Reinforcing structure suitable for stand cantilever beam and construction method of reinforcing structure

Abstract

The invention discloses a reinforcing structure suitable for a stand cantilever beam and a construction method of the reinforcing structure. The method comprises the following steps that 1, the cantilever end of a cantilever folding beam is unloaded; step 2, performing pressure grouting in the crack at the top end of the cantilever folding beam to form a crack reinforcing area; 3, chiseling the side face of the frame column and the inclined bottom face of the cantilever folding beam within the beam end triangular haunching area range to expose folding beam stirrups and lower longitudinal steel bars of the cantilever folding beam; beam end triangular haunching area steel bars are installed; and 4, a formwork for enclosing the beam end triangular haunched area is erected, concrete pouring is conducted, and the beam end triangular haunched area is formed. By means of the method, the potential safety hazards of structural aging, defects in the construction process, environmental corrosion influences, overload use and the like due to long-term use of the stadium stand cantilever beam are solved, construction is convenient, and the requirements for structural safety and normal use can be met.

Description

Technical Field

[0001] The invention relates to the technical field of structural reinforcement and reconstruction, and in particular to a reinforcement structure suitable for a cantilever beam of a stand and a construction method thereof. Background Art

[0002] With the country's emphasis on national fitness, sports buildings have ushered in rapid development in recent years. In order to meet the functional use of the building, the spectator stands are usually designed as stepped. In order to ensure that the sight of the lower audience is not blocked, and at the same time, no structural columns are set and the number of spectators is increased as much as possible, the stands of the stadiums use cast-in-place concrete inclined beams + stepped precast concrete steps. Most of the end structures are cast-in-place concrete cantilevered folded beams. The cantilever span of the folded beams is generally 4~6m. This cantilever span is large, and the construction of the cantilevered structure folded beams of the stands is relatively difficult, which requires a high level of technical skills from the construction unit. Once the formwork is removed or the maintenance is not in place during the construction process, the end of the cantilevered beam is very easy to crack, forming non-(stress) load cracks, and even through the seams; and in the normal use of the building function, there are long-term audience dynamic loads or overload use, which leads to fatigue of the old beam ends to form stress cracks, coupled with the influence of long-term environmental corrosion, this beam end has a great structural safety hazard. In this type of building, a suspended ceiling is usually installed under the beam. If there is no structural health monitoring, it is not easy to be discovered manually after the cover. At the same time, the cantilevered folded beam is a statically determinate structure with no margin for structural collapse. Once it is damaged, it is a brittle failure without obvious warning. Therefore, if the cracks are allowed to develop for a long time, the structure will collapse, causing casualties and property losses.

[0003] In summary, the reinforcement of the cantilever beams of the stadium stands is of great significance for ensuring the safety of spectators, improving the user experience, extending the life of the building, adapting to functional changes, meeting regulatory requirements, saving costs, improving earthquake resistance, maintaining public safety, maintaining architectural characteristics and promoting sustainable development. Summary of the invention

[0004] The present invention provides a reinforcement structure suitable for cantilever beams of stands and a construction method thereof, by which potential safety hazards of cantilever beams of stands in sports stadiums due to structural aging over a long period of use, defects during construction, environmental corrosion, overload use, etc., are solved, which is convenient for construction and can meet the requirements of structural safety and normal use.

[0005] The technical problem to be solved is: the cantilever beams of the stands will develop fatigue cracks at the ends due to long-term structural aging, defects in the construction process, environmental corrosion, long-term audience dynamic loads or overload use.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention discloses a reinforcement structure suitable for a cantilever beam of a grandstand, comprising a frame column and a cantilever folded beam connected to the frame column, wherein pressure grouting is performed at cracks at top ends of the cantilever folded beams to form crack reinforcement zones; a triangular armpit zone at the end of the beam is arranged between the bottom surface of the cantilever folded beam and the frame column, and the triangular armpit zone at the end of the beam is fixedly connected to the frame column and the cantilever folded beam, respectively.

[0007] The present invention provides a reinforcement structure suitable for a cantilever beam of a stand. Further, the triangular armpit area at the beam end includes a longitudinal lower steel bar, a longitudinal upper steel bar, an armpit area stirrup connecting the longitudinal lower steel bar and the longitudinal upper steel bar, a structural steel bar and a concrete structure. One end of the longitudinal lower steel bar and the longitudinal upper steel bar are implanted in a frame column, the other end of the longitudinal lower steel bar is overlap-welded with the lower longitudinal steel bar of the cantilever folded beam, and the other end of the longitudinal upper steel bar is implanted in the cantilever folded beam. One end of the structural steel bar is embedded in the concrete structure, and the other end is embedded in the cantilever folded beam and overlapped and welded with the folded beam stirrups of the cantilever folded beam.

[0008] The present invention provides a reinforcement structure suitable for a cantilever beam of a grandstand. Furthermore, one end of the structural steel bar implanted in the concrete structure extends downward to between a lower longitudinal steel bar and an upper longitudinal steel bar.

[0009] The present invention provides a reinforcement structure suitable for a cantilever beam of a grandstand. Furthermore, the lower longitudinal steel bars and the upper longitudinal steel bars are both divided into two sections, and the two sections of the lower longitudinal steel bars and the upper longitudinal steel bars are connected by a mechanical sleeve.

[0010] The present invention provides a reinforcement structure suitable for cantilever beams of stands. Furthermore, the structural steel bars and the folded beam stirrups are arranged in the same plane.

[0011] The present invention provides a reinforcement structure suitable for a cantilever beam of a stand. Furthermore, a concrete interface agent is arranged at the junction of the triangular haunch area at the beam end and the new and old concrete of the cantilever folded beam.

[0012] The present invention provides a reinforcement structure suitable for a cantilever beam of a grandstand. Furthermore, ultra-fine high-strength concrete grouting material is injected into the crack at the top end of the cantilever folded beam to form a crack reinforcement zone.

[0013] The present invention provides a construction method, comprising the following steps: Step 1: Unload the cantilever end of the cantilever folded beam; Step 2: Dig grooves at the top and both sides of the crack at the top of the cantilever folded beam, and inject pressure grouting into the crack to form a crack reinforcement zone; Step 3: Chisel the side of the frame column within the triangular axil area at the beam end and the inclined bottom surface of the cantilever folded beam to expose the folded beam stirrups and lower longitudinal steel bars of the cantilever folded beam; implant one end of the structural steel bar into the cantilever folded beam and overlap and weld the structural steel bar and the folded beam stirrups, and extend the other end to the triangular axil area at the beam end; then set the longitudinal upper steel bar and the longitudinal lower steel bar within the triangular axil area at the beam end, implant one end of the longitudinal lower steel bar into the frame column, and the other end into the cantilever folded beam and overlap and weld the lower longitudinal steel bar; implant one end of the longitudinal upper steel bar into the frame column, and the other end into the cantilever folded beam; Step 4: Set up formwork to enclose the triangular armpit area at the end of the beam and pour concrete to form the triangular armpit area at the end of the beam.

[0014] The invention provides a construction method, further comprising arranging a vertical support at the cantilever end of the cantilever folded beam to unload the cantilever folded beam.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This application method solves the potential safety hazards of cantilevered folded beams in stadium stands due to long-term structural aging, defects during construction, environmental corrosion, overload use, etc. It is convenient and quick to construct, and can meet the requirements of structural safety and normal use of buildings. Compared with demolition and reconstruction, reinforcing existing structures has better economic benefits. Reinforcement can extend the service life of buildings while reducing the cost and time consumption caused by demolition and reconstruction. It has excellent comprehensive economic benefits, broad market prospects, and provides guidance for subsequent projects; 2. The present application combines durability reinforcement and bearing capacity reinforcement to repair the structure of the cantilever folded beam. Without dismantling the original structure, the cantilever folded beam is reinforced. By grouting in the cracks at the ends of the cantilever folded beam to form a crack reinforcement zone, the crack resistance of the cantilever folded beam ends under normal use is improved, and the shear and bending bearing capacity of the cantilever folded beam are improved in conjunction with the triangular armpit area at the beam ends. While solving the crack hidden dangers of the cantilever folded beam, the durability of the building is improved. Moreover, this treatment measure can be constructed without dismantling the stand boards, piers, and frame beams, without affecting the normal use of the building, significantly enhancing the safety of the structure, and having the advantages of easy construction and reliable connection. 3. The supporting effect of the cantilever folded beam is enhanced by specially arranging the steel bars in the triangular armpit area at the beam end.

[0016] The present invention will be further described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a plan view schematic diagram of the present invention; Figure 2 for Figure 1 Middle AA section view.

[0018] Reference numerals: 1. Frame column; 2. Frame beam; 3. Cantilever folded beam; 3.1. Lower longitudinal reinforcement; 3.2. Folded beam stirrups; 4. Edge beam; 5. Pier; 6. Grandstand slab; 7. Crack reinforcement area; 8. Triangular haunch area at beam end; 8.1. Lower longitudinal reinforcement; 8.2. Upper longitudinal reinforcement; 8.3. Haunch area stirrups; 8.4. Structural reinforcement; 8.5. Concrete structure. DETAILED DESCRIPTION

[0019] like Figure 1-Figure 2 As shown, the present invention discloses a reinforcement structure suitable for a cantilever beam of a stand and a construction method thereof.

[0020] Embodiment 1: The reinforcement structure includes a frame column, a frame beam arranged on the top of the frame column, a cantilevered folding beam arranged obliquely downward and fixedly connected to the side of the frame column, and an edge beam arranged at the cantilevered end of the cantilevered folding beam. The cantilevered folding beam is provided with a step-shaped pier, and the pier is equipped with a grandstand panel.

[0021] The crack reinforcement zone is formed by pressure grouting at the crack at the top of the cantilever folded beam, and a triangular armpit zone at the beam end is provided between the bottom surface of the cantilever folded beam and the frame column. The triangular armpit zone at the beam end is fixedly connected to the frame column and the cantilever folded beam respectively. The crack reinforcement zone is formed by grouting in the crack at the end of the cantilever folded beam, so as to improve the crack resistance of the beam end of the cantilever folded beam under normal use, and the shear and bending bearing capacity of the cantilever folded beam are improved in combination with the triangular armpit zone at the beam end, so as to solve the hidden danger of cracks in the cantilever folded beam and improve the durability of the building. Moreover, this treatment measure can be constructed without dismantling the stand panels, piers and frame beams, and will not affect the normal use of the building, which significantly enhances the safety of the structure and has the advantages of easy construction and reliable connection.

[0022] Specifically, the triangular armpit area at the end of the beam includes lower longitudinal steel bars, upper longitudinal steel bars, armpit area stirrups connecting the lower longitudinal steel bars and the upper longitudinal steel bars, structural steel bars and concrete structures. The lower longitudinal steel bars and the upper longitudinal steel bars are evenly spaced in multiple rows along the width direction of the triangular armpit area at the end of the beam. One end of the lower longitudinal steel bars and the upper longitudinal steel bars are implanted in the frame column with an implantation length of not less than 10d, where d is the diameter of the lower longitudinal steel bars. The other end of the lower longitudinal steel bars is lap-welded to the lower longitudinal steel bars of the cantilever folded beam. Single-sided welding can be used, and the lap length is not less than 10d, where d is the diameter of the lower longitudinal steel bars. The other end of the upper longitudinal steel bars is implanted in the cantilever folded beam with an implantation length of not less than 10d, where d is the diameter of the upper longitudinal steel bars. The lower longitudinal steel bars and the upper longitudinal steel bars are divided into two sections, and the two sections of the lower longitudinal steel bars and the upper longitudinal steel bars are connected by mechanical sleeves.

[0023] The structural steel bar is U-shaped, with its open end facing the direction of the cantilever folded beam. One end of the structural steel bar is embedded in the concrete structure, and the other end is embedded in the cantilever folded beam and overlapped and welded with the folded beam stirrups of the cantilever folded beam. The overlap length is not less than 10d, where d is the diameter of the structural steel bar. Among them, one end of the structural steel bar embedded in the concrete structure extends downward to between the lower longitudinal steel bar and the upper longitudinal steel bar. The structural steel bar and the folded beam stirrups are arranged in the same plane. The structural steel bar is welded with the original folded beam stirrups to form an integral hoop, which facilitates construction on the one hand and enhances the connection strength between structures on the other.

[0024] In addition, a concrete interface agent is installed at the junction of the new and old concrete in the triangular armpit area at the beam end and the cantilevered folded beam to ensure the bonding strength between the new and old concrete.

[0025] Ultra-fine high-strength concrete grouting material is injected into the cracks at the top of the cantilever folded beam to form a crack reinforcement zone, thereby improving the crack resistance of the cantilever folded beam end under normal use.

[0026] Embodiment 2: The construction method of the reinforced structure includes the following steps: Step 1: Check the development of cracks at the ends of cantilevered folded beams, conduct crack safety assessment, and analyze to determine whether structural reinforcement is required. If structural reinforcement is required, set up temporary vertical supports under the edge beams at the cantilevered ends of the cantilevered folded beams to ensure that the cantilevered folded beams are in a completely unloaded state.

[0027] Step 2: Dig a V-shaped groove at the top and both sides of the crack at the top of the cantilevered folded beam, rinse it clean, use ultra-fine high-strength grouting material to pressure-inject grouting into the crack and seal it to ensure the density of the crack grouting and form a crack reinforcement zone.

[0028] Step 3: Roughen the sides of the frame columns within the triangular armpit area at the beam end and the inclined bottom surface of the cantilevered folded beam to expose the folded beam stirrups and lower longitudinal steel bars of the cantilevered folded beam, and clean them with clean water.

[0029] One end of the structural reinforcement is implanted into the cantilever folded beam and the structural reinforcement is overlapped and welded to the folded beam stirrups, and the other end is extended to the triangular axil area at the beam end; then, upper longitudinal reinforcement and lower longitudinal reinforcement are arranged within the triangular axil area at the beam end, one end of the upper longitudinal reinforcement is implanted into the frame column, and the other end is implanted into the cantilever folded beam, and the two sections of upper longitudinal reinforcement are connected by a mechanical sleeve; one end of the lower longitudinal reinforcement is implanted into the frame column, and the other end is implanted into the cantilever folded beam and overlapped and welded to the lower longitudinal reinforcement, and the two sections of lower longitudinal reinforcement are connected by a mechanical sleeve.

[0030] Step 4: Set up the formwork to enclose the triangular haunch area at the beam end and pour concrete to form the triangular haunch area at the beam end. After completing the triangular haunch area at the beam end, perform a load test on the cantilever folded beam and conduct health monitoring to check the cracks at the top of the cantilever folded beam and the deflection of the cantilever end to ensure that they are consistent with the theoretical numerical analysis.

[0031] The embodiments described above are merely descriptions of preferred implementation modes of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A reinforcement structure for cantilever beams of stands, comprising a frame column and a cantilever folding beam connected to the frame column, characterized in that: The crack at the top of the cantilever folded beam is pressure-grouted to form a crack reinforcement zone; a triangular armpit area at the beam end is arranged between the bottom surface of the cantilever folded beam and the frame column, and the triangular armpit area at the beam end is fixedly connected to the frame column and the cantilever folded beam respectively.

2. A reinforcement structure suitable for cantilever beams of stands according to claim 1, characterized in that: The triangular armpit area at the beam end includes a longitudinal lower steel bar, a longitudinal upper steel bar, an armpit area stirrup connecting the longitudinal lower steel bar and the longitudinal upper steel bar, a structural steel bar and a concrete structure. One end of the longitudinal lower steel bar and the longitudinal upper steel bar are implanted in the frame column, the other end of the longitudinal lower steel bar is overlap-welded with the lower longitudinal steel bar of the cantilever folded beam, and the other end of the longitudinal upper steel bar is implanted in the cantilever folded beam; One end of the structural steel bar is embedded in the concrete structure, and the other end is embedded in the cantilever folded beam and overlapped and welded with the folded beam stirrups of the cantilever folded beam.

3. The reinforcement structure for cantilever beams of a grandstand according to claim 2, characterized in that: One end of the structural steel bar implanted in the concrete structure extends downward to between the longitudinal lower steel bar and the longitudinal upper steel bar.

4. The reinforcement structure for cantilever beams of a stand according to claim 2, characterized in that: The longitudinal lower steel bars and the longitudinal upper steel bars are divided into two sections, and the two sections of the longitudinal lower steel bars and the longitudinal upper steel bars are connected by mechanical sleeves.

5. The reinforcement structure for cantilever beams of a stand according to claim 2, characterized in that: The structural steel bars are arranged coplanarly with the folded beam stirrups.

6. The reinforcement structure for cantilever beams of a stand according to claim 2, characterized in that: A concrete interface agent is arranged at the junction of the new and old concrete of the triangular haunch area at the beam end and the cantilevered folded beam.

7. The reinforcement structure for cantilever beams of a stand according to claim 1, characterized in that: Ultra-fine high-strength concrete grouting material is injected into the crack at the top end of the cantilever folded beam to form a crack reinforcement zone.

8. A method for constructing a reinforcement structure applicable to cantilever beams of a stand as described in any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Unload the cantilever end of the cantilever folded beam; Step 2: Dig grooves at the top and both sides of the crack at the top of the cantilever folded beam, and inject pressure grouting into the crack to form a crack reinforcement zone; Step 3: Chisel the side of the frame column within the triangular axil area at the beam end and the inclined bottom surface of the cantilever folded beam to expose the folded beam stirrups and lower longitudinal steel bars of the cantilever folded beam; implant one end of the structural steel bar into the cantilever folded beam and overlap and weld the structural steel bar and the folded beam stirrups, and extend the other end to the triangular axil area at the beam end; then set the longitudinal upper steel bar and the longitudinal lower steel bar within the triangular axil area at the beam end, implant one end of the longitudinal lower steel bar into the frame column, and the other end into the cantilever folded beam and overlap and weld the lower longitudinal steel bar; implant one end of the longitudinal upper steel bar into the frame column, and the other end into the cantilever folded beam; Step 4: Set up formwork to enclose the triangular armpit area at the end of the beam and pour concrete to form the triangular armpit area at the end of the beam.

9. The construction method for reinforcing the structure of the cantilever beam of a grandstand according to claim 8, characterized in that: A vertical support is arranged at the cantilever end of the cantilever folded beam to unload the cantilever folded beam.

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