Construction method for replacing temperature post-pouring belt with expansion reinforcing plate belt

Abstract

The application relates to a construction method for replacing temperature post-pouring belts with expansion reinforcing plate belts, and belongs to the technical field of building protection. In the construction method, the temperature post-pouring belt part of a floor is replaced by a concrete reinforcing belt, the reinforcing of the concrete reinforcing belt is increased, and the performance of the concrete at the part is adjusted, so that the expansion performance of the concrete at the part is improved, and the purpose of canceling the construction of the temperature post-pouring belts of each floor of a main building is achieved, thereby solving the problems of material waste, high construction cost, long construction period and leakage hidden troubles caused by the construction of the temperature post-pouring belts.

Description

Technical Field

[0001] This invention relates to the field of building protection technology, and more particularly to expansion joint protection components for buildings. Background Technology

[0002] During the main structural construction phase, according to structural design requirements, once the concrete structure construction length exceeds a certain distance, temperature-controlled post-cast strips are required to reduce the impact of stress caused by concrete temperature shrinkage on the structure. The principle for setting these strips is as follows: every 40m along the foundation length, a temperature-controlled post-cast strip should be left, penetrating the top slab, bottom slab, and walls. The joint width should not be less than 800mm, and it should preferably be located within the middle range of three equal divisions between column spacings. An additional waterproof layer should be applied to the bottom slab and exterior walls at the temperature-controlled post-cast strip location. The concrete for the post-cast joint should be poured two months after the concrete on both sides is poured, and its strength grade should be one level higher. Early-strength, shrinkage-compensating concrete should preferably be used. The strips should be placed layer by layer from the foundation to the top floor. For high-rise residential buildings, if temperature-controlled post-cast strips are installed on each floor slab (including the top and bottom slabs) during the main structural construction, separate supports are required for the formwork of the temperature-controlled post-cast strips. These supports must also be installed separately for this area during formwork removal, continuing until the concrete in the temperature-controlled post-cast strip is poured. This results in material waste and increased construction costs. Furthermore, the concrete for the temperature-controlled post-cast strips must be poured some time after the concrete on both sides has been poured, impacting subsequent secondary structure and floor / ground construction, thus affecting the construction schedule. Additionally, the temperature-controlled post-cast strip area is a vulnerable area for leakage in the main structure; improper handling may lead to leakage problems during later use, affecting the structure's functionality. Summary of the Invention

[0003] The purpose of this invention is to provide a construction method that uses expansion-strengthened strips to replace temperature-reinforced post-cast strips in floor slabs. By replacing the temperature-reinforced post-cast strips with concrete reinforcement strips and adjusting the properties of the concrete in that area, the expansion and contraction properties of the concrete in that area are improved. Ultimately, this method aims to eliminate the need for temperature-reinforced post-cast strips on each floor of the main building, thereby solving the problems of material waste, high construction costs, long construction periods, and potential leakage risks associated with the construction of temperature-reinforced post-cast strips.

[0004] The specific plan is as follows: A construction method that uses expansion-reinforced strips instead of temperature-controlled post-cast strips includes the following steps: S1: When setting up the formwork, the formwork and support frame of the post-pouring strip at the original temperature in the drawings and the surrounding floor slab formwork system shall be set up as a whole by simultaneously and continuously supporting the entire area. S2: When tying the floor slab reinforcement, first lay the bottom reinforcement of the floor slab, and set up a reinforcing strip area within 2m on both sides of the original temperature post-cast strip area in the drawing. Set up the longitudinal and transverse bottom reinforcing bars in the reinforcing strip area, and tie the bottom reinforcing bars to the bottom reinforcement of the floor slab. S3: After step S2 is completed, tie the bottom reinforcement bars of the floor slab. After tying, tie the top reinforcement bars of the reinforcement strip area. After tying, set up stirrups to ensure the spacing between the upper and lower reinforcement bars. S4: After S3 is completed, the area within the reinforcing strip is divided using wire mesh; S5: When pouring concrete, first pour the concrete in the floor slab area except for the reinforcing strip area. After the concrete is poured, use expansive concrete to pour the concrete in the reinforcing strip area. S6: When removing the formwork, the formwork at the reinforcing strip is removed together with the other formwork.

[0005] Furthermore, the reinforcing steel bar is a C8@200 type steel bar.

[0006] Furthermore, in step S2, the bottom reinforcing bars of the reinforced strip area extend into the adjacent floor slab for a seismic anchorage length LaE on each side.

[0007] Furthermore, in step S3, the top reinforcing bars of the reinforced strip area extend into the adjacent floor slab for a seismic anchorage length LaE on each side.

[0008] Furthermore, the LaE length is 15-20 times the diameter of the C8@200 type steel bar.

[0009] Furthermore, in step S5, the reinforced slab area and other parts of the adjacent floor slab are cast in one go before the concrete initially sets.

[0010] Furthermore, during concrete pouring in step S5, a vibrator is used to thoroughly compact the concrete.

[0011] Furthermore, step S5 also includes the following sub-steps: S51: Using finite element analysis software, import the parameters of the original structural drawings, input the concrete material properties, set the boundary parameters, accurately simulate the hydration heat and temperature shrinkage process of the reinforced strip area, and calculate and classify low, medium and high stress levels. S52: Adaptive concrete mix design: Determine the dosage of expansion agent for different stress zones based on stress level and concrete formula; S53: Graded pouring and quality control: Before pouring, mark the range of each stress zone, first pour ordinary expansive concrete in the low stress zone, and then proceed to the medium and high stress zones in sequence.

[0012] Furthermore, a dedicated fixing clamp is used to fix the fiber Bragg grating sensor to the steel reinforcement frame in the reinforcing plate area. The fiber Bragg grating sensor is connected to a control system.

[0013] Furthermore, the fiber grating sensors are respectively disposed in the low-stress region, medium-stress region and high-stress region of the reinforcing plate.

[0014] Compared with the prior art, the present invention has at least one of the following technical effects: 1. When constructing the main building's concrete structure using conventional methods, the formwork for the floor slabs and side walls must first be configured according to the design drawings. The formwork and support system for the temperature-reinforced concrete strip need to be set up separately from the support systems on both sides. During concrete pouring, wire mesh needs to be installed at the temperature-reinforced concrete strip to intercept the concrete and prevent it from flowing into the strip. When the formwork is removed after the floor slab concrete reaches a certain strength, independent supports for the temperature-reinforced concrete strip must be provided until the concrete in that area is poured. Using concrete reinforcement strips avoids the need for internal temperature-reinforced concrete strips during the main structure construction. When the floor slab formwork is erected and removed, the formwork for the temperature-reinforced concrete strip is erected and removed simultaneously with the surrounding structural components. This eliminates the need to wait for the concrete on both sides of the temperature-reinforced concrete strip to shrink and stabilize before pouring the concrete in that area. This provides conditions for the subsequent secondary structure and floor construction after the main structure is completed, accelerating the construction progress and saving construction time.

[0015] 2. Using the traditional method, temperature-controlled post-cast strips are left in the interior walls and floors of the main building. When pouring the concrete for the temperature-controlled post-cast strips after a certain period of time, a special person needs to be assigned to remove the laitance and loose surface concrete on both sides of the temperature-controlled post-cast strips and moisten them with neat cement slurry. Later, a waterproof layer needs to be set at the joint to prevent leakage. If not handled properly, the temperature-controlled post-cast strips are very likely to become weak points for leakage, affecting the functionality of the structure. If a reinforcing strip is set at the temperature-controlled post-cast strip location during the main structure construction, this part can be poured together with the surrounding floor slabs and walls in one go, forming a whole. This not only avoids the hidden danger of leakage at the temperature-controlled post-cast strip location, but also ensures that there is no joint between the temperature-controlled post-cast strip and the concrete floor slabs on both sides after demolding, resulting in a good overall appearance and quality. 3. According to the design requirements, the closure time for the temperature-controlled post-cast strip is 42 days after the concrete pouring on both sides is completed. During this period, in order to ensure that the concrete of the floor slab on both sides of the temperature-controlled post-cast strip does not deform due to the load on the upper part of the floor slab, the formwork and formwork support system on both sides of the temperature-controlled post-cast strip must be removed only after the concrete pouring at the temperature-controlled post-cast strip is completed and cured to the design requirements. Reinforced strips are used to replace the construction of the temperature-controlled post-cast strip in this part. During the construction of the main structure, the temperature-controlled post-cast strip area is poured and cured at the same time as other parts of the floor slab. After the strength reaches the design requirements, it is completely removed. This avoids the additional material and labor input caused by the need to set up independent supports for the temperature-controlled post-cast strip. It also reduces the time and labor input for grinding the floor slab after the temperature-controlled post-cast strip construction is completed, effectively reducing the on-site construction cost.

[0016] 4. Improved accuracy in stress matching, reducing cracking risk from the source: By accurately simulating the heat of hydration and shrinkage process using software such as Midas Gen, the reinforced strip area is divided into low, medium and high stress zones and matched with concrete with differentiated expansion rates. This solves the problem of insufficient or excessive expansion of traditional fixed-ratio concrete. Combined with subsequent sensor verification (±1με accuracy), the crack incidence rate in the reinforced strip area is significantly reduced compared to traditional technology.

[0017] 5. Fiber optic grating sensors collect temperature (±0.5℃ accuracy) and strain data in real time, set graded early warning thresholds according to simulated theoretical values, and automatically alarm when the threshold is exceeded; the monitoring data feeds back into the model for correction, which greatly improves the accuracy of subsequent engineering simulations and significantly enhances the targeted nature of risk management. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a partial schematic diagram of the steel reinforcement binding structure of the main building floor slab in this application.

[0020] Figure label: 1-Bottom reinforcing bar; 2-Top reinforcing bar; 3-LaE section of reinforcing bar; 4-Bottom bar; 5-Top bar. Detailed Implementation

[0021] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0022] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0023] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0024] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0025] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0027] In traditional construction methods, to reduce structural cracking caused by concrete temperature changes and according to design drawings, a temperature-controlled post-cast strip is required when the main structure exceeds a certain length, based on actual site conditions. However, this post-cast strip is extremely inconvenient for on-site construction, requiring separate support and waiting for the concrete on both sides to reach its curing time (generally at least 42 days) before it can be sealed. To ensure both construction progress and quality, a reinforced strip is used instead of the temperature-controlled post-cast strip in the main structure. See appendix Figure 1 A construction method that uses expansion-reinforced strips instead of temperature-controlled post-cast strips includes the following steps: S1: When setting up the formwork, the formwork and support frame of the original temperature-controlled post-pouring strip in the drawings are set up as a whole with the surrounding floor slab formwork system using a simultaneous and continuous full-span support method. This full-span support means arranging the spacing of the uprights, the step distance, and the position of the sweeping rods according to the construction plan requirements to ensure the safety of the formwork support system. When setting up the floor slab formwork, the setting of the temperature-controlled post-pouring strip is not considered (in the design of the drawings, the temperature-controlled post-pouring strip is set up simultaneously and continuously with the formwork of the adjacent floor slab, that is, the setting of the temperature-controlled post-pouring strip is not considered, and the temperature-controlled post-pouring strip is omitted). It is laid along the entire length to ensure the integrity of the structure. That is, during construction, the main building floor slab formwork support frame is set up according to the conventional construction method. The formwork support frame must be set up strictly according to the construction plan to determine the upright height, upright spacing, and step distance of the formwork support frame to ensure the overall rigidity and stability of the formwork support frame. When construction reaches the original temperature-controlled post-pouring strip position in the drawings (which does not exist in actual construction and is not set up), the formwork is set up as a whole at this position according to the construction method of the reinforcing strip. When laying the formwork, it is laid together with the surrounding floor slab.

[0028] S2: When tying the floor slab reinforcement, first lay the bottom reinforcement 4 on the floor slab formwork according to the reinforcement specifications and spacing (see Appendix). Figure 1 A reinforcing strip area shall be set within 2m on both sides of the original temperature post-cast strip area in the drawing (see Appendix). Figure 1 In the area between the two dotted lines, C8@200 longitudinal and transverse bottom reinforcing bars 1 are set in this area. When tying the bottom reinforcing bars 1, they are tied to the bottom reinforcing bars 4 at the bottom of the floor slab. It is strictly forbidden to miss tying them. S3: After the binding in step S2 is completed and self-inspection is passed, notify the supervision unit for acceptance. After acceptance, bind the bottom reinforcement 5 of the floor slab. After binding, bind the top reinforcement 2 of the reinforcing strip. After binding, set up stirrups to ensure the spacing between the upper and lower layers of reinforcement. The bottom reinforcement 5 of the floor slab is laid on the formwork according to the reinforcement specifications and spacing. After binding, C8@200 longitudinal and transverse top reinforcement 2 is set in the reinforcing strip area. When binding the top reinforcement 2, it is tied to the bottom reinforcement 5 of the floor slab. It is strictly forbidden to miss binding. After binding, set up stirrups to ensure the spacing between the upper and lower layers of reinforcement. On-site workers are required to set up spacers and stirrups according to the plan requirements to ensure that the reinforcement type, specifications, and spacing meet the design requirements. When laying the floor slab reinforcement, the longitudinal and transverse slab reinforcements are laid continuously when passing through the original temperature post-cast strip area, and stirrups are set between the bottom reinforcement 5 and the bottom reinforcement 4 of the floor slab.

[0029] When laying the floor slab reinforcement, the longitudinal and transverse reinforcement bars should be installed continuously along the length of the temperature-controlled post-cast strip. During tying, on-site workers are required to install spacers and stirrups according to the plan requirements to ensure that the reinforcement type, specifications, and spacing meet the design requirements. After the floor slab reinforcement is tied, reinforcement bars should be added at the temperature-controlled post-cast strip location using the reinforced strip construction method (i.e., adding reinforcing bars). The width of the reinforcing strip is 2000mm. The reinforcing bars within the reinforcing strip (i.e., reinforcing bars) are C8@200 in both the longitudinal and transverse directions, extending into the adjacent floor slab by a length of LaE on each side. The length of LaE is 15-20 times the diameter of the C8@200 reinforcement bar, preferably 15 times. See Appendix. Figure 1 The LaE segment 3 of the reinforcing steel in the middle, Figure 1 The area between the two dashed lines is the reinforced slab area, and the area outside the dashed lines is the other area of ​​the adjacent floor slab. The LaE segment 3 of the reinforcing steel is the length that extends into the adjacent floor slab area; the binding requirements for the reinforcing steel are the same as those for the ordinary reinforcing steel in the floor slab.

[0030] S4: After the reinforcement is tied and accepted, the area of ​​the reinforcing strip is divided with wire mesh to ensure that the concrete in the reinforcing strip and the concrete of the main building slab do not seep into each other during concrete pouring, and the wire mesh acts as a barrier. S5: When pouring concrete, first pour the concrete for the floor slab except for the reinforcing strip. After the concrete is poured, use expansive concrete to pour the concrete inside the reinforcing strip. Use a vibrator to fully vibrate the concrete during pouring to avoid concrete quality defects caused by insufficient vibration, which would affect the construction quality.

[0031] After the steel reinforcement passes inspection, concrete can be poured. The concrete for the walls and beams should be poured first. During the pouring process, the quality of the concrete raw materials should be strictly controlled, and the concrete should be fully vibrated on site to ensure that the concrete is dense. When pouring concrete in the reinforcing strip, expansive concrete should be used in this part to ensure that the concrete will not crack in this part due to temperature shrinkage later. During the concrete pouring process, it is required to be fully vibrated and fully bonded with the surrounding floor slab concrete.

[0032] Different parts of the reinforced strip area have different temperature expansion and contraction properties. Using concrete with the same expansion rate will result in cracks due to insufficient or excessive expansion. Therefore, it is necessary to conduct shrinkage stress simulation analysis and staged pouring for different areas of the reinforced strip. Step S5, which uses expansive concrete for pouring, also includes sub-steps of shrinkage stress simulation analysis of the reinforced strip area and staged pouring of concrete with different expansion rates. S51: Using Midas Gen or ABAQUS software, import the parameters of the original structural drawings, input material properties such as concrete strength, coefficient of thermal expansion, and modulus of elasticity, set the environmental temperature and humidity, constraint conditions (including structural constraints (reinforcement / formwork fixing), support constraints (pile foundation / raft support), construction load and concrete shrinkage constraints) and other boundary parameters, accurately simulate the hydration heat and temperature shrinkage process of the post-cast strip area at the original temperature, and calculate and classify low, medium and high stress levels; S52: Adaptive Concrete Mix Design: Determine the dosage of expansive agent for different stress zones based on stress level and concrete formula. For example, the concrete formula may use P·O42.5 cement, Grade II fly ash, medium sand, and 5-25mm crushed stone, with polycarboxylate superplasticizer to adjust workability. After trial mixing, test the compressive strength and expansion rate, and add expansive agent to adjust the expansion rate, for example, 1.5‰ for low stress zone, 2.0‰ for medium stress zone, and 2.5‰ for high stress zone, to determine the final mix proportion. The selected material combination can take into account strength, heat of hydration control, and workability, adapting to the stress compensation requirements of graded expansive concrete and avoiding cracks and leakage. S53: Graded pouring and quality control: Before pouring, mark the range of each stress zone, first pour ordinary expansive concrete in the low stress zone, and then proceed to the medium and high stress zones in sequence; use an immersion vibrator to compact the concrete, overlap the vibration at the joint for 30 seconds, cover with geotextile to keep it moist after pouring, and adjust the curing cycle according to the stress level (extend to 14 days for high stress zone).

[0033] Compared to the original technology's extensive approach of using concrete with a fixed expansion rate and relying on experience to divide zones, staged casting uses professional software to precisely simulate and grade stress, matching concrete with different expansion rates to avoid cracks caused by insufficient or excessive expansion from the source. It selects suitable materials that balance strength and hydration heat control, solving the temperature difference cracking problem of the original technology. It achieves one-time casting and avoids the construction period delays caused by secondary pouring of temperature-controlled strips in the original technology, while eliminating the risk of joint leakage. Furthermore, staged curing improves quality stability, taking into account safety, economy, and construction efficiency.

[0034] S6: After the concrete is poured, cover it with a film and cure it in time. After it reaches the required age and strength, remove the formwork. When removing the formwork, remove the formwork at the reinforced strip along with other formwork to shorten the construction period. After the concrete strength reaches the design requirements, remove the formwork and supports. During the removal process, remove the formwork from top to bottom in accordance with the construction plan to ensure on-site construction safety.

[0035] The reinforced strip area is a key area for temperature-induced stress shrinkage, requiring post-monitoring of stress values ​​in this area. Therefore, the document also includes a post-stress monitoring and early warning step S7 for the reinforced strip, which includes the following sub-steps: S71. Before the S53 pouring step, use a special fixing clamp to fix the fiber optic grating sensor to the steel reinforcement skeleton in the low, medium and high stress areas of the reinforcing strip, respectively, to ensure that the sensor is stable in position and does not shift during the concrete pouring process. During the fixing process, care should be taken to avoid damaging the sensor, and good contact between the sensor and the steel reinforcement should be ensured to accurately transmit strain. The sensor spacing is set to 500mm to ensure that the temperature and strain changes of the reinforcing strip can be monitored comprehensively and accurately. The above sensors are connected to a control system. The fiber Bragg grating sensor selected in this invention exhibits excellent performance in temperature and strain monitoring, meeting the requirements of a temperature accuracy of ±0.5℃ and a strain accuracy of ±1με. Its working principle is based on the wavelength drift characteristics of the fiber Bragg grating; when the external temperature or strain changes, the center wavelength of the fiber Bragg grating changes accordingly. Temperature and strain information can be obtained by detecting this wavelength change.

[0036] Lead the sensor's optical fiber out and use a fiber optic fusion splicer to fusion-sponge it with the transmission optical fiber, ensuring good splice quality and stable signal transmission. After splicing, protect the splice point by wrapping it with a protective sleeve to prevent mechanical damage and chemical corrosion during concrete pouring. During concrete pouring, closely monitor the sensor's status and avoid collisions with the sensor and optical fiber by construction equipment such as vibrators to ensure the sensor functions properly.

[0037] S72. Simulation Calculation of Theoretical Values ​​for Low, Medium, and High Stress Zones: First, import structural drawings into the aforementioned Midas Gen or ABAQUS software to establish a 3D solid model, accurately mapping the dimensions and reinforcement parameters of the reinforcing strip and surrounding floor slabs. Next, input the constitutive relationships of materials such as P·O42.5 cement, including strength and coefficient of thermal expansion, and set the environmental temperature and humidity change curves and floor slab support constraints. Then, simulate the entire process of concrete hydration heat release (heating stage) and subsequent cooling and shrinkage. Calculate the superposition of temperature stress and shrinkage stress at each node using software algorithms, simultaneously generating stress-temperature change curves for each zone (recording stress values ​​corresponding to different ages and temperatures). After statistically analyzing the stress distribution data, divide the zone into numerical ranges: for example, high stress zone (theoretical value ≥ 150 με), medium stress zone (100-150 με), and low stress zone (< 100 με), forming precise zoning results. S73. The control system processes and analyzes the stress and temperature data transmitted from the fiber optic grating sensor. When the stress-strain value of the sensor in the high-stress area exceeds the high-stress area warning value, the stress-strain value of the sensor in the medium-stress area exceeds the medium-stress area warning value, or the stress-strain value of the sensor in the low-stress area exceeds the low-stress area warning value, an automatic alarm is triggered, reminding the user to take timely supplementary or reinforcement measures. The warning values ​​for the high-stress area, medium-stress area, and low-stress area are set with reference to the theoretical values ​​for the low, medium, and high stress areas calculated by finite element simulation in step S51. For example, the warning values ​​can be set according to the principle of "reserving safety redundancy + matching stress characteristics": for example, a high-stress area warning value of 100 με (stress is most concentrated, reserving a 50 με safety margin for strict warning); a medium-stress area warning value of 110 με (matching the middle of the theoretical range, balancing warning timeliness and false alarm rate); and a low-stress area warning value of 120 με (theoretical value is lower, relaxing the threshold to avoid invalid warnings), ensuring accurate warnings and providing a buffer time for handling.

[0038] To improve the accuracy of finite element simulation calculations in low, medium, and high stress regions and avoid inaccurate matching of concrete expansion rate in step S52 due to simulation deviations, it is also necessary to correct the model parameters by incorporating actual sensor monitoring data. Therefore, a finite element simulation accuracy correction step S8 is also included, which comprises the following sub-steps: S81. Data Acquisition and Screening: The sensors in step S7 continuously collect real-time strain (accuracy ±1με) and temperature (accuracy ±0.5℃) data in the low, medium and high stress zones. Abnormal data with drastic changes in hydration heat within 7 days after pouring are removed, and the daily average data during the stable period (within 28 days) is retained as the basis for feedback. S82. Model Parameter Correction: Import the selected measured data into Midas Gen / ABAQUS software and compare it with the original simulated stress-temperature curve. If the measured strain is more than 10% higher than the simulated value, correct the thermal expansion coefficient of concrete (e.g., from 12×10).-6 / ℃ adjusted to 12.5×10 -6 / ℃,;If the strain deviation at the connection between the reinforcing strip and the surrounding floor slab and the supporting structure (at the support) is large, optimize the constraint parameters (such as adjusting the stiffness coefficient of the fixed end). S83. Closed-loop verification: After correction, rerun the simulation and compare the new simulation results with subsequent measured data until the deviation is ≤5%, forming an optimized parameter database for finite element modeling of similar projects in the future, thereby improving the initial accuracy of the simulation.

[0039] Through the closed-loop interaction between the above-mentioned sensor measured data and simulation data, the accuracy of stress classification and concrete adaptation is improved: First, by screening the measured data during the stable period (eliminating data with abnormal hydration heat), a reliable basis is provided for parameter correction; Second, key parameters such as the coefficient of thermal expansion, support constraints (support constraints refer to the limiting effect on structural displacement and rotation when the reinforcing strip and surrounding floor slabs are connected to the pile foundation, raft foundation, wall and other supporting structures), concrete elastic modulus, shrinkage coefficient, hydration heat parameters, and environmental temperature and humidity change curves are specifically corrected (the theoretical standard values / empirical values ​​of the above parameters are corrected to fit the actual engineering situation and improve the accuracy of simulation and adaptation), eliminating the discrepancy between the stress-temperature data calculated by the finite element simulation and the fiber optic transmission. The deviation of the sensor's measured data (reduced from over 10% to ≤5%) can improve the accuracy of stress grading, ensuring that the low, medium and high stress zones divided by S51 match the actual stress, avoiding inaccurate matching of the concrete expansion rate in S52 due to simulation deviation (such as insufficient admixture in high stress zones causing cracking), thus ensuring crack resistance from the source. Eliminating deviation can also optimize the reliability of monitoring and early warning, making the S73 grading early warning threshold (setting the high stress zone to 100με, etc.) more consistent with the actual stress distribution, reducing false alarms / missed alarms, and providing accurate basis for supplementary reinforcement; thirdly, it forms an optimized parameter database, providing an accurate modeling foundation for subsequent similar projects, fundamentally improving the reliability of shrinkage stress grading and strengthening the crack control effect.

[0040] The main materials and tools used in the construction method of this invention are as follows: Timber, formwork, uprights, tie rods, measuring tape, hammer, steel bars, concrete, vibrator, etc.

[0041] The innovative aspects of the construction method of this invention include at least one of the following: 1) When constructing the main structure, use expansive concrete and reinforced steel bars to form floor slab reinforcement strips instead of the temperature-controlled post-cast strips required in the drawings; 2) During on-site formwork erection, the temperature-reinforced strip area designed in the drawings is erected continuously and simultaneously with the formwork of the adjacent floor slab, meaning the location of the temperature-reinforced strip does not need to be considered. When binding the floor slab reinforcement, longitudinal and transverse reinforcing bars are installed at the top and bottom of the original temperature-reinforced strip area according to the design changes. The transverse reinforcing bars extend into the floor slab on both sides (laE) and are tied to the longitudinal reinforcement bars with wire. After the reinforcement binding is completed, relevant units conduct acceptance testing. When pouring concrete in this area (reinforced strip area), expansive concrete is used to compensate for concrete deformation caused by shrinkage at the temperature-reinforced strip.

[0042] 3) When pouring concrete in the reinforced slab strip area, use a vibrator to fully vibrate the concrete, and pour the reinforced slab strip and other parts of the adjacent floor slab at one time (the two concrete pours should be completed before cooling), to maintain the integrity of the plain concrete structure and avoid construction joints. After the concrete is poured, cover it in time for heat preservation and moisture retention to ensure the quality of concrete construction.

[0043] The overall benefits include at least one of the following: 1) It accelerated the construction progress and shortened the construction time. When constructing the main building's concrete structure using conventional methods, the formwork for the floor slabs and side walls must first be configured according to the design drawings. The formwork and support system for the temperature-reinforced concrete strip need to be set up separately from the support systems on both sides. During concrete pouring, wire mesh needs to be installed at the temperature-reinforced concrete strip to intercept the concrete and prevent it from flowing into the strip. When the formwork is removed after the floor slab concrete reaches a certain strength, independent supports for the temperature-reinforced concrete strip must be provided until the concrete in that area is poured. Using concrete reinforcement strips avoids the need for temperature-reinforced concrete strips inside the main building during the main structure construction. When the floor slab formwork is erected and removed, the formwork for the temperature-reinforced concrete strip is erected and removed simultaneously with the surrounding structural components. This eliminates the need to wait for the concrete on both sides of the temperature-reinforced concrete strip to shrink and stabilize before pouring the concrete in that area. This provides conditions for the subsequent construction of the secondary structure and floor slabs after the main structure is completed, accelerating the construction progress and saving construction time. 2) Improved construction quality and reduced the risk of water leakage. If a traditional method is used to leave a temperature-controlled post-cast strip in the interior walls and floors of the main building, when pouring the concrete for the temperature-controlled post-cast strip after a certain period of time, a specialist must be assigned to remove the laitance and loose surface concrete on both sides of the temperature-controlled post-cast strip and moisten it with neat cement slurry. Later, a waterproof layer must be installed at the joint to prevent leakage. If not handled properly, the temperature-controlled post-cast strip is very likely to become a weak point that can lead to leakage, affecting the functionality of the structure. However, if a reinforcing strip is set at the temperature-controlled post-cast strip during the construction of the main structure, this part can be poured together with the surrounding floor slabs and walls in one go, forming a whole. This not only avoids the hidden danger of leakage at the temperature-controlled post-cast strip, but also ensures that there is no joint between the temperature-controlled post-cast strip and the concrete floor slabs on both sides after demolding, resulting in a good overall appearance and quality. 3) It shortens the material usage time, reduces labor input, and lowers construction costs. According to design requirements, the closure of the temperature-controlled post-cast strip should be carried out 42 days after the completion of concrete pouring on both sides. During this period, to ensure that the concrete of the floor slabs on both sides of the temperature-controlled post-cast strip does not deform due to the load on the upper part of the floor slab, the formwork and formwork support system on both sides of the temperature-controlled post-cast strip must not be removed until the concrete at the temperature-controlled post-cast strip is poured and cured to the design requirements. Reinforcing strips are used instead of the temperature-controlled post-cast strip in this area. During the main structure construction, the temperature-controlled post-cast strip area is poured and cured simultaneously with other parts of the floor slab. After reaching the design strength, it is completely removed. This avoids the additional material and labor input required for setting up independent supports for the temperature-controlled post-cast strip, and also reduces the time and labor invested in grinding the floor slab after the temperature-controlled post-cast strip construction, effectively reducing on-site construction costs.

[0044] The selection of specific parameters in the above implementation plan is only for clearly illustrating how the concept is implemented, and is not a limitation on the concept embodied in the plan. That is, within the scope of the concept protection, the specific parameters can be adjusted according to the actual situation.

Claims

1. A construction method that uses expansion-reinforced strips instead of temperature-controlled post-cast strips, characterized in that, Includes the following steps: S1: When setting up the formwork, the formwork and support frame of the original temperature post-pouring strip area and the surrounding floor slab formwork system are set up as a whole by using a simultaneous and continuous full-span support method. S2: When binding the floor slab reinforcement, first lay the bottom reinforcement (4) at the bottom of the floor slab. Set up a reinforcing strip area within 2m on both sides of the original temperature post-cast strip area. Set up longitudinal and transverse bottom reinforcing bars (1) in the reinforcing strip area. Bind the bottom reinforcing bars (1) to the bottom reinforcement (4) at the bottom of the floor slab. S3: After step S2 is completed, tie the bottom reinforcement bars (5) of the floor slab. After tying, tie the top reinforcement bars (2) of the reinforcement strip area. After tying, set up the stirrups to ensure the spacing between the upper and lower reinforcement bars. S4: After S3 is completed, the area within the reinforcing strip is divided using wire mesh; S5: When pouring concrete, first pour the concrete in the floor slab area except for the reinforcing strip area. After the concrete is poured, use expansive concrete to pour the concrete in the reinforcing strip area. S6: When removing the formwork, the formwork at the reinforcing strip should be removed together with the other formwork. Step S5 also includes the following sub-steps: S51: Using finite element analysis software, import the parameters of the original structural drawings, input the concrete material properties, set the boundary parameters, accurately simulate the hydration heat and temperature shrinkage process of the reinforced strip area, and calculate and classify low, medium and high stress levels. S52: Adaptive concrete mix design: Determine the amount of expansion agent for different stress zones based on stress level and concrete formula; S53: Graded pouring and quality control: Before pouring, mark the stress zone range of the reinforced strip area, pour ordinary expansive concrete in the low stress zone first, and then pour medium and high stress zones in sequence.

2. The construction method as described in claim 1, which uses an expansion-reinforced plate strip instead of a temperature-controlled post-cast strip, is characterized in that... The reinforcing steel bars are C8@200 type steel bars.

3. The construction method as described in claim 2, which uses an expansion-reinforced plate strip instead of a temperature-controlled post-cast strip, is characterized in that... In step S2, the length of the bottom reinforcing steel bar (1) in the reinforcing strip area extending into the adjacent floor slab on each side is taken as the seismic anchorage length LaE.

4. The construction method as described in claim 3, which uses an expansion-reinforced plate strip instead of a temperature-controlled post-cast strip, is characterized in that... In step S3, the length of the top reinforcing steel bar (2) in the reinforcing strip area extending into the adjacent floor slab on each side is taken as the seismic anchorage length LaE.

5. The construction method using expansion-reinforced strips instead of temperature-controlled post-cast strips as described in claim 3 or 4, characterized in that, The length of LaE is 15-20 times the diameter of C8@200 type steel bars.

6. The construction method as described in claim 1, which uses an expansion-reinforced plate strip instead of a temperature-controlled post-cast strip, is characterized in that... In step S5, the reinforced strip area and other parts of the adjacent floor slab are poured in one go before the concrete initially sets.

7. The construction method as described in claim 1, which uses an expansion-reinforced plate strip instead of a temperature-controlled post-cast strip, is characterized in that... In step S5, when pouring concrete, a vibrator is used to fully vibrate it.

8. The construction method as described in claim 1, which uses an expansion-reinforced plate strip instead of a temperature-controlled post-cast strip, is characterized in that... The fiber Bragg grating sensor is fixed to the steel reinforcement frame in the reinforcing plate area using a fixing clamp. The fiber Bragg grating sensor is connected to a control system.

9. The construction method as described in claim 8, which uses an expansion-reinforced plate strip instead of a temperature-controlled post-cast strip, is characterized in that... The fiber optic grating sensors are respectively located in the low-stress region, medium-stress region, and high-stress region.

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