A construction method for super-high transfer layer of frame-tube structure

Abstract

This invention relates to the field of civil construction technology. This method for constructing a super-high transfer layer in a frame-tube structure has a wider range of applications, including situations where concentrated line loads exceed 200 kN / m and where the transfer layer is located 10 or 20 stories or higher. By allowing the transfer components themselves to bear the load and by adding steel reinforcement to the floor slab below the transfer layer, the number of supporting layers at the bottom of the transfer layer is reduced, the turnover efficiency of circulating materials is improved, and construction costs are significantly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of civil engineering construction, and in particular to a construction method for a super-high position transfer layer of a frame-tube structure. Background Art

[0002] The structural transfer layer of a super-high-rise building is typically used to switch between upper and lower functional areas, such as between residential and commercial buildings, or between apartments and star-rated hotels. The design of the transfer layer requires detailed calculation of the lateral stiffness changes between the upper and lower structures. During construction, the transfer components are subjected to very large linear loads, requiring considerable investment of construction resources and a high level of attention to construction quality and safety. This is a key process and a difficult point in the structural construction phase. The Technical Code for Concrete Structures of High-Rise Buildings (JGJ-3) stipulates that the location of the transfer layer should not exceed three floors for an earthquake resistance level of 8, no more than five floors for an earthquake resistance level of 7, and can be appropriately increased for an earthquake resistance level of 6.

[0003] The Technical Code for Concrete Structures of High-Rise Buildings JGJ-3 stipulates that conversion structural components can be conversion beams, trusses, hollow trusses, box structures, diagonal braces, etc., and thick plates can be used in non-seismic design and 6-degree seismic design.

[0004] Transfer beams are the most commonly used transfer structural components at home and abroad. The concentrated line load is between 40kN / m and 120kN / m. The construction conditions of overweight transfer structural components, such as concentrated line loads above 200kN / m, have not been fully considered.

[0005] Traditional transfer layers are generally located at the 3rd to 5th floors, which is relatively low. Traditional construction methods do not fully consider the construction conditions of ultra-high transfer layers, such as when the transfer layer is located at the 10th or 20th floors or above.

[0006] The traditional transfer layer formwork engineering design does not take into account the transfer components' own participation in bearing the load, and the turnover material cost is high.

[0007] In traditional construction methods, the formwork and supports of multiple floors below the transfer layer are not removed first, which reduces the turnover efficiency of circulating materials and increases the cost of measures.

[0008] In the traditional control of large-volume concrete cracks, automatic monitoring of the internal temperature of large-volume conversion components is not carried out, and the temperature measurement efficiency is low. Summary of the Invention

[0009] In response to the shortcomings of the existing technology, the present invention provides a construction method for an ultra-high-position transfer layer of a frame-tube structure, which solves the problems of the existing transfer layer construction technology, such as the small scope of application, low transfer layer position, high construction cost, and difficult to control construction quality.

[0010] To achieve the above objectives, the present invention is implemented through the following technical solutions: A construction method for a super-high transfer layer of a frame-tube structure, comprising the following steps:

[0011] Determine the location of the transfer layer within the building according to the building structure, and carry out in-depth design and construction of the transfer layer structure;

[0012] Process and manufacture the transfer layer steel bars according to national standards;

[0013] Tie the steel bars of the floor slab of the next floor of the transfer layer in accordance with national standards and pour the concrete of the floor slab of the next floor;

[0014] Installing bottom layer formwork and bottom layer support below the conversion layer;

[0015] Installing the lower transfer beam and adjacent beam and slab reinforcement on the transfer layer, and pouring the first layer of concrete after passing the inspection;

[0016] When the concrete strength reaches a certain proportion of the design strength, the support at the bottom of the lower transfer beam is released and the top is returned;

[0017] Tie the steel bars at the shear wall of the transfer layer and pour the second layer of concrete after passing the inspection;

[0018] Installing a conversion layer template and a conversion layer support on the conversion layer;

[0019] Installing the upper transfer beam and adjacent beam and slab reinforcement on the transfer layer, and pouring the third layer of concrete after acceptance, so that the first layer of concrete, the second layer of concrete, and the third layer of concrete constitute a combined transfer component;

[0020] Preferably, the core tube portion (the core tube is reserved before construction, such as an elevator shaft or a stairwell) is higher than the transfer floor to facilitate the construction of the transfer floor.

[0021] Furthermore, the position of the transfer layer in the building is determined according to the building structure, and the transfer layer structure is further designed and constructed, including the following steps:

[0022] Determine the concrete pouring zones;

[0023] designing vertical joints between the first layer of concrete, the second layer of concrete, and the third layer of concrete constituting the transfer layer;

[0024] Preferably, the step width is determined according to specific circumstances to improve the integrity of the conversion layer;

[0025] Adding reinforcement to the horizontal joints between the upper transfer beam, the lower transfer beam and the shear wall;

[0026] Determine the number of supporting layers at the bottom of the transfer layer by computer software calculation, calculate the additional steel bars in the floor slab below the transfer layer, and determine the type and quantity of the additional steel bars;

[0027] Structural calculations and designs are performed on the installation, use, and removal of the formwork and support at the bottom of the combined conversion component, with emphasis placed on the structural calculations of the conditions where the lower conversion beam is cast and the combined conversion component is cast, to determine the specifications and models of the bottom formwork and the bottom support system.

[0028] Furthermore, when determining the concrete pouring partition, the lower conversion beam is poured together with the adjacent beam and slab, the upper conversion beam is poured together with the adjacent beam and slab, the shear wall is poured separately, and the plane partition of the conversion layer is determined according to the size of the building floor area and the total amount of concrete.

[0029] Furthermore, before the upper transfer beam and the lower transfer beam are cast, multiple sets of thermocouples are embedded in the upper transfer beam or the lower transfer beam, and a dedicated instrument is used to automatically monitor the temperature inside the concrete through the thermocouples, and a temperature curve is drawn to ensure that the temperature difference between each monitoring point is less than 25°C.

[0030] Preferably, a temperature difference of less than 25 degrees Celsius can prevent cracks in the concrete.

[0031] Furthermore, additional steel bars are added to the floor slab below the transfer layer, and the model and quantity of the additional steel bars are designed based on the requirement that only 1-2 layers of support need to be reinforced at the bottom.

[0032] Furthermore, calculations are made on the working conditions of each formwork during the construction of the transfer layer. When the concrete strength of the lower transfer beam reaches a certain proportion of the design strength, the support below the lower layer is first removed, the support at the bottom of the lower transfer beam is loosened and returned to the top. The load of the upper combined transfer component is then borne jointly by the lower transfer beam and the lower formwork and support.

[0033] Furthermore, the vertical joints between the first layer of concrete, the second layer of concrete and the third layer of concrete constituting the transfer layer are designed to be stepped.

[0034] Furthermore, the side formwork of the upper transfer beam or the lower transfer beam is removed after the internal temperature of the poured concrete reaches a peak value and when the temperature difference between the concrete surface temperature and the ambient temperature is less than 25°C. Beneficial effects

[0035] The present invention provides a method for constructing a super-high transfer layer in a frame-tube structure. This method has the following beneficial effects: It has a wider range of applicability, is applicable to situations with concentrated line loads exceeding 200 kN / m, and is applicable to situations where the transfer layer is located at the 10th or 20th floor or higher.

[0036] By having the conversion components themselves bear the load and adding steel bars in the floor slab below the conversion layer, the number of supporting layers at the bottom of the conversion layer is reduced, the turnover efficiency of circulating materials is improved, and the construction cost is greatly reduced.

[0037] After the temperature inside the poured concrete reaches its peak, the side formwork of the transfer beam is removed when the temperature difference between the concrete surface temperature and the ambient temperature is less than 25°C. Multiple sets of thermocouples are embedded inside the large-volume transfer component, and special instruments are used to automatically monitor the internal temperature of the concrete. Temperature curves are drawn to assist construction, and the temperature differences between each monitoring point are compared to avoid cracks in the concrete and ensure project quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a side view of the frame-tube structure conversion layer of the present invention.

[0039] Figure 2 It is a cross-sectional view of the frame-tube structure conversion component of the present invention.

[0040] Figure 3 This is a layered diagram of concrete pouring for the conversion component of the present invention.

[0041] Figure 4 Schematic diagram of a stepped construction joint according to the present invention. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] By those skilled in the art, the components in this case are connected in sequence. The specific connection and operation sequence should refer to the following working principle. The detailed connection means are well-known technologies in this field. The following mainly introduces the working principle and process.

[0044] See also Figure 1-4 The present invention provides a technical solution: taking the frame core tube structure transfer layer on the 24th floor as an example, the height from the ground is 98m, the transfer layer is 38m long, 34.6m wide and 7m high, and the combined transfer component is C-shaped, consisting of a lower transfer beam, an intermediate shear wall and an upper transfer beam, as shown in the attached figure. Figure 2 The upper and lower transfer beams are 1.5m high and 1.5m wide. The concrete strength grade of the composite transfer components is C40, while the concrete strength grade of the ordinary beam and slab is C30. Through the transfer layer conversion, the frame columns are staggered and one is added on each side. The linear load of the C-type composite structural components reaches 250kN / m.

[0045] The implementation is as follows:

[0046] Concrete pouring zones were determined: The vertical section was divided into three layers. The lower transfer beam was poured together with the 24th-floor beam and slab, using two sections of suspended formwork and a 2.25m thick pouring layer. The shear wall was poured separately, with a 4m thick pouring layer. The upper transfer beam was poured together with the 25th-floor beam and slab, with a 1.5m thick pouring layer. The horizontal section was divided into two zones.

[0047] The vertical joints between the three layers of concrete of the transfer layer conversion components are designed to be stepped, with a step width of 1.5m to improve the integrity of the transfer layer.

[0048] Additional steel bars are added to the horizontal joints between the transfer beam and the shear wall. The specific type, quantity and length of the steel bars are determined based on shear resistance calculations and approved by the design review.

[0049] Determine the number of supporting layers at the bottom of the transfer layer, which supports 2 layers, for a total of 22 layers and 23 layers. Calculate the additional reinforcement in the 23rd floor slab. After design review and approval, add double-layer third-level 14@200 reinforcement within 6m of the surrounding floor slabs of the 23rd floor.

[0050] In order to enhance the shear resistance of the concrete construction joints between each layer, 4 rows of reinforcement bars are added to the construction joints between the transfer beams and the shear walls.

[0051] Structural calculations and designs are carried out for various working conditions of installation, use and removal of the bottom formwork and support of the conversion component, with emphasis on the structural calculations of the working conditions when the lower conversion beam is cast and the overall conversion component is cast. After design review and approval, when the concrete strength grade of the lower conversion beam reaches 70% of the design strength, the spiral top at the bottom of the beam is loosened and returned to the top.

[0052] The formwork support system adopts a disc-type scaffolding support system, and the special construction plan will be implemented after expert review and approval.

[0053] Concrete pouring uses a high-pressure ground pump and a remote-controlled concrete placing boom, which is arranged inside the core tube.

[0054] The vertical joints between the three layers of concrete are designed to be stepped with a step width of 1.5m to improve the overall stability of the transfer layer. Figure 4 .

[0055] According to the temperature conditions, 3 days after the casting of the lower conversion beam of the combined conversion component is completed, a compressive test of the concrete curing test block under the same conditions is carried out. When the strength reaches more than 70% of the design strength, the bottom support of the beam is loosened and the top is returned. At the same time, the 22nd floor formwork and support are removed and used in rotation. The lower conversion beam and the 23rd floor formwork and support jointly bear the load of the upper conversion component. The demolding time of the formwork and support of other parts of the 23rd floor is carried out in accordance with the specifications.

[0056] In order to lower the temperature of large-volume concrete entering the mold and control the maximum temperature inside the concrete, a concrete mix ratio with ice cubes is adopted, and 60kg of ice cubes are added to each cubic meter of concrete; in order to prevent cracks caused by excessive temperature difference between the concrete surface and the interior, the beam side and shear wall formwork are removed 3 days after pouring concrete, when the temperature difference between the concrete surface temperature and the ambient temperature is less than 25℃.

[0057] Five sets of thermocouples are embedded inside the transfer beam, and special instruments are used to automatically monitor the internal temperature of the concrete. A temperature curve is drawn and the temperature difference between each monitoring point is compared. The temperature difference between each monitoring point is less than 25°C, and the highest temperature inside the concrete is 65°C, which meets the requirements and effectively avoids the occurrence of temperature difference cracks in large-volume concrete.

[0058] The outer protective scaffolding adopts a segmented integrated climbing frame, with a total of 16 climbing frames, 2 unloading platforms are set up, and the climbing frame connectors are fixed on the shear wall surface. The climbing height each time is 3.5m.

[0059] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include," "comprise," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations. The phrase "includes an element defined by..." does not exclude the presence of other identical elements in the process, method, article, or device that includes the element.

[0060] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A construction method for a super-high transfer layer of a frame-tube structure, characterized in that: The following steps are involved: Determine the location of the transfer layer within the building based on the building structure, and conduct in-depth design and construction of the transfer layer structure, including: determining the concrete pouring zones; designing the vertical joints between the first, second, and third layers of concrete that constitute the transfer layer; adding reinforcement to the horizontal joints between the upper and lower transfer beams and the shear walls; determining the number of support layers at the bottom of the transfer layer through computer software calculations, calculating the additional reinforcement in the floor slab below the transfer layer, and determining the type and quantity of the additional reinforcement; conducting structural calculations and designs for the installation, use, and removal of the formwork and support at the bottom of the combined transfer component, with a focus on the structural calculations for the completed pouring conditions of the lower transfer beam and the combined transfer component, and determining the specifications and types of the bottom formwork and bottom support system; Process and manufacture the transfer layer steel bars according to national standards; Tie the steel bars of the floor slab of the next floor of the transfer layer in accordance with national standards and pour the concrete of the floor slab of the next floor; Installing bottom layer formwork and bottom layer support below the conversion layer; Installing the lower transfer beam and adjacent beam and slab reinforcement on the transfer layer, and pouring the first layer of concrete after passing the inspection; When the concrete strength reaches a certain proportion of the design strength, the support at the bottom of the lower transfer beam is released and the top is returned; Tie the steel bars at the shear wall of the transfer layer and pour the second layer of concrete after passing the inspection; Installing a conversion layer template and a conversion layer support on the conversion layer; An upper conversion beam and adjacent beam and slab reinforcements are installed on the conversion layer, and a third layer of concrete is poured after acceptance, so that the first layer of concrete, the second layer of concrete and the third layer of concrete constitute a combined conversion component, wherein, before pouring the upper conversion beam and the lower conversion beam, multiple sets of thermocouples are embedded inside the large-volume upper conversion beam or the lower conversion beam, and a special instrument is used to automatically monitor the internal temperature of the concrete through the thermocouples, and a temperature curve is drawn to ensure that the temperature difference between each monitoring point is less than 25°C; after the internal temperature of the poured concrete reaches a peak, the side formwork of the upper conversion beam or the lower conversion beam is dismantled when the temperature difference between the concrete surface temperature and the ambient temperature is less than 25°C.

2. The construction method of a super-high transfer layer of a frame-tube structure according to claim 1 is characterized in that: When determining the concrete pouring zones, the lower transfer beam is poured together with the adjacent beams and slabs, the upper transfer beam is poured together with the adjacent beams and slabs, and the shear wall is poured separately. The plane zones of the transfer layer are determined according to the size of the building floor area and the total amount of concrete.

3. The construction method of a super-high transfer layer of a frame-tube structure according to claim 1 is characterized in that: Additional steel bars are added to the floor slab below the transfer layer, and the model and quantity of the additional steel bars are designed based on the requirement that only 1-2 layers of support need to be reinforced at the bottom.

4. The construction method of a super-high transfer layer of a frame-tube structure according to claim 1 is characterized in that: Calculate the working conditions of each formwork for the construction of the transfer layer. When the concrete strength of the lower transfer beam reaches a certain proportion of the design strength, first remove the support below the lower layer, loosen the support at the bottom of the lower transfer beam and return it to the top. The load of the upper combined conversion component is jointly borne by the lower transfer beam and the lower formwork and support.

5. The construction method of a super-high transfer layer of a frame-tube structure according to claim 1 is characterized in that: The vertical joints between the first layer of concrete, the second layer of concrete and the third layer of concrete constituting the transfer layer are designed to be stepped.

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