CN108019000A - A kind of high-strength high ductility concrete of assembled exempts from sleeve connection structure and connection method - Google Patents

Abstract

The invention provides an assembled high-strength and high-ductility concrete sleeve-free connection structure and a connection method, which include a prefabricated reinforced concrete beam, the prefabricated reinforced concrete beam includes stirrups and lap joint longitudinal bars arranged at the lower part of the beam, and the upper part of the stirrups is exposed , there are reserved stirrups on the outer side of the longitudinal reinforcement of the overlapping section; the lower part of the precast reinforced concrete beam is staggered and overlapped by the longitudinal reinforcement of the overlapping section, and spiral stirrups are provided at the overlapping joint of the longitudinal reinforcement of the overlapping section, and the upper part of the precast reinforced concrete beam It is connected by sequentially passing through the reserved stirrups and the stirrups set in the prefabricated reinforced concrete beams. The lap joint is poured with high-strength and high-ductility concrete, and the upper part of the prefabricated reinforced concrete beams is post-cast with concrete. Utilizing the ultra-high strength and bonding performance of high-strength and high-ductility concrete can greatly shorten the overlapping length of steel bars, reduce or even eliminate the use of reserved stirrups, avoid bending and anchoring of beam steel bars, and solve the problem of steel bar congestion in joint areas. Because no sleeve is used, it is convenient to manufacture in the factory, easy to install, and easy to control the quality without professionals.

Description

An assembled high-strength and high-ductility concrete sleeve-free connection structure and connection method

technical field

The invention belongs to the technical field of assembled concrete structures, and in particular relates to an assembled high-strength and high-ductility concrete sleeve-free connection structure and a connection method.

Background technique

Since the prefabricated components are prefabricated in the factory, the quality of the prefabricated components can be well guaranteed, and the safety of the prefabricated structure mainly depends on the connection between these components and the surrounding components. Reliable connection quality can realize the transmission of the specified internal force according to the design requirements, and will not cause problems in use and appearance. If there are defects in the quality of the joint connection, it will cause problems in use such as cracks and leakage, and it will affect the force transmission between components and components, components and supporting structures, causing problems in bearing capacity and safety, and even causing structural disintegration. , resulting in serious consequences such as collapse. The earthquake damage survey of various major earthquakes found that in the overall collapsed buildings, the prefabricated beams and columns were less damaged, and the main cause of the collapse was the failure of the connections between the various components in the frame structure.

At present, the main methods of steel bar connection for prefabricated structural members in my country include welding connection, mechanical connection, lashing lap joint, sleeve grouting connection, restraint paddle anchor connection and other forms. Among them, welding connection and mechanical connection are extremely difficult to be applied in the connection of fabricated structural members in practice due to the extremely difficult on-site construction; lashing lap joints are only used in prefabricated laminated panels and joints due to the long lap length and poor connection performance. The connection of steel bars in some beams; sleeve grouting connection and restraint oar-anchor connection are two connection methods available for prefabricated concrete structures at present, but due to the large size, heavy weight and complex connection structure of prefabricated components, coupled with the fact that China's construction The low labor force level in the industry increases the difficulty of prefabricated building construction that requires a high degree of refinement. Therefore, both the sleeve grouting connection and the restraint paddle-anchor connection have disadvantages such as difficult alignment and complicated operation. Once the steel bars collide during construction Or if the error is large, the installation will not be possible, which will affect the construction period and cause waste.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned defects in the prior art, and provide a simple, safe and reliable assembled high-strength and high-ductility concrete sleeve-free connection structure and connection method.

The technical scheme provided by the invention is as follows:

An assembled high-strength and high-ductility concrete sleeve-free connection structure includes a prefabricated reinforced concrete beam, the prefabricated reinforced concrete beam includes a prefabricated reinforced concrete left beam and a prefabricated reinforced concrete right beam, and the prefabricated reinforced concrete beam includes stirrups and design In the longitudinal reinforcement of the overlapping section at the lower part of the beam, the upper part of the stirrup is exposed, and the outer side of the longitudinal reinforcement of the overlapping section is provided with a reserved stirrup;

The prefabricated reinforced concrete left beam and the lower part of the prefabricated reinforced concrete right beam are staggered and overlapped through the longitudinal reinforcement of the overlapping section, and spiral stirrups are provided at the staggered overlapping of the longitudinal reinforcement of the overlapping section, and the prefabricated reinforced concrete left beam and the prefabricated reinforced concrete The upper part of the concrete right beam is connected by longitudinal bars passing through the reserved stirrups and the inner stirrups of the prefabricated reinforced concrete beam in sequence.

It also includes a prefabricated reinforced concrete upper column and a prefabricated reinforced concrete lower column. Post-casting holes are reserved on the prefabricated reinforced concrete upper column, and a prefabricated core column is prefabricated in the center of the lower end surface, and the prefabricated core column is used for assembling the prefabricated For the support of the reinforced concrete upper column, the four corners of the prefabricated reinforced concrete upper column and the prefabricated reinforced concrete lower column are provided with overlapping section longitudinal bars, and each end of the overlapping section longitudinal bar is provided with an anchor plate, and the precast reinforced concrete upper column The column and the prefabricated reinforced concrete lower column are staggered and overlapped through the longitudinal reinforcement of the overlapping section, the spiral stirrup at the staggered overlapping of the longitudinal reinforcement of the overlapping section, the reserved stirrup outside the longitudinal reinforcement of the overlapping section, and the post-filled high-strength and high-strength reinforcement at the joint. ductile concrete for connection.

It also includes a prefabricated reinforced concrete upper column and a prefabricated reinforced concrete lower column, the prefabricated reinforced concrete upper column and the prefabricated reinforced concrete lower column are respectively in the shape of an inverted step and a step, and the two steps are opposite to form two overlapping sections, the The upper and lower steps of the prefabricated reinforced concrete upper column and the prefabricated reinforced concrete lower column are preset with lap joint longitudinal bars and reserved stirrups, the prefabricated reinforced concrete upper column is reserved with post-pouring holes, and the prefabricated reinforced concrete A leveling nut is provided at the end of the longitudinal reinforcement of the overlapping section of the upper column, and an anchor plate is provided at the end of the longitudinal reinforcement of the overlapping section of the prefabricated reinforced concrete lower column, and the prefabricated reinforced concrete upper column and the prefabricated reinforced concrete lower column pass through The longitudinal reinforcement of the two overlapping sections is staggered and overlapped, the spiral stirrup at the overlapped longitudinal reinforcement of the overlapping section, the reserved stirrup outside the longitudinal reinforcement of the overlapping section, and the high-strength and high-ductility concrete filled after the joint are connected.

The prefabricated core column is 1/2-2/3 of the section of the prefabricated reinforced concrete upper column.

The overlapping length of the longitudinal reinforcement of the overlapping section is 5-15 times the diameter of the longitudinal reinforcement.

The anchoring plate is a round or square steel plate with a thickness of 10-20 mm and a diameter or side length 2-3 times that of the longitudinal rib.

The diameter of the spiral stirrup is 4-8mm, the reserved stirrup spacing is 20-30mm, and the circumferential diameter is 2-4 times the diameter of the steel bar.

The components of the high-strength and high-ductility concrete are cement, fly ash, silica fume, sand, PE fiber, steel fiber and water, wherein, in terms of mass percentage, cement: fly ash: silica fume: sand: water=1 : 0-0.3: 0.1-0.4: 0.76: 0.22-0.32; based on the total volume of cement, fly ash, silica fume, sand and water mixed uniformly, the volume content of PE fiber is 1%-1.5%, The volume content of steel fiber is 0.5%-2%.

The present invention also provides an assembly-type high-strength and high-ductility concrete sleeve-free connection method, using the assembly-type high-strength and high-ductility concrete sleeve-free connection structure, hoisting the prefabricated reinforced concrete beam to a predetermined position, and connecting the prefabricated reinforced concrete left beam and The lower part of the prefabricated reinforced concrete right beam is staggered and overlapped through the longitudinal reinforcement of the overlapping section, and then the spiral stirrup is wound around the overlapping joint, and the upper part passes through the reserved stirrup and the stirrup successively through the longitudinal reinforcement. Binding, and then pouring high-strength and high-ductility concrete to realize the prefabricated connection.

The beneficial effects of the present invention are:

(1) Utilizing the ultra-high strength and bonding performance of high-strength and high-ductility concrete can greatly shorten the lap length of steel bars, and the connection between old and new concrete is reliable.

(2) High-strength and high-ductility concrete has the characteristics of high tensile strength and tensile strain hardening. Therefore, the use of reserved stirrups can be reduced or even eliminated, avoiding the bending and anchoring of beam reinforcement, and solving the problem of reinforcement congestion in the joint area.

(3) High-strength and high-ductility concrete has the characteristics of ultra-high strength and high ductility, and the seismic performance of components is improved, so it can be used in high-intensity areas.

(4) Since this connection method does not use a sleeve, it is easy to manufacture in the factory, easy to install, reduces the process, and is easy to control the quality without professionals, which is in line with the current situation in our country.

Further details will be described below in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is the structural representation of the lap joint connection of prefabricated beam of the present invention;

Figure 2 is a structural schematic diagram of a 100% lap connection of a prefabricated column;

Fig. 3 is a structural schematic diagram of a 50% lap connection of a prefabricated column;

Fig. 4 is the failure pattern of the core area of ordinary concrete joints with reserved stirrups;

Figure 5 is the hysteresis curve of the core area of ordinary concrete joints with reserved stirrups;

Fig. 6 is the damage pattern of the core area of the high ductility concrete (HDC) joint without reserved stirrups;

Fig. 7 is the hysteretic curve of the core area of high ductility concrete (HDC) joints without reserved stirrups.

In the figure: 1. Prefabricated reinforced concrete right beam; 2. Prefabricated reinforced concrete left beam; 3. Longitudinal reinforcement; 4. Reserved stirrup; 5. Anchor plate; 6. Spiral stirrup; 7. Prefabricated core column; 8. Post-pouring hole; 9. Leveling nut; 10. Prefabricated reinforced concrete upper column; 11. Prefabricated reinforced concrete lower column.

Detailed ways

Example 1:

This embodiment provides an assembled high-strength and high-ductility concrete sleeve-free connection structure as shown in Figure 1, including a prefabricated reinforced concrete beam, and the prefabricated reinforced concrete beam includes a prefabricated reinforced concrete left beam 2 and a prefabricated reinforced concrete right beam 1. The prefabricated reinforced concrete beam includes stirrups and longitudinal bars of the overlapping section arranged at the lower part of the beam, the upper part of the stirrups is exposed, and the outer side of the longitudinal bars of the overlapping section is provided with a reserved stirrup 4;

The prefabricated reinforced concrete left beam 2 and the lower part of the prefabricated reinforced concrete right beam 1 are staggered and overlapped by the longitudinal reinforcement of the overlapping section, and the overlapping section of the longitudinal reinforcement is provided with a spiral stirrup 6, and the prefabricated reinforced concrete left beam 2 and the upper part of the prefabricated reinforced concrete right beam 1 are connected by the longitudinal reinforcement 3 passing through the reserved stirrups 4 and the inner stirrups of the prefabricated reinforced concrete beam in sequence. Post-cast concrete.

Example 2:

On the basis of Example 1, this example provides an assembled high-strength and high-ductility concrete sleeve-free connection structure as shown in Figure 2, which also includes a prefabricated reinforced concrete upper column 10 and a prefabricated reinforced concrete lower column 11. The post-casting hole 8 is reserved on the prefabricated reinforced concrete upper column 10, and the center of the lower end surface is prefabricated with a prefabricated core column 7, and the prefabricated core column 7 is used to support the prefabricated reinforced concrete upper column 10 during assembly. The four corners of the reinforced concrete upper column 10 and the prefabricated reinforced concrete lower column 11 are provided with overlapping longitudinal bars, and each end of the overlapping segment longitudinal bars is provided with an anchor plate 5, and the prefabricated reinforced concrete upper column 10 and the prefabricated reinforced concrete lower column The column 11 is constructed by staggered overlapping of longitudinal reinforcement in the overlapping section, the spiral stirrup 6 at the staggered overlapping of longitudinal reinforcement in the overlapping section, the reserved stirrup 4 on the outside of the longitudinal reinforcement in the overlapping section, and high-strength and high-ductility concrete filled after the joint. connect.

Construction process: Step 1: Binding the beam and column steel skeleton in the precast factory. After the binding is completed, put the steel skeleton into the prefabricated formwork. Right beam 1 and prefabricated reinforced concrete left beam 2), prefabricated columns (including prefabricated reinforced concrete upper column 10 and prefabricated reinforced concrete lower column 11.

Step 2: Hoist the prefabricated column to the predetermined position on site, wind the spiral stirrup 6 at the overlap of the longitudinal reinforcement of the overlapping section, bind the reserved stirrup 4 placed in advance, and then pour high-strength and high-ductility concrete, The prefabricated reinforced concrete upper column 10 and the prefabricated reinforced concrete lower column 11 are connected, as shown in FIG. 2 , to complete the connection of the columns.

As shown in FIG. 2 , the connection of the columns in this embodiment is 100% lap connection, and the prefabricated core column 7 functions as support and positioning during component assembly. Wherein, the overlapping length of the longitudinal ribs in the overlapping section is 5-15 times the diameter of the longitudinal ribs 3 . The anchor plate 5 is a round or square steel plate with a thickness of 10-20 mm and a diameter or side length 2-3 times that of the longitudinal rib 3 . The diameter of the spiral stirrup 6 is 4-8mm, the distance between the reserved stirrup 4 is 20-30mm, and the circumferential diameter is 2-4 times the diameter of the steel bar.

The components of the high-strength and high-ductility concrete are cement, fly ash, silica fume, sand, PE fiber, steel fiber and water, wherein, in terms of mass percentage, cement: fly ash: silica fume: sand: water=1 : 0-0.3: 0.1-0.4: 0.76: 0.22-0.32; based on the total volume of cement, fly ash, silica fume, sand and water mixed uniformly, the volume content of PVA fiber is 1%-1.5%, The volume content of steel fiber is 0.5%-2%.

Due to the characteristics of tensile strain hardening and multi-crack development of high-strength and high-ductility concrete, the amount of stirrups 4 reserved in the connection area can be appropriately reduced, and the reduction can be taken as the minimum stirrup ratio, that is, the shear resistance of fibers can be equivalent to the minimum stirrup ratio. The shear effect of stirrup ratio, as shown in Figure 4 and Figure 5, the core area of ordinary concrete joints with reserved stirrups is severely damaged, and the hysteresis curve is obviously pinched, while the unprepared joints shown in Figures 6 and 7 The core area of the high ductility concrete joints with stirrups presents the characteristics of multiple cracks, and the hysteretic curve is full. The high-strength and high-ductility concrete in this embodiment belongs to high-ductility concrete.

Example 3:

On the basis of Example 1, this example provides an assembled high-strength and high-ductility concrete sleeve-free connection structure as shown in Figure 3, which also includes a prefabricated reinforced concrete upper column 10 and a prefabricated reinforced concrete lower column 11. The prefabricated reinforced concrete upper column 10 and the prefabricated reinforced concrete lower column 11 are respectively inverted steps and steps, and the two steps are opposite to form two overlapping sections. The prefabricated reinforced concrete upper column 10 and the prefabricated reinforced concrete lower column 11 Lap section longitudinal bars and reserved stirrups 4 are preset at the upper and lower steps of the upper and lower steps, post-pouring holes 8 are reserved on the prefabricated reinforced concrete upper column 10, and the lap section longitudinal bars of the prefabricated reinforced concrete upper column 10 The end of the bar is provided with a leveling nut 9, and the end of the longitudinal bar of the overlapping section of the prefabricated reinforced concrete lower column 11 is provided with an anchor plate 5, and the prefabricated reinforced concrete upper column 10 and the prefabricated reinforced concrete lower column 11 pass through two places. The longitudinal reinforcement in the overlapping section is staggered and overlapped, the spiral stirrup 6 at the overlapped longitudinal reinforcement of the overlapping section, the reserved stirrup 4 outside the longitudinal reinforcement of the overlapping section, and the high-strength and high-ductility concrete filled after the joint are connected.

Assembly construction: hoist the prefabricated column to the predetermined position on site, level the column through the leveling nut 9 or other leveling supports, wrap the spiral stirrup at the overlap of the longitudinal reinforcement of the overlapping section, and place the binding in advance Reserve the stirrups 4, and then pour high-strength and high-ductility concrete to connect the columns, as shown in Figure 3, to complete the connection of columns (beams).

In this example, the connection of the columns is a 50% lap connection. The cross-sectional size of the prefabricated reinforced concrete upper column 10 is 500mm´500mm, the cross-sectional dimension of the prefabricated reinforced concrete lower column 11 is 300mm´600mm; times the steel bar diameter; the anchor plate 5 is circular with a thickness of 15mm and a diameter three times that of the longitudinal bar 3.

Among them, the components of high-strength and high-ductility concrete in this example are cement, fly ash, silica fume, sand, PE fiber, steel fiber and water, wherein, by mass percentage, cement: fly ash: silica fume: sand: Water = 1: 0.9: 0.1: 0.76: 0.28; based on the total volume of cement, fly ash, silica fume, sand and water mixed uniformly, the volume content of PE fiber is 1.5%, and the volume content of steel fiber is 0.5%~1%.

Among them: the maximum particle size of sand is 1.26mm; the PE fiber is PA600 fiber produced by Shanghai Luoyang Technology Co., Ltd., with a length of 8mm, a diameter of 26µm, a tensile strength of 1200MPa, and an elastic modulus of 30GPa; the steel fiber is made of Shanghai Copper-coated steel fiber with hooks produced by a company, with a diameter of 0.22 mm, a length of 13 mm, and a tensile strength of 2800 MPa; the cement is PO 52.5R Portland cement; the fly ash is Class I fly ash; the loss on ignition of the silica fume used 5%, the silica content is 88%, and the specific surface area is 18000 m ² /kg.

Example 4:

This embodiment provides a sleeve-free connection method for assembled high-strength and high-ductility concrete. Using the assembled high-strength and high-ductility concrete sleeve-free connection structure, the prefabricated reinforced concrete beam is hoisted to a predetermined position, and the prefabricated reinforced concrete left beam 2 The lower part of the prefabricated reinforced concrete right beam 1 is staggered and overlapped through the longitudinal reinforcement of the overlapping section, and then the spiral stirrup 6 is wound around the overlapping joint. Reserve stirrups for binding, and then pour high-strength and high-ductility concrete to realize the prefabricated connection.

The parts not specifically described in this embodiment belong to common knowledge and technologies in the technical field, and will not be described in detail here.

The above examples are only illustrations of the present invention, and do not constitute a limitation to the protection scope of the present invention. All designs that are the same as or similar to the present invention fall within the protection scope of the present invention.

Claims (9)

1. An assembled high-strength and high-ductility concrete sleeve-free connection structure, characterized in that it includes a prefabricated reinforced concrete beam, and the prefabricated reinforced concrete beam includes a prefabricated reinforced concrete left beam (2) and a prefabricated reinforced concrete right beam (1) , the prefabricated reinforced concrete beam includes stirrups and longitudinal bars of overlapping sections arranged at the lower part of the beams, the upper part of the stirrups is exposed, and reserved stirrups (4) are provided outside the longitudinal bars of the overlapping sections; The lower part of the prefabricated reinforced concrete left girder (2) and the prefabricated reinforced concrete right girder (1) are staggered and overlapped by the longitudinal reinforcement of the overlapping section, and a spiral stirrup (6) is provided at the staggered overlapping of the longitudinal reinforcement of the overlapping section. The prefabricated reinforced concrete left beam (2) and the upper part of the prefabricated reinforced concrete right beam (1) are connected by the longitudinal reinforcement (3) passing through the reserved stirrups (4) and the inner stirrups of the prefabricated reinforced concrete beams sequentially. High-strength and high-ductility concrete is poured after the section, and the upper part of the prefabricated reinforced concrete beam is post-cast concrete. 2. A prefabricated high-strength and high-ductility concrete sleeve-free connection structure according to claim 1, characterized in that it also includes a prefabricated reinforced concrete upper column (10) and a prefabricated reinforced concrete lower column (11), the prefabricated A post-casting hole (8) is reserved on the reinforced concrete upper column (10), and a prefabricated core column (7) is prefabricated in the center of the lower end surface, and the prefabricated core column (7) is used for the prefabricated reinforced concrete upper column ( 10), the four corners of the prefabricated reinforced concrete upper column (10) and the prefabricated reinforced concrete lower column (11) are provided with lap section longitudinal reinforcement, and each lap section longitudinal reinforcement end is provided with an anchor plate (5) , the prefabricated reinforced concrete upper column (10) and the prefabricated reinforced concrete lower column (11) are staggered and overlapped by the longitudinal reinforcement of the overlapping section, the spiral stirrup (6) at the overlapping overlapping section of the longitudinal reinforcement, and the overlapping section The reserved stirrup (4) on the outside of the longitudinal reinforcement is connected with the high-strength and high-ductility concrete filled after the joint. 3. A prefabricated high-strength and high-ductility concrete sleeve-free connection structure according to claim 1, characterized in that it also includes a prefabricated reinforced concrete upper column (10) and a prefabricated reinforced concrete lower column (11), the prefabricated The reinforced concrete upper column (10) and the prefabricated reinforced concrete lower column (11) are in the shape of an inverted step and a step, respectively, and the two steps are opposite to form two overlapping sections. The prefabricated reinforced concrete upper column (10) and prefabricated steel bars The upper and lower steps of the lower concrete column (11) are preset with lap joint longitudinal bars and reserved stirrups (4), and the prefabricated reinforced concrete upper column (10) is reserved with post-casting holes (8), so A leveling nut (9) is provided at the end of the longitudinal reinforcement of the overlapping section of the prefabricated reinforced concrete upper column (10), and an anchor plate (5 ), the prefabricated reinforced concrete upper column (10) and the prefabricated reinforced concrete lower column (11) are overlapped by the longitudinal reinforcement of the two overlapping sections, the spiral stirrups (6) at the overlapped longitudinal reinforcement of the overlapping sections, The reserved stirrups (4) on the outside of the longitudinal reinforcement of the overlapping section are connected with the high-strength and high-ductility concrete filled after the connection. 4. An assembled high-strength and high-ductility concrete sleeve-free connection structure according to claim 2, characterized in that: the prefabricated core column (7) is 1/2- 2/3. 5. A prefabricated high-strength and high-ductility concrete sleeve-free connection structure according to any one of claims 1-4, characterized in that: the overlapping length of the longitudinal reinforcement of the overlapping section is 5-15 times the overlapping length The diameter of the longitudinal reinforcement of the joint. 6. An assembled high-strength and high-ductility concrete sleeve-free connection structure according to any one of claims 1-4, characterized in that: the anchor plate (5) is a round or square steel plate with a thickness of 10- 20mm, diameter or side length is 2-3 times of longitudinal rib (3). 7. An assembled high-strength and high-ductility concrete sleeve-free connection structure according to any one of claims 1-4, characterized in that: the diameter of the spiral stirrup (6) is 4-8mm, and the stirrup is reserved (4) The spacing is 20-30mm, and the circumferential diameter is 2-4 times the diameter of the steel bar. 8. A prefabricated high-strength and high-ductility concrete sleeve-free connection structure according to any one of claims 1-4, characterized in that: the components of the high-strength and high-ductility concrete are cement, fly ash, silica fume , sand, PE fiber, steel fiber and water, among which, by mass percentage, cement: fly ash: silica fume: sand: water = 1: 0-0.3: 0.1-0.4: 0.76: 0.22-0.32; The total volume of fly ash, silica fume, sand and water mixed uniformly is the base, the volume content of PE fiber is 1%-1.5%, and the volume content of steel fiber is 0.5%-2%. 9. A sleeve-free connection method for assembled high-strength and high-ductility concrete, using the sleeve-free connection structure for assembled high-strength and high-ductility concrete as claimed in claim 1, characterized in that: the prefabricated reinforced concrete beam is hoisted to a predetermined position , the lower part of the prefabricated reinforced concrete left beam (2) and the prefabricated reinforced concrete right beam (1) are cross-lapped through the longitudinal reinforcement of the overlapping section, and then the spiral stirrup (6) is wound around the overlapping joint, and the upper part passes through the longitudinal reinforcement in turn The reserved stirrup (4) is connected with the stirrup (3), and then the reserved stirrup is bound, and then high-strength and high-ductility concrete is poured to realize the prefabricated connection.