a pre-tensioned prestressed concrete open-pore beam (7) is bound well in the node core area according to a designed position, then a UHPC node core area (4) is poured, and a template is arranged to prevent UHPC from entering a beam overlapping layer (8);

step 6: after the UHPC node core area (4) is maintained to have enough strength, hoisting a precast concrete flat plate (or a composite slab, a double T plate and a secondary beam) (19) to the precast prestressed concrete beam (7) and fixing;

and 7: pouring a beam laminated layer (8) and a plate laminated layer (20);

and 8: after the concrete of the beam laminated layer (8) and the plate laminated layer (20) is cured to reach enough strength, tensioning the prestressed tendon (9);

and step 9: and repeating the manufacturing process to finish the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore beam frame structure system.

The foregoing description is only exemplary of the invention, and it is obvious that the present invention is not limited to the above-described mode, i.e., the description is not restrictive, and the invention can be easily modified, changed or substituted without departing from the method concept and technical solution of the present invention, and the modifications and changes are all within the protection scope of the present invention.

Claims (9)

1. A post-tensioned unbonded co-tensioned precast prestressed concrete open-pore beam frame structure connected by UHPC comprises a precast (or cast-in-place) concrete upper column (1), a precast (or cast-in-place) concrete lower column (2), a post-tensioned unbonded co-tensioned precast prestressed concrete open-pore superposed beam (3), an UHPC node core area (4) and a superposed slab (18);

the prefabricated concrete upper column is characterized in that an upper longitudinal main rib (5) is arranged in the prefabricated concrete upper column (1), a lower longitudinal main rib (6) is arranged in the prefabricated concrete lower column (2), a prefabricated pre-tensioned prestressed concrete open-pore superposed beam (3) without binding is internally provided with a prefabricated pre-tensioned prestressed concrete open-pore beam (7), a beam superposed layer (8) and a post-tensioned prestressed rib (9), the prefabricated pre-tensioned prestressed concrete open-pore beam (7) is provided with common steel bars (10) and pre-tensioned prestressed ribs (17), a hanging rib (21) or a steel bar mesh sheet (22) can be arranged around an orifice if necessary, the steel bar mesh sheet can also adopt a welded steel bar mesh, a top through long steel bar (11) is arranged in the beam superposed layer (8), and a laminated slab (18) consists of a prefabricated concrete slab (19) and a slab superposed layer (20) poured on the slab;

the method is characterized in that the upper longitudinal main rib (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 rib (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 common steel bar (10) and the pretensioned prestressed rib (17) extend out of the end surface of the prefabricated pretensioned prestressed concrete open pore beam (7) and are directly anchored in the UHPC node core area (4);

the prestressed concrete beam is characterized in that the pretensioned prestressed tendons (17) comprise straight-line and fold-line-shaped tendons, and the post-tensioned unbonded prestressed tendons (9) comprise straight-line, fold-line and curved-line-shaped tendons;

the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore superposed beam is characterized in that the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore superposed beam (3) is subjected to construction checking calculation according to a pre-tensioned prestressed concrete open-pore simply supported beam before a beam superposed layer (8), a plate superposed layer (20) and a UHPC node core area (4) are poured, and after the node core area (4), the beam superposed layer (8) and the plate superposed layer (20) are poured, when the strength of the node and the superposed layer concrete reaches the design requirements, the unbonded prestressed rib (9) is tensioned, and after the tensioning is finished, the construction stage checking calculation is performed according to a frame beam; the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore composite beam has different sections of upper chords at the pore opening before the beam composite layer, the slab composite layer and the UHPC node core area are poured and different stress states, and construction checking calculation is carried out on the upper chords and the lower chords at the pore opening of the precast pre-tensioned prestressed concrete open-pore composite beam; after the prestress is established, the construction checking calculation and the checking calculation of the normal use limit state of the post-tensioned unbonded prestressed tendon (9) are calculated by effective prestress, and the stress increment is considered when the checking calculation of the bearing capacity limit state is carried out; under earthquake load, the recovery performance of the unbonded prestressed tendons (9) to the nodes is considered.

2. The UHPC connected post-tensioned unbonded pre-stressed concrete open-cell beam frame structure system according to claim 1, wherein the post-tensioned unbonded pre-stressed concrete open-cell laminated beam (3) is composed of a pre-tensioned pre-stressed concrete open-cell beam (7), a beam laminated layer (8) and post-tensioned unbonded pre-stressed tendons (9); the composite slab (18) consists of a precast concrete slab (19) and a slab composite (20) cast on the slab.

3. The UHPC-connected post-tensioned unbonded co-tensioned precast prestressed concrete open-cell beam frame structure system as claimed in claim 1, wherein the post-tensioned unbonded prestressed tendon (9) is pre-embedded in the precast pre-tensioned prestressed concrete open-cell beam (7) member, passes through the UHPC node core area (4) and has two ends extending out of the UHPC node core area (4), and has two ends respectively fixedly provided with a clamp (15) and an anchorage device (16), one end of the clamp is arranged outside a column and the other end of the anchor device is arranged in a beam overlapping layer.

4. A UHPC connected post-tensioned unbonded co-tensioned precast prestressed concrete open-cell beam 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 surface of the post-tensioned unbonded co-tensioned precast prestressed concrete open-cell superposed beam (3) are provided with recessed grooves.

5. UHPC connected post-tensioned unbonded pre-stressed concrete open-pored beam frame structure system according to claim 1, characterized in that the precast concrete upper column (1) is fixed in position with positive support (12).

6. The UHPC-connected post-tensioned unbonded co-tensioned precast prestressed concrete open-cell beam frame structure system as claimed in claim 1, wherein stirrups (13) in the precast concrete upper column (1), the precast concrete lower column (2) and the post-tensioned unbonded co-tensioned precast prestressed concrete open-cell superposed beam (3) are divided into a dense region and a non-dense region, stirrups (14) in the UHPC node core region (4) are arranged according to design requirements, the shear bearing capacity calculation of the core region is calculated according to a softened tension and compression bar model, steel fibers in the UHPC are considered to be equivalent to horizontal stirrups and vertical longitudinal bars, the contribution of the horizontal stirrups and the vertical longitudinal bars to the shear resistance of the node core region is considered, and the beneficial contribution of the unbonded pre-tensioned bars to the shear resistance of the node is considered.

7. The UHPC connected post-tensioned unbonded pre-stressed concrete open-pored beam frame structure system according to claim 1, characterized in that the top surfaces of the pre-tensioned pre-stressed concrete open-pored beam (7) and the pre-stressed concrete slab (19) are provided with a matte layer.

8. A method of designing a UHPC connected post-tensioned unbonded co-tensioned pre-stressed concrete open-pored beam frame structure system according to claim 1, characterized in that: except that the beam and the column are designed according to the existing specification and the invention patent, the position of the open hole in the beam is positioned at the 1/3 section of the midspan as far as possible, and when the open hole is positioned at the 1/3 section of the beam end, the distance from the edge of the open hole close to the node to the inner edge of the node is larger than 1.5 times of the height of the beam.

9. The utility model provides a post-tensioned unbonded co-tensioning precast prestressed concrete open-cell beam frame structure that UHPC connects which characterized in that includes the following steps:

step 1: manufacturing a precast concrete lower column (2), a precast concrete upper column (1), a precast pre-tensioned prestressed concrete open pore beam (7) and a precast concrete slab (19); wherein enough anchoring length is reserved for the prefabricated concrete lower column (2) and the prefabricated concrete upper column (1) to extend out of the longitudinal bar anchoring node core area (4); when the pre-tensioned prestressed concrete open pore beam (7) is prefabricated, pre-tensioned prestressed tendons (17) are firstly tensioned on a pedestal, post-tensioned unbonded prestressed tendons (9) are pre-embedded in the beam according to the design position, sufficient structural lengths are reserved at two ends respectively, then concrete is poured, the pre-tensioned prestressed tendons (17) are released when the concrete is cured to sufficient strength, and sufficient anchoring lengths are reserved at the beam end;

step 2: after the maintenance of the prefabricated parts is finished, hoisting the prefabricated concrete lower column (2) and installing the prefabricated concrete lower column on the foundation, and then installing a proper number of stirrups (14) on the extended longitudinal main reinforcements (6);

and step 3: hoisting the prefabricated pre-tensioned prestressed concrete open pore beam (7) to the top surface of the prefabricated concrete lower column (2), enabling the bottom surface of the prefabricated pre-tensioned prestressed concrete open pore beam (7) to be flush with the top surface of the prefabricated concrete lower column (2), enabling the end part of the prefabricated pre-tensioned prestressed concrete open pore beam (7) to be placed on the prefabricated concrete lower column (2) and fixed by a support, wherein the support can be avoided due to the pre-tensioned prestressing effect in the beam; wherein, the common steel bars (10) and the pretensioned prestressed tendons (17) extending out of the pretensioned prestressed concrete beams (7) at the two sides are reasonably avoided and directly anchored or bent and anchored in the node core area according to the construction requirements;

and 4, step 4: hoisting the precast concrete upper column (1) to be right above the precast concrete lower column (2), fixing the precast concrete upper column (1) at a corresponding position by using a reliable support (12), and binding the stirrup (14) installed in the step 2 and the column longitudinal bar together; wherein, the longitudinal bars extending out of the upper and lower precast concrete columns are reasonably avoided in the core area of the node and are directly anchored;

and 5: enabling top full-length steel bars (11) to penetrate through stirrups (13) reserved in a beam overlapping layer region and a node core region (4) and be bound well, then binding unbonded prestressed ribs (9) which are pre-buried and extend out of a pre-tensioned prestressed concrete open-pore beam (7) in the node core region according to a designed position, then pouring a UHPC node core region (4), and setting a template to prevent UHPC from entering a beam overlapping layer (8) part;

and 6: after the UHPC node core area (4) is maintained to a sufficient strength, hoisting a precast concrete slab (or a composite slab, a double T plate and a secondary beam) (19) to the precast prestressed concrete beam (7) and fixing;

and 7: pouring a beam laminated layer (8) and a plate laminated layer (20);

and 8: after the concrete of the beam laminated layer (8) and the plate laminated layer (20) is cured to reach enough strength, tensioning the prestressed tendon (9);

and step 9: and repeating the manufacturing process to finish the post-tensioned unbonded co-tensioned precast prestressed concrete open-pore beam frame structure system.

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