Novel large-span beam string structure

Abstract

The invention relates to a novel large-span beam string structure which comprises an active prestress device, a supporting rod, a steel strand, a passive prestress device and a support beam. A smooth groove surface and a second limiting bolt are arranged at the tail end of the supporting rod, and a steel strand groove is defined by the smooth groove surface and the second limiting bolt; the front ends of the supporting rods are connected with the passive prestress devices, and the passive prestress devices act on the enclosure beams. The steel strand penetrates through the steel strand grooves, and the two ends of the steel strand penetrate through the embedded sleeves on the enclosure beams and are connected with the active prestress device. One side face of the supporting rod is fixedly connected with one side face of the angle steel, a limiting groove hole is formed in the other side face of the angle steel, a first limiting bolt fixedly arranged on the supporting rod is clamped into the limiting groove hole, the first limiting bolt can slightly slide along the limiting groove hole, and the angle between the supporting rod and the enclosure beam is slightly adjusted along with the supporting rod. The first limiting bolt plays a role in stress and self-adaptive adjustment at the same time.

Description

Technical Field

[0001] The invention relates to a novel large-span beam string structure for large-span support of a foundation pit, and belongs to the technical field of building construction, in particular to the technical field of foundation pit beam string. Background Art

[0002] With the continued advancement of urban construction, the demand for land and space has grown dramatically. This has led to the continuous expansion of foundation pit projects, characterized by deeper excavation depths, larger areas, and increasingly complex surrounding environments. Under the constraints of relevant laws and regulations, coupled with the complex and ever-changing surrounding environment of construction sites, pile-anchor support has been fraught with difficulties in practical application. Consequently, internal support has gradually become the predominant method of foundation pit support.

[0003] While concrete supports offer advantages in terms of rigidity and cost-effectiveness for foundation pit support, they also have significant drawbacks. Construction cycles are long due to the need for formwork, concrete pouring, and prolonged curing, which severely restricts excavation progress. Concrete support beams are typically large in cross-section, occupying significant space within the foundation pit, hindering the efficient operation of earthmoving machinery and impacting the construction of the main structure. These supports are non-reusable and difficult to remove. The crushing process of high-strength concrete generates significant construction waste, accompanied by vibration, dust pollution, and the risk of working at height. Their design has limited adaptability; once cast, they cannot be adjusted, making it difficult to effectively respond to geological changes or design changes. Furthermore, their environmental performance is insufficient, as cement production itself is an energy-intensive and high-emission process, and post-demolition waste disposal poses significant challenges. The heavy and solid nature of concrete supports is particularly disadvantageous in projects with tight deadlines, limited space, stringent environmental requirements, or complex geological conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a novel, long-span beam string structure. By integrating a series of technical measures, a long-span beam string is achieved, thereby reducing the use of steel supports and formwork, thereby improving construction efficiency and shortening the construction period. Furthermore, the beam string and prestressing device are fully assembled, allowing for easy disassembly and reuse, thus enhancing environmental performance. Dual prestressing, through active prestressing (steel strands) and passive prestressing (jacks), enhances the strength and adaptability of the beam string, allowing for effective response and adjustment to sudden geological changes or design changes. Small lateral displacements of sliding bolts are used to reduce local stress and further enhance adaptability. In summary, this invention addresses the aforementioned issues with concrete supports.

[0005] The present invention specifically adopts the following technical means: A novel large-span tensioned beam structure comprises an active prestressing device 1, a strut 6, a steel strand 5, a passive prestressing device 4, and a support beam 7; the tail end of the strut 6 is provided with a smooth groove surface 602a and a second limit bolt 601, which form a steel strand groove 602; the front end of the strut 6 is connected to the passive prestressing device 4, which acts on the enclosure beam 2; the steel strand 5 passes through each steel strand groove 602, and both ends pass through the embedded sleeve 9 on the enclosure beam 2 and are connected to the steel strand groove 602. The active prestressed device 1 is connected; one side of the strut 6 is fixedly connected to one side of the angle steel 301, and a limiting slot 301a is provided on the other side of the angle steel 301. The first limiting bolt 302 fixedly arranged on the strut 6 is inserted into the limiting slot 301a. The first limiting bolt 302 can slide slightly along the limiting slot 301a, and the strut 6 will adjust the angle with the guard beam slightly accordingly. The first limiting bolt 302 plays the role of force bearing and adaptive adjustment at the same time.

[0006] Preferably, the smooth groove surface 602a is an arc-shaped surface.

[0007] Preferably, it also includes a fixed plate 10 and several sliding bolts 13; the passive prestressed device 4 includes a jack 401, and the first piston rod 403 of the jack is connected to the pressure sensor 404, and the pressure sensor 404 is in the shape of a plate with several through holes evenly arranged thereon; the fixed plate 10 is provided with several horizontal countersunk holes, and the sliding bolts 13 are inserted from the countersunk holes, pass through the fixed plate 10 and the through holes in turn, and are fixedly connected to the threaded section of the sliding bolts 13 using the first nut 14; the embedded rebar 11 with a threaded section at the outer end is embedded on the guard beam 2, and the embedded rebar 11 passes through the preset opening on the fixed plate 10 and is fixedly connected to the threaded section of the embedded rebar 11 using the second nut 15; when the passive prestressed device 4 is pressurized, the pressure sensor 404 can slide slightly laterally along the countersunk holes.

[0008] Furthermore, the countersunk hole has a waist-shaped stepped hole structure, and the bolt head of the sliding bolt 13 is sunk into the waist-shaped stepped hole, and the bolt head does not protrude from the fixing plate 10.

[0009] Preferably, the passive prestressed device 4 has a prestressed node groove 402, two jacks 401 are arranged side by side in the prestressed node groove 402, the pressure sensor 404 is circular plate-shaped and corresponds one-to-one with the jack 401, and four sliding bolts 13 are passed through a single pressure sensor 404.

[0010] Furthermore, the brace 6 has the same width as the prestressed node groove 402 and maintains the same width in the length direction.

[0011] Preferably, the support beam 7 is supported by a column 8 .

[0012] Preferably, the active prestressed device 1 includes a perforated jack 104 sleeved on the outside of the steel strand 5, a first anchor 102, a second anchor 105, a guide member 103, and a clip 101; the clip 101 is conical and can be inserted into the small holes of the first anchor 102 and the second anchor 105 to achieve locking; the second piston rod 104b of the perforated jack 104 is facing the second anchor 105, and the tail push rod 104a of the perforated jack 104 is against the prefabricated pier on the guard beam 2; the guide member 103 is a split and detachable structure, located between the perforated jack 104 and the first anchor 102, and is used to prevent the clip 101 on the first anchor 102 from falling off and to guide the steel strand 5.

[0013] The beneficial effects of the present invention are: 1) Dual prestressing methods: one is to actively tension the steel strands through an active prestressing device to achieve prestressing, and the other is to extend the struts through a passive prestressing device (jacking), thereby passively tensioning the steel strands and applying prestress, which has a better prestressing effect; 2) Using steel strands instead of steel tie rods as the tensile components of the beam string allows for more balanced force distribution, enabling the construction of long-span beam string structures. This large-span beam string provides a larger working surface for construction, significantly reducing the use of concrete supports within the foundation pit. Installation and removal are quick and easy, energy-efficient, and environmentally friendly, shortening construction cycles. 3) In the design using steel strands, angle steel 301 is fixed to the strut 6, and a first limiting bolt 302 is provided on the support beam 7. Both can realize the function of bearing force, and because the force is applied at a single point, small changes in the angle of the strut 6 can be achieved, thereby improving adaptability; 4) As a preferred solution, by providing a countersunk hole on the fixed plate, the sliding bolt together with the pressure sensor can make a small lateral sliding movement under the limitation of the countersunk hole, which can improve the adaptability and reduce local stress.

[0014] 5) All components, including the fixed plate, passive prestressing device, and active prestressing device, are assembled and recyclable, eliminating construction waste. The structural design can be promptly changed based on project changes, ensuring high adaptability and flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is an overall schematic diagram of a novel large-span beam string structure of the present invention.

[0016] Figure 2 This is a partial enlarged view of one of the support poles.

[0017] Figure 3 This is a partial enlarged view of one of the passive prestressing devices.

[0018] Figure 4 This is an enlarged view of the back side of one of the passive prestressing devices.

[0019] Figure 5 It is a schematic diagram of the passive prestressing device's jacks, prestressed node slots and other structures.

[0020] Figure 6 It is a schematic diagram of the connection between the passive prestressing device and the fixed plate.

[0021] Figure 7 This is an enlarged view of the steel strand trough at the end of the strut.

[0022] Figure 8 It is a structural diagram of the active prestressing device.

[0023] Figure 9 This is an enlarged detail of the installation location of the active prestressing device.

[0024] In the figure, 1. Active prestressing device, 2. Enclosing beam (crown beam or waist beam), 3. Limiting device, 4. Passive prestressing device, 5. Steel strand, 6. Strut, 7. Support beam, 8. Column, 9. Embedded casing, 10. Fixing plate, 11. Embedded rebar, 13. Sliding bolt, 14. First nut, 15. Second nut; 101. Clip, 102. First anchor, 103. Guide member, 104. Perforated jack, 105. Second anchor, 104a. Push rod, 104b. Second piston rod; 301. Angle steel, 302. First limiting bolt, 301a. Limiting slot; 401. Jack, 402. Prestressed node slot, 403. First piston rod, 404. Pressure sensor, 405. Hexagon socket bolt; 601. Second limit bolt, 602. Steel strand groove, 602a. Smooth groove surface. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] See also Figure 1 This embodiment introduces a large-span beam string structure, which includes several parts such as an active prestressing device 1, a strut 6, a steel strand 5, a passive prestressing device 4, and a support beam 7.

[0027] The function of achieving a "large span" is mainly because the steel strand 5 is used to replace the steel tie rods of the ordinary tension beam in the foundation pit. The force on the steel strand 5 is more uniform, which is conducive to achieving a large span tension beam, thereby reducing the use of steel supports in the foundation pit.

[0028] See also Figure 2 and Figure 7 The tail end of the support rod 6 is provided with a smooth groove surface 602a and a second limiting bolt 601, which form a steel strand groove 602 for the steel strand to pass through.

[0029] See also Figure 1 and Figure 2 The front end of the support rod 6 is connected to the passive prestressing device 4, which acts on the enclosure beam 2 (which can be a crown beam or a waist beam); the steel strand 5 passes through each steel strand groove 602, and both ends pass through the embedded sleeve 9 on the enclosure beam 2 and are connected to the active prestressing device 1; See also Figure 2 , one side of the strut 6 is fixedly connected to one side of the angle steel 301, and a limiting slot 301a is provided on the other side of the angle steel 301. The first limiting bolt 302 fixedly provided on the strut 6 is inserted into the limiting slot 301a. The first limiting bolt 302 can slide slightly along the limiting slot 301a, and the strut 6 can adjust the angle with the guard beam slightly accordingly. The first limiting bolt 302 plays the role of both force bearing and adaptive adjustment. Here, the angle steel 301 with the limiting slot 301a replaces the clamp commonly used in the prior art. Compared with the clamp, the angle steel 301 has a stronger force bearing capacity, and because it is a single-point force bearing, combined with the sliding effect of the movement of the steel strand in the steel strand groove, the strut 6 can be adaptively fine-tuned in angle.

[0030] In this embodiment, preferably, the smooth groove surface 602a is an arc-shaped surface.

[0031] See also Figure 4-6 , further comprising a fixing plate 10 and a plurality of sliding bolts 13; the passive prestressing device 4 comprises a jack 401, a first piston rod 403 of the jack being connected to a pressure sensor 404, the pressure sensor 404 being in the shape of a plate with a plurality of through holes evenly arranged thereon; the fixing plate 10 is provided with a plurality of transverse countersunk holes, the sliding bolts 13 are inserted from the countersunk holes, pass through the fixing plate 10 and the through holes in sequence, and are fixedly connected to the threaded section of the sliding bolts 13 using a first nut 14; Continue to see Figure 4-6 The guard beam 2 is pre-embedded with a threaded outer end of a pre-embedded anchor 11. The anchor 11 passes through a pre-set opening in the fixing plate 10 and is fixedly connected to the threaded section of the anchor 11 using a second nut 15. When the passive prestressing device 4 applies pressure, the pressure sensor 404 can slightly slide laterally along the countersunk slot. This enhances the self-adjusting capability of the passive prestressing device, reduces local stress, improves adaptability, and contributes to the structural stability of long-span beam-string systems.

[0032] Specifically, the countersunk hole is a waist-shaped stepped hole. The bolt head of the sliding bolt 13 is sunk into the waist-shaped stepped hole, and the bolt head does not extend out of the fixing plate 10. Figure 4 , but the figure does not show the structure inside the stepped hole in detail.

[0033] See also Figure 5 The passive prestressing device 4 has a prestressed node groove 402, in which two jacks 401 are arranged side by side. The pressure sensor 404 is in a circular plate shape and corresponds one-to-one with the jack 401. Four of the above-mentioned sliding bolts 13 are passed through a single pressure sensor 404.

[0034] Combine Figure 1 It can be seen that the brace 6 has the same width as the prestressed node slot 402 and maintains the same width in the length direction. This structure actually thickens the brace, which can enhance the overall strength of the brace, is convenient for manufacturing, and has better stress stability.

[0035] Continue to see Figure 1 , the support beam 7 is supported by the column 8.

[0036] See also Figure 8-9 The active prestressing device 1 includes a perforated jack 104 sleeved on the outside of the steel strand 5, a first anchor 102, a second anchor 105, a guide member 103, and a clip 101; the second piston rod 104b of the perforated jack 104 faces the second anchor 105, and the tail mandrel 104a of the perforated jack 104 abuts against the precast pier on the guard beam 2; The clip 101 is conical. During the specific operation, the clip 101 is first manually inserted into the small hole of the second anchor 105, and the second anchor 105 is placed near the second piston rod 104b. Then the perforated jack 104 is opened, and the clip 101 quickly locks the second anchor 105 on the left; with the jacking action of the jack, the top rod 104a applies force to the pier on the guard beam, and the first anchor 102 on the right is also locked by the corresponding clip 101, thereby realizing the locking function; wherein, the guide member 103 is a split-type detachable structure, located between the perforated jack 104 and the first anchor 102, and is used to prevent the clip 101 on the first anchor 102 from falling off and to guide the steel strand 5.

[0037] The prestressing system of the present invention primarily consists of two hydraulic systems: a through-type jack and a transverse jack. These two systems can be used collaboratively or independently to meet different working conditions. A pressure sensor connected to the transverse jack can monitor the prestressing value of the steel struts in real time, thereby determining the performance of the entire prestressing system.

[0038] The present invention adopts a dual prestressing method. One method is to actively tension the steel strands through an active prestressing device to achieve prestressing. The other method is to extend the struts through a passive prestressing device (jacking) to achieve passive tensioning of the steel strands and thus apply prestressing. The effect of prestressing is better. Using steel strands instead of steel tie rods as the tensile components of the beam string allows for more balanced force distribution, enabling the construction of long-span beam string structures. This large-span beam string provides a larger working surface for construction, significantly reducing the use of concrete supports in the foundation pit. Installation and removal are quick and easy, energy-efficient, and environmentally friendly, shortening construction cycles. In the design using steel strands, angle steel 301 is fixed on the strut 6, and a first limiting bolt 302 is provided on the support beam 7. Both can realize the function of bearing force, and due to the single-point force, a small change in the angle of the strut 6 can be realized, thereby improving the adaptability. As a preferred solution, by providing a countersunk hole on the fixed plate, the sliding bolt together with the pressure sensor can make a small lateral sliding movement under the limitation of the countersunk hole, which can improve the adaptability and reduce local stress.

[0039] All components, including the fixed plate, passive prestressing device, and active prestressing device, are assembled and recyclable, eliminating construction waste. The structural design can be promptly changed based on project changes, ensuring high adaptability and flexibility.

[0040] The above are preferred embodiments of the present invention. Those skilled in the art may also make various changes or improvements thereon. Without departing from the overall concept of the present invention, these changes or improvements should fall within the scope of protection claimed by the present invention.

Claims

1. A novel long-span beam string structure, characterized by: It includes an active prestressing device (1), a support rod (6), a steel strand (5), a passive prestressing device (4), and a support beam (7); The rear end of the support rod (6) is provided with a smooth groove surface (602a) and a second limiting bolt (601), which enclose a steel strand groove (602); the front end of the support rod (6) is connected to the passive prestressing device (4), and the passive prestressing device (4) acts on the enclosure beam (2); The steel strands (5) pass through the respective steel strand grooves (602), and both ends pass through the embedded sleeves (9) on the enclosure beam (2) and are connected to the active prestressing device (1); One side of the support rod (6) is fixedly connected to one side of the angle steel (301), and a limiting slot hole (301a) is provided on the other side of the angle steel (301). A first limiting bolt (302) fixedly arranged on the support rod (6) is inserted into the limiting slot hole (301a). The first limiting bolt (302) can slide slightly along the limiting slot hole (301a), and the support rod (6) can adjust the angle with the surrounding beam slightly accordingly. The first limiting bolt (302) plays the role of both force bearing and self-adaptive adjustment.

2. The novel long-span beam string structure according to claim 1, characterized in that: The smooth groove surface (602a) is an arc-shaped surface.

3. The novel long-span beam string structure according to claim 1, characterized in that: It also includes a fixing plate (10) and a plurality of sliding bolts (13); The passive prestressing device (4) includes a jack (401), a first piston rod (403) of the jack is connected to a pressure sensor (404), and the pressure sensor (404) is in a plate shape with a plurality of through holes evenly arranged thereon; The fixing plate (10) is provided with a plurality of transverse countersunk holes, and the sliding bolt (13) is inserted from the countersunk holes, passes through the fixing plate (10) and the through hole in sequence, and is fixedly connected to the threaded section of the sliding bolt (13) using a first nut (14); The guard beam (2) is pre-embedded with a pre-embedded rebar (11) having a threaded section at the outer end, the pre-embedded rebar (11) passing through a preset opening on the fixing plate (10), and being fixedly connected to the threaded section of the pre-embedded rebar (11) by a second nut (15); When the passive prestressing device (4) applies pressure, the pressure sensor (404) can slide slightly laterally along the countersunk-type recessed hole.

4. The novel long-span beam string structure according to claim 3, characterized in that: The countersunk hole has a waist-shaped stepped hole structure, and the bolt head of the sliding bolt (13) is sunk into the waist-shaped stepped hole, and the bolt head does not protrude from the fixing plate (10).

5. The novel long-span beam string structure according to claim 3, characterized in that: The pressure sensor (404) is fixedly connected to the first piston rod (403) of the jack (401) via a hexagon socket bolt (405) at the center.

6. The novel long-span beam string structure according to claim 5, characterized in that: The passive prestressing device (4) has a prestressing node groove (402), two jacks (401) are arranged in parallel in the prestressing node groove (402), the pressure sensor (404) is in a circular plate shape and corresponds one-to-one with the jacks (401), and four sliding bolts (13) are passed through a single pressure sensor (404).

7. The novel long-span beam string structure according to claim 4, characterized in that: The bracing rod (6) has the same width as the prestressed node groove (402), and maintains the same width in the length direction.

8. The novel long-span beam string structure according to claim 1, characterized in that: The support beam (7) is supported by a column (8).

9. The novel long-span beam string structure according to claim 1, characterized in that: The active prestressing device (1) comprises a perforated jack (104) sleeved on the outside of the steel strand (5), a first anchor (102), a second anchor (105), a guide member (103), and a clip (101); The clip (101) is tapered and can be inserted into the small holes of the first anchor (102) and the second anchor (105) to achieve locking; The second piston rod (104b) of the perforated jack (104) faces the second anchor (105), and the tail top rod (104a) of the perforated jack (104) abuts against the prefabricated pier on the guard beam (2); The guide member (103) is a split, detachable structure, located between the perforated jack (104) and the first anchor (102), and is used to prevent the clip (101) on the first anchor (102) from falling off and to guide the steel strand (5).

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