Reinforced concrete structure truss with active pressure tank device

Abstract

The utility model provides a kind of steel reinforced concrete structure truss using active pressure tank device, belong to civil engineering foundation pit supporting technical field. Stable beam is transversely arranged at the junction of inclined web support beam of steel reinforced concrete structure truss in foundation pit, and active pressure tank device is arranged at the junction of straight web support beam of steel reinforced concrete structure truss;Active pressure tank device loads active pressure to straight web support beam;A plurality of stabilizing members are arranged between stable beams.The steel reinforced concrete structure truss using active pressure tank device of the utility model, by active pressure tank loading, pre-compression inner support is generated to reach the thrust and pre-reduces compression deformation, reduces inner support deformation, thereby reduce the deformation of supporting system and improve the stability of supporting system or reduce component section.

Description

Technical Field

[0001] This utility model provides an active pressure box device and a reinforced concrete truss structure, belonging to the field of foundation pit support technology in civil engineering. Background Technology

[0002] Civil engineering construction often requires the excavation of deep foundation pits. To prevent the foundation pit from collapsing and to control the stability of the foundation pit wall, lateral supports need to be installed inside the foundation pit to balance the thrust generated by the deformation of the foundation pit.

[0003] Currently, reinforced concrete structures are the main structural form for internal bracing of deep foundation pits. The advantages of this system are high load-bearing capacity, good structural integrity, good plasticity of reinforced concrete adaptability to various structural forms, and relatively small structural deformation. The disadvantages are that the hardening and drying shrinkage deformation of the concrete structure is still relatively large, and the stress on long members can lead to large deformation of the components, affecting the overall stress distribution of the truss system, or causing the foundation pit deformation to exceed the design allowable range, or resulting in an excessively large structural cross-section, which is economically unreasonable. Utility Model Content

[0004] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a reinforced concrete truss structure with an active pressure box device to solve one or more problems in the prior art.

[0005] To achieve the above objectives, the technical solution of this utility model is as follows: A reinforced concrete truss structure employing an active pressure box device, wherein a stabilizing beam is arranged laterally at the joint of the inclined web support beam of the reinforced concrete truss structure located in the foundation pit, and an active pressure box device is arranged at the joint of the straight web support beam of the reinforced concrete truss structure. The active pressure box device applies active pressure to the straight web support beam; Several stabilizing elements are arranged between the stabilizing beams.

[0006] Furthermore, the active pressure box device includes a large-tonnage jack and a load-bearing steel plate; The straight web support beams are equipped with load-bearing steel plates at the ends near the active pressure box device. The driving end and fixed end of the large-tonnage jack are connected to the load-bearing steel plates at the ends of the straight web support beams on both sides.

[0007] Furthermore, the active pressure box device also includes a sealing steel plate and a force-converting steel component. After the large-tonnage jack applies active pressure to the load-bearing steel plate in stages, several force-transferring steel components are arranged between the two load-bearing steel plates, and the outside of the force-transferring steel components is wrapped with a closed steel plate.

[0008] Furthermore, a camel beam is provided below the active pressure box device.

[0009] Furthermore, columns are provided below the camel beam to support the camel beam and the reinforced concrete truss structure.

[0010] Gaskets are provided between the driving end and the fixed end of the large-tonnage jack and the load-bearing steel plate.

[0011] Furthermore, the material of the enclosed steel plate is Q235a steel plate.

[0012] Furthermore, the power-changing steel component is a solid Q235a steel column.

[0013] Compared with the prior art, the beneficial technical effects of this utility model are as follows: (I) After the supporting truss of this utility model is poured to the design strength, the active pressure box is loaded in stages to the design internal support force requirement. Then, the stabilizing components and force-replacing steel components are connected and installed. After reaching the required strength, the jacks are removed and the steel bars inside the pressure box are installed. The sealing steel plate is installed, and micro-expansion concrete or grout is poured. By loading the active pressure box, the internal support is pre-compressed to generate thrust and pre-reduced compression deformation, thereby reducing the deformation of the internal support and thus reducing the deformation of the support system, improving the stability of the support system, or reducing the cross-section of the components.

[0014] (ii) The present invention pre-applies pressure to the truss, and the thrust generated by the inward deformation of the support is first offset by the pre-applied load, thereby controlling the internal force and deformation of the support structure.

[0015] (iii) The compression component of this utility model reduces deformation in advance to improve the internal force of the component, so as to give full play to the bearing capacity performance of the component, and can make the component cross section and arrangement more reasonable, thereby reducing the project cost. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the component arrangement of this utility model.

[0017] Figure 2 for Figure 1 Enlarged structural diagram at point A in the middle.

[0018] Figure 3 This is a schematic diagram of the arrangement of the active pressurization box and stabilizing components of this utility model.

[0019] Figure 4 This is a schematic diagram of the active pressure box of this utility model.

[0020] Figure 5 This is a schematic diagram of the internal structure of the active pressure chamber of this utility model.

[0021] Figure 6 This is a schematic diagram of the arrangement of the large-tonnage jacks of this utility model.

[0022] Figure 7This is a schematic diagram of the layout of the large-tonnage jack and the force-converting steel components of this utility model.

[0023] The following are labels in the attached diagram: 1. Reinforced concrete truss structure; 11. Inclined web support beam; 12. Straight web support beam; 13. Shim; 2. Stabilizing beam; 3. Active pressure box device; 4. Stabilizing component; 5. Large tonnage jack; 6. Load-bearing steel plate; 7. Enclosed steel plate; 8. Force-changing steel component; 9. Camel beam; 10. Column. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description of a reinforced concrete truss structure employing an active pressure box device, in conjunction with the accompanying drawings and specific embodiments, provides further clarity. The advantages and features of this utility model will become clearer from the following description. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clearly illustrate the purpose of the embodiments of this utility model. Please refer to the accompanying drawings for a clearer understanding of the objectives, features, and advantages of this utility model. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes and to aid those skilled in the art, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this utility model, should still fall within the scope of the technical content disclosed in this utility model.

[0025] like Figure 1 As shown: The connection between the reinforced concrete truss 1 on both sides of the foundation pit is provided by an active pressure box device 3 and several stabilizing components 4, i.e., the location marked at point A. The active pressure box device 3 provides active pressure.

[0026] like Figure 2 , Figure 3 As shown: A stabilizing beam 2 is arranged laterally at the joint of the inclined web support beam 11 of the reinforced concrete truss 1. The stabilizing beam 2 enhances the stiffness and stability of the truss end. The stabilizing beam 2 is cast together with the reinforced concrete truss 1.

[0027] An active pressure box device 3 is arranged at the joint of the straight web support beams 12 of the reinforced concrete truss 1 on both sides, and several stabilizing members 4 are arranged between the stabilizing beams 2. The stabilizing members 4 connect the ends of the reinforced concrete truss 1 to enhance the connection strength of the truss.

[0028] like Figures 4 to 7 As shown: The active pressure box device 3 includes a large-tonnage jack 5, a load-bearing steel plate 6, a sealing steel plate 7, and a force-converting steel component 8.

[0029] The straight web support beam 12 of the reinforced concrete truss 1 is provided with load-bearing steel plates 6 at the ends near the active pressure box device 3. The width B and height H of the load-bearing steel plates 6 match the ends of the straight web support beam 12 of the reinforced concrete truss 1.

[0030] The two ends of the large-tonnage jack 5, namely the driving end and the fixed end, are connected to the load-bearing steel plates 6 at the ends of the straight web support beams 12 on both sides.

[0031] After the large-tonnage jack 5 applies active pressure in stages to the load-bearing steel plate 6, several force-changing steel components 8 are arranged between the two load-bearing steel plates 6, and the outside of the force-changing steel components 8 is wrapped by a closed steel plate 7.

[0032] Below the active pressure box device 3 between the straight web support beams 12 on both sides, there is a camel beam 9, which bears the load at the end of the truss by vertical support.

[0033] Below the camel beam 9, there is a column 10 for supporting the camel beam 9 and the reinforced concrete truss 1.

[0034] The load-bearing steel plate 6 is pre-installed (welded) with steel reinforcement connectors. The length of the pressure box is designed according to the selected large-tonnage jack 5, and the closed steel plate 7 and the force-changing steel parts 8 are processed.

[0035] Gaskets 13 are provided between the driving end and the fixed end of the large-tonnage jack 5 and the load-bearing steel plate 6. The gaskets 13 are made of high-strength wear-resistant material, and their thickness is precisely calculated according to the model of the large-tonnage jack 5 and the loading pressure to ensure that stress can be effectively dispersed during loading, and to avoid stress concentration at the contact surface between the load-bearing steel plate 6 and the large-tonnage jack 5, thereby protecting the structural integrity.

[0036] In this embodiment, the force-changing steel component 8 is a solid Q235a steel column, and the closed steel plate 7 is also made of Q235a steel. Q235a steel has good mechanical properties and processing performance. Its yield strength and tensile strength can meet the stress requirements during the active pressure loading process. At the same time, it is easy to perform cutting, welding and other processing operations, ensuring that the connection between the force-changing steel component 8 and the closed steel plate 7 is firm and reliable, and guaranteeing the overall strength and rigidity of the active pressure box device 3. The large-tonnage jack 5 has a stroke greater than 15cm and a maximum loading force greater than 3 / 4 of the calculated axial force. The stroke is designed to meet the large compression deformation requirements that the truss may generate during the loading process, ensuring that sufficient stroke can be provided to achieve the preset active pressure loading amount. The loading force requirement takes into account various load combinations and stress conditions that may exist in actual engineering. By reserving a certain safety reserve, it is ensured that the active pressure box device 3 can stably and effectively apply active pressure to the straight web support beam 12, thereby achieving pre-compression control of the reinforced concrete truss 1.

[0037] After the active pressure box device 3 is processed, the processing quality should be checked. The weld of the steel bar connector should meet the requirements of the second-level weld. When installing the formwork steel bars before pouring the reinforced concrete truss 1, the closed steel plate 7 at the bottom of the design position should be installed in place.

[0038] After the camel beam 9 is poured first, the reinforcing steel and the large-tonnage jack 5 are installed. Before the large-tonnage jack 5 is pressurized, the reinforced concrete truss 1 can slide relative to the camel beam 9. After the pressure is applied and stabilized, the reinforced concrete truss 1 is fixed to the camel beam 9 and the column 10 to form a stable truss system.

[0039] The active pressure box device 3 is loaded to the design value. The displacement dimensions of the load-bearing steel plate 6 are measured, and the reinforcing bars and force-changing steel components 8 are processed and installed and fixed. The connecting stabilizer 4 is connected using micro-expansion concrete or grout. After the strength reaches the design value, the large-tonnage jack 5 and its support are removed, the reinforcing bars are tied, the side steel plates of the active pressure box device 3 are installed, micro-expansion concrete or grout is poured, the top steel plate of the active pressure box device 3 is sealed, and the reinforced concrete structural truss 1 and the camel beam 9 are anchored to form a solid connection. After the large-tonnage jack 5 is loaded, the stabilizer 4 is installed, and the large-tonnage jack 5 is removed only after the design strength is reached.

[0040] According to the design, the load is applied in stages while the deformation of the components is measured. The total load value should exceed the design load value by 10%. A large-tonnage jack 5 is used to apply load to the active pressure box device 3. Each load is 1 / 5 of the total value. After resting for 5 minutes, the pressure gauge value is observed. After measuring the deformation value, the pressure is increased by another 1 / 5. After resting for 5 minutes, the pressure gauge value is observed. The deviation between the measured load force and deformation and the theoretical calculation is within 5%. The reinforced concrete truss 1 is in normal working condition.

[0041] The practical application of this embodiment in engineering is described below: A 600mm x 800mm main support truss beam with a cross-section of 600T is used to support the second layer of a 12m deep foundation pit with reinforced concrete (C35) and a compressive force of 600T. The truss is 66m long, and the controlled compressive deformation is 10mm (at the ends), or 0.0303%. The hardening shrinkage deformation is 66m x 0.3mm / m = 19.8mm. The compressive deformation under stress is: δ=LxN / G=66mx600x1000x10n / (600mmx800mm) / (3.15MPax10000)=26.19mm In the above formula: L: length of the component, N: compressive internal force of the component, G: elastic modulus of C35 concrete.

[0042] The combined deformation of the two items is 19.8mm + 26.19mm = 45.99mm, and the end displacement is 45.99 / 2 = 22.995mm, exceeding the design deformation control value. To eliminate hardening shrinkage deformation and the 12.995mm of compressive deformation under stress, an active pressure box is used to compress the stressed component. The required loading force is: P=δxAxG=12.995mmx600mmx800mmx3.15MPax10000 / (66mx1000x10n)=297.703T In the above formula: P: load, δ: compression deformation, A: cross-sectional area of ​​the component, G: elastic modulus of C35 concrete.

[0043] Once the design loading force and preset deformation control values ​​are reached, excavation of the foundation pit can commence. During the excavation and internal support work, the deformation and pressure changes of the supports should be continuously monitored. Within the design variation range, the support system can continue to function without affecting its operation.

[0044] Another application scenario in engineering is the internal forces of components under normal operating conditions: N=P / A=600x1000x10n / (600mmx800mm)=12.5MPa In the above formula: N: internal force, P: load, A: cross-sectional area of ​​the component.

[0045] The compressive deformation is 26.19 mm. If active pressure is applied to increase the internal force of the member to 15 MPa (within the allowable range of the specification), and half the load is applied, the member cross-section is as follows: A=NxP=15 / 2MPax600mmx800mm=360T,300T / 7.5MPa=400000mm2 In the above formula: A: cross-sectional area of ​​the component, N: internal force, P: load.

[0046] Compared to the original cross-section, 400,000 / (600 x 800) = 83.33% The design application of this utility model is as follows: The active pressure box device 3 is pre-installed on the supporting truss according to the design. Loading of the active pressure box device 3 begins once the truss structure strength reaches the design value. After the active pressure box device 3 and its stabilizing components 4 are poured, the design bearing capacity is reached, allowing for earthwork excavation. The pressure caused by the inward deformation after the excavation is first borne by the pre-jacking force, then compresses the supporting components. Within the designed deformation range, the deformation of the reinforced concrete supporting structure is much smaller. Taking a 66m long, 600mm x 800mm cross-section C35 reinforced concrete supporting beam as an example, calculations show that an active load of 297.703T can eliminate concrete shrinkage deformation and compress the supporting components by 12.995mm. The 297.703T active thrust generated before the internal support is subjected to force can offset the inward deformation after the foundation pit deformation, or fully utilize the component's bearing capacity by reducing the component's cross-section (corresponding stability calculations are required).

[0047] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A reinforced concrete truss structure employing an active pressure box device, characterized in that: A stabilizing beam (2) is arranged laterally at the joint of the inclined web support beam (11) of the reinforced concrete truss (1) located in the foundation pit, and an active pressure box device (3) is arranged at the joint of the straight web support beam (12) of the reinforced concrete truss (1). The active pressure box device (3) applies active pressure to the straight web support beam (12); Several stabilizing elements (4) are arranged between the stabilizing beams (2).

2. The reinforced concrete truss structure employing an active pressure box device according to claim 1, characterized in that: The active pressure box device (3) includes a large-tonnage jack (5) and a load-bearing steel plate (6). The straight web support beam (12) is provided with load-bearing steel plates (6) at the ends near the active pressure box device (3). The driving end and the fixed end of the large tonnage jack (5) are respectively connected to the load-bearing steel plates (6) at the ends of the straight web support beam (12) on both sides.

3. The reinforced concrete truss structure employing an active pressure box device according to claim 2, characterized in that: The active pressure box device (3) also includes a closed steel plate (7) and a force-converting steel component (8). After the large-tonnage jack (5) applies active pressure to the load-bearing steel plate (6) in stages, several force-changing steel components (8) are arranged between the two load-bearing steel plates (6), and the outside of the force-changing steel components (8) is wrapped by a closed steel plate (7).

4. The reinforced concrete truss structure employing an active pressure box device according to claim 1, characterized in that: A camel beam (9) is provided below the active pressure box device (3).

5. The reinforced concrete truss structure employing an active pressure box device according to claim 4, characterized in that: The camel beam (9) is provided with a column (10) for supporting the camel beam (9) and the reinforced concrete truss (1).

6. The reinforced concrete truss structure employing an active pressure box device according to claim 2, characterized in that: Gaskets (13) are provided between the driving end and the fixed end of the large-tonnage jack (5) and the load-bearing steel plate (6).

7. The reinforced concrete truss structure employing an active pressure box device according to claim 3, characterized in that: The material of the closed steel plate (7) is Q235a steel plate.

8. The reinforced concrete truss structure employing an active pressure box device according to claim 3, characterized in that: The force-changing steel component (8) is a solid Q235a steel column.

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