A back bolt type stone material curtain wall standardization construction method

Abstract

The application provides a back-bolt type stone curtain wall standardization construction method and relates to the field of building curtain wall construction, and comprises the following steps: S1, installing a reference section keel and re-measuring actual grid three-dimensional coordinates, the reference section is re-measured and verified after stress release; S2, synchronizing the measured coordinates to a stone processing end, obtaining processing coordinates through weighted correction (beta=0.85~0.95) of system deviation, and processing back-bolt holes, implanting back bolts and pre-assembling hanging parts according to the processing coordinates; S3, synchronously and in parallel, on-site continuing to install remaining keels and pre-assembling stone hanging components at the processing end; S4, hanging and fastening the stone in stages; and S5, sealing treatment. The application drives stone processing by reference keel measured coordinates, realizes accurate matching between processing and on-site dimensions, greatly shortens the construction period through parallel construction of the on-site and the processing end, and effectively controls installation stress through the processes of initial tightening of vertical keels, stress release of temperature difference and temperature selection final tightening. The application has low rework rate, high precision and short construction period.

Description

Technical Field

[0001] This invention relates to the field of building curtain wall construction, and more specifically, to a standardized construction method for back-bolted stone curtain walls. Background Technology

[0002] Back-bolted stone curtain walls are widely used in the exterior wall decoration of high-rise and super high-rise buildings due to their advantages such as reliable connection, good seismic performance, and convenient replacement. The typical construction process is as follows: vertical and horizontal joists are installed on the main building structure to form a metal frame; back-bolt holes are then machined on the back of the stone panels and back bolts are inserted; hangers are installed; and finally, the stone hanging components are attached to the joists and adjusted for fixation.

[0003] The existing construction methods for back-bolted stone curtain walls mainly have the following technical problems: (i) The processing is out of sync with the on-site dimensions, resulting in a high rework rate. Current technology typically involves installing the keel and processing the stone according to theoretical design drawings. However, due to factors such as errors in civil construction, deviations in embedded part positioning, and cumulative errors in keel installation, the actual grid dimensions after keel installation often deviate significantly from the design values. When all the keels are installed on-site, and the stone panels processed to theoretical dimensions are transported to the site, problems such as misalignment, misalignment of hangers and keels, and uneven panel joints frequently occur. This results in a large amount of stone needing to be cut, trimmed, or reprocessed on-site, with a rework rate exceeding 15%, severely restricting construction efficiency and causing material waste.

[0004] (ii) Sequential processes and lengthy construction period Traditional construction methods follow a sequential process of "full keel installation → stone processing → hanging." Only after all the keels are installed can on-site measurements be taken and stone processing orders placed. The stone processing cycle is usually 15 to 30 days, during which time on-site workers can only wait, resulting in idle labor and making it difficult to shorten the overall construction period.

[0005] (iii) Lack of stress control makes it difficult to guarantee installation accuracy. Current technology lacks effective stress relief and temperature compensation measures for keel installation. Vertical keels undergo thermal expansion and contraction due to temperature differences. If bolts are tightened during periods of extreme temperature, such as early morning or afternoon, additional stress will be generated inside the keel after temperature changes, causing it to bend and deform, thus affecting the flatness and long-term stability of the stone installation. Furthermore, stone installation often involves leveling each piece individually, which easily leads to the accumulation of errors on one side, making it difficult to achieve a uniform stress distribution throughout the installation.

[0006] Therefore, there is an urgent need to propose a standardized construction method that can eliminate keel installation deviations, achieve matching of processing and on-site dimensions, enable parallel construction, and precisely control stress. Summary of the Invention

[0007] The purpose of this invention is to solve the problems mentioned in the background art, and to propose a standardized construction method for back-bolted stone curtain walls.

[0008] The technical solution adopted by this invention to solve its technical problem is: A method for installing back-bolted stone curtain walls includes the following steps: S1 lays out anchors on the main building structure, installs the reference section vertical keel and the reference horizontal keel, and re-measures and outputs the actual grid three-dimensional coordinates of the reference keel. S2 synchronizes the measured coordinates of the reference keel to the stone processing end, performs a systematic deviation weighted correction on the measured coordinates to obtain the final processing coordinates, and processes back-cut bolt holes on the back of the stone panel according to the processing coordinates, inserts the back bolts and pre-installs the hangers to produce the stone hanging component. Simultaneously, the remaining vertical and horizontal keels were installed on site S3, and the stone hanging components were prefabricated in batches at the processing end. S4 attaches the stone hanging component to the corresponding horizontal keel hanging piece, adjusts the position, and then tightens all the connecting pieces; S5 seals the seams and edges of the boards.

[0009] 2. The method for installing back-bolted stone curtain walls according to claim 1, characterized in that, in step S2, the weighted correction of system deviation is used to calculate the final hole position machining coordinates using the following formula:

[0010] In the formula: ( , () is the measured grid coordinate of the baseline keel; , The overall system deviation value of the reference keel is the arithmetic mean of the differences between the measured coordinates and the theoretical design coordinates of each reference keel. This is the system deviation correction factor, with a value range of 0.85 to 0.95.

[0011] The The value is determined based on statistical regression analysis of a large amount of engineering measured data. The lower limit of 0.85 is the safety threshold for adjustment margin, and the upper limit of 0.95 is the critical value to avoid local stress distortion. The specific calculation is as follows: =0.85+0.10×( / 200), where The building height (unit: meters) is when When H=200, the value is ≥200; adjustments are made based on the project schedule requirements: the aforementioned schedule reduction rate refers to the reduction ratio compared to the planned schedule of the traditional sequential construction scheme (i.e., stone processing is carried out only after all the keel installations are completed). This reduction rate is predetermined by the overall project schedule target. When the schedule reduction rate is ≥20%, The value was lowered by 0.02 to 0.03 from the original calculation. When the accuracy level requirement is ultra-high (allowable deviation of plate gap width ≤ 1.0mm), The value was adjusted upwards by 0.02 to 0.03 from the original calculated value; ultimately... The value is the corrected value and rounded to two decimal places, still within the range of 0.85 to 0.95.

[0012] Furthermore, the construction preparation and surveying / layout procedures are completed before step S1: Complete the approval of the special plan and conduct tests on the curtain wall's wind pressure, water tightness, air tightness, and in-plane deformation performance to confirm that the main structure's strength meets the standards; Complete the re-inspection of incoming materials and the pull-out test of post-installed anchor bolts; Verify the civil engineering axis and elevation, mark the keel and grid control lines, and carry out the layout work under the condition that the wind force is no greater than level 4.

[0013] Furthermore, in step S1, the anchor includes a pre-embedded plate and a post-installed anchor bolt. The pre-embedded plate with excessive deviation is reinforced, and the post-installed anchor bolt is used after passing the pull-out test. The base keel is fixed to the anchor by L-shaped connecting angle brackets. The connecting angle brackets are equipped with stainless steel bolts and anti-corrosion washers, and have three-way adjustment: front-back, left-right, and up-down. The standard section of vertical keel should cover both ends of the building facade and have at least one control vertical keel in the middle; when the building height H>100m or the facade area>5000㎡, no less than two middle control vertical keels and corresponding horizontal keels should be added. After the retest is completed, at least three additional verification points are selected on the inner and outer sides and the upper and lower edges of the reference section for deviation verification. If the average deviation of the verification points is similar to the overall systematic deviation of the reference section, then the deviation is considered to be correct. , If the difference does not exceed ±3mm, the benchmark section is considered to have overall representativeness; otherwise, the layout range of the benchmark section is adjusted, and a complete re-measurement, overall system deviation value calculation and verification are carried out again until the condition is met, so as to ensure that the benchmark section data has true overall representativeness.

[0014] Furthermore, the vertical keel is made of aluminum alloy profiles or hot-dip galvanized square steel pipes, and the damaged parts of the steel components are treated with rust prevention. During installation, first fix the two vertical keels at both ends and pull the guide line, then install the middle vertical keel in sequence; The vertical keel is extended using a core tube sleeve connection, with an expansion joint reserved at the extension point; After the vertical keel is in place, it is initially tightened and fixed. After stress release is completed through at least one complete day-night temperature difference cycle, the verticality is re-measured when the temperature of the day is close to the annual average temperature of the project location. Then, the final tightening is completed. The temperature close to the annual average temperature means that the absolute value of the difference between the temperature of the day and the annual average temperature of the project location is not greater than 5℃. The complete day-night temperature difference cycle means a natural day cycle with an ambient temperature change range of not less than 10℃. If the local day-night temperature difference is less than 10℃, the resting time is extended to 48 hours, or an artificial heating / cooling cycle is adopted to simulate an equivalent temperature difference cycle. The final tightening can only be carried out after the stress is released. The reference section vertical keel is also tightened according to the initial tightening and temperature-selective final tightening process in this step. After the stress of the reference section keel is released and the final tightening is stable, the three-dimensional coordinate re-measurement in step S1 is carried out.

[0015] Furthermore, after the vertical keel is installed, a waterproof baffle is fixed to the inside of the vertical keel; Insulation material is fixed between the building walls and the keel, and a moisture-proof and vapor-barrier layer is laid simultaneously.

[0016] Furthermore, the horizontal keel is made of aluminum alloy profile or hot-dip galvanized angle steel and is fixed to the vertical keel by bolt connection or welding; the spacing of the horizontal keel is set according to the stone grid.

[0017] Furthermore, in step S2, the stone panel is made of granite, marble, or sandstone, and the thickness of the panel is matched to the building height. Before processing, the stone panels are cut, edge-ground, and numbered; The back bolt hole is a rear-cut structure with a tapered enlarged hole at the bottom. The back bolt is made of stainless steel and is equipped with isolation, buffer and locking components. Before inserting the back bolt, inject a measured amount of stone-specific sealant into the bottom of the tapered enlarged hole of the back bolt hole, then insert the back bolt and pre-tighten it; The injection volume of the quantitative stone-specific sealant (Unit: ml) Determined by the following formula: ,in Volume of the conical pore (unit: ml). This is the glue injection coefficient, with a value ranging from 0.70 to 0.85; Conical enlarged hole volume = , The depth of the tapered hole (mm). The diameter of the larger end of the enlarged hole (mm). The pin hole diameter is (mm); when the stone panel thickness is 25~30mm and the pin hole diameter is 6~8mm... Approximately 2.5~3.5ml, corresponding injection volume Approximately 1.8~3.0ml; in engineering, 2ml can be used as the baseline value, and adjusted proportionally according to the above formula based on the actual pore diameter and depth; in engineering, a pore diameter and depth comparison table can also be prepared in advance, or a graduated quantitative dispensing gun can be used to directly inject according to the calculated volume.

[0018] Furthermore, in step S4, the stone slabs are hung from bottom to top, and the stone hanging components are aligned with the horizontal keel hangers and smoothly inserted into the groove; during the hanging process, the stone slabs are adjusted in three directions to control the flatness of the slab surface and the width of the slab joints. After leveling and verification, tighten all bolts and simultaneously install the anti-vibration pads and limiting components; The curtain wall facade is divided into several construction zones. In each zone, the reference stone panels at the four corners and the center are installed first. After calibration and fixing, the installation is extended along the horizontal left and right symmetrical direction and the vertical up and down synchronous direction with the reference block as the origin. Stone fastening is carried out in three stages, with the specific sequence as follows: ① When initially aligning the parts, perform a first-level pre-tightening, controlling the initial tightening torque to be 50%~60% of the final tightening torque design value; ② With the reference plate as the center, expand the installation in a horizontally symmetrical and vertically synchronous direction. After the installation of three adjacent plates is completed, perform three-dimensional fine adjustment and execute two-level locking to lock the connectors to 80%~90% of the design value so that the local area is evenly stressed. ③ After all the panels on the entire floor or in the entire zone have been installed, conduct an overall review and use a torque wrench to perform a three-stage final tightening at 100% of the design value.

[0019] Furthermore, in step S5, a galvanized support plate is installed at the interlayer position and filled with fireproof and heat-insulating material; Foam strips are filled into the joints between boards, and weather-resistant sealant specifically for stone is applied to the outside. Special aluminum profiles are used for finishing the inside and outside corners and edges, and the ends are sealed. The joint sealing is applied in two stages: first, the deep part of the joint is filled to form a bottom sealing layer, and after it is surface dry, a surface sealant is applied and shaped; the surface temperature of the substrate is controlled at 5~35℃ and the relative humidity is not greater than 80% during the application of the sealant, avoiding the period of direct sunlight at high temperature; after the sealing treatment is completed, the stone slab surface is cleaned and the surface protective film is removed to protect the finished product; after completing the water spray test and appearance inspection, the project data is sorted out and the final acceptance is carried out.

[0020] Compared with the prior art, the beneficial effects of the present invention are: 1. Eliminate keel installation deviations to achieve precise matching between stone panels and keels. This invention fundamentally shifts the accuracy benchmark from "theoretical design value" to "actual on-site value" by installing only the reference section keel on the main structure, re-measuring its actual three-dimensional coordinates, and directly using the measured coordinates as the processing basis for the stone back bolt holes. Simultaneously, through quantitative regulations and representative verification of the reference section layout rules, and by adding control keels and re-verifying when verification fails, it ensures that the sampled coordinates accurately reflect the overall deviation pattern.

[0021] Meanwhile, a system deviation weighted correction algorithm (target schedule compression rate and accuracy level correction) is adopted to partially compensate for the measured coordinates. This avoids the local stress distortion that may result from full compensation and also reserves a reasonable margin for installation and adjustment. Experimental data shows that after adopting this invention, the on-site cutting / rework rate is reduced from 15% to below 1.5% using the traditional method, the qualified rate of board joint width is increased from 82% to over 96%, and the surface flatness deviation is reduced from 3.5mm to below 1.8mm.

[0022] 2. Enables parallel construction on-site and at the processing end, significantly shortening the construction period. This invention synchronizes the reference keel coordinates to the stone processing end, allowing the remaining keels to continue installation on-site. Simultaneously, the processing end prefabricates stone mounting components in batches, forming a fully parallel operation mode. It is particularly important to emphasize that the processing end's back bolt hole machining, back bolt insertion, and pre-installation of mounting components typically takes 7-15 days. This period completely overlaps with the on-site keel continuation and stress release period in step S3. Therefore, the aforementioned waiting time is not included in the total construction period of the critical path, fully leveraging the advantages of parallel operation. Taking a 10,000㎡ curtain wall as an example, the traditional method has a total construction period of approximately 120 days, while the standard solution of this invention can be shortened to 85 days, and the rapid construction solution can be shortened to 70 days, significantly improving construction efficiency.

[0023] 3. Effectively control thermal stress in the keel and improve long-term installation stability. This invention employs a process for vertical keel installation: "initial tightening → at least one complete day-night temperature difference cycle → final tightening at a selected temperature," and clearly defines the quantitative standard for the temperature difference cycle (a natural day or equivalent 48 hours of static rest with a temperature difference ≥10℃, or simulating an equivalent temperature difference cycle using artificial heating / cooling cycles). In particular, it explicitly requires that the reference section of the keel also undergo this stress release process before it can be used as a measurement benchmark, avoiding the temporal logic defect of distorted benchmark data due to unreleased stress in the reference section itself. This measure ensures that the keel is finally tightened under the most representative temperature conditions, releasing the additional stress generated by thermal expansion and contraction, and preventing keel bending and panel warping caused by temperature difference deformation. The back bolt pull-out force dispersion coefficient is reduced from 0.25 in the traditional method to below 0.12, indicating a significant improvement in the stress uniformity and reliability of the connection node.

[0024] 4. Graded fastening and symmetrical expansion installation ensure uniform stress on the panel. This invention employs a three-stage tightening process: first-stage pre-tightening (during installation), second-stage locking (after leveling three adjacent panels), and third-stage final tightening (after the entire layer is completed). It provides clear torque control ranges for each stage of tightening and an extended installation method based on a "reference panel – horizontally symmetrical, vertically synchronous" approach. Compared to traditional independent leveling of each panel, this method effectively prevents unidirectional error accumulation and localized stress concentration, avoids micro-cracks in the stone panels due to installation stress, and improves the wind pressure and seismic resistance of the curtain wall. Attached Figure Description

[0025] Figure 1 This is a flowchart of the overall process of the present invention. Figure 2 and Figure 3 This is a schematic diagram of the existing back-bolted stone curtain wall installation structure. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The present invention will be further described with reference to the accompanying drawings and embodiments: This invention proposes a standardized construction method for back-bolted stone curtain walls. Its core innovation lies in establishing a standardized production line that is "data-driven, parallel collaborative, and hierarchically precise," from main structure construction to stone panel installation. This method fundamentally solves the problems in traditional back-bolted curtain wall construction, such as the mismatch between factory-processed stone panels and actual on-site dimensions due to accumulated deviations in keel installation, resulting in extensive on-site cutting and rework, as well as low installation accuracy, poor efficiency, and stress concentration.

[0027] The following is combined Figure 1 A specific implementation of this method is described in detail below. This method mainly includes the following steps: S1: Installation of the reference keel and remeasurement of three-dimensional coordinates During the main structural construction phase, the first step is to prepare for construction and conduct surveying and layout based on the design drawings. Prior to this, a specific plan approval and physical performance tests of the curtain wall (wind pressure, water tightness, air tightness, and in-plane deformation) must be completed to ensure the main structural strength meets standards. Incoming materials must undergo re-inspection, and post-installed anchor bolts must pass a pull-out test. Layout work should be carried out under wind conditions not exceeding level 4 to ensure the initial accuracy of the baseline.

[0028] Subsequently, anchors are installed on the main building structure. The anchors include pre-embedded plates and post-installed anchors. Pre-embedded plates with excessive deviations need to be reinforced, and post-installed anchors can only be put into use after passing the pull-out test.

[0029] Next, install the vertical and horizontal joists for the reference section. To ensure the reference section is sufficiently representative, the vertical joists for the reference section should include at least the boundary joists at both ends of the building facade and at least one control joist in the middle. The horizontal joists for the reference section should include at least one control joist at the bottom, top, and middle levels. When the building height H > 100m or the facade area > 5000㎡, at least two additional middle control joists and corresponding horizontal joists should be added to ensure that the sampled coordinates fully reflect the overall deviation pattern.

[0030] The reference keel is fixed to the anchor using L-shaped connecting angle brackets with three-way adjustment (front-back, left-right, and up-down). The angle brackets are equipped with stainless steel bolts and anti-corrosion washers. The installation sequence is as follows: first, install the reference section vertical keel and check its verticality; then, install the reference section horizontal keel on the vertical keel. After the reference section keel is installed, it needs to be tightened according to the initial tightening and temperature-selective final tightening process in the subsequent steps. Only after the reference section keel has undergone at least one complete day-night temperature difference cycle to release stress and stabilize after final tightening can subsequent three-dimensional coordinate remeasurement be carried out to avoid distortion of the reference data due to unreleased stress in the reference section itself.

[0031] After the re-measurement was completed, a high-precision total station was used to measure and output the actual three-dimensional coordinates of the reference keel. Simultaneously, at least three additional check points were selected on the inner and outer sides and upper and lower edges of the reference section for deviation verification. If the average deviation of the check points is consistent with the overall systematic deviation of the reference section... , If the difference does not exceed ±3mm, the benchmark section is considered to have overall representativeness; otherwise, the layout range of the benchmark section is adjusted (such as densifying the intermediate control keel), and a complete retest, overall system deviation value calculation and verification are carried out again until the condition is met, so as to ensure that the benchmark section data has true overall representativeness.

[0032] Key Innovations: Traditional methods involve installing all the keel sections before measurement, at which point accumulated errors become uncorrectable. This step innovatively installs only the benchmark section of the keel and immediately remeasures its actual spatial coordinates. Furthermore, through quantification and representative verification of the benchmark section layout rules (including a re-verification mechanism for failed verification), it ensures that the small sample benchmark accurately reflects the overall deviation pattern. This reversed "measure first, then do" process shifts the accuracy benchmark for all subsequent work from "theoretical design values" to "actual on-site values," effectively eliminating systematic deviations generated by upstream processes such as main structure construction, embedded plate positioning, and keel installation.

[0033] S2: Deviation Weighted Correction and Prefabrication of Stone Hanging Components The measured grid coordinates of all benchmark keel obtained in step S1 are synchronized to the stone processing end via a BIM platform or dedicated data link. At the processing end, this invention employs an innovative system deviation weighted correction algorithm to process the measured coordinates to obtain the final processing coordinates.

[0034] Calculate the final hole position machining coordinates of the i-th back bolt hole using the following formula. ;

[0035] In the formula: ( , () is the measured grid coordinate of the baseline keel; , The overall system deviation value of the reference keel (i.e., the arithmetic mean of the differences between the measured coordinates and the theoretical design coordinates of each reference keel). This is the system deviation correction factor, with a value range of 0.85 to 0.95.

[0036] The The value is determined based on statistical regression analysis of a large amount of engineering measured data. The lower limit of 0.85 is the safety threshold for adjustment margin (below this value, the correction effect is not obvious, and the workload of on-site adjustment is too large), and the upper limit of 0.95 is the critical value to avoid local stress distortion (above this value, it is easy to overcompensate and amplify local errors). The specific calculation is as follows: =0.85+0.10×( / 200), where The building height (unit: meters) is when Take when ≥200 =200; Simultaneously, adjustments are made based on the construction period requirements: the aforementioned construction period compression rate refers to the reduction ratio compared to the planned construction period of the traditional sequential construction scheme (i.e., stone processing is carried out only after all the keel installations are completed). This compression rate is predetermined by the overall project schedule target. When the construction period compression rate ≥ 20%, Adjust the value downwards by 0.02~0.03 from the original calculated value; when the accuracy level requirement is ultra-high (allowable deviation of plate joint width ≤ 1.0mm), The value was adjusted upwards by 0.02 to 0.03 from the original calculated value; ultimately... The value is the corrected value and rounded to two decimal places, still within the range of 0.85 to 0.95.

[0037] The closer the value is to 0.85, the more conservative the correction, and the greater the reliance on the adjustment capability of the hangers. It is suitable for projects with tight schedules and general keel installation accuracy. The closer the value is to 0.95, the more thorough the correction, making it suitable for projects with stringent installation accuracy requirements, such as high-rise buildings and areas with high wind pressure; generally recommended for general engineering projects. =0.90.

[0038] Based on the calculated final processing coordinates, high-precision back-cut bolt holes are machined on the back of the stone panel. Bolt hole processing parameters: hole diameter 6~8mm, tapered enlargement angle 90°~120°, hole depth tolerance ±0.5mm, bottom is a tapered enlargement structure.

[0039] Subsequently, a measured amount of stone-specific sealant is injected into the bottom of the tapered enlarged hole of the back bolt hole. The injection volume of the measured amount of stone-specific sealant... (Unit: ml) Determined by the following formula: ,in Volume of the conical pore (unit: ml). This is the glue injection coefficient, with a value ranging from 0.70 to 0.85; Conical enlarged hole volume = , The depth of the tapered hole (mm). The diameter of the larger end of the enlarged hole (mm). The pin hole diameter is (mm); when the stone panel thickness is 25~30mm and the pin hole diameter is 6~8mm... Approximately 2.5~3.5ml, corresponding injection volume The volume is approximately 1.8~3.0 ml; it is recommended to use 2 ml as a baseline reference value in engineering, and adjust it according to the actual hole diameter and depth according to the formula above. In engineering, a hole diameter and depth comparison table can also be prepared in advance, or a graduated quantitative dispensing gun can be used to directly inject according to the calculated volume to improve the convenience and accuracy of on-site operation.

[0040] Next, insert stainless steel back bolts and pre-tighten them. Finally, pre-install the hangers onto the back bolts and pre-tighten and level them to obtain the stone hanging assembly.

[0041] Key Creative Points: The core of this creative step lies in the system deviation weighted correction algorithm. Traditional methods either directly use theoretical values ​​for processing, leading to installation difficulties on-site; or use measured values ​​of the keel for complete compensation, but this amplifies local measurement errors and may cause unexpected stress on the stone panel in extreme locations. This invention introduces... The coefficient (0.85~0.95) creatively implements an "incomplete compensation" strategy. Its technical advantages are: ① Avoid stress concentration; ② Absorb residual error; ③ Achieve flexible connections.

[0042] [Specifically, in this step, the "target time reduction rate" is used as...] The adjustment parameter of the coefficient, since the compression rate is predetermined by the overall project schedule target, avoids logical loops that use construction results as input parameters, thus... The determination of the value is feasible before construction.

[0043] Furthermore, pre-applying sealant before inserting the back plug effectively fills the voids at the bottom of the hole, preventing moisture intrusion and loosening of the back plug, significantly improving the durability of the connection joint. The selection criteria for the coefficients and the machining parameters for the back bolt holes enable those skilled in the art to directly reproduce the technical solution.

[0044] S3: Parallel construction and batch prefabrication Simultaneously, the remaining vertical and horizontal keels were installed on-site, while the processing end simultaneously prefabricated stone hanging components in batches according to the corrected coordinates.

[0045] During on-site keel installation, aluminum alloy profiles or hot-dip galvanized square steel pipes are used for the vertical keels. During installation, the two ends of the vertical keels are fixed first, and a guide line is laid, then the middle vertical keels are installed sequentially. Vertical keel extensions are achieved using core tube sleeves, with expansion joints reserved at the extension points. Specifically, after the vertical keels are in place, initial tightening is performed. After at least one complete day-night temperature difference cycle, once stress release is complete, the verticality is re-measured during a period when the daily temperature is close to the annual average temperature of the project location, and then final tightening is completed. The complete day-night temperature difference cycle refers to a natural day cycle with an ambient temperature variation of not less than 10℃. If the local day-night temperature difference is less than 10℃, the settling time is extended to 48 hours, or an artificial heating / cooling cycle is used to simulate an equivalent temperature difference cycle (temperature difference not less than 10℃). Final tightening can only be performed after stress release is complete, ensuring the method is operable in different climatic regions.

[0046] The term "close to the annual average temperature" refers to the absolute value of the difference between the current day's temperature and the annual average temperature of the project location not exceeding 5℃. It should be emphasized that the reference section vertical keel in step S1 is also tightened using the same initial tightening and temperature-selective final tightening process as in this step. Only after the stress in the reference section keel is released and the final tightening is stable should the three-dimensional coordinate remeasurement in step S1 be performed to ensure the long-term stability of the reference data.

[0047] It should be noted that this stress release period (at least one full calendar day) completely overlaps with the processing period (usually 7-15 days) required for the stone processing end to perform back bolt hole processing, back bolt insertion, and pre-installation of the hanger in step S2. Therefore, this waiting time is not included in the total construction period of the critical path, and the advantages of parallel operation are fully preserved, effectively relieving the tension between the stress release process and the time compression target.

[0048] Key Creative Aspects: This step enables parallel operation of "on-site keel installation" and "in-plant stone processing," significantly reducing the overall construction period. The "initial tightening - stress release - temperature-selective final tightening" process for vertical keel installation is another innovative detail. By quantitatively defining the temperature difference cycle and using an equivalent manual substitution scheme, this method becomes operable in different climatic regions, avoiding insufficient stress release due to excessively small temperature differences. Furthermore, the clear definition of the stress release sequence in the reference section eliminates the logical risk of measurement reference drift.

[0049] S4: Stone installation and graded fastening The prefabricated stone mounting components are attached to the corresponding horizontal keel brackets from bottom to top. During installation, the curtain wall facade is divided into several construction zones. In each zone, the reference stone panels at the four corners and center are installed first. After calibration and fixing, the installation is expanded in a horizontally symmetrical and vertically synchronized manner, with the reference blocks as the origin.

[0050] The stone fastening adopts a three-level standard, with the specific timing as follows: Level 1 (Initial pre-tightening): After the plate is aligned and inserted into the groove, Level 1 pre-tightening is performed. The initial tightening torque is controlled to be 50%~60% of the final tightening torque design value to ensure that the plate does not fall off. Level 2 (zonal leveling): With the reference plate as the center, the installation is expanded in a horizontally symmetrical and vertically synchronous direction. After the installation of three adjacent plates is completed, three-dimensional fine adjustment is carried out to ensure the overall flatness of the local area and the uniformity of the plate gap width. The connectors are locked to 80%~90% of the design value so that the adjacent plates are evenly stressed. Level 3 (Final Tightening of the Entire Floor): After all the panels of the entire floor or the entire section have been installed, all connecting bolts are checked as a whole and tightened to 100% of the design value using a torque wrench. At the same time, anti-vibration pads and limiting components are installed.

[0051] Key Creative Aspects: The "sequential three-stage tightening" and "reference plate-symmetrical expansion" installation methods proposed in this step represent a significant improvement over the traditional "bottom-up, piece-by-piece leveling" approach. The "symmetrical expansion" method evenly distributes errors to both sides, preventing accumulation. Strictly binding the timing of the "three-stage tightening" and "symmetrical expansion" (i.e., expanding while leveling in sections, and finally tightening uniformly) ensures "stress homogenization" throughout the entire installation process. Furthermore, by quantifying the torque values ​​at each stage, it effectively prevents warping of the stone panels and internal micro-cracks caused by excessive tightness at a single point or excessive looseness at adjacent points.

[0052] S5: Sealing and Finished Product Protection The joint sealing process involves two applications: first, foam strips are filled and stone-specific weather-resistant sealant is injected into the depth of the joint to form a bottom sealing layer; after it dries to the surface, a top layer of sealant is applied and shaped into a concave arc surface with a scraper.

[0053] During the adhesive application process, the substrate surface temperature should be controlled between 5 and 35°C, and the relative humidity should not exceed 80%, avoiding periods of direct sunlight and high temperatures. Galvanized support plates should be installed between layers and filled with fire-resistant and heat-insulating material. Specialized aluminum profiles should be used for finishing corners and edges, with sealed ends. After completion, the stone slab surface should be cleaned, the protective film removed, and finished product protection implemented. A water spray test and final acceptance should then be conducted.

[0054] Key Creative Aspects: Conventional sealant applied in a single application is prone to forming penetrating water seepage channels due to sealant shrinkage or internal air bubbles. The "two-application" process of this invention creates a "double-insurance" waterproof structure, significantly improving the water tightness and air tightness of the curtain wall.

[0055] Examples and Data Validation To further highlight the inventiveness and technical advantages of this invention, three specific embodiments are provided below, and data are compared with traditional construction methods.

[0056] Example 1 (Standard Scheme) The standard process described in S1-S5 of this invention is adopted. In step S2, the correction coefficient β is set to 0.90. 30mm thick granite is selected as the stone material, and the depth of the back bolt hole is 15mm. The injection volume is calculated according to the injection formula of this invention (2ml is recommended as a baseline reference value). The average temperature during construction is 15℃.

[0057] Example 2 (High-precision solution) Based on Example 1, this method is designed for ultra-high-rise buildings with extremely high wind pressure requirements.

[0058] In step S1, the vertical keel of the reference section is densified to one keel for every two spans.

[0059] In step S2, The value is 0.95 (according to...). (Calculated for distances ≥200 meters).

[0060] The stress relief cycle in step S3 is extended to 3 day-night temperature difference cycles (if the day-night temperature difference is <10℃, artificial heating / cooling cycle simulation or static 144 hours is used).

[0061] In the three-stage tightening process of step S4, a torque wrench is introduced, and the final tightening torque is uniformly controlled to ±5% of the design value.

[0062] Example 3 (Rapid Construction Solution) Building upon Example 1, and specifically for projects with tight deadlines, the parallel collaboration efficiency of steps S1 to S3 is maximized by utilizing a BIM platform to synchronize the measured coordinates of the keel with the stone processing data in real time.

[0063] In step S2, A value of 0.85 is chosen to maximize the adjustability of the hanger and reduce the stringent requirements for machining precision. Because... The reduced value makes the processing size closer to the conventional nominal size, enhances the versatility and interchangeability of stone components, and greatly improves the speed of hoisting and positioning; the three-way adjustment range of the hangers is sufficient, and fine-tuning can be quickly completed through standardized operations after installation, so the overall installation time is further shortened compared with the standard solution.

[0064] Comparative example (traditional method) The traditional back-bolt construction method is adopted: after all the keel is installed, the whole measurement is carried out, the stone is processed in the factory based on the theoretical size, and if any mismatch is found during on-site installation, it is cut, hole-repaired or shims are added for adjustment. Each piece is installed and leveled.

[0065] Data Comparison

[0066] Data Analysis and Conclusions: The data in the table above clearly shows that: 1. Improved efficiency: Due to the implementation of parallel construction and precise prefabrication, the on-site installation speed and total construction period of each embodiment of the present invention are significantly better than traditional methods. The construction period of embodiment three is shortened by more than 40%.

[0067] 2. Leap in quality: Through “deviation correction” and “graded fastening”, the installation accuracy and connection reliability of the present invention are far superior to those of traditional methods. Example 2 achieves a level of near-zero defects.

[0068] 3. Enhanced durability: Thanks to the "pre-injection" and "double-application of sealant" processes, the water tightness of the curtain wall of this invention is fundamentally guaranteed, and the leakage rate is greatly reduced.

[0069] The above data verifies the standardized construction method proposed in this invention. Through substantial innovations in each step (data-driven, incomplete compensation, stress release, parallel collaboration, graded fastening, and double sealing), it systematically solves the pain points of traditional processes and brings unexpected technical improvements in construction efficiency, installation accuracy, structural safety, and long-term durability.

[0070] It should be noted that, Figure 2 as well as Figure 3 The conventional anchoring and hanging node structure of existing back-bolted stone curtain walls is shown. The construction method of the present invention is applicable to such existing node structures, and its specific construction is known in the art. Figure 2 and Figure 3 This is only used to illustrate the applicable scenarios of the method of the present invention, and its specific component composition and connection form are not intended to limit the technical solution of the present invention.

[0071] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for installing back-bolted stone curtain walls, characterized in that, Includes the following steps: S1 lays out anchors on the main building structure, installs the reference section vertical keel and the reference horizontal keel, and re-measures and outputs the actual grid three-dimensional coordinates of the reference keel. S2 synchronizes the measured coordinates of the reference keel to the stone processing end, performs a systematic deviation weighted correction on the measured coordinates to obtain the final processing coordinates, and processes back-cut bolt holes on the back of the stone panel according to the processing coordinates, inserts the back bolts and pre-installs the hangers to produce the stone hanging component. Simultaneously, the remaining vertical and horizontal keels were installed on site S3, and the stone hanging components were prefabricated in batches at the processing end. S4 attaches the stone hanging component to the corresponding horizontal keel hanging piece, adjusts the position, and then tightens all the connecting pieces; S5 seals the seams and edges of the boards.

2. The method for installing back-bolted stone curtain walls according to claim 1, characterized in that, In step S2, the weighted correction of system deviation is used to calculate the final hole position machining coordinates using the following formula: In the formula: ( , () is the measured grid coordinate of the baseline keel; , The overall system deviation value of the reference keel is the arithmetic mean of the differences between the measured coordinates and the theoretical design coordinates of each reference keel. This is the system deviation correction factor, with a value range of 0.85 to 0.

95. The The value is determined based on statistical regression analysis of a large amount of engineering measured data. The lower limit of 0.85 is the safety threshold for adjustment margin, and the upper limit of 0.95 is the critical value to avoid local stress distortion. The specific calculation is as follows: =0.85+0.10×( / 200), where The building height (unit: meters) is when When H=200, the value is ≥200; adjustments are made based on the project schedule requirements: the aforementioned schedule reduction rate refers to the reduction ratio compared to the planned schedule of the traditional sequential construction scheme (i.e., stone processing is carried out only after all the keel installations are completed). This reduction rate is predetermined by the overall project schedule target. When the schedule reduction rate is ≥20%, The value was lowered by 0.02 to 0.03 from the original calculation. When the accuracy level requirement is ultra-high (allowable deviation of plate gap width ≤ 1.0mm), The value was adjusted upwards by 0.02 to 0.03 from the original calculated value; ultimately... The value is the corrected value and rounded to two decimal places, still within the range of 0.85 to 0.

95.

3. The method for installing back-bolted stone curtain walls according to claim 1, characterized in that, Before step S1, the construction preparation and surveying / layout procedures must be completed: Complete the approval of the special plan and conduct tests on the curtain wall's wind pressure, water tightness, air tightness, and in-plane deformation performance to confirm that the main structure's strength meets the standards; Complete the re-inspection of incoming materials and the pull-out test of post-installed anchor bolts; Verify the civil engineering axis and elevation, mark the keel and grid control lines, and carry out the layout work under the condition that the wind force is no greater than level 4.

4. The method for installing back-bolted stone curtain walls according to claim 1, characterized in that, In step S1, the anchor includes a pre-embedded plate and a post-installed anchor. The pre-embedded plate with excessive deviation is reinforced, and the post-installed anchor is used after passing the pull-out test. The base keel is fixed to the anchor by L-shaped connecting angle brackets. The connecting angle brackets are equipped with stainless steel bolts and anti-corrosion washers, and have three-way adjustment: front-back, left-right, and up-down. The standard section of vertical keel should cover both ends of the building facade and have at least one control vertical keel in the middle; when the building height H>100m or the facade area>5000㎡, no less than two middle control vertical keels and corresponding horizontal keels should be added. After the retest is completed, at least three additional verification points are selected on the inner and outer sides and the upper and lower edges of the reference section for deviation verification. If the average deviation of the verification points is similar to the overall systematic deviation of the reference section, then the deviation is considered to be correct. , If the difference does not exceed ±3mm, the benchmark section is considered to have overall representativeness; otherwise, the layout range of the benchmark section is adjusted, and a complete re-measurement, overall system deviation value calculation and verification are carried out again until the condition is met, so as to ensure that the benchmark section data has true overall representativeness.

5. The method for installing back-bolted stone curtain walls according to claim 4, characterized in that, The vertical keel is made of aluminum alloy profiles or hot-dip galvanized square steel pipes, and the damaged parts of the steel components are treated with rust prevention. During installation, first fix the two vertical keels at both ends and pull the guide line, then install the middle vertical keel in sequence; The vertical keel is extended using a core tube sleeve connection, with an expansion joint reserved at the extension point; After the vertical keel is in place, it is initially tightened and fixed. After stress release is completed through at least one complete day-night temperature difference cycle, the verticality is re-measured when the temperature of the day is close to the annual average temperature of the project location. Then, the final tightening is completed. The temperature close to the annual average temperature means that the absolute value of the difference between the temperature of the day and the annual average temperature of the project location is not greater than 5℃. The complete day-night temperature difference cycle means a natural day cycle with an ambient temperature change range of not less than 10℃. If the local day-night temperature difference is less than 10℃, the resting time is extended to 48 hours, or an artificial heating / cooling cycle is adopted to simulate an equivalent temperature difference cycle. The final tightening can only be carried out after the stress is released. The reference section vertical keel is also tightened according to the initial tightening and temperature-selective final tightening process in this step. After the stress of the reference section keel is released and the final tightening is stable, the three-dimensional coordinate re-measurement in step S1 is carried out.

6. The method for installing back-bolted stone curtain walls according to claim 5, characterized in that, After the vertical keel is installed, a waterproof baffle is fixed inside the vertical keel; Insulation material is fixed between the building walls and the keel, and a moisture-proof and vapor-barrier layer is laid simultaneously.

7. The method for installing back-bolted stone curtain walls according to claim 6, characterized in that, The horizontal keel is made of aluminum alloy profile or hot-dip galvanized angle steel and is fixed to the vertical keel by bolt connection or welding; the spacing of the horizontal keel is set according to the stone grid.

8. The method for installing back-bolted stone curtain walls according to claim 1, characterized in that, In step S2, the stone panel is made of granite, marble or sandstone, and the thickness of the panel is matched with the building height. Before processing, the stone panels are cut, edge-ground, and numbered; The back bolt hole is a rear-cut structure with a tapered enlarged hole at the bottom. The back bolt is made of stainless steel and is equipped with isolation, buffer and locking components. Before inserting the back bolt, inject a measured amount of stone-specific sealant into the bottom of the tapered enlarged hole of the back bolt hole, then insert the back bolt and pre-tighten it; The injection volume of the quantitative stone-specific sealant (Unit: ml) Determined by the following formula: ,in Volume of the conical pore (unit: ml). This is the glue injection coefficient, with a value ranging from 0.70 to 0.85; Conical enlarged hole volume = , The depth of the tapered hole (mm). The diameter of the larger end of the enlarged hole (mm). The pin hole diameter is in mm; when the stone panel thickness is 25~30mm and the pin hole diameter is 6~8mm... Approximately 2.5~3.5ml, corresponding injection volume Approximately 1.8~3.0ml; in engineering, 2ml can be used as the baseline value, and adjusted proportionally according to the above formula based on the actual pore diameter and depth; in engineering, a pore diameter and depth comparison table can also be prepared in advance, or a graduated quantitative dispensing gun can be used to directly inject according to the calculated volume.

9. The method for installing back-bolted stone curtain walls according to claim 8, characterized in that, In step S4, the stone slabs are hung from bottom to top, and the stone hanging components are aligned with the horizontal keel hangers and smoothly inserted into the groove; during the hanging process, the stone slabs are adjusted in three directions to control the flatness of the slab surface and the width of the slab joints. After leveling and verification, tighten all bolts and simultaneously install the anti-vibration pads and limiting components; The curtain wall facade is divided into several construction zones. In each zone, the reference stone panels at the four corners and the center are installed first. After calibration and fixing, the installation is extended along the horizontal left and right symmetrical direction and the vertical up and down synchronous direction with the reference block as the origin. Stone fastening is carried out in three stages, with the specific sequence as follows: ① When initially aligning the parts, perform a first-level pre-tightening, controlling the initial tightening torque to be 50%~60% of the final tightening torque design value; ② With the reference plate as the center, expand the installation in a horizontally symmetrical and vertically synchronous direction. After the installation of three adjacent plates is completed, perform three-dimensional fine adjustment and execute two-level locking to lock the connectors to 80%~90% of the design value so that the local area is evenly stressed. ③ After all the panels on the entire floor or in the entire zone have been installed, conduct an overall review and use a torque wrench to perform a three-stage final tightening at 100% of the design value.

10. The method for installing back-bolted stone curtain walls according to claim 9, characterized in that, In step S5, a galvanized support plate is installed between the layers and filled with fireproof and heat-insulating material. Foam strips are filled into the joints between boards, and weather-resistant sealant specifically for stone is applied to the outside. Special aluminum profiles are used for finishing the inside and outside corners and edges, and the ends are sealed. The sealing of the board joints is applied in two stages: first, the deep part of the board joint is filled to form a bottom sealing layer, and after it is surface dry, the top layer of sealant is applied and shaped; the surface temperature of the substrate is controlled at 5~35℃ and the relative humidity is not greater than 80% during the application of sealant, and the high temperature direct sunlight period is avoided. After the sealing process is completed, the stone slab surface is cleaned and the protective film is removed to protect the finished product; after completing the water spray test and visual inspection, the project data is organized and the project is accepted upon completion.

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