Construction methods for openings in unbonded prestressed floor slabs and supporting hanger structures

Abstract

This invention provides a method for constructing openings in unbonded prestressed floor slabs and a supporting hanger structure. The method includes: measuring and setting out to determine the location of permanent openings in the unbonded prestressed floor slab; determining the area for temporary openings using architectural drawings and detection instruments; establishing a construction model for creating openings in the unbonded prestressed floor slab; simulating the entire process of creating openings using the construction model, and analyzing and determining the preset construction sequence for temporary openings, the preset prestressed tendon cutting grouping and construction procedures, and the deflection deformation values ​​of the unbonded prestressed floor slab under different construction conditions; excavating temporary openings according to the preset temporary opening construction sequence; executing the preset prestressed tendon cutting grouping and construction procedures; and constructing permanent openings. This application, through simulation analysis, understands the impact of various working conditions on the floor slab structure, determines the optimal location and number of temporary openings, and the prestressed tendon cutting grouping and construction procedures, thereby improving construction efficiency.

Description

Technical Field

[0001] This invention relates to the field of building equipment technology, and in particular to a method for constructing openings in unbonded prestressed floor slabs and a supporting hanger structure. Background Technology

[0002] Currently, China's reform and opening up has been underway for over 40 years, and the first batch of large airport terminals have been in use for over 30 years. Their functional design and quality experience can no longer meet current requirements. Therefore, to enhance airport functionality without altering the existing main structural system, the airport needs to be transformed into a safe, intelligent, and people-oriented facility. Due to the functional upgrades, elevator shafts and ventilation shafts need to be added to the existing floor slabs, requiring modifications to the existing floor slabs by creating openings. Since the airport floor slabs are unbonded prestressed slabs, creating openings requires cutting, stress release, tensioning, and opening of some unbonded prestressed tendons, inevitably affecting the original stress distribution and force transmission path of the floor slab, posing a risk of damage to surrounding floor structures. Conventional construction often involves adding temporary anchorages and permanent anchorage openings separately. Temporary anchorage is achieved using C-type anchorages, and the prestressed tendons are cut at the permanent anchorage openings, permanent anchorages are installed, and finally, the permanent openings are created.

[0003] Among the aforementioned conventional methods of creating openings, a large number of temporary openings are created, which has an adverse effect on the stability of the structural beams and slabs. During construction, there are also many openings near the edges that require protection and a large amount of work for opening repair, which is not conducive to construction organization.

[0004] In other words, the existing technology has the problem that the large number of temporary openings has an adverse effect on the stability of the structural beams and slabs, and that the construction process also involves a large amount of work on protecting and repairing the numerous openings near the edges, which is detrimental to the construction organization. Summary of the Invention

[0005] This invention provides a construction method and support hanger structure for the modification of unbonded prestressed floor slabs with openings, which solves the problem that the large number of temporary openings has an adverse effect on the stability of the structural beams and slabs, as well as the problem that the construction process also involves a large amount of work on protecting and repairing the numerous edge openings, which is detrimental to the construction organization.

[0006] This invention provides a method for constructing openings in the renovation of unbonded prestressed floor slabs, comprising:

[0007] Step S10: Measure and lay out to determine the location of permanent openings in the unbonded prestressed floor slab;

[0008] Step S20: Determine the area for setting up temporary openings using the building as-built drawings and detection instruments;

[0009] Step S30: Establish a construction model for opening in the modification of an unbonded prestressed floor slab;

[0010] Step S40: Simulate the entire process of modifying the opening through the construction model, and analyze and determine the construction sequence of the preset temporary opening, the preset prestressed tendon cutting group and construction procedure, and the deflection deformation value of the unbonded prestressed floor slab under different construction conditions.

[0011] Step S50: Excavate temporary openings according to the preset temporary opening construction sequence;

[0012] Step S70: Perform the preset prestressed tendon cutting grouping and construction procedures;

[0013] Step S100: Construct and open the permanent opening.

[0014] In one embodiment, the deflection deformation value of the unbonded prestressed floor slab under different construction conditions includes a first simulated deflection deformation value. Between steps S40 and S50, a judgment step S60 is also included: judging whether the monitored deflection value of the unbonded prestressed floor slab during the excavation of the temporary opening is greater than the first simulated deflection deformation value. If the monitored deflection value of the unbonded prestressed floor slab is not greater than the first simulated deflection deformation value, then step S50 is executed.

[0015] In one implementation, if the monitored deflection value of the unbonded prestressed floor slab is greater than the first simulated deflection deformation value, then proceed to step S80: adjust the construction sequence of the preset temporary opening so that the monitored deflection value is not greater than the first simulated deflection deformation value, and then execute step S50.

[0016] In one embodiment, the deflection deformation value of the unbonded prestressed floor slab under different construction conditions includes a second simulated deflection deformation value. Between steps S50 and S70, a judgment step S90 is also included: judging whether the monitored deflection value of the unbonded prestressed floor slab is greater than the second simulated deflection deformation value during the execution of the preset prestressed tendon cutting group and construction procedure. If the monitored deflection value of the unbonded prestressed floor slab is not greater than the second simulated deflection deformation value, then step S70 is executed.

[0017] In one embodiment, if the monitored deflection value of the unbonded prestressed slab is greater than the second simulated deflection value, then proceed to step S110: adjust the preset prestressed tendon cutting group and construction sequence so that the monitored deflection value is not greater than the second simulated deflection value, and then proceed to step S70.

[0018] In one embodiment, step S40, the pre-setting of prestressed tendon cutting groups and construction procedures specifically includes the following steps:

[0019] Step S401: Divide the prestressed tendons that need to be cut into multiple groups;

[0020] Step S402: Construct multiple sets of prestressed tendons in a preset order.

[0021] In one embodiment, the construction of the prestressing tendons in step S402 includes the following steps:

[0022] Step S4021: Temporary anchoring and cutting of prestressed tendons;

[0023] Step S4022, secondary tensioning for permanent anchoring;

[0024] Step S4023: Temporary opening restored.

[0025] In one implementation, step S20 specifically includes the following steps:

[0026] Step S201: Based on the location of the permanent opening and the distribution of prestressed tendons in the building as-built drawings, the area for opening temporary openings is initially determined.

[0027] Step S202: Using a X-ray detector for non-destructive testing, the position of the prestressed tendons is accurately located, and the precise area for opening the temporary opening is determined.

[0028] The present invention also provides a support hanger structure for the construction of the permanent opening as described in claim 1, comprising:

[0029] The support frame is set on an unbonded prestressed floor slab.

[0030] The suspension assembly is fixed at one end to the permanent opening cutting layer and at the other end to the support frame.

[0031] The suspension assembly can remove the permanent opening cutting layer to expose the permanent opening.

[0032] In one embodiment, the suspension assembly includes:

[0033] Telescopic device, fixed to the support frame; and

[0034] The boom has one end passing through the permanent opening and cutting layer, and the other end of the boom is connected to the telescopic device. The end of the boom that passes through the permanent opening and cutting layer is threaded.

[0035] A support plate with threaded holes is provided on it, and one end of the hanger rod that passes through the permanent opening and cuts the layer is threadedly connected to the threaded holes.

[0036] The telescopic device can remove the cutting layer from the permanent opening by lowering or raising the boom.

[0037] Compared with existing technologies, the beneficial effects of this invention are as follows: By utilizing simulation software, a comprehensive model of the floor slab modification and opening process is established, simulating the entire process, including temporary opening, temporary anchoring and cutting of prestressed tendons, secondary tensioning and permanent anchoring, temporary opening restoration, and permanent opening construction. Through full-process simulation, the opening, prestressed tendon cutting grouping, and construction sequence are determined; and the deflection deformation values ​​of unbonded prestressed floor slabs under different construction conditions are analyzed. This introduction of computer model simulation, through simulation analysis, allows for understanding the impact of each condition on the floor slab structure, determining the optimal location and number of temporary openings, as well as the prestressed tendon cutting grouping and construction sequence. Under safety control conditions, synchronous and rapid grouping construction improves construction efficiency. It avoids the problem of a large number of temporary openings negatively impacting the stability of the structural beams and slabs, and the problem of numerous edge openings requiring protection and extensive repair work during construction, which is detrimental to construction organization. Attached Figure Description

[0038] Figure 1 This is a flowchart illustrating the construction method for creating openings in the modification of unbonded prestressed floor slabs according to an embodiment of the present invention.

[0039] Figure 2 This is a flowchart illustrating the specific method for constructing openings in the unbonded prestressed floor slab renovation according to an embodiment of the present invention.

[0040] Figure 3 This is a schematic diagram of the structure for modifying the opening in the unbonded prestressed floor slab according to the present invention.

[0041] Figure 4 This is a schematic diagram of the temporary opening for modifying the unbonded prestressed floor slab according to the present invention.

[0042] Figure 5 This is a schematic diagram illustrating the construction process of temporary opening and tension anchoring without tension release according to the present invention.

[0043] Figure 6 This is a schematic diagram of the concave pad structure of the present invention.

[0044] Figure 7 This is a schematic diagram of the simulated opening structure of the present invention;

[0045] Figure 8 This is a schematic diagram of the simulated hole-opening conditions of the present invention.

[0046] Figure 9 This is a schematic diagram showing the sequence of openings in this invention.

[0047] Figure 10 This is a schematic diagram of the modified support frame structure with openings according to the present invention.

[0048] Figure 11 This is a schematic diagram of the modified opening support hanger structure of the present invention.

[0049] Figure 12 This is a schematic diagram of the working structure of the support hanger after the opening is opened according to the present invention.

[0050] In the diagram: 10. Support frame; 20. Suspension assembly; 21. Telescopic device; 22. Hanger rod; 23. Support plate; 30. Steel pad; 40. Temporary anchor; 50. Permanent anchor; 60. Tensioning bracket; 70. Through-hole jack; 100. Floor slab; 101. Permanent opening; 102. Temporary opening; 1021. Intermediate temporary opening; 1022. Temporary openings on both sides; 103. Prestressed steel reinforcement. Detailed Implementation

[0051] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] like Figure 1 As shown, the present invention provides a method for constructing openings in the renovation of unbonded prestressed floor slabs, comprising:

[0053] Step S10: Measure and lay out to determine the location of permanent openings in the unbonded prestressed floor slab;

[0054] Step S20: Determine the area for setting up temporary openings using the building as-built drawings and detection instruments;

[0055] Step S30: Establish a construction model for opening in the modification of an unbonded prestressed floor slab;

[0056] Based on the midas FEA finite element analysis software, an overall structural model was established according to the as-built drawings. The model includes prestressed structural beams, slabs, structural columns, and elements such as steel bars and prestressing tendons. Based on the location of temporary and permanent openings, structural elements were grouped, and self-weight loads, construction loads, and prestressing loads were added.

[0057] Step S40: Simulate the entire process of modifying the opening using a construction model, and analyze and determine the pre-set temporary opening construction sequence, pre-set prestressed tendon cutting group and construction procedure, and the deflection deformation value of the unbonded prestressed floor slab under different construction conditions (including the opening construction sequence, prestressed tendon cutting group and construction procedure).

[0058] Based on the construction schedule and layout requirements, a pre-defined sequence for opening construction is established; adjacent openings are grouped and constructed simultaneously. According to the pre-defined sequence for temporary opening construction, prestressed tendon grouping, and cutting sequence, construction stages are added using analysis software. Each structural unit and load is activated or deactivated at each stage to simulate the entire process of opening modification, determining the deflection values ​​of the unbonded prestressed slab under different construction conditions. If the deformation values ​​meet the specifications, the pre-defined construction sequence satisfies the construction requirements; otherwise, the pre-defined grouping and construction sequence are adjusted.

[0059] Step S50: Excavate temporary openings according to the preset temporary opening construction sequence;

[0060] Step S70: Perform the preset prestressed tendon cutting grouping and construction procedures;

[0061] Step S100: Construct and open the permanent opening.

[0062] In the above setup, simulation software is used to establish an overall model of the floor slab modification and opening, simulating the entire process of opening modification. This process includes temporary opening creation, temporary anchoring and cutting of prestressed tendons, secondary tensioning and permanent anchoring, temporary opening restoration, and permanent opening creation. Through full-process simulation, the grouping and construction sequence for opening creation and prestressed tendon cutting are determined. The deflection deformation values ​​of unbonded prestressed floor slabs under different construction conditions are analyzed. This introduction of computer model simulation, through simulation analysis, allows for understanding the impact of various conditions on the floor slab structure, determining the optimal location and number of temporary openings, as well as the grouping and construction sequence for prestressed tendon cutting. Under safety control conditions, synchronous and rapid grouping and construction improves construction efficiency. This avoids the adverse effects on the stability of structural beams and slabs caused by a large number of temporary openings, and also avoids the problems of numerous edge openings requiring protection and extensive opening repair work, which are detrimental to construction organization.

[0063] Specifically, such as Figure 1 As shown, in one embodiment, the deflection deformation value of the unbonded prestressed floor slab under different construction conditions includes a first simulated deflection deformation value. Between steps S40 and S50, a judgment step S60 is also included: judging whether the monitored deflection value of the unbonded prestressed floor slab during the excavation of the temporary opening is greater than the first simulated deflection deformation value. If the monitored deflection value of the unbonded prestressed floor slab is not greater than the first simulated deflection deformation value, then step S50 is executed.

[0064] Specifically, such as Figure 1 As shown, in one embodiment, if the monitored deflection value of the unbonded prestressed floor slab is greater than the first simulated deflection deformation value, then proceed to step S80: adjust the construction sequence of the preset temporary opening so that the monitored deflection value is not greater than the first simulated deflection deformation value, and then execute step S50.

[0065] In the above setup, the floor slab deflection value is monitored in real time by the monitoring system and compared with the first simulated deflection value under the corresponding working conditions. By adjusting and optimizing the synchronous construction sequence of the opening, the actual value is controlled within the first simulated deflection value, ensuring that the final deflection does not exceed the specification requirements.

[0066] It should be noted that before determining step S60, try to excavate a temporary opening according to the above-mentioned preset temporary opening construction sequence to obtain the above-mentioned monitoring deflection value.

[0067] Specifically, such as Figure 1 and Figure 2 As shown, in one embodiment, the deflection deformation value of the unbonded prestressed floor slab under different construction conditions includes a second simulated deflection deformation value. Between steps S50 and S70, a judgment step S90 is also included: judging whether the monitored deflection value of the unbonded prestressed floor slab is greater than the second simulated deflection deformation value during the execution of the preset prestressed tendon cutting group and construction procedure. If the monitored deflection value of the unbonded prestressed floor slab is not greater than the second simulated deflection deformation value, then step S70 is executed.

[0068] Specifically, such as Figure 1 and Figure 2 As shown, in one embodiment, if the monitored deflection value of the unbonded prestressed slab is greater than the second simulated deflection deformation value, then proceed to step S110: adjust the preset prestressed tendon cutting group and construction sequence so that the monitored deflection value is not greater than the second simulated deflection deformation value, and then execute step S70.

[0069] In the above setup, a monitoring system is set up to monitor the floor slab's condition and health, and to monitor the floor slab's deflection deformation value in real time. The monitoring data is fed back to the simulation analysis system, which compares the monitored deflection deformation value with the second simulated deflection deformation value under the simulated working condition. This ensures that the monitored deflection value is less than or equal to the second simulated deflection deformation value under the corresponding working condition. If the monitored value is greater than the second simulated deflection deformation value under the corresponding working condition, the simulation analysis is adjusted to reduce the number of simultaneous construction groups, thereby regulating and controlling the floor slab's deflection deformation value to be less than or equal to the second simulated deflection deformation value under the corresponding working condition, thus meeting the construction safety requirements of the construction specifications.

[0070] It should be noted that before determining step S90, try to follow the above-mentioned preset prestressed tendon cutting group and construction procedure to obtain the above-mentioned monitoring deflection value.

[0071] Specifically, such as Figure 1 and Figure 2 As shown, in one embodiment, step S40, the pre-setting of prestressed tendon cutting and grouping and the construction process specifically includes the following steps:

[0072] Step S401: Divide the prestressed tendons that need to be cut into multiple groups;

[0073] Step S402: Construct multiple sets of prestressed tendons in a preset order.

[0074] Specifically, such as Figure 1 and Figure 2 As shown, in one embodiment, the construction of prestressed tendons in step S402 includes the following steps:

[0075] Step S4021: Temporary anchoring and cutting of prestressed tendons;

[0076] Step S4022, secondary tensioning for permanent anchoring;

[0077] Step S4023: Temporary opening restored.

[0078] Specifically, such as Figure 1 and Figure 2 As shown, in one embodiment, step S20 specifically includes the following steps:

[0079] Step S201: Based on the location of the permanent opening and the distribution of prestressed tendons in the building as-built drawings, the area for opening temporary openings is initially determined.

[0080] Step S202: Using a X-ray detector for non-destructive testing, the position of the prestressed tendons is accurately located, and the precise area for opening the temporary opening is determined.

[0081] like Figure 12 As shown, the present invention also provides a support hanger structure for the construction of the aforementioned permanent opening, which includes a support frame 10 and a suspension assembly 20: wherein the support frame 10 is disposed on an unbonded prestressed floor slab, one end of the suspension assembly 20 is fixed to the permanent opening cutting layer, and the other end of the suspension assembly 20 is fixed to the support frame 10; wherein the suspension assembly 20 is capable of removing the permanent opening cutting layer to expose the permanent opening.

[0082] Specifically, such as Figure 12 As shown, in one embodiment, the suspension assembly 20 includes: a telescopic device 21 fixed to the support frame 10; and a rod 22, one end of which passes through the permanent opening cutting layer, the other end of which is connected to the telescopic device 21, and the end of the rod 22 passing through the permanent opening cutting layer is threaded; a support plate 23 having a threaded hole, and the end of the rod 22 passing through the permanent opening cutting layer is threadedly connected to the threaded hole; wherein, the telescopic device 21 can remove the permanent opening cutting layer from the permanent opening by lowering or raising the rod 22.

[0083] The following is combined Figures 2 to 12Taking the method of opening a large-span unbonded prestressed floor slab as an example, a complete embodiment of this application is illustrated below:

[0084] To ensure the safety and smooth progress of the renovation and opening of multiple permanent openings 101 in the existing floor slab 100, temporary openings 102 need to be added and the prestressed steel bars 103 in the corresponding areas need to be cut. The renovation and opening construction, as well as the cutting and secondary tensioning of the prestressed steel bars 103, directly affect the stress, deformation and subsequent load-bearing capacity of the floor slab.

[0085] When a permanent opening 101 needs to be made in the renovation of a large-span floor slab 100, in order to ensure the structural stability and safety of the floor slab 100 during the opening process, reduce the risk of stress mutation and ejection of the prestressed steel bars 103, and improve construction efficiency, the construction method in this example controls the impact of the renovation opening on the floor slab.

[0086] Specifically, simulation analysis was conducted using a computer-based simulation model to analyze the entire process of the renovation, including the opening of temporary opening 102, temporary anchoring and cutting of prestressed steel bars 103, secondary tensioning and permanent anchoring, restoration of temporary opening 102, and construction of permanent opening 101. Through the simulation of the entire process, the grouping and construction sequence of opening temporary opening 102 and cutting of prestressed steel bars were determined. The deflection deformation values ​​of unbonded prestressed slabs under different construction conditions were also analyzed.

[0087] Specifically, the construction sequence for the opening modification is 1.1 → 1.2 → 1.3; the prestressed tendon cutting is done from the middle to the sides, i.e., temporary opening 1021 in the middle → temporary openings 1022 on both sides. Each group includes multiple openings (temporary openings 102) or prestressed steel bars 103, which are constructed simultaneously. The simulated floor slab deformation deflection values ​​for each construction condition are shown in Table 1 below:

[0088] Table 1. Simulation analysis of floor slab deformation and deflection values ​​under various construction conditions.

[0089]

[0090] Model analysis determines the deflection deformation values ​​for each theoretical working condition, and controls the cumulative maximum deflection value within 80% of the standard requirements; this value serves as the threshold for structural monitoring.

[0091] Specifically, a non-destructive testing method using a X-ray detector is employed. Through X-ray transmission imaging, a distribution map of the reinforcing bars in the designated area is generated, and the location of the prestressed reinforcing bars 103 is accurately located. Based on the location of the prestressed reinforcing bars 103, the location of temporary openings is precisely set, and the temporary openings and prestressed bars are marked.

[0092] The temporary opening 102 is equipped with a rapid secondary tensioning and anchoring system without release tension, including a steel plate 30, a temporary anchor 40, a permanent anchor 50, a tensioning bracket 60, and a through-hole jack 70.

[0093] Among them, the steel plate 30 is a concave plate, which is connected to the concrete structure with structural adhesive; it reinforces the structural floor slab and supports temporary anchoring, secondary tensioning, and permanent anchoring; the temporary anchor 40 temporarily anchors both ends of the prestressed tendons at the opening to avoid sudden release of prestressing stress during cutting, which could affect the stability of the floor slab structure or cause injury from the ejection of prestressed tendons; after the prestressed steel bar 103 is temporarily anchored, it is cut, and sufficient working length must be reserved for secondary tensioning. The minimum working length is the sum of the steel plate thickness, the length of the tensioning bracket, the through-hole jack, and the extension allowance; the tensioning bracket 60 includes the steel legs and the supporting top plate of the reserved opening, providing working space for switching from temporary anchors to permanent anchors, and providing a supporting surface for the advancement of secondary tensioning;

[0094] Specifically, the prestressed steel bar 103 is rapidly re-tensioned and anchored without being released, using a temporary anchor 40 for temporary anchoring, and the prestressed steel bar 103 is cut off; a permanent anchor 50, a tensioning bracket 60, and a through-hole jack 70 are sequentially inserted, with the through-hole jack 70 bolted to the bracket; the tensioning bracket 60 fixes the prestressed steel bar 103 for initial tensioning, and when the tension stress reaches 80% of the design tension stress, it is slowly removed; the position of the permanent anchor 50 is adjusted, and the prestressed steel bar is re-tensioned to the design stress for permanent anchoring.

[0095] Specifically, a monitoring system is set up to monitor the deflection deformation value of the floor slab in real time. The monitoring data is fed back to the simulation analysis system, and the monitoring deflection deformation value is compared with the deflection value of the simulated working condition to ensure that the monitored deflection value is less than or equal to the deflection value of the corresponding simulated working condition. If it is greater than the deflection value of the corresponding simulated working condition, the simulation analysis is adjusted to reduce the number of groups working simultaneously, so as to regulate and control the deflection deformation value of the floor slab to be less than or equal to the deflection value of the corresponding simulated working condition, thereby meeting the construction safety requirements of the construction specifications.

[0096] Specifically, a permanent opening 101 is created, and a support hanger structure is installed to support and lift the floor slab to be removed, allowing for overall cutting and demolition. The support hanger structure includes a support frame 10, a suspension chain (telescopic device 21), a hanger rod 22, and a support plate 23. The support frame 10, made of structural steel, spans the opening and bears the weight of the floor slab after the opening. The suspension chain connects the support frame 10 and the hanger rod 22, and can be extended and shortened to adjust the height. The hanger rod 22 is a solid steel rod that passes through the opening and has threads at the bottom for connecting to the support plate 23. The support plate 23, connected to the hanger rod 22 via threads, is used to lift the demolished floor slab.

[0097] Specifically, the supporting hanger structure, depending on the size of the opening to be opened, employs two or more sets working together to lift and lower the floor slab to be removed from the opening.

[0098] Specifically, the method for creating openings in large-span unbonded prestressed floor slabs includes the following steps:

[0099] Step 1: According to the requirements for the renovation of unbonded prestressed floor slabs, measure and lay out the area for permanent openings and mark it; according to the area for permanent openings and the distribution of prestressing tendons in the building as-built drawings, preliminarily determine the area for temporary openings; use a X-ray detector for non-destructive testing to detect the temporary openings, accurately locate the prestressing tendons and marks, and determine the accurate location area for setting up the temporary openings.

[0100] Step 2: Simulation Analysis and Establishment: Using finite element software, an overall model of the floor slab modification and opening is established to simulate the entire process of the modification and opening. The process includes the opening of temporary openings, temporary anchoring and cutting of prestressed tendons, secondary tensioning and permanent anchoring, temporary opening restoration and permanent opening construction. Through full-process working condition simulation, the opening opening, prestressed tendon cutting grouping and construction sequence are determined. The deflection deformation values ​​of unbonded prestressed floor slabs under different construction conditions are analyzed. In this example, the opening modification grouping construction sequence is 1.1→1.2→1.3; the prestressed tendon cutting is from the middle to the two sides, that is, the middle temporary opening 1021 → the two side temporary openings 1022.

[0101] Step 3: According to the simulated construction sequence, temporary openings are constructed, with symmetrical construction on both sides, and prestressed tendons are chiseled out.

[0102] Step 4: Rapidly re-tension and anchor the prestressed tendons without releasing tension, using temporary anchorages with openings, and cut the prestressed tendons. Then, sequentially insert permanent anchorages, tensioning supports, and through-hole jacks, connecting the jacks to the supports with bolts. The through-hole jacks fix the prestressed tendons for initial tensioning. When the tension stress reaches 80% of the design tension stress, slowly remove the jacks. Adjust the position of the permanent anchorages, re-tension to the design stress, and permanently anchor. Seal the temporary opening and proceed with cutting the next set of prestressed tendons until all prestressed tendons within the permanent opening are cut.

[0103] Step 5: Construct the permanent opening: Install the support frame structure, drill holes at the drop point of the opening to be opened, pass through the hanger rod, and install the support plate; cut the floor slab, and use the support frame structure to lift the floor slab of the opening as a whole; adjust the suspension chain to lower it to the lower floor slab, and the modification of the opening begins.

[0104] It should be noted that the condition of the floor slab is monitored throughout the entire process of the renovation and opening. The floor slab deflection deformation is monitored in real time to ensure that the monitored deflection value is less than or equal to the deflection value of the corresponding simulated working condition. If it is greater than the deflection value of the corresponding simulated working condition, the simulation analysis system is fed back to adjust the group construction sequence and reduce the number of groups to be constructed at the same time, so that the monitored deflection value is less than or equal to the deflection value of the corresponding simulated working condition, until all permanent openings are constructed.

[0105] In this invention, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0106] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0107] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0108] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A construction method of a bondedless prestressed floor reconstruction opening operation, characterized by, It includes: Step S10: Measure and lay out to determine the location of permanent openings in the unbonded prestressed floor slab; Step S20: Determine the area for setting up temporary openings using the building as-built drawings and detection instruments; Step S30: Establish a construction model for opening in the modification of an unbonded prestressed floor slab; Step S40: Simulate the entire process of modifying the opening using the construction model, and analyze and determine the construction sequence of the preset temporary opening, the preset prestressed tendon cutting group and construction procedure, and the deflection deformation value of the unbonded prestressed floor slab under different construction conditions. Step S50: Excavate the temporary opening according to the preset temporary opening construction sequence; Step S70: Perform the preset prestressed tendon cutting grouping and construction procedures; Step S100: Construct and open the permanent opening; The deflection deformation value of the unbonded prestressed floor slab under different construction conditions includes the first simulated deflection deformation value. Between step S40 and step S50, there is also a judgment step S60: judging whether the monitored deflection value of the unbonded prestressed floor slab during the excavation of the temporary opening is greater than the first simulated deflection deformation value. If the monitored deflection value of the unbonded prestressed floor slab is not greater than the first simulated deflection deformation value, then step S50 is executed. The deflection deformation value of the unbonded prestressed floor slab under different construction conditions includes the second simulated deflection deformation value. Between step S50 and step S70, a judgment step S90 is also included: judging whether the monitored deflection value of the unbonded prestressed floor slab is greater than the second simulated deflection deformation value during the execution of the preset prestressed tendon cutting group and construction procedure. If the monitored deflection value of the unbonded prestressed floor slab is not greater than the second simulated deflection deformation value, then step S70 is executed. If the monitored deflection value of the unbonded prestressed floor slab is greater than the first simulated deflection deformation value, then proceed to step S80: adjust the construction sequence of the preset temporary opening so that the monitored deflection value is not greater than the first simulated deflection deformation value, and then execute step S50. If the monitored deflection value of the unbonded prestressed floor slab is greater than the second simulated deflection deformation value, then proceed to step S110: adjust the preset prestressed tendon cutting group and construction sequence so that the monitored deflection value is not greater than the second simulated deflection deformation value, and then execute step S70.

2. The method for constructing openings in the renovation of unbonded prestressed floor slabs according to claim 1, characterized in that, In step S40, the pre-set prestressed tendon cutting and grouping and construction process specifically includes the following steps: Step S401: Divide the prestressed tendons that need to be cut into multiple groups; Step S402: Construct multiple sets of prestressed tendons in a preset order.

3. The method for constructing openings in the renovation of unbonded prestressed floor slabs according to claim 2, characterized in that, The construction of prestressed tendons in step S402 includes the following steps: Step S4021: Temporary anchoring and cutting of prestressed tendons; Step S4022, secondary tensioning for permanent anchoring; Step S4023: Temporary opening restored.

4. The method for constructing openings in the renovation of unbonded prestressed floor slabs according to claim 2, characterized in that, Step S20 specifically includes the following steps: Step S201: Based on the location of the permanent opening and the distribution of prestressed tendons in the as-built drawings, the area for opening temporary openings is initially determined. Step S202: Using a X-ray detector for non-destructive testing, the position of the prestressed tendons is accurately located, and the precise area for opening the temporary opening is determined.

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