Detachable force transmission rod device in post-pouring belt after basement reverse construction and use method thereof

Abstract

The basement post-construction strip post-tensioning device and use method of the basement post-construction strip post-tensioning device belong to the technical field of building structure engineering, and comprise a profile steel, an end plate, an adjusting bolt, a pressure transmission piece and a device use method; the application further releases additional internal force on both sides of the post-construction strip caused by the post-tensioning device by removing the bolt and the pressure transmission piece before the post-construction strip is poured with concrete, the quality is controllable, the purpose of the post-construction strip is fully achieved, the vertical deformation difference of the structure on both sides of the post-construction strip is transmitted by the bending deformation of the bolt rod between the end plates, the vertical shear stiffness of the device is reduced, the free settlement of the structure on both sides of the post-construction strip is adapted, and the additional internal force of the structure caused by the vertical deformation difference is reduced; the bolt and the pressure transmission piece are very convenient to install and remove, the removed bolt and other components can be repeatedly used, and the application is economical and environment-friendly; the application is suitable for various cast-in-place and fabricated concrete structure post-construction strip positions needing to transmit lateral earth pressure in the basement top-down method structure.

Description

Technical Field

[0001] This invention belongs to the field of building structure engineering technology, and specifically relates to a detachable force transmission rod device installed in the post-cast strip of the main structure during construction to support the pressure of the retaining wall. Background Technology

[0002] In the reverse construction of basements in deep foundation pits, the main structure of the basement must not only bear the lateral earth pressure transmitted from the support structure or retaining wall, but also cope with problems such as concrete shrinkage, uneven settlement and temperature stress caused by excessive length and other factors.

[0003] Typically, post-cast strips are required in the main structure. These strips divide large-volume or ultra-long concrete structures into several sections. The post-cast strip concrete is poured after the previously poured concrete has largely shrunk, releasing the earlier deformation. However, in foundation pit engineering, the presence of post-cast strips can prevent the effective transmission of soil pressure borne by the support structure or basement continuous wall. Therefore, dowel bars need to be installed at intervals within the post-cast strip to connect the horizontal structural members on both sides, such as beams and thick slabs, to improve structural rigidity. These components ensure smooth pressure transmission and resist lateral thrust from the soil.

[0004] In current engineering practice, the structures on both sides of the post-cast strip need to bear the vertical loads during construction and the vertical deformation forces caused by the rebound of the basement soil. Therefore, there is a certain degree of difference in vertical deformation between the structures on both sides of the post-cast strip. This requires that the dowel bars not only transmit soil pressure and release the tensile force generated by concrete shrinkage, but also release the vertical shear force between the post-cast strips to prevent local damage caused by the additional internal forces of the structure due to the shear stiffness of the dowel bars after the post-cast strip is poured.

[0005] Therefore, there is a need for a force transmission device that can effectively resist the soil pressure of the retaining wall during the construction phase and also release a certain amount of tensile and shear deformation of the main structure. This device can be quickly disassembled before the post-pouring strip is poured to further release tensile, compressive and shear forces, thereby adapting to the deformation requirements on both sides of the post-pouring strip and being easy to install. Summary of the Invention

[0006] The purpose of this invention is to provide a force transmission rod device that overcomes the problems of the prior art.

[0007] A detachable dowel bar device for post-cast strip in reverse construction of basement, characterized in that it includes steel profiles, end plates, adjusting bolts, and pressure transmission components. The number of steel sections is two, and each of the two steel sections has an end plate at one end and a free end at the other end; Bolt holes are provided on the two end plates respectively, and the diameter of the bolt holes is 2mm larger than the diameter of the adjusting bolt; the adjusting bolt passes through the corresponding bolt holes on the two end plates, and a nut is provided at the end of the adjusting bolt; a pressure transmission element is sleeved on the adjusting bolt; The free end of the steel section is embedded in the concrete beams or slabs on both sides of the post-cast strip, and the embedded length is the bonding anchorage length; and the weak axis of the steel section in the post-cast strip is parallel to the bottom surface of the foundation pit.

[0008] The steel profile is one of the following: I-beam, channel steel, and angle steel.

[0009] The number of adjusting bolts is four or more.

[0010] The pressure transmission component is a pressure spring or a steel sleeve.

[0011] When the pressure transmission component is a pressure spring, the nut is adjusted to cause the pressure transmission component between the two end plates to contract and deform.

[0012] When the pressure transmission component is a steel sleeve, the inner wall of the steel sleeve is provided with threads; the distance between the two end plates is the same as the length of the pressure transmission component, and a gap is reserved between the nut on one side and the end plate.

[0013] A method of using a dowel bar device, using a detachable anti-compression dowel bar device in the post-cast strip of any of the above-mentioned basement reverse construction, includes the following steps, which are performed in sequence: steel profile, end plate, adjusting bolt and pressure transmission component; S1. Based on the magnitude of the lateral earth pressure of the foundation pit, the width of the post-cast strip, the expected concrete shrinkage, and the difference in vertical deformation of the structures on both sides, the type of steel, the thickness of the end plate, the diameter of the adjusting bolt, and the stiffness or length of the pressure transmission component are determined by calculation. Bolt holes matching the size of the adjusting bolt are reserved on the end plate. The diameter of the bolt hole should be at least 2mm larger than the diameter of the adjusting bolt. S2. Weld one end of the steel section selected in step S1 to the corresponding end plate, and leave the other end of the steel section untreated. S3. Fix the free ends of the two steel sections to both sides of the post-pouring strip according to the design position to prevent the steel sections from shifting during concrete pouring; the pre-embedded length of the steel sections on both sides of the post-pouring strip should meet the bonding requirements, and the length of the steel sections in the post-pouring strip should ensure the gap between the end plates of the steel sections on both sides. S4. After pouring the concrete on both sides of the pouring strip, implement curing. During the pouring process, prevent the steel section from shifting. S5. Adjustable bolts are installed between the end plates of the steel section inside the post-cast strip, and pressure transmission components are fitted on them. S6. When the basement support structure deforms, the force transmission device transmits lateral earth pressure through the bearing pressure between the end plate and the pressure transmission component, thus becoming a lateral constraint of the support structure. When the concrete on both sides of the post-cast strip shrinks, the adjusting bolt is under tension, and the gap between the end plates increases. When there is a vertical deformation difference between the concrete on both sides, the adjusting bolt relies on bending deformation to be sheared. Its shear stiffness is relatively small, which can release a certain amount of differential deformation. S7. Before the post-cast strip is closed, the adjusting bolts and pressure transmission components of the force transmission device are removed in batches according to the needs of the support structure and the stress, so that the steel on both sides are completely separated and the constraint stress in the force transmission device is further released.

[0014] In step S6, when the pressure transmission component is a pressure spring, the spring extends and the pressure decreases. When the pressure transmission component is a steel sleeve, the squeezing force between the steel sleeve and the end plate decreases or disengages, thereby releasing a certain amount of tension, weakening the constraint on the structures on both sides, and reducing the additional stress caused by shrinkage.

[0015] Through the above design scheme, this application can further release the additional internal force brought about by the connection of the force transmission rods on both sides of the post-cast strip by removing the bolts and pressure transmission components before the concrete of the post-cast strip is poured. The quality is controllable, ensuring the full realization of the purpose of setting the post-cast strip. The vertical deformation difference between the two sides of the post-cast strip is transmitted by the bending deformation of the bolt rod between the end plates of this application, which reduces the vertical shear stiffness of the device, adapts to the free settlement of the two sides of the post-cast strip, and reduces the additional internal force brought to the structure by the vertical deformation difference. The bolts and pressure transmission components of this invention are very convenient to install and remove, and the removed bolts and other parts can be reused, which is economical and environmentally friendly. This application is applicable to the post-cast strip parts of various cast-in-place and prefabricated concrete structures that need to transmit lateral earth pressure in the reverse construction method of basement, and has good prospects for promotion and application. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: Figure 1 This is a schematic diagram of the structure of this application; Figure 2 yes Figure 1 The main view; Figure 3 yes Figure 1 Top view; Figure 4 yes Figure 1 Side view; Figure 5 This is an assembly diagram of the end plate, pressure transmission component, and adjusting bolts of this application; Figure 6 This is a schematic diagram of the steel sleeve structure of this application. Figure 1 ; Figure 7This is a schematic diagram of the steel sleeve structure of this application. Figure 2 ; Figure 8 This is a cross-sectional view of the present invention; In the diagram: 1-Steel section, 2-End plate, 3-Adjusting bolt, 4-Pressure transmission component. Detailed Implementation

[0017] A detachable dowel bar device for post-cast strip construction in basement reverse construction, characterized in that it includes a steel section 1, an end plate 2, an adjusting bolt 3, and a pressure transmission component 4; The number of steel sections 1 is two, and each of the two steel sections 1 has an end plate 2 at one end and a free end at the other end; Bolt holes are provided on the two end plates 2 respectively, and the diameter of the bolt holes is 2mm larger than the diameter of the adjusting bolt 3; the adjusting bolt 3 passes through the corresponding bolt holes of the two end plates 2, and a nut is provided at the end of the adjusting bolt 3; a pressure transmission element 4 is sleeved on the adjusting bolt 3; The free end of the steel section 1 is embedded in the concrete beams or slabs on both sides of the post-cast strip, and the embedded length is the bonding anchorage length; and the weak axis of the steel section 1 in the post-cast strip is parallel to the bottom surface of the foundation pit.

[0018] The steel section 1 is one of I-beams, channel steel, and angle steel.

[0019] The number of adjusting bolts 3 is four or more.

[0020] The pressure transmission component 4 is a pressure spring or a steel sleeve.

[0021] When the pressure transmission component 4 is a pressure spring, the nut is adjusted to cause the pressure transmission component 4 between the two end plates 2 to contract and deform.

[0022] When the pressure transmission component 4 is a steel sleeve, the inner wall of the steel sleeve is provided with threads; the distance between the two end plates 2 is the same as the length of the pressure transmission component 4, and a gap is reserved between the nut on one side and the end plate 2.

[0023] A method for using a dowel bar device, employing a detachable compressive dowel bar device in the post-cast strip of any of the aforementioned basement reverse construction methods, includes the following steps, performed sequentially: S1. Based on the magnitude of the lateral earth pressure of the foundation pit, the width of the post-cast strip, the expected concrete shrinkage, and the difference in vertical deformation of the structures on both sides, the model of the steel section 1, the thickness of the end plate 2, the diameter of the adjusting bolt 3, and the stiffness or length of the pressure transmission component 4 are determined by calculation. Bolt holes that match the size of the adjusting bolt 3 are reserved on the end plate 2. The diameter of the bolt holes should be at least 2mm larger than the diameter of the adjusting bolt 3. S2. Weld one end of the steel section 1 selected in step S1 to the corresponding end plate 2, and leave the other end of the steel section 1 untreated. S3. Fix the free ends of the two steel sections 1 to both sides of the post-pouring strip according to the design position to prevent the steel sections from shifting during concrete pouring; the pre-embedded length of the steel section 1 on both sides of the post-pouring strip should meet the bonding requirements, and the length of the steel section 1 in the post-pouring strip should ensure the gap between the end plates 2 of the steel sections 1 on both sides. S4. After pouring the concrete on both sides of the pouring strip, implement curing. During the pouring process, prevent the steel section 1 from being misaligned. S5. Adjustable bolts 3 are installed between the end plates 2 of the steel section 1 in the post-cast strip, and pressure transmission components 4 are sleeved on the adjusting bolts 3. S6. When the basement support structure deforms, the force transmission device transmits lateral earth pressure through the bearing pressure between the end plate 2 and the pressure transmission component 4, thus becoming a lateral constraint of the support structure. When the concrete on both sides of the post-cast strip shrinks, the adjusting bolt 3 is under tension, and the gap between the end plates 2 increases. When there is a vertical deformation difference between the concrete on both sides, the adjusting bolt 3 relies on bending deformation to be sheared. Its shear stiffness is relatively small, which can release a certain amount of differential deformation. S7. Before the post-cast strip is closed, the adjusting bolts 3 and pressure transmission components 4 of the force transmission device are removed in batches according to the needs of the support structure and the stress, so that the steel on both sides are completely separated and the constraint stress in the force transmission device is further released.

[0024] In step S6, when the pressure transmission component 4 is a pressure spring, the spring extends and the pressure decreases. When the pressure transmission component 4 is a steel sleeve, the squeezing force between the steel sleeve and the end plate 2 decreases or disengages, thereby releasing a certain amount of tension, weakening the constraint on the structures on both sides, and reducing the additional stress caused by shrinkage.

[0025] The end plates 2 welded to the ends of the two steel sections 1 are placed opposite each other in the post-pouring strip, and the distance between the end plates 2 corresponds to the reserved gap in the project. The strength grade, diameter, and end plate thickness of adjusting bolt 3 should be calculated and adopted according to the project conditions; Section 1 can be selected from one of I-beams, channel steel, and angle steel. The specific type of section 1 is determined by factors such as stress and the width of the post-pouring strip. When the pressure transmission component 4 uses a pressure spring, tightening the nut compresses the pressure spring to compress the steel section 1. When most of the horizontal pressure of the retaining wall is applied to the force transmission rod during construction, the nut can be loosened appropriately to further release the horizontal shrinkage deformation of the concrete. When the pressure transmission component 4 uses a steel sleeve, the distance between the gaps between the two end plates 2 is equal to the length of the steel sleeve 4, and a gap is reserved between the nut on one side and the end plate 2 to release the shrinkage tension of the concrete on both sides of the post-cast strip.

Claims

1. A detachable dowel bar device for post-cast strips in reverse construction of basements, characterized in that: Includes structural steel (1), end plate (2), adjusting bolt (3) and pressure transmission component (4); The number of the steel section (1) is two, and each of the two steel sections (1) has an end plate (2) at one end and a free end at the other end; Bolt holes are provided on the two end plates (2) respectively, and the diameter of the bolt holes is 2mm larger than the diameter of the adjusting bolt (3); the adjusting bolt (3) passes through the bolt holes corresponding to the two end plates (2), and a nut is provided at the end of the adjusting bolt (3); a pressure transmission component (4) is sleeved on the adjusting bolt (3). The free end of the steel section (1) is embedded in the concrete beams or slabs on both sides of the post-cast strip, and the embedded length is the bonding anchorage length; and the weak axis of the steel section (1) in the post-cast strip is parallel to the bottom surface of the foundation pit.

2. The detachable dowel bar device in the post-pouring strip of basement reverse construction according to claim 1, characterized in that: The steel section (1) is one of I-beams, channel steel, and angle steel.

3. The detachable dowel bar device in the post-pouring strip of basement reverse construction according to claim 1, characterized in that: The number of adjusting bolts (3) is four or more.

4. The detachable dowel bar device in the post-pouring strip of basement reverse construction according to claim 1, characterized in that: The pressure transmission component (4) is a pressure spring or a steel sleeve.

5. The detachable dowel bar device in the post-pouring strip of basement reverse construction according to claim 4, characterized in that: When the pressure transmission component (4) is a pressure spring, the nut is adjusted to cause the pressure transmission component (4) between the two end plates (2) to contract and deform.

6. The detachable dowel bar device in the post-pouring strip of basement reverse construction according to claim 4, characterized in that: When the pressure transmission component (4) is a steel sleeve, the inner wall of the steel sleeve is provided with threads; the distance between the two end plates (2) is the same as the length of the pressure transmission component (4), and a gap is reserved between the nut on one side and the end plate (2).

7. A method of using a dowel bar device, employing a detachable dowel bar device in the post-cast strip of a basement reverse construction as described in any of claims 1-6, comprising the following steps, performed sequentially: S1. Based on the magnitude of the lateral earth pressure of the foundation pit, the width of the post-cast strip, the expected concrete shrinkage, and the difference in vertical deformation of the structures on both sides, the model of the steel section (1), the thickness of the end plate (2), the diameter of the adjusting bolt (3), and the stiffness or length of the pressure transmission component (4) are determined by calculation. Bolt holes that match the size of the adjusting bolt (3) are reserved on the end plate (2). The diameter of the bolt hole should be more than 2mm larger than the diameter of the adjusting bolt (3). S2. Weld one end of the steel section (1) selected in step S1 to the corresponding end plate (2), and leave the other end of the steel section (1) untreated. S3. Fix the free ends of the two steel sections (1) to the two sides of the post-pouring strip according to the design position to prevent the steel sections from shifting during concrete pouring; the pre-embedded length of the steel section (1) on both sides of the post-pouring strip should meet the bonding requirements, and the length of the steel section (1) in the post-pouring strip should ensure the gap between the end plates (2) of the steel sections (1) on both sides. S4. After pouring the concrete on both sides of the pouring strip, implement curing. During the pouring process, prevent the steel section (1) from being misaligned. S5. An adjustable bolt (3) is installed between the end plates (2) of the inner steel section (1) of the post-cast strip, and a pressure transmission component (4) is sleeved on the adjusting bolt (3). S6. When the basement support structure deforms, the force transmission device transmits lateral earth pressure through the bearing pressure between the end plate (2) and the pressure transmission component (4), thus becoming the lateral constraint of the support structure. When the concrete on both sides of the post-cast strip shrinks, the adjusting bolt (3) is under tension, and the gap between the end plates (2) increases. When there is a vertical deformation difference between the concrete on both sides, the adjusting bolt (3) is under shear due to bending deformation. Its shear stiffness is small, and it can release a certain amount of differential deformation. S7. Before the post-cast strip is closed, the adjusting bolts (3) and pressure transmission components (4) of the force transmission device are removed in batches according to the needs of the support structure and the stress, so that the steel on both sides can be completely separated and the constraint stress in the force transmission device can be further released.

8. The construction and installation method of the force transmission rod device according to claim 7, characterized in that: In step S6, when the pressure transmission component (4) is a pressure spring, the spring is stretched and the pressure is reduced. When the pressure transmission component (4) is a steel sleeve, the squeezing force between the steel sleeve and the end plate (2) is reduced or separated, thereby releasing a certain tension, weakening the constraint on the structure on both sides, and reducing the additional stress caused by shrinkage.

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