An anti-seismic and anti-progressive collapse frame structure based on UHPC

Abstract

The present invention discloses a seismic and anti - progressive collapse frame structure based on UHPC, which includes a plurality of precast concrete columns, a plurality of reserved channels, a plurality of precast concrete composite beams, a plurality of bottom longitudinal bars of beams, a plurality of beam stirrups, a plurality of top longitudinal bars of beams, a plurality of lapping bars, a plurality of post - cast composite layers, and a plurality of post - cast UHPC regions. The precast concrete columns and the precast concrete composite beams are connected through the post - cast UHPC regions. The top longitudinal bars of the beams pass through the reserved channels, the post - cast composite layers and the post - cast UHPC regions, the lapping bars pass through the reserved channels and the post - cast UHPC regions, and the bottom longitudinal bars of the beams are lap - connected with the lapping bars in the post - cast UHPC regions. In the present invention, UHPC is used in the main stress - bearing areas of the frame structure, and the excellent compressive, tensile, bonding and energy - dissipating capabilities of UHPC are flexibly applied to the structure, innovating the form of the prefabricated concrete frame structure, and improving the seismic performance and anti - progressive collapse performance of the structure at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of building structures, and in particular to an earthquake-resistant and progressive collapse-resistant frame structure based on UHPC. Background Art

[0002] (1) Under accidental loads, local damage to the structure causes partial or complete collapse of the structure, which is called progressive collapse of the structure. Currently, we urgently need a structural form that can meet the requirements of both earthquake resistance and progressive collapse resistance.

[0003] (2) In the design of anti-progressive collapse, the compression arch bearing capacity and catenary bearing capacity of the structure are improved by increasing the longitudinal reinforcement ratio of the beam. However, too high a reinforcement ratio often leads to increased costs and inconvenience in the construction of beam-column nodes.

[0004] (3) Ultra-high performance concrete (UHPC) is a high-performance cement-based composite material with ultra-high compressive strength, tensile strength, excellent bonding properties and energy dissipation capacity. However, due to its high cost, the overall use of UHPC in a structure often results in high costs. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a high-performance prefabricated concrete frame structure that can meet the requirements of earthquake resistance and progressive collapse resistance while saving materials.

[0006] Technical solution: To achieve the purpose of the present invention, the technical solution adopted by the present invention is: an earthquake-resistant and progressive collapse-resistant frame structure based on UHPC, comprising a plurality of precast concrete columns 1 and a plurality of precast concrete composite beams 2;

[0007] Each precast concrete column 1 is provided with two reserved channels 11 penetrating the precast concrete column 1 at the upper and lower parts thereof, and the overlapping steel bars 4 in the reserved channels 11 are fixedly connected to the reserved channels 11;

[0008] Each of the precast concrete composite beams 2 is provided with a beam bottom longitudinal reinforcement 21 and a beam stirrup 22. The portion of the beam bottom longitudinal reinforcement 21 extending out of the precast concrete composite beam 1 is tied and connected with the lap reinforcement 4. The connection portion is located in the post-cast UHPC area 6. The precast concrete column 1 and the precast concrete composite beam 2 are integrally fixedly connected through the post-cast UHPC area 6.

[0009] The post-cast superimposed layer 5 is located at the upper part of the precast concrete superimposed beam 2, and the beam top longitudinal reinforcement 3 passes through the post-cast superimposed layer 5, the post-cast UHPC area 6 and the reserved channel 11, and the overall connection is completed by pouring the post-cast superimposed layer 5, the post-cast UHPC area 6 and the reserved channel 11.

[0010] like Figure 2As shown, the precast concrete column 1 is provided with a reserved channel 11 for the lap reinforcement 4 and the beam top longitudinal reinforcement 3 to pass through.

[0011] like Figure 3 As shown, the beam end of the precast concrete composite beam 2 is trapezoidal, the length of the trapezoidal area is 15-25 times the diameter of the beam longitudinal reinforcement, and a reserved hole is provided at the beam end. This design is to facilitate the pouring of UHPC during construction and make the post-cast UHPC and the precast concrete composite beam 2 more tightly connected.

[0012] Preferably, the reserved holes 23 are located between the gaps between the beam stirrups 22, and the length thereof is equal to the stirrup spacing.

[0013] Preferably, the reserved channel 11 has the same cross-sectional size as the post-cast composite layer 5, the top surface of the reserved channel 11 located at the upper part of the precast concrete column 1 and the top surface of the post-cast composite layer 5 are located in the same plane, and the bottom surface of the reserved channel 11 located at the lower part of the precast concrete column 1 and the bottom surface of the precast concrete composite beam 2 are located in the same plane.

[0014] Preferably, the overlap distance of the beam bottom longitudinal reinforcement 21 is 10-20 times the diameter of the beam bottom longitudinal reinforcement 21.

[0015] Preferably, the length of the post-cast UHPC area 6 is 20-30 times the diameter of the longitudinal reinforcement 21 at the bottom of the beam, and the UHPC is cast.

[0016] Preferably, the post-cast superimposed layer 5 is cast with ordinary concrete, and the reserved channel 11 is cast with UHPC.

[0017] Preferably, the beam top longitudinal reinforcement 3 passes through the beam stirrups 22 and is tied and connected with the beam stirrups 22 .

[0018] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0019] (1) During an earthquake, the UHPC at the beam end can dissipate a large amount of seismic energy. In addition, the use of UHPC at the beam end can move the plastic hinge on the beam away from the beam end, thereby dissipating more seismic energy. Under accidental loads, the precast column suddenly fails. Due to the superior compressive performance of UHPC, the UHPC in the compression zone of the beam end can improve the structural compression arch bearing capacity. For the beam reinforcement overlap area in the tension zone of the beam end, due to the excellent tensile and bonding properties of UHPC, the catenary bearing capacity of the structure can be improved.

[0020] (2) The use of UHPC in the beam end area reduces the lap length of the steel bars. In the design of progressive collapse resistance, the use of UHPC to replace part of the steel bars can reduce the amount of steel bars used in the design and reduce the material cost.

[0021] (3) A UHPC post-casting area is reserved at the beam end to facilitate the steel bar binding connection and improve the connection performance of the longitudinal reinforcement at the bottom of the beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the earthquake-resistant and progressive collapse-resistant frame structure of the present invention;

[0023] Figure 2 It is a schematic diagram of a precast concrete column of the present invention;

[0024] Figure 3 It is a schematic diagram of the precast concrete composite beam of the present invention;

[0025] Figure 4 for Figure 1 A three-dimensional enlarged schematic diagram of the middle area A;

[0026] Figure 5 for Figure 1 A three-dimensional enlarged schematic diagram of the middle area B;

[0027] In the figure: 1-precast concrete column, 11-reserved channel, 2-precast concrete composite beam, 21-beam bottom longitudinal reinforcement, 22-beam stirrups, 23-reserved holes, 3-beam top longitudinal reinforcement, 4-lap reinforcement, 5-post-cast composite layer, 6-post-cast UHPC area. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings:

[0029] The present invention proposes an earthquake-resistant and progressive collapse-resistant frame structure based on UHPC, which includes a plurality of precast concrete columns 1 and a plurality of precast concrete composite beams 2; each of the precast concrete columns 1 is provided with two reserved channels 11 penetrating the precast concrete columns at the upper and lower parts, and the lap steel bars 4 in the reserved channels 11 are fixedly connected to the reserved channels 11; each of the precast concrete composite beams 2 is provided with beam bottom longitudinal bars 21 and beam stirrups 22, and the portion of the beam bottom longitudinal bars 21 extending out of the precast concrete composite beam 1 is overlapped and connected with the lap steel bars 4, and the connection portion is located in a post-cast UHPC area 6, and the precast concrete column 1 and the precast concrete composite beam 2 are integrally fixedly connected through the post-cast UHPC area 6; the post-cast composite layer 5 is located at the upper part of the precast concrete composite beam 2, and the beam top longitudinal bars 3 pass through the post-cast composite layer 5, the post-cast UHPC area 6 and the reserved channels 11, and the overall connection is completed by pouring the post-cast composite layer 5, the post-cast UHPC area 6 and the reserved channels 11.

[0030] Furthermore, the beam end of the precast concrete composite beam 2 is trapezoidal, the length of the trapezoidal area is 15-25 times the diameter of the beam longitudinal reinforcement, and a reserved hole 23 is provided at the beam end.

[0031] Furthermore, the reserved channel 11 has the same cross-sectional size as the post-cast composite layer 5, the top surface of the reserved channel 11 located at the upper part of the precast concrete column 1 and the top surface of the post-cast composite layer 5 are located in the same plane, and the bottom surface of the reserved channel 11 located at the lower part of the precast concrete column 1 and the bottom surface of the precast concrete composite beam 2 are located in the same plane.

[0032] Furthermore, the post-cast superimposed layer 5 is cast with ordinary concrete, and the reserved channel 11 and the post-cast UHPC area 6 are cast with UHPC.

[0033] See also Figures 1 to 5 The construction method of the present invention comprises the following steps:

[0034] Step 1: Process the precast concrete column 1 and the precast concrete composite beam 2 in the factory;

[0035] Step 2: hoist the precast concrete column 1 and pass the overlapping steel bars 4 through the reserved channel 11;

[0036] Step 3: Hoist the precast concrete composite beam 2, tie the bottom longitudinal reinforcement 21 of the beam with the lap reinforcement 4, and then extend the top longitudinal reinforcement 3 of the beam into the reserved channel 11 and the inside of the beam stirrup 22 until Figure 1 At the position shown, the longitudinal reinforcement 21 and the stirrups 22 of the beam top are tied;

[0037] Step 4: Casting on site and then pouring the superimposed layer 5;

[0038] Step 5: Casting the reserved channel 11 and post-cast UHPC area 6 on site;

[0039] Step 6: Repeat steps 1 to 5 to complete the overall frame.

[0040] The above descriptions are only some embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An anti-seismic and anti-progressive collapse frame structure based on UHPC, characterized in that: It includes multiple precast concrete columns, multiple precast concrete composite beams, multiple lapped steel bars, multiple post-cast composite layers, multiple reserved channels and multiple post-cast UHPC areas; each of the precast concrete columns is provided with two reserved channels penetrating through the precast concrete column, and the lapped steel bars in the reserved channels are fixedly connected to the reserved channels. Each of the precast concrete composite beams is provided with bottom longitudinal bars and stirrups of the beam. The part of the bottom longitudinal bars of the beam extending out of the precast concrete composite beam is lapped and connected with the lapped steel bars, and the connection part is located in the post-cast UHPC area. Through the post-cast UHPC area, the precast concrete column and the precast concrete composite beam are integrally and fixedly connected. The post-cast composite layer is located above the precast concrete composite beam. The top longitudinal bars of the beam pass through the post-cast composite layer, the reserved channels and the post-cast UHPC area. The overall connection is completed by casting the post-cast composite layer, the post-cast UHPC area and the reserved channels. The top longitudinal bars of the beam pass through the inside of the stirrups of the beam and are tied and connected with the stirrups of the beam; The end of each precast concrete composite beam is of a trapezoidal cross-section and is provided with reserved holes; the cross-sectional dimensions of the reserved channels are the same as those of the post-cast composite layer. The top surface of the reserved channel located above the precast concrete column is in the same plane as the top surface of the post-cast composite layer, and the bottom surface of the reserved channel located below the precast concrete column is in the same plane as the bottom surface of the precast concrete composite beam; ordinary concrete is cast in the post-cast composite layer, and UHPC materials are cast in the reserved channels and the post-cast UHPC areas. Among them, the material distribution in the UHPC area is based on the optimized design of key stress nodes to form a distributed energy dissipation structure, thereby improving the anti-seismic performance and anti-progressive collapse ability of the overall frame; the lapping distance of the bottom longitudinal bars of the precast concrete composite beam is 10-20 times the diameter of the bottom longitudinal bars of the beam.

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